The most common rheumatological emergency seen in the emergency department (ED) is acute monoarthritis (see Ch. 14.2). This chapter discusses the important emergencies associated with general rheumatological conditions. Many of these are multisystem diseases and emergencies may be related either to a primary joint problem or to an extra-articular manifestation of the disease. As many of these conditions are autoimmune, suppression of the immune system is usually central to their management. This can be complicated by infection, which can relate to usual pathogens but also opportunistic infection.

RHEUMATOID ARTHRITIS

Rheumatoid arthritis (RA) affects 1–2% of the population across most ethnic subgroups and is two to three times more common in females than males. RA is a systemic inflammatory condition of unknown aetiology characterized by widespread synovitis resulting in joint erosions and destruction. It may also produce extra-articular manifestations, including vasculitis and visceral involvement.

Management typically involves symptom relief with non-steroidal anti-inflammatory drugs (NSAIDs) and/or corticosteroids, and prevention of disease progression with disease modifying antirheumatic drugs (DMARDs). These include methotrexate, leflunomide, sulfasalazine and hydroxychloroquine. Newer, so-called biologic agents act by inhibiting tumour necrosis factor-α (TNF-α) (infliximab, etanercept, adalimumab) or interleukin-1 (anakinra) and are currently used for patients who fail traditional DMARD therapy. Rituximab is also recently available for those who fail the aforementioned medications – its mechanism of action is B-cell depletion. See Chapter 14.3 for further details on the clinical features of RA, its diagnosis, useful investigations and principles of management.

EMERGENCIES IN RA – ARTICULAR MANIFESTATIONS

Acute monoarthritis

The patient with established RA may present with an acutely painful, hot, swollen joint that may be a manifestation of the underlying condition. Alternatively, it may signal septic arthritis, a condition to which patients with RA are 2–3 times more susceptible than matched controls.¹ The possibility of septic arthritis should be considered in a patient with RA who has acute monoarthritis out of keeping with their disease activity. See Chapter 14.2 for the approach to acute monoarthritis.

Cervical spine involvement

Cervical spine involvement in RA is a common finding with a prevalence of up to 61%.² It is more common in those with long-standing, erosive disease and disease of greater severity and activity.³ Cervical spine involvement is associated with increased mortality.⁴ Involvement of the cervical spine may manifest as atlanto-axial subluxation (most commonly anterior movement on the axis) or subluxation of lower cervical vertebrae. Either of these can result in cervical myelopathy.

Cervical spine subluxation is frequently asymptomatic, up to 44% in one study.³ The most common symptom of cervical spine involvement is neck pain that may radiate towards the occiput. Other suggestive symptoms include slowly progressive spastic quadriparesis, sensory loss in hands or feet and paraesthesiae or weakness in the distribution of cervical nerve roots.

Important ‘red flag’ features suggestive of cervical myelopathy are shown in Table 14.1.1.

Table 14.1.1 Symptoms and signs of cervical myelopathy

Symptoms

Pain

Weakness

Peripheral paraesthesiae

Gait disturbance

Sphincter dysfunction

Changes in consciousness

Respiratory dysfunction

Signs

Spasticity

Weakness

Hyperreflexia of deep tendon reflexes

Extensor plantar response

Gait ataxia

Respiratory irregularity

Investigations

Plain X-rays of the cervical spine (lateral view) may demonstrate an increase in separation between the odontoid and arch of C1. Prior to taking flexion-extension films, perform plain ‘peg’ X-rays through the open mouth to exclude odontoid fracture or severe atlanto-axial subluxation. Computerized tomography (CT) can occasionally provide additional useful information; however, if there is concern regarding myelopathy, magnetic resonance imaging (MRI) is the most sensitive imaging technique.

Management

The primary implication of RA of the cervical spine in the ED is when endotracheal intubation is required. Inappropriate manipulation of the rheumatoid cervical spine in preparation for intubation can result in significant morbidity and even mortality from atlanto-axial and subaxial subluxation. Where possible, patients with RA who are scheduled to undergo surgery should have imaging of their cervical spine performed prior to intubation. Anaesthetic consultation may be required.

Patients with subluxation and signs of spinal cord compression are a neurosurgical emergency and prompt referral is essential.

EMERGENCIES IN RA – EXTRA-ARTICULAR MANIFESTATIONS

Rheumatoid vasculitis

Vasculitis in RA can occur in both small- and medium-sized vessels. Patients typically have long-standing, aggressive joint disease.

Clinical features

Presentations with rheumatoid vasculitis are varied and non-specific. Patients frequently present with constitutional symptoms and fatigue. The most common manifestation is of cutaneous vasculitis with deep skin ulcers on the lower limbs,⁵ digital ischaemia and gangrene (medium vessels) or palpable purpura (small vessels). Mononeuritis multiplex is another common presentation and results from infarction of the vasa nervorum due to vasculitis. It typically has an acute onset.

Medium vessel rheumatoid vasculitis can also produce organ infarction and necrosis. Rheumatoid vasculitis may mimic polyarteritis nodosa (PAN) with involvement of the renal arteries, and less commonly the mesenteric circulation. Pericarditis may accompany rheumatoid vasculitis but coronary vasculitis is rare. Ocular manifestations include episcleritis and peripheral ulcerative keratitis. Central nervous system (CNS) involvement is rare.

Investigations

Rheumatoid factor titre is typically elevated in rheumatoid vasculitis, although this is a non-specific finding. Rheumatoid vasculitis in the absence of rheumatoid factor is rare. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are also elevated. Check a mid-stream urine specimen for active urinary sediment and a full blood count, urea and electrolytes.

Further investigations are directed by the relevant organ system involved and usually require specialist consultation:

• skin biopsy

• nerve conduction studies/electromyography (EMG)

• sural nerve biopsy

• kidney biopsy.

Angiography findings are non-specific and not always diagnostic.

Diagnosis

Suspect rheumatoid vasculitis in patients with a long-standing history of seropositive RA who presents with constitutional symptoms and one of the above clinical features, such as a typical rash, digital gangrene, red eye, neurological symptoms or active urinary sediment.

Management

Systemic rheumatoid vasculitis has a poor prognosis without immune-suppressive therapy. Urgent rheumatology consultation is required as treatment usually consists of high-dose corticosteroids as well as cyclophosphamide.

Summary of other extra-articular manifestations of RA

Lung disease

Lung disease may manifest as a pleural-based disease such as pleurisy or pleural effusions, or parenchymal lung disease such as interstitial lung disease (the most common manifestation), organizing pneumonia and rheumatoid nodules. Caplan’s syndrome occurs when RA is associated with pneumoconiosis. Important differential diagnoses include infection due to immune-suppression, treatment-related toxicity (e.g. methotrexate-induced pneumonitis) and other medical comorbidities such as chronic obstructive pulmonary disease.

Pleural disease often resolves without treatment, alternatively a NSAID may be used. Parenchymal disease as documented on chest X-ray or high-resolution CT requires specialist treatment.

Cardiac disease

Pericarditis occurs in 30% of RA patients based on echocardiography, but less than 10% have any clinical features. It generally occurs when there is active joint and other extra-articular disease. Management consists of NSAIDs or prednisolone.

Myocarditis is a rare manifestation of RA. It can be granulomatous and depending on its location may produce valvular (especially mitral) incompetence or conduction defects.

Sjogren’s syndrome

Sjogren’s syndrome may present in its primary form as a systemic disease, but can also occur secondary to RA and other connective tissue disorders. The classic symptoms are dry gritty eyes, dry mouth or both. Treatment is usually symptomatic in patients with no other features.

Felty’s syndrome

Felty’s syndrome is characterized by seropositive RA, splenomegaly and neutropenia. There may be other cytopenias, as well as leg ulcers.

Kidney disease

Renal involvement in RA is rare and includes vasculitis and glomerulonephritis. Secondary amyloidosis can occur in patients with long-standing active disease. However, many medications used in RA are nephrotoxic, in particular NSAIDs and ciclosporin.

Neurological disease

Vasculitis may produce mononeuritis multiplex, as mentioned previously, otherwise central nervous system involvement is rare.

Cardiovascular disease in RA and other connective tissue diseases

Patients with RA and other connective tissue diseases such as systemic lupus erythematosus (SLE) have an increased risk of ischaemic heart disease (IHD).⁶ This occurs independently of traditional risk factors such as smoking or dyslipidaemia, and is more common in those with extra-articular disease.⁷ The higher incidence of IHD could be related to disease factors such as widespread inflammation, or to medications used such as NSAIDs (including selective COX-2 inhibitors) and corticosteroids.

The emergency physician needs a low threshold for ruling out ischaemic causes of chest pain in the RA patient. Routine investigations are no different to those undertaken for non-RA patients. A patient with suggestive history but negative cardiac biomarkers and normal electrocardiograms should proceed to stress testing as per the recommendations for the general population. Management of acute coronary syndrome in RA is no different.

SYSTEMIC LUPUS ERYTHEMATOSUS

SLE is a multisystem, autoimmune disease. It is the prototype disease of immune complex deposition resulting in tissue damage across a variety of organ systems. It is one of the most common autoimmune conditions among women of childbearing age.

Clinical features

Common presenting features of SLE include general constitutional symptoms such as fatigue, malaise and weight loss. There are a variety of skin manifestations that can occur in SLE which are lupus-specific (malar rash, discoid lupus, subacute cutaneous lupus erythematosus) or non-specific (panniculitis, alopecia, oral ulceration). Arthralgias or an acute non-erosive arthritis are the most common presenting symptoms of SLE. Myositis may also occur. Another common manifestation is serositis producing pleurisy, pericarditis or peritonitis. SLE also causes renal and CNS disease (see below) and rarely can involve the lung (pneumonitis, pulmonary hypertension) and the heart (myocarditis, endocarditis).

Investigations

A full blood examination often reveals cytopenias which are a common feature of SLE. Biochemistry investigations may indicate renal involvement. Clotting abnormalities may include a prolonged activated partial thromboplastin time due to the lupus anticoagulant. ESR and CRP may be raised.

Serological abnormalities

Serological abnormalities may reveal decreased levels of complement components C3 and C4, as well as the presence of auto-antibodies. The antinuclear antibody (ANA) is present in 95% of patients with SLE, but may also occur in a variety of other connective tissue and inflammatory diseases. The anti-Smith (Sm) and anti-dsDNA (double-stranded DNA) antibodies are more specific for SLE but less sensitive. The anti-Sm is obtained as part of a panel of tests for extractable nuclear antigens (ENA).

Other tests are directed towards the organ system involved, for example mid-stream urine specimen looking for proteinuria or glomerular haematuria (>70% dysmorphic red blood cells or red-cell casts) or chest X-ray for the patient with serositis.

Assessing SLE disease activity

It is important in the ED to determine SLE disease activity. Useful symptoms of disease activity include mouth ulcers, alopecia and constitutional symptoms, as well as organ-specific symptoms such as arthralgia or pleuritic chest pain.

Investigations used to assess disease activity include complement levels (low in active SLE), CRP and ESR (elevated), as well as anti-dsDNA titre. These are not diagnostic and many people with quiescent SLE may remain hypocomplementaemic or display elevated anti-dsDNA titres.

A mid-stream urine for urinary sediment is an essential part of the assessment of the SLE patient, as a marker of renal involvement.

Management

Management of SLE is directed by the organ system involved, and includes topical therapies for cutaneous lupus and NSAIDs for arthralgias and mild serositis. Most patients with SLE will be on an antimalarial such as hydroxychloroquine, which is helpful for skin and musculo-skeletal manifestations, as well as organ involvement. Many patients will also be on corticosteroids. Those with major organ involvement will also be taking other immunosuppressants such as methotrexate, cyclophosphamide or azathioprine. Mycophenolate mofetil is emerging as an alternative to cyclophosphamide for lupus nephritis.

Lupus nephritis

Early diagnosis of lupus nephritis is essential in instituting prompt management and preventing the progression of renal damage. Patients may be asymptomatic, or present with nocturia or ‘frothy’ urine. Other presentations include hypertension, the nephritic syndrome and the nephrotic syndrome.

Urinalysis is the most useful investigation in detecting lupus nephritis, and proteinuria is the most common abnormality detected. The fresh urine specimen should be sent for phase contrast microscopy in order to detect the presence of dysmorphic erythrocytes (>70 % indicates glomerular disease) or cellular casts.

Urinalysis can expedite the investigation and further management of this potentially organ-threatening condition. Prompt referral to a rheumatologist or renal physician for consideration of renal biopsy and further management is indicated.

Neuropsychiatric SLE

There are a myriad of neuropsychiatric manifestations of neuropsychiatric SLE. Neurological presentations include:

• stroke (due to vasculitis, emboli, atherosclerosis or antiphospholipid antibodies)

• seizure

• migraine

• aseptic meningitis.

Psychiatric presentations include:

These presentations are non-specific and have a broad differential diagnosis which includes medication side effects, infection and tumour. Unfortunately, there is no specific diagnostic test which helps differentiate SLE from other potential aetiologies. Thus, the diagnosis is made from a range of diagnostic tests and clinical features. The role of the emergency physician in this setting is to exclude common non-SLE presentations such as meningitis or intracranial haemorrhage.

Imaging studies are necessary in addition to tests for SLE activity (see above). CT brain scan may detect changes of acute infarction but is also useful in excluding other unrelated causes such as haemorrhage or tumour. MRI is more sensitive in detecting white matter abnormalities although these are frequently non-specific.

Cerebrospinal fluid (CSF) analysis is essential to exclude infection, but may be normal in SLE. Changes such as elevated protein, low glucose or even a positive ANA are non-specific and do not always reflect active SLE. The electro-encephalogram is occasionally useful in cases of suspected non-convulsive status epilepticus with unexplained altered conscious level.

GIANT CELL (TEMPORAL) ARTERITIS AND OTHER VASCULITIDES

Giant cell (temporal) arteritis

Giant cell arteritis (GCA) is the most common vasculitis and almost exclusively affects Caucasians. It is a large and medium vessel vasculitis of unknown aetiology, which predominantly affects the cranial branches of arteries originating from the aortic arch.

Polymyalgia rheumatica (PMR) is a syndrome of inflammatory pain and stiffness in the shoulder and pelvic girdles that occurs alone or frequently in association with GCA.

Epidemiology

GCA and PMR rarely occur before the age of 50 years of age.⁸ The mean age at diagnosis is approximately 72 years, with an incidence of GCA of roughly 1 in 500 of people over the age of 50 years. The incidence and prevalence of PMR are less well studied.

Clinical features

The most common symptom of GCA is headache, usually localizing to the temporal region, although it can be more diffuse. The area is often tender and worsened by brushing the hair. Most patients complain of constitutional symptoms such as malaise, fatigue, anorexia and weight loss. Jaw claudication (pain after a period of chewing) is the most specific symptom for GCA, although not sensitive, as it is only present in 34%.⁸ On examination the temporal arteries may be thickened, ‘ropey’ and tender with an absent or reduced pulse.

The most significant complication of GCA is anterior ischaemic optic neuropathy resulting in sudden painless loss of vision. Less commonly, other branches of the aorta may be involved resulting in hemiparesis, arm claudication, aortic dissection or myocardial infarction.

Polymyalgia rheumatica

PMR usually affects the neck, shoulder and pelvic girdles resulting in stiffness and inflammatory pain, worse in the morning and after rest. The pain is often poorly localized and there may be muscle atrophy late in the disease. There can also be evidence of synovitis affecting the shoulders, knees, wrists and hands.

The relationship between onset of symptoms of GCA and PMR is highly variable. PMR symptoms may occur before, after or with GCA symptoms.

Differential diagnosis of PMR and GCA

The differential diagnosis of PMR includes late-onset RA, inflammatory myositis and other myopathies, fibromyalgia and hypothyroidism. GCA can mimic any of the other vasculitides. Non-arteritic anterior ischaemic optic neuropathy can also mimic GCA.

Investigations

The classic non-specific laboratory finding in GCA and/or PMR is a markedly elevated ESR (often >100 mm/h). CRP is also usually elevated, and full blood count often shows a mild normochromic normocytic anaemia.

A temporal artery biopsy confirms the diagnosis of GCA and is particularly useful when the diagnosis is doubtful or the presentation atypical. Unfortunately, there is a false negative rate of 10–30%, so a negative biopsy does not exclude GCA.

Criteria for diagnosis

The ACR classification criteria for GCA are helpful in differentiating GCA from other forms of vasculitis.⁹ They include age at onset >50 years, a new headache, temporal artery tenderness or decreased pulsation and an ESR >50. An abnormal artery biopsy showing vasculitis with mononuclear infiltrate or granulomatous inflammation with multi-nucleated giant cells is also required to confirm the diagnosis.

Management

Corticosteroids are the treatment of choice and should not be withheld to perform a biopsy, if there is a strong clinical suspicion. The initial dose for GCA is unclear, but prednisone 1mg/kg/day is usually indicated ¹⁰ especially for ischaemic complications; however, lower doses such as prednisone 40–50mg have been used.¹¹ The dose of prednisone for PMR alone is lower at 10–20mg/day.¹¹ Most patients do not require hospital admission, provided a temporal artery biopsy can be organized within a few days. However, patients with visual loss at diagnosis require urgent treatment, often with pulsed parenteral corticosteroids, and inpatient admission. Patients with GCA should also be commenced on aspirin.

An approach to the systemic vasculitides

The systemic vasculitides are a group of disorders characterized by an inflammatory infiltrate in the walls of blood vessels resulting in damage to the vessel wall. The clinical manifestations depend upon the size of vessel and location in the vascular tree and may result in systemic or organ-specific manifestations. Table 14.1.2 classifies vasculitic syndromes according to vessel size (there is much overlap).

Table 14.1.2 Classification of systemic vasculitis according to vessel size

Vessel size	Vasculitis
Large	Takayasu’s arteritis
Large	Giant cell arteritis
Medium	Polyarteritis nodosa
Medium	Kawasaki disease
Small	Wegener’s granulomatosis (ANCA+)
	Microscopic polyangiitis (ANCA+)
	Churg–Strauss syndrome
	Henoch–Schonlein purpura
	Cryoglobulinaemic vasculitis
	Leukocytoclastic cutaneous vasculitis

Investigations and diagnosis

Baseline investigations should include FBE, U&E, LFTs and clotting studies as well as CRP and ESR. Blood cultures should be taken if the patient is systemically unwell.

A panel of auto-immune serological tests is carried out in suspected cases. This includes ANA, ENA, rheumatoid factor, dsDNA, anti-cyclic citrullinated peptides (anti-CCP), complement levels (C3, C4), antineutrophil cytoplasmic antibodies (ANCA) and cryoglobulins. PAN is associated with hepatitis B and cryoglobulinaemic vasculitis with hepatitis C infection.

Collection of a mid-stream urine specimen to look for glomerular haematuria is mandatory when vasculitis is suspected. Imaging is required such as chest X-ray, CT scan of the chest or sinuses or other areas depending on the suspected organ involved. The definitive diagnosis of vasculitis requires biopsy of affected tissue or angiography.

Differential diagnosis of systemic vasculitis

Other conditions which may mimic vasculitis include:

• infections such as infective endocarditis, meningococcaemia, gonococcaemia

• disorders of haemostasis and thrombosis such as thrombotic thrombocytopenic purpura, antiphospholipid syndrome

• malignancy such as lymphoma, myxoma

• sarcoidosis.

Management of systemic vasculitis

Treatment is usually with high-dose corticosteroids and, depending on the condition, additional immunosuppression such as cyclophosphamide. Urgent specialist referral is essential.

Emergencies associated with rheumatology therapy

The medications used most commonly in rheumatology include NSAIDs, corticosteroids and DMARDs. Over the past 5 to 10 years, the ‘biologic’ DMARDs have become available for the treatment of RA, psoriatic arthritis and ankylosing spondylitis. These medications are all associated with adverse effects which occasionally result in serious morbidity.

Non-steroidal anti-inflammatory drugs

NSAIDs are used for symptom relief in a variety of conditions, especially inflammatory joint pain. They are of equal efficacy, although those with shorter half lives appear to have less gastrointestinal toxicity.¹² NSAIDs should be used in the lowest possible dose for the shortest duration and combination of NSAIDs (not aspirin) should be avoided.¹²

The most common adverse effects of NSAIDs seen as an emergency include peptic ulcer disease and acute renal failure, both related to inhibition of prostaglandin synthesis. GI toxicity is more common in the elderly, those on anticoagulants and with high doses or prolonged duration of NSAIDs. Prescribe a proton pump inhibitor when there is concern about GI toxicity. The COX-2 selective inhibitors such as celecoxib have a reduced incidence of peptic ulcer disease, but a similar incidence of other adverse effects including hypertension, peripheral oedema and cardiac failure and in particular an increased risk of cardiovascular deaths with prolonged courses.

Corticosteroids

Corticosteroids are the mainstay of treatment for most inflammatory rheumatological conditions. At high doses they provide rapid control of inflammatory disease and are often required for long-term management at low doses. Long-term use is associated with numerous adverse effects such as diabetes, hypertension and osteoporosis. In addition, psychosis and mood disorders related to corticosteroid use as well as peptic ulcer disease may present as an emergency.

Immunosuppressants/disease modifying antirheumatic drugs

This heterogeneous group of medications is used to prevent joint destruction in the inflammatory arthritides and as steroid-sparing therapy in many connective tissue diseases. They include methotrexate, leflunomide, hydroxychloroquine, sulfasalazine, ciclosporin, azathioprine and cyclophosphamide. Each drug has its own range of adverse effects, but common adverse effects presenting at an ED include cytopenias, rashes including the Stevens–Johnson syndrome, abnormal liver function tests, GI toxicity and heightened susceptibility to infections (see Table 14.1.3).

Table 14.1.3 Adverse effects of disease modifying antirheumatic drugs (DMARDs)

DMARD	Adverse effects
Methotrexate	Nausea and other GI upset, mouth ulcers, abnormal liver function (transaminases), bone marrow suppression, rash, alopecia, pneumonitis Teratogenic Increased bone marrow toxicity in renal impairment – withhold in acute renal failure
Leflunomide	Abnormal liver function (transaminases), diarrhoea, rash, alopecia, hypertension, peripheral neuropathy Teratogenic
Hydroxychloroquine	Nausea, rash, dizziness (‘cinchonism’), retinal toxicity at higher doses (all uncommon)
Sulfasalazine	GI upset, uncommonly abnormal liver function and bone marrow suppression, rashes (rarely, Stevens–Johnson syndrome)
Ciclosporin	Renal impairment, hypertension, electrolyte disturbance, hyperuricaemia and gout, gingival hyperplasia, hirsutism
Cyclophosphamide	Bone marrow suppression especially neutropenia, GI upset, bladder toxicity, including haemorrhagic cystitis (acute) and bladder cancer (chronic), opportunistic infections Teratogenic
Azathioprine	GI upset, rash, systemic symptoms, abnormal liver function, bone marrow suppression, skin cancers, infections

GI, gastrointestinal.

Biologic disease modifying antirheumatic drugs

The so-called ‘biologic’ DMARDs are a newer and expanding collection of therapies directed against molecules that mediate joint destruction and help drive the inflammatory process. Principally, agentsare directed against TNF-α such as adalimumab, etanercept and infliximab, and against interleukin-1 (IL-1) such as anakinra. More recently, rituximab has become available for those who fail the above therapies. Its main function is to deplete B lymphocytes from peripheral circulation. These therapies are being increasingly used for those who fail conventional DMARD therapy for RA.

Adverse effects of biologic DMARDs

Adverse effects associated with the use of TNF-α inhibitors include a heightened risk of all infections, particularly soft-tissue and joint infections, as well as re-activation of tuberculosis. Other opportunistic infections appear more common such as listeriosis. Patients may also develop local injection site reactions and infusion-related reactions, which may be delayed. Less common adverse effects include a form of drug-induced lupus and demyelination.

Presentations of treatment-related emergencies

Bone marrow suppression

Anaemia, leukopenia and thrombocytopenia all occur in patients taking DMARDs such as methotrexate, cyclophosphamide, sulfasalazine and azathioprine. The patient who presents with sepsis and leukopenia is a medical emergency and requires resuscitation, supportive care and broad-spectrum parenteral antibiotics.

Cytopenia in a patient taking methotrexate is uncommon but those at increased risk include the elderly and with renal impairment, related to the drug’s mechanism of action as an inhibitor of dihydrofolate reductase. Management involves temporary cessation of treatment and administration of folinic acid.

The most common adverse effect of cyclophosphamide is myelosuppression, particularly leukopenia. The white cell nadir occurs at 2 weeks post infusion following intravenous therapy. Patients on oral therapy may experience a gradual decrease in white cell count.

Bone marrow suppression may also occur as a side effect of azathioprine treatment especially if given in combination with allopurinol, which inhibits its metabolism, thus potentiating bone marrow toxicity. Cytopenias are also more common in patients with deficient thiopurine methyltransferase enzyme. Sulfasalazine therapy is uncommonly complicated by bone marrow suppression.

Infections

Treatment of rheumatological conditions is directed at immunosuppression, thus infections are a common and expected adverse effect of corticosteroids, certain DMARDs and, in particular, anti-TNF-α therapy. Although studies have shown RA patients to have a de novo increased risk of infection, biologic DMARDs may further increase this risk.

Some studies have reported an increased risk of infection and serious infection in patients receiving anti-TNF therapy, although the largest study of infection risk in patients on anti-TNF agents showed that while there is an increased risk of skin and soft tissue injections, there was no significant difference in risk of serious infections.¹³ Patients on anti-TNF therapy who develop infections are advised to temporarily cease their treatment and to commence antibiotics. If in doubt, they should be admitted to hospital to receive parenteral antibiotics. There is also an increased risk of re-activation of tuberculosis and possibly of infections with other organisms such as Listeria and Salmonella.¹³ Rigorous tuberculosis screening prior to commencement of anti-TNF therapy should now be universal.

DMARD-related pneumonitis

Methotrexate and leflunomide both result in lung toxicity. The incidence of methotrexate-induced lung toxicity is difficult to assess but uncommon. The most common type of toxicity is a hypersensitivity pneumonitis, but other forms of lung injury may also occur. Clinical features are non-specific and include constitutional symptoms, cough and progressive dyspnoea. Subacute presentations are more common, although acute and chronic presentations may also occur, with rapid progress to respiratory failure in more acute situations. Patients at higher risk for methotrexate-induced lung injury have prolonged duration of methotrexate treatment, pre-existing rheumatoid involvement of the lungs and pleura, increased extra-articular manifestations, diabetes mellitus, previous DMARD use and low serum albumin.¹⁴ Age and smoking also appear to be important.

Imaging reveals interstitial opacities and patchy consolidation. High-resolution CT scanning typically shows a ground-glass appearance. The main differential diagnosis is of a respiratory infection which may be due to typical pathogens or opportunistic infections such as Pneumocystis jirovecii.

Management is supportive with empiric antibiotic therapy in case of infection. Corticosteroids are also used. Patients may become seriously ill and require intensive care, but mortality is still low (1%).

Leflunomide may also cause lung injury, typically in the first few months of therapy and usually when given in combination with methotrexate.

Allopurinol hypersensitivity syndrome

Minor hypersensitivity reactions to allopurinol occur in around 2% of patients and usually consist of a mild rash. Rarely, a severe hypersensitivity syndrome may present as an unwell patient with fever, erythematous rash, abnormalities of liver function, peripheral blood eosinophilia and acute renal failure due to interstitial nephritis.¹⁵ It is more common in those with renal impairment who do not have appropriate dose reduction. This presentation has a mortality rate of 25%. Treatment is supportive.

References

1 Margaretten ME, Kohlwes J, Moore D, et al. Does this adult patient have septic arthritis? Journal of American Medical Association. 2007;297:1478-1488.

2 Collins DN, Barnes CL, Fitzrandolph RL. Cervical spine instability in rheumatoid patients having total hip or knee arthroplasty. Clinical Orthopaedics and Related Research. 1991;272:127-135.

3 Neva MH, Hakkinen A, Makinen H, et al. High prevalence of asymptomatic cervical spine subluxation in patients with rheumatoid arthritis waiting for orthopaedic surgery. Annals of Rheumatic Diseases. 2006;65:884-888.

4 Riise T, Jacobsen BK, Gran JT. High mortality in patients with rheumatoid arthritis and atlantoaxial subluxation. Journal of Rheumatoloy. 2001;28:2425-2429.

5 Genta MS, Genta RM, Gabay C. Systemic rheumatoid vasculitis: a review. Seminars in Arthritis and Rheumatism. 2006;36:88-98.

6 Turesson C, Jarenros A, Jacobsson L. Increased incidence of cardiovascular disease in patients with rheumatoid arthritis: results from a community based study. Annals of Rheumatic Diseases. 2004;63:952-955.

7 Turesson C, Jarenros A, Jacobsson L. Severe extra-articular disease manifestations are associated with an increased risk of first ever cardiovascular events in patients with rheumatoid arthritis. Annals of Rheumatic Diseases. 2007;66(1):70-75.

8 Smetana GW, Shmerling RH. Does this patient have temporal arteritis? Journal of American Medical Association. 2002;287:92-101.

9 Hunder GG, Bloch DA, Michel BA, et al. The American College of Rheumatololgy 1990 criteria for the classification of giant cell arteritis. Arthrtitis Rheumatics. 1990;33:1122-1128.

10 Spiera RF, Spiera H. Therapy for giant cell arteritis: can we do better? Arthritis Rheumatics. 2006;54:3071-3074.

11 Kyle V, Hazleman BL. Treatment of polymyalgia and giant cell arteritis: 1. Steroid regimens in the first two months. Annals of Rheumatic Diseases. 1989;48:658-661.

12 Therapeutic Guidelines. Rheumatology, Version 1. Melbourne: Therapeutics Guidelines Ltd, 2006.

13 Dixon WG, Watson K, Lunt M, et al. Rates of serious infection, including site-specific and bacterial intracellular infection in rheumatoid arthritis patients receiving anti-tumour necrosis factor therapy. results from the British Society of Rheumatology Biologics Register. 2006;54:2368-2376.

14 Alarcon GS, Kremer JM, Macaluso M, et al. Risk factors for methotrexate-induced lung injury in patients with rheumatoid arthritis: a multicentre, case control study. Annals of Internal Medicine. 1997;127:356-364.

15 Guttierez-Macias A, Lizarralde-Palacios E, Martinez-Odriozola P, et al. Fatal allopurinol hypersensitivity syndrome after treatment of asymptomatic hyperuricaemia. British Medical Journal. 2005;331:623-624.

SEPTIC ARTHRITIS

The assessment of a patient with acute monoarthritis is focused on excluding a septic arthritis. Septic arthritis can cause rapid joint destruction, and mortality has been reported as high as up to 15%.¹

Pathogenesis and pathology

Non-gonococcal bacterial arthritis occurs when bacteria enter the synovial lining of a joint via the haematogenous route, local spread from nearby soft tissue infections or following penetrating trauma or injury to a joint.

When the bacteria reach the synovium they trigger an inflammatory response, and bacteria and inflammatory cells enter the synovial fluid in the joint space, causing swelling and destruction of articular cartilage. These destructive changes may extend to subchondral bone and produce irreversible damage within days. The commonest causative organisms are staphylococci and streptococci.

Epidemiology and risk factors

The prevalence of septic arthritis among patients presenting to an emergency department with acute monoarthritis is up to 27%.²

Risk factors for septic arthritis include inflammatory arthritis (especially rheumatoid arthritis), diabetes mellitus and systemic factors such as age greater than 80 years, as well as local factors such as recent joint surgery, joint prosthesis and overlying skin infection. These individual risk factors increase the risk of septic arthritis by two- to three-fold.³ Skin infection overlying a prosthetic joint increases the risk of infection by 15-fold.³

Clinical features

Septic arthritis presents with joint pain and swelling in over 80% of cases, which may or may not be associated with systemic symptoms such as sweats and rigors.³ The hip and knee joints are the most commonly involved joints.

The patient may be febrile and the affected joint is usually swollen, warm, erythematous and tender. Classically, there is reduced ability to actively move the joint and marked pain on passive movement. Unfortunately, the symptoms and signs are non-specific and a patient with septic arthritis may present with all or only certain of these features. Thus, septic arthritis cannot be excluded with confidence on the history and examination alone.

Differential diagnosis

The differential diagnosis of acute monoarthritis is shown in Table 14.2.1. Ask the patient about a history of previous rheumatological disease such as rheumatoid arthritis, gout or other inflammatory arthritis, as well as risk factors for infection such asimmunosuppression, including steroids and diabetes. Recent trauma or history of a bleeding diathesis or anticoagulant is also relevant. Finally, ask the patient about any recent sexually transmitted infection, including gonococcal infection or non-specific urethritis, and any systemic features, including uveitis and/or gastrointestinal infection, which may point towards a reactive arthritis.

Table 14.2.1 Most common presentations with acute monoarthritis to an emergency department ⁴

Gout

Reactive arthritis such as post-viral, Reiters

Acute exacerbation of pre-existing inflammatory arthritis

Rheumatoid arthritis

Septic arthritis

Note: Orthopaedic-related joint problems such as trauma and/or haemarthrosis, plus osteoarthritis(OA) were not included in this series.

Clinical investigations

Blood tests

Send blood for a full blood count, which may reveal an elevated peripheral white blood cell count, as well as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). ESR and CRP are non-specific and not sensitive for septic arthritis, but may help in the differential diagnosis. Blood cultures are taken in the presence of fever. Finally, a serum urate may be elevated, but can be normal in acute gout.

X-rays

Imaging may be normal in septic arthritis, as it takes at least 1 week for destructive changes to appear on plain X-ray. Magnetic resonance imaging, if available, is non-specific but may be helpful to determine if the pathology is in the joint or juxta-articular bone.

Joint aspiration

The most useful investigation is synovial fluid aspiration and analysis. Send the aspirate in a sterile container for Gram stain and culture, as well as for polarizing light microscopy to look for the presence of urate (strongly negative birefringent) crystals or calcium pyrophosphate crystals (weakly positive birefringent crystals).

Place some of the aspirate in an EDTA tube for a cell count to be performed. The likelihood of septic arthritis increases from 2.9% with a synovial white cell count greater than 25 000/μL up to 28% with a synovial white cell count of greater than 100 000/μL. Synovial glucose and protein levels are unhelpful.

Criteria for diagnosis septic arthritis

There is no ‘gold standard’ test for the diagnosis of septic arthritis. Gram stain of synovial fluid has a sensitivity of only 50% maximum, while culture has a sensitivity of up to 85%.³ However, combined with an appropriate clinical presentation, the presence of micro-organisms in synovial fluid on Gram stain and/or a positive synovial fluid culture with high synovial white cell count are diagnostic.

Treatment

Treatment of septic arthritis requires parenteral antibiotics, and urgent referral to orthopaedics for surgical drainage, with the patient admitted to hospital. Commence empirical antibiotic therapy with dicloxacillin or flucloxacillin 2 g i.v. 6-hourly, or cephalothin 2 g i.v. 6-hourly if patient is allergic to penicillin to cover against staphylococcus, until guided by microbiology results.

The patient with suspected hip sepsis or sepsis affecting a prosthetic joint must be referred to orthopaedics urgently without attempting joint aspiration.

GOUT

Gout is an intra-articular inflammatory response to monosodium urate crystal deposition usually related to hyperuricaemia. It is more common in males than females, but is extremely rare in the premenopausal female.

Aetiology and pathogenesis

Uric acid is derived from purine metabolism. Hyperuricaemia is the strongest predictor for gout and relates to either over-production or under-excretion of uric acid. Hyperuricaemia may also cause radiolucent renal calculi.

Over-production of uric acid is due to dietary factors such as beer, shellfish and other purine-rich foods, or endogenous factors associated with high cell turnover such as a haematological malignancy. Reduced excretion is related to chronic kidney disease, hypovolaemia, acidosis and medications such as diuretics, ciclosporin, pyrazinamide and ethambutol and low-dose aspirin. There is frequently a family history of gout.

Epidemiology

The peak incidence of acute gout occurs in men between the ages of 30 and 60 years and in women between 55 and 70 years. The presentation of gout in younger patients should prompt a search for a secondary cause (including lifestyle factors). Gout is more common in Maori and Polynesian populations.

Clinical features

The classic presentation is of acute onset of a hot, swollen and painful first metatarsophalangeal joint (75% of cases) known as podagra. Other commonly affected joints include other joints in the foot, the ankle, knee and small joints of the hand.

Common triggers of an acute attack include binges of alcohol or purine-rich foods, dehydration, severe illness such as sepsis, trauma and surgery. Sudden cessation or the introduction (especially in an acute attack) of hypo-uricaemic agents such as allopurinol or probenecid can also precipitate gouty arthritis, as can the introduction or a dose change of a diuretic.

Untreated, the symptoms will abate over the course of several days to 2 weeks. Occasionally, the patient may appear systemically unwell during an acute attack with malaise and septic symptoms. Examination reveals a tender, warm and erythematous joint with severely restricted range of movement. The patient may also be febrile. Presentations of acute gout may also be polyarticular.

Recurrent untreated acute gout and hyperuricaemia results in chronic tophaceous gout, where the patient is no longer pain-free between attacks. Examination will reveal joint deformity and tophus formation on the ears, fingers and around the elbows.

Investigations and diagnosis

Synovial fluid aspiration

Synovial fluid aspirate identifying monosodium urate crystals is diagnostic of acute gout. The crystals may be phagocytosed, and the synovial fluid will have a high white cell count. Send fluid for Gram stain and culture to rule out septic arthritis, which may rarely coexist with gout. Podagra in the typical clinical scenario has a sensitivity of 96% and specificity of 95% for acute gout.⁵

Blood tests

Hyperuricaemia on blood testing is not diagnostic of gout, and although up to 5% of adults may have a raised serum uric acid at some point, only one-fifth (1% overall) will ever have an attack of gout. Conversely, in about one-third of patients with gout the serum uric acid level is normal during an acute attack. Other blood tests such as FBE, ESR and CRP are sent, and may be abnormal including elevated inflammatory markers. Check the renal function with serum urea and creatinine, to both identify a potential aetiology and help guide treatment such as avoidance or reduced doses of non-steroidal anti-inflammatory drugs (NSAIDs).

Radiology

Plain X-ray is performed to exclude injury, but should be normal in the acute attack other than soft-tissue swelling. Peri-articular punched-out erosions are seen in chronic gouty arthritis, which when associated with calcium deposition, deforming arthritis and soft-tissue swelling are quite characteristic of chronic tophaceous gout.

Management

The aim is to treat the acute pain and then prevent chronic relapse with hypo-uricaemic drugs.

Acute attack

Non-steroidal anti-inflammatory drugs

After excluding infection, give either colchicine and/or an NSAID in the absence of any contraindications. Give diclofenac 50 mg tds orally followed by 25 mg tds orally, or naproxen 500 mg followed by 250 mg tds orally until symptoms subside. A selective COX-2 inhibitor such as celecoxib 100 mg bd orally is preferred in patients with a history of peptic ulcer disease, although there is a similar risk of renal dysfunction in the elderly or with pre-existing renal disease.

Colchicine

When NSAIDs are contraindicated, colchicine is used. Doses of colchicine of 0.5 mg 6- or 8-hourly orally have equivalent efficacy and a lower rate of gastrointestinal toxicity compared to higher doses.⁶ The higher doses such as colchicine 1.0 mg followed by 0.5 mg up to four times daily, with a maximum cumulative dose of 8 mg for an acute attack, are no longer recommended. All colchicine doses should be less with renal impairment, and may be restricted by the onset of nausea, vomiting and diarrhoea. Avoid prolonged colchicine use in patients with renal impairment as this may lead to a peripheral myoneuropathy.

Corticosteroids

Give patients with gout refractory to the above treatment or in whom both medications are contraindicated corticosteroids, such as prednisolone from 25 to 50 mg daily for 3 days then weaned over the course of 1 to 2 weeks.^7,⁸ An alternative approach is to give intra-articular corticosteroid for monoarticular gout provided sepsis has been excluded. Educate all patients to correct lifestyle factors where appropriate.

Recurrent attacks

Urate lowering therapy

A second attack of gout usually requires urate lowering therapy, although this is not usually commenced in the emergency setting, as treatment must be delayed until the acute flare up has settled. Allopurinol, a xanthine oxidase inhibitor, prevents the production of uric acid from xanthine. It is introduced at a low dose once the acute attack has settled and gradually titrated up to a maximum of 300 mg daily.⁹ Typically, the patient will remain on a low-dose NSAID or colchicine (and/or prednisolone) as prophylaxis against precipitating further acute attacks. An alternative uricosuric agent to allopurinol is probenecid which should be avoided in renal impairment.

Acute Pseudogout

Acute pseudogout causes acute monoarthritis and is one of the several potential presentations of calcium pyrophosphate dihydrate (CPPD) deposition disease. It is more commonly seen in females and patients over 65 years old.

Aetiology and pathogenesis

Calcium pyrophosphate disease is characterized by deposition of CPPD crystals in cartilage causing chondrocalcinosis. When released, there may be uptake in other synovial structures and an inflammatory response producing acute synovitis, tenosynovitis or bursitis.

Advanced age is the strongest risk factor. Other associations are a family history, metabolic diseases such as haemochromatosis, Wilson’s disease, hyperparathyroidism, hypophosphataemia or hypomagnesaemia and mechanical factors such as previous injury or osteoarthritis (OA).

Clinical features

CPPD deposition disease presents in a variety of ways. The two most common are acute pseudogout and chronic pyrophosphate arthropathy, which may mimic OA. CPPD deposition disease may also mimic rheumatoid arthritis or ankylosing spondylitis, as well as the neuropathic joint. Other presentations include tenosynovitis, bursitis or as an incidental radiographic finding of chondrocalcinosis.

Acute pseudogout typically presents in older patients, and the knee is the most commonly affected joint. Other common sites include the wrist, shoulder, elbow and ankle. Occasionally, there may be an oligoarticular presentation. Presentation is with a hot, red and swollen joint. There may be septic symptoms and the patient may be febrile. Triggers include trauma, surgery or illness, but most cases are spontaneous.

Investigations and clinical diagnosis

Joint aspiration

Diagnosis of pseudogout depends on the demonstration of CPPD crystals in synovial fluid, which is frequently blood stained. Polarizing light microscopy demonstrates weakly positive birefringent rhomboid-shaped crystals.

Plain X-rays

Plain X-rays of the joint may reveal chondrocalcinosis seen in fibrocartilage such as the knee menisci, triangular cartilage of the wrist and pubic symphysis. Other characteristic findings are of marked degenerative change in joints that are not usually affected by OA.

Younger patients presenting with polyarticular chondrocalcinosis should be screened for an underlying metabolic cause, checking serum calcium, magnesium, phosphate, alkaline phosphatase, parathyroid hormone, thyroid function and iron studies.

Management

Symptoms of acute pseudogout frequently improve once the joint has been aspirated. Intra-articular injection of corticosteroid is also appropriate for acute monoarthritis, once infection has been excluded. In addition, rest and splintage for 48–72h is beneficial.

Give oral analgesics and NSAIDs similar to acute gout for polyarticular pseudogout, as performing multiple joint injections is also impractical and painful. Take great care using NSAIDs in the elderly, and choose the smallest doses to avoid renal impairment and precipitating heart failure.

HAEMARTHROSIS

Haemarthrosis is bleeding into a joint which may be traumatic and related to intra-articular injury, or non-traumatic related to an underlying bleeding diathesis.

Aetiology

The causes of haemarthrosis are listed in Table 14.2.2.

Table 14.2.2 Causes of haemarthrosis

Traumatic
• Fracture • Ligamentous (e.g. anterior cruciate or peripheral meniscal tear in the knee)

Non-traumatic
• Bleeding diathesis, e.g. haemophilia, von Willebrand’s disease • Anticoagulant use • Neuropathic joint • Acute pseudogout • Septic arthritis • Pigmented villonodular synovitis • Vascular abnormalities such arteriovenous malformation, haemangioma

Clinical features

A haemarthrosis causes a painful swollen joint with a reduced range of movement joint. The joint is often warm. Ask about a history of trauma, and if minimal or absent a bleeding disorder such as haemophilia should be considered. Also ask about troublesome bleeding during a previous operation, or following dental instrumentation, and about a family history.

Investigations and diagnosis

Perform plain radiography to exclude a fracture. Consider a computerized tomogrphy scan if there is a high index of clinical suspicion but normal plain imaging. Send a full blood count and a coagulationscreen if there is no history of significant trauma. Haemarthrosis is diagnosed on aspiration of synovial fluid. An intra-articular fracture is indicated by observing fat globules floating on the surface of the blood.

Management

Management includes rest, immobilization, ice and compression as well as analgesia. Aspiration frequently provides some pain relief if performed within 24 h of onset. NSAIDs should be avoided in patients with a bleeding diathesis.

Haemophilia or other bleeding diathesis

Haemarthrosis due to haemophilia or other disorders of clotting factor deficiency requires immediate factor replacement therapy to a level of 40–50% of normal. This should be performed as soon as possible after the presentation, in consultation with a haematology specialist.

Often the patient will be able to advise on their normal treatment (and usually knows what factor they are deficient in, their usual basal levels and how much replacement is necessary in an acute bleed). Vitamin K and administration of fresh frozen plasma may be required in patients with elevated INR related to warfarin toxicity.

SERONEGATIVE SPONDYLOARTHROPATHIES

Monoarthritis is occasionally a presentation of a seronegative spondyloarthropathy such as reactive arthritis, psoriatic arthritis, inflammatory bowel disease-associated arthritis.

Clinical features suggesting reactive arthritis include a recent history of infective diarrhoea, or sexually transmitted infection, urethritis or uveitis. The patient may appear ill and be febrile with a tachycardia. The patient should be asked about a history of psoriasis or inflammatory bowel disease in the past.

Check for sites of enthesitis with inflammation at a tendon insertion points such as the Achilles tendon or plantar facia around the heel, or dactylitis causing ‘sausage-shaped’ digits.

Summary of the approach to the management of acute monoarthritis

The British Society for Rheumatology in conjunction with other medical associations published guidelines in 2006 regarding an approach to the hot swollen joint.¹⁰ These guidelines are summarized below:

1 The hot, swollen and tender joint should be considered as septic arthritis until proven otherwise. This may occur in the absence of fever.

2 Synovial fluid must be obtained and sent for appropriate investigations prior to commencement of antibiotics. In situations of high clinical suspicion, a negative Gram stain or culture does not exclude septic arthritis.

3 Other investigations should include blood cultures, CRP, ESR and full blood count.

4 X-ray of the affected joint should be performed as a baseline.

5 Septic joints require aspiration to dryness in addition to parenteral antibiotics.

6 Prosthetic joints and suspected hip sepsis require an urgent orthopaedic opinion.

7 The presentation of a hot and swollen first metatarso-phalangeal joint is almost always gout, and is diagnosed clinically.

References

1 Gupta MN, Sturrock RD, Field M, et al. Prospective comparative study of patients with culture proven and high suspicion of adult onset septic arthritis. Annals of Rheumatic Diseases. 2003;62:327-331.

2 Jeng GW, Wang CR, Liu ST, et al. Measurement of synovial tumour necrosis factor-alpha in diagnosing emergency patients with bacterial arthritis. American Journal of Emergency Medicine. 1997;15:626-629.

3 Margaretten ME, Kohlwes J, Moore D, et al. Does this adult patient have septic arthritis? Journal of American Medical Association. 2007;297:1478-1488.

4 Sharma M, Leirisalo-Repo M. Arthritis patient as an emergency case at a university hospital. Scandinavian Journal of Rheumatology. 1997;26:30-36.

5 Zhang W, Doherty M, Pascual E, et al. EULAR evidence based recommendations for gout. Part 1: Diagnosis. Annals of Rheumatic Diseases. 2006;65:1301-1311.

6 Morris I, Varughese G, Mattingly P, et al. Colchicine in acute gout. British Medical Journal. 2003;327:1275-1276.

7 Cronstein BN, Terkeltaub R. The inflammatory process of gout and its treatment. Arthritis Respiratory Therapy. 2006;8(suppl 1):S3.

8 Rheumatology Guidelines, Version 1. Melbourne: Therapeutic Guidelines Ltd, 2006.

9 Zhang W, Doherty M, Bardin T, et al. EULAR evidence based recommendations for gout. Part 1: Management. Annals of Rheumatic Diseases. 2006;65:1312-1324.

10 Coakley G, Mathews C, Field M, et al. BSR and BHPR, BOA, RCGP and BSAC guidelines for management of the hot swollen joint in adults. Rheumatology. 2006;45:1039-1041.

Introduction

Polyarticular rheumatic disease is a frequent adult rheumatological presentation to the emergency department. This chapter focuses on the more common diseases encountered, the initial assessment and management, and most appropriate follow-up. These include rheumatoid arthritis (RA), the seronegative spondyloarthropathies, including psoriatic arthropathy, reactive arthritis with reference to arthritides occurring in association with enteric and urogenital infections, and infectious arthritis, including viral arthritis and rheumatic fever. Management principles include establishing the diagnosis, treating the acute problem and arranging appropriate follow-up.

ACUTE POLYARTHRITIS

Polyarthritis syndromes may be difficult to diagnose accurately due to the wide range of differential diagnoses, as shown in Table 14.3.1. Important measures are to rule out infection, quantify underlying inflammation and document extra-articular involvement.

Table 14.3.1 Differential diagnosis of polyarthritis syndromes ¹

Inflammatory
Rheumatoid arthritis Inflammatory osteoarthritis Systemic connective tissue disease, including SLE, vasculitis, Behçet’s disease, relapsing polychondritis Seronegative spondyloarthropathies, commonly psoriatic arthropathy Gout Pseudogout (calcium pyrophosphate arthropathy) Drug induced, including lupus syndromes Infectious arthritis – bacterial including mycobacteria, endocarditis, protozoal, viral Reactive or post-infectious arthritis including rheumatic fever

Inflammatory

Rheumatoid arthritis

Inflammatory osteoarthritis

Systemic connective tissue disease, including SLE, vasculitis, Behçet’s disease, relapsing polychondritis

Seronegative spondyloarthropathies, commonly psoriatic arthropathy

Gout

Pseudogout (calcium pyrophosphate arthropathy)

Drug induced, including lupus syndromes

Infectious arthritis – bacterial including mycobacteria, endocarditis, protozoal, viral

Reactive or post-infectious arthritis including rheumatic fever

Non-inflammatory
Neoplastic/paraneoplastic disease including hypertrophic pulmonary osteoarthropathy Sarcoidosis Endocrine disease such as haemochromatosis, acromegaly Haematological disease such as haemophilia, leukaemia

Diagnosis and clinical features

History ^2,³

Take a focused history to include the following.

Examination ⁴

Perform a detailed physical examination and document:

• vital signs, painful joints with swollen soft tissue and their distribution

• cutaneous stigmata of underlying diseases such as psoriatic nails, rash and subcutaneous nodules, oral, genital or digital ulceration

• features of end-organ involvement such as a cardiac murmur, pleural or pericardial rub and pulmonary crackles

• lumbosacral spine and pelvis including sacroiliac joints.

Investigations ^1,²

Laboratory studies

Send blood for baseline haematology and biochemistry including full blood count (FBC), urea, electrolytes and liver function tests (ELFTs) and non-specific inflammatory markers, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).

Send serum antibody or antigen tests as indicated by the history including for infectious exposure such as hepatitis B serology, streptococcal antigen test and an auto-antibody panel including antinuclear antibody (ANA), rheumatoid factor and antibodies against cyclic citrullinated peptide (anti-CCP). Antibody tests in particular should be interpreted with caution and interpreted in the context of each individual patient, due to their varying sensitivities and specificities.⁵

Joint aspiration

Joint aspiration and analysis of synovial fluid are of particular use in establishing the diagnosis of septic arthritis and crystal arthropathy (see Ch. 14.2).

Imaging studies

Imaging studies such as plain X-rays may demonstrate diagnostic features in erosive arthropathy, but these do not occur for some time after the acute onset.

RHEUMATOID ARTHRITIS

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disorder of unknown aetiology characterized by symmetric synovitis, erosive polyarthritis and numerous extra-articular manifestations. It occurs in up to 2% of the general population and is two to three times more common in women.⁶ Its onset is often indolent, and may lack the characteristic symmetry of joint involvement. Uncommonly it presents as an acute monoarthritis.

Clinical features

Characteristic presentations in RA include the following.⁸^–¹⁰

Upper limb

The wrist, metacarpophalangeal and proximal interphalangeal joints are typically affected, with sparing of the distal interphalangeal joints. Swan-necking and Boutonnière deformities are common, together with ulnar deviation at the metacarpophalangeal joints. Fixed flexion deformities may result in entrapment neuropathies, in particular carpal tunnel syndrome with median nerve involvement. Tenosynovitis may lead to tendon rupture, particularly of the extensor pollicis longus, or degenerative changes in the long extensors of the middle, ring and the little fingers with rupture of these tendons.

Lower limb

The hip and knee are frequently involved. Metatarsophalangeal joint subluxation may occur. Talonavicular joint inflammation causes pronation and eversion deformity, with overlying muscle spasm. A Baker’s cyst due to posterior herniation of the joint capsule of the knee joint may occur, and require differentiation from a deep vein thrombosis by Doppler ultrasound. Entrapment of the posterior tibial nerve causes burning paraesthesiae on the sole of the foot.

Cervical spine

Cervical arthritis is common and may result in critical spinal problems from degeneration of the transverse ligament of the C1 vertebra that produces C1–2 instability in up to 5% of patients, and can result in cervical cord compression or vertebral artery insufficiency. In addition, decreased motion and myelopathy may result from longstanding joint involvement.

Extra-articular manifestations

The extra-articular manifestations of RA are protean, and may involve any organ system due to local inflammation causing functional or neurological deficits, rheumatoid vasculitis or distant inflammation. Patients may also present with the side effects of the treatment, including sepsis related to immunosuppression. Sepsis with encapsulated organisms is of particular concern in patients with Felty’s syndrome of RA, neutropenia and splenomegaly.¹¹

Investigations

Laboratory studies

Send blood for FBC and ELFTs and non-specific markers of inflammation such as ESR, and CRP, with assays for serum rheumatoid factor and anti-CCP.¹² Anti-CCP is less sensitive but more specific than rheumatoid factor for RA, and is more frequently positive early in the disease process. It is also thought to identify individuals at higher risk of erosive disease.¹³ Send blood cultures as well as mid-stream urine for suspected sepsis.

Joint aspiration

Joint aspiration is essential to exclude co-existent or primary sepsis of any sudden hot, swollen joint.

Imaging

Initial plain imaging of affected joints at first presentation does not usually demonstrate erosive changes, but is useful in patients with longstanding disease. However, in any patient with any cervical or neurological features, always request plain X-rays of the cervical spine to look for an atlanto-dens interval of greater than 2.5 mm, which is diagnostic of instability.¹⁴ Include a chest X-ray if there is a fever and/or any respiratory features. Request an ultrasound examination to differentiate deep vein thrombosis from a Baker’s cyst.

Emergency management

The goals of emergency therapy are the relief of acute pain and reduction of joint inflammation. Longer term goals include restoration and maintenance of joint function, and the prevention of periarticular bony and cartilage destruction. Important principles include education, rest and exercise. Use non-steroidal anti-inflammatory drugs (NSAIDs), and the input of a multidisciplinary allied health team incorporating occupational therapy and physiotherapy.

Medication falls broadly under the categories of NSAIDs and disease-modifying anti-rheumatic drug (DMARD) therapy. Readers are referred to Chapter 14.1 for a brief overview of these medications and common adverse effects, as well as the references at the end of this chapter.¹⁵^–¹⁸

Other long-term measures include orthopaedic and orthotic intervention. Surgery involving joint fusion, synovectomy, total joint arthroplasty and reconstruction may be required.

Early consultation with a rheumatologist is essential, particularly for patients with acute or first presentations. Exclusion of infection even for mild or moderate presentations is always imperative, and then to control symptoms with simple analgesics including NSAIDs and discharge for specialist follow-up. Admit patients if there is evidence of end-organ involvement, severe symptoms requiring nursing or allied health management, or if they are unable to tolerate oral therapies.

Prognosis ^19,²⁰

The spontaneous remission rate in RA is less than 10%. High titres of rheumatoid factor, which is positive in up to 75% of cases or a high anti-CCP, the presence of nodules, and human leukocyte antigen (HLA)-DR4 haplotype are markers of severity. Overall, a patient’s life expectancy is shortened by 10–15 years by infection, pulmonary and renal disease, and gastrointestinal bleeding.

SERONEGATIVE ARTHROPATHIES

The seronegative arthropathies are characterized by inflammation of the axial spine with sacroiliitis and spondylitis in particular, enthesopathy which is inflammation at the attachments of tendons and ligaments to bones, dactylitis, asymmetric polyarthritis, eye inflammation often of the lower limb and varied mucocutaneous features.²¹ They are labelled ‘seronegative’ as serum rheumatoid factor is typically absent.

Epidemiology

The term ‘seronegative arthropathies’ covers conditions such as AS, reactive arthritis which occurs in the setting of viral or bacterial infection, psoriatic arthropathy and arthritis associated with IBD. The prevalence of the seronegative spondyloarthropathies varies widely, and is thought to parallel the prevalence of the HLA-B27 gene.

However, the exact role of HLA-B27 in the pathogenesis of the spondyloarthropathies has not been clearly defined. The proportion of HLA-B27 positive individuals who develop symptomatic arthropathy varies widely from 16% in patients with AS to 70% of patients with spondylitis in the setting of IBD.²² HLA-B27 positive individuals may be less efficient at the intracellular removal of certain inciting bacteria, although this is controversial.²³

Although diagnostic criteria exist for AS, they have yet to be validated for many of the other seronegative arthropathies. One of the problems is the late development of radiographic changes, particularly those of sacroiliitis. A useful set of criteria based on clinical findings, rather than on radiographic confirmation, has been developed by the European Spondyloarthropathy Study Group.²⁴

Criteria for the classification of spondyloarthropathy²⁴

Inflammatory spinal pain or synovitis (asymmetric, or predominantly lower limb), plus one or more of:

• positive family history

• psoriasis

• IBD

• alternate buttock pain

• enthesopathy

• sacroiliitis.

This discussion focuses on psoriatic arthropathy and reactive arthritis from among the conditions above.

PSORIATIC ARTHROPATHY

Psoriatic arthropathy is a heterogeneous disease with an identity distinct from other inflammatory arthritides. It occurs in 10% of patients with psoriasis, but may affect up to 40% of hospitalized psoriasis patients with widespread skin involvement.²⁵ It occurs between the ages of 30 years and 60 years, with an equal prevalence in males and females. It is thought to be inherited in a polygenic pattern that is significantly influenced by environmental factors including trauma and infectious agents. Multiple studies have confirmed the important role of class I HLA, particularly B13, B16 and B27 and certain C-subclasses.^26,²⁷ The arthropathy pattern may be pauci-articular, but more than five peripheral joints are usually involved.

Diagnosis and clinical features

The diagnosis of psoriatic arthropathy is essentially clinical, requiring the demonstration of coexisting synovitis and psoriasis. A set of simple clinical diagnostic criteria (abbreviated to the CASPAR criteria) were recently proposed by a large international study group.²⁸

The CASPAR diagnostic criteria for psoriatic arthropathy

Established inflammatory joint disease, and at least three points from the following features:

• current psoriasis (2 points)

• a history of psoriasis (in the absence of current psoriasis –1 point)

• a family history of psoriasis (in the absence of current or past history – 1 point)

• dactylitis (1 point)

• juxta-articular new bone formation (1 point)

• rheumatoid factor negativity (1 point)

• nail dystrophy (1 point).

Five clinical subtypes are recognized, including asymmetric oligoarthritis, symmetric small joint polyarthritis, predominant distal interphalangeal joint involvement, psoriatic spondyloarthropathy and arthritis mutilans.²⁹ Major extra-articular organ manifestations such as aortic insufficiency and pulmonary fibrosis occur rarely. However, up to 30% of patients have mild inflammation at the eye, most commonly conjunctivitis.

Asymmetric oligoarthritis

This occurs in 30–50% of patients.³⁰ It presents as an oligoarthritis involving a single large joint, in association with a ‘sausage-shaped’ or dactylitic digit or toe. Dactylitis occurs due to a combination of arthritis and tenosynovitis. Distal interphalangeal joint involvement is typical, and is almost invariably associated with psoriatic nail changes of pitting, ridging and onycholysis. Enthesopathy occurs most frequently with this form of the disease, and commonly manifests as plantar fasciitis or epicondylitis at the elbow.

Symmetric small joint polyarthritis

This occurs in 30% of patients, in a pattern strongly resembling RA, but with more frequent distal interphalangeal joint involvement.³⁰

Psoriatic spondyloarthropathy

This occurs in 5% of patients.³⁰ It is often asymptomatic, but may present with inflammatory low back pain due to sacroiliitis in up to 30% of cases.

Arthritis mutilans

‘Arthritis mutilans’ is a rare (<5% of patients), but well-characterized feature of psoriatic arthritis, with severely deforming arthritis including telescoping of the fingers or toes from osteolysis of the metacarpal or metatarsal bones and phalanges.³⁰

Dermatological features

Dermatological features include typical erythematous, scaling plaques on the extensor surfaces of the elbows and knees, scalp and ears, and nail changes. The nail changes include pitting with usually greater than 20 pits, ridging with transverse depressions, and onycholysis with separation of the nail from the underlying nail bed.²⁵ Nodules and vasculitic features such as digital ulcers do not occur.

Psoriatic arthritis can be difficult to distinguish from the other seronegative spondyloarthropathies in the absence of dermatological features or a positive family history.

Investigations

ESR and CRP are raised, but the rheumatoid factor and autoantibody screen are negative. Plain imaging studies of affected joints may reveal typical radiographic features, including soft tissue swelling, bone proliferation at the base of digital phalanges coupled with resorption of the distal tufts (the ‘pencil-in-cup’ deformity) and fluffy periostitis.³¹ Chest radiographs are useful as a baseline when clinical examination suggests cardiac or pulmonary involvement.

Emergency and ongoing management

Emergency treatment involves the relief of pain and reduction of joint inflammation, with appropriate specialist follow-up. Education, rest and exercise, and referral to a multidisciplinary allied health team are the mainstay of ongoing management.

NSAIDs are useful for acute symptomatic relief, and intra- or peri-articular corticosteroids may be used for short-term relief of painful arthritis or enthesitis. Long-term therapy with disease modifying agents, such as sulphasalazine or methotrexate, is instituted at specialist review.³² Oral corticosteroids are usually avoided, as their cessation often exacerbates the psoriasis. Therapy with tumour necrosis factor α antagonists³² such as infliximab or etanercept has recently been approved to rheumatologists under strict access criteria for severe disease resistant to other DMARD therapy.

Emergency management of skin disease includes topical treatments such as emollients and keratolytic agents.³³ Phototherapy and photo-chemotherapy may be instituted on early dermatological consultation. Admit patients if their symptoms are severe enough to preclude oral therapy or safe discharge pending outpatient specialist follow-up.

Prognosis

Psoriatic arthropathy generally runs a more benign course than RA, but patients nonetheless suffer from considerable morbidity. Adverse prognostic factors include onset before 20 years of age, erosive disease and extensive skin involvement.³⁰

REACTIVE ARTHRITIS

Reactive arthritis is aseptic peripheral arthritis following certain infections, which include bacterial infections of the urogenital tract usually by Chlamydia trachomatis, or of the gastrointestinal tract with organisms such as Shigella, Salmonella and Campylobacter. It may also follow viral infections such as HIV, although in the case of HIV, coinfection with sexually transmitted organisms rather than the virus itself is thought to cause the symptoms.³⁴ The seroconversion illness of HIV with its own constellation of articular symptoms is considered to be a separate entity.

Epidemiology

The prevalence of reactive arthritis has been difficult to define owing to diagnostic uncertainty particularly in the setting of asymptomatic sexually transmitted infection. The male preponderance is up to 9:1 following sexually transmitted infection, but males and females are equally affected following gastrointestinal tract infection.³⁵ The peak incidence is around the age of 35 years, and up to 75% of patients are HLA-B27 positive.³⁵ An important exception is with the reactive peripheral arthritis that occurs in 20% of patients with idiopathic IBD, a condition that may mimic gastrointestinal tract infection, but where patients are usually HLA-B27 negative.

Diagnosis and clinical features

The diagnosis of reactive arthritis is clinical. It typically manifests within a month of gastrointestinal or genitourinary infection, although the latter is frequently asymptomatic.³⁶ Musculoskeletal manifestations include myalgias and asymmetric polyarthritis affecting the knees, ankles and small joints of the feet in particular, although peripheral upper limb involvement is seen. Affected joints demonstrate marked inflammatory features with erythema, swelling, warmth and exquisite pain on active or passive movement. Fever and malaise are common.

Arthropathy and extra-articular manifestations

Symptomatic spondylitis and sacroiliitis cause low back and buttock pain and occur frequently. Dactylitis and enthesopathy are characteristic features of this disease with heel pain from plantar fasciitis or Achilles tendonitis.³⁶

Extra-articular features associated with reactive arthritis include keratoderma blennorrhagicum; the scattered, thickened, hyperkeratotic skin lesions with pustules and crusts seen in Reiter syndrome, and circinate balanitis. An inflammatory aortitis occurs in 1% of patients and may result in aortic valvular incompetence, and/or heart block. Keratoderma blennorhagicum on the soles or palms may coalesce to form plaques virtually indistinguishable from those of psoriasis.³⁷ Circinate balanitis causes shallow meatal ulcers that are moist in uncircumcised men or hyperkeratotic and plaque-like in circumcised men.³⁷

The peripheral arthritis associated with IBD is migratory and occurs in a similar distribution. Common features include large joint effusions, particularly involving the knee, and sacroiliitis or spondylitis.³⁸ Unlike peripheral arthritis following genitourinary infection, the spondylitis of IBD-associated arthropathy does not tend to settle with treatment of the bowel inflammation. Cutaneous features associated with this form of arthropathy occur mainly on the lower limbs, and include erythema nodosum and pyoderma gangrenosum.³⁸

Investigations

Blood testing

An active inflammatory response is seen in the acute phase with a neutrophil leukocytosis and thrombocytosis, and raised ESR and CRP. The presence of a mild normochromic, normocytic anaemia suggests chronic disease. Send blood for HLA-B27. Document the preceding genitourinary or gastrointestinal organism by stool culture or cervical/urethral swabs.³⁹ Rheumatoid factor and ANA are negative.

Joint aspiration

Joint aspiration may be necessary to exclude intra-articular sepsis (see Ch. 14.2). The synovial fluid may be turbid, viscous and with a neutrophil leukocytosis up to 50 000/mm³, but Gram stain and bacterial culture are negative, and unlike true septic arthritis, the synovial glucose level is not significantly reduced compared to serum levels.³⁹ Macrophages with intracytoplasmic vacuoles containing ingested neutrophils are occasionally seen.

Radiography

Radiographic abnormalities are unusual with an acute arthritis, but are seen after several months. As with psoriatic arthropathy, a common finding is a ‘fluffy’ periosteal reaction, particularly at the calcaneus, and evidence of sacroiliitis or spondylitis with bridging syndesmophytes in longstanding disease.

Emergency and ongoing management

Exclude infection by synovial aspiration and culture for a markedly inflamed joint and early consultation with a rheumatologist, particularly in patients with a first presentation. Provide symptom relief with NSAIDs as the mainstay of emergency treatment. Corticosteroids may be given after rheumatological consultation, either systemic or topically for the skin manifestations. Disease modifying therapy with sulfasalazine may be initiated at specialist follow-up if NSAID therapy fails to control symptoms.

Give antibiotics such as doxycycline 100 mg orally bd for 7 days or azithromycin 1 g orally once for documented urethritis or cervicitis, and remember partner contact tracing and treatment. An infectious diseases opinion is useful in these cases.³⁹

Admit patients with suspected septic arthritis until it is excluded, or if they are unable to tolerate simple oral therapies. Request a cardiology opinion for major cardiac involvement with valvular disease or a conduction abnormality, and a gastroenterology opinion when IBD is suspected, although the role of treatment and the effect on the arthropathy is unclear. Multidisciplinary physical therapy is essential on an outpatient basis.

Prognosis

Signs and symptoms usually remit within 6 months. However, up to 50% of patients suffer from recurrent arthritis, and up to 30% develop chronic arthropathy.⁴⁰ Post-dysenteric cases have a better prognosis than post-chlamydial cases. Poor prognostic signs include early onset under the age of 16 years, hip involvement and the presence of dactilytis.

POLYARTICULAR CRYSTAL ARTHROPATHY

Crystal-induced arthropathies result from the deposition of crystal in joint spaces, such as in gout or pseudogout. Both diseases cause debilitating joint inflammation resulting from the lysis of neutrophil polymorphs that have ingested monosodium urate in the case of gout or calcium pyrophosphate crystals in pseudogout. Although usually monoarticular, polyarticular involvement can occur in up to 5% of cases. See Chapter 14.2 for a detailed discussion of these diseases.

INFECTIOUS POLYARTHRITIS

Septic bacterial arthritis is most often monoarticular. However, it can present with polyarticular involvement. Infectious polyarthritis may occur as aseptic manifestation of certain viral infections, and following streptococcal infection as acute rheumatic fever (ARF).

Viral arthritis

Arthralgia affecting several joints is common in numerous viral infections, but few viruses cause frank polyarthritis. In general, these are self-limiting and managed symptomatically. Those viruses involved include alphaviruses such as the Ross River virus (RRV), parvovirus B19 and hepatitis B and hepatitis C virus.

Alphaviruses

Alphaviruses are a mosquito-borne genus of the Togaviridae family. They are responsible for epidemics of febrile polyarthritis, including Ross River, Barmah Forest and Sindbis viruses in Australia, West Nile virus that has recently been documented in the USA, Chikungunya virus in East Africa, South and South-East Asia, O’nyong-nyong virus in East Africa and Mayaro virus in South America.⁴¹

Ross River virus

RRV is endemic to Australia, New Zealand and South Pacific islands, and is the most common arboviral disease in Australia. RRV is transmitted by the Ochlerotatus (formerly Aedes) vigilex mosquito via a marsupial reservoir.⁴² Epidemics of acute febrile polyarthritis are most common between January and May, but can occur after periods of heavy rains.

Diagnosis and clinical features of Ross River virus

A detailed travel history is essential. There is usually low grade fever and other constitutional symptoms. A rash varying in distribution, character and duration occurs up to 2 weeks before, during or after the other symptoms. Polyarticular symptoms are present in most patients with a symmetric arthritis or arthralgia primarily affecting the wrist, knee, ankle and small joints of the extremities. Cervical lymphadenopathy occurs frequently, and paraesthesiae and tenderness of the palms and soles in a small percentage of cases.⁴³

The diagnosis is predominantly clinical, particularly in endemic areas in the event of a local outbreak, and confirmed by serology.

Investigations

Serology for Ross River virus

Serology testing distinguishes RRV from other causes of febrile polyarthritis such as Barmah Forest virus. A significant rise in IgM antibody titre to RRV indicates acute infection, or the virus itself may be isolated from the serum of acutely unwell patients. Radiographs are unremarkable and uneconomic as the disease is largely self-limiting.⁴⁴

Emergency and ongoing management

Patients with RRV require symptomatic treatment with simple analgesics or NSAIDs. Occasionally, a brief course of low-dose prednisolone may be used. RRV is a notifiable disease.⁴² Conventional personal preventative measures such as protective clothing, effective mosquito repellent and avoidance of mosquito-prone areas should be recommended, as no vaccine currently exists. Refer to a rheumatologist if symptoms are severe or refractory to simple treatment measures.

Prognosis of Ross River virus infection

The illness is usually self-limiting, but prolonged symptoms may occur, and there may be relapses of decreasing intensity, separated by remissions, for up to a year or more.

Parvovirus B19

Human parvovirus B19 infection is caused by a small, single-stranded DNA virus that has a predilection for erythroid precursor cells and is transmitted by respiratory secretions. It causes the self-limiting illness Erythema infectiosum or ‘slapped cheek disease’ or ‘fifth disease’ in children. In adults, however, parvovirus B19 manifests with severe flu-like symptoms, and as many as 75% develop joint symptoms. It may be responsible for up to 12% of adult patients presenting with acute polyarthritis, most notably in those who have frequent exposure to children.⁴⁵

Diagnosis and clinical features

The characteristic rash is usually absent in adults. An acute polyarthritis improves over 2 weeks, with symmetric involvement of peripheral small joints, including the hands (proximal interphalangeal and metacarpophalangeal joints in particular), wrists, knees and ankle joints. Morning stiffness is a prominent feature. These features are similar to those seen in patients with RA, and in fact up to 50% of affected patients meet the ACR diagnostic criteria for RA.⁴⁶ Uncommon but important extra-articular features of parvovirus B19 infection are detailed below.⁴⁷

Extra-articular features of parvovirus

• Development of an aplastic crisis in patients with chronic haemolytic anaemia.

• Bone marrow suppression in immunocompromised patients.

• Hydrops foetalis in women infected during pregnancy.

• Henoch–Schönlein purpura.

• Thrombotic thrombocytopenic purpura.

• Wegener’s granulomatosis or polyarteritis nodosa (rare).

Investigations

Always send an FBC, particularly given the potential for an aplastic crisis and bone marrow suppression. Non-specific markers of inflammation are likely to be elevated. Specific serological diagnosis is made by demonstrating high IgM antibody titres specific to the virus, and by isolation of the viral DNA by polymerase chain reaction (PCR). IgG antibodies to parvovirus B19 indicate past infection and are common in the adult population.⁴⁸

Transient, moderate elevations of rheumatoid factor, anti-DNA, antilymphocyte or anticardiolipin antibodies sometimes occur.⁴⁸ Radiographs of the affected joints are normal.

Emergency and ongoing management

Rest and NSAIDs are the mainstay of emergency treatment, except in pregnant women, as NSAIDs are contraindicated in the third trimester.⁴⁹ A short course of prednisolone may be required. Significant extra-articular manifestations may require admission and consultation with the appropriate specialist. Blood transfusion or intravenous immunoglobulin infusions may be necessary.

Prognosis

Joint symptoms are self-limited in the majority of adult patients, but up to 10% may have prolonged relapsing and remitting symptoms lasting up to 9 years.⁵⁰

Hepatitis B and Hepatitis C Viruses

The common hepatitis viruses A, B and C all cause viral polyarthritis. Hepatitis B virus (HBV) is responsible for 20–25%, and hepatitis A (HAV) up to 14% of causes in patients with viral polyarthritis.⁵¹ The polyarthritis of HAV tends to occur during the infectious phase, and is self-limiting. The polyarthritis of HBV occurs in early infection during a period of significant viraemia, and is thought to be due to immune complexes.

Diagnosis and clinical features

HBV polyarthritis is acute and severe, and manifests in a symmetric, migratory or additive fashion most commonly involving the hand and knee joints.⁵² Other large axial joints may be involved, and significant early morning stiffness is often present. The arthritis may precede the development of jaundice, and persist for several weeks after jaundice has developed.

Hepatitis C virus (HCV) polyarthritis is rapidly progressive and symmetrical, involving the hands, wrists, shoulders, knees and hips.⁵³ Carpal tunnel syndrome and tenosynovitis may occur. It is unusual for polyarthritis to be the first manifestation of the underlying disease in either HBV or HCV. Nonetheless, ask about exposure risk factors for these viruses such as intravenous drug abuse, unprotected sexual intercourse, past blood transfusions, tattoos, as well as about previous jaundice. Both hepatitis B and hepatitis C disease are associated with a number of important extra-articular, extra-hepatic manifestations.

Extra-articular, extra-hepatic manifestations

• HBV: polyarteritis nodosa, systemic necrotizing vasculitis, membranous glomerulonephritis.⁵⁴

• HCV: mixed cryoglobulinaemia causing palpable purpura, arthritis and serum cryoglobulinaemia with cutaneous phenomena such as Raynaud’s syndrome and digital ulcers, and membranous glomerulonephritis.^53,⁵⁵

Investigations

Blood testing

Send blood for ELFTs for evidence of raised transaminases with elevated bilirubin, hepatitis B surface antigen; antihepatitis B surface antigen IgM to indicate acute infection and/or viral DNA quantification by PCR. Check also for anti-HCV IgM and for viral DNA quantification by PCR.

Also check FBC and for ESR, CRP, cryogobulins and rheumatoid factor in the presence of a rash, ulcers or other vasculitic phenomena. Radiographs are normal other than showing soft tissue swelling.

Emergency and ongoing management

Commence symptomatic treatment of the polyarthritis with NSAIDs in the emergency department. Refer refractory HBV- or HCV-associated polyarthritis to a rheumatology specialist and/or combined hepatology clinic. Disease modifying agents such as prednisolone and sulphasalazine may be used cautiously with careful monitoring of the liver function tests and for increasing viraemia.⁵⁶

Prognosis

The prognosis varies depending on the treatment of the underlying disease and on the presence of vasculitic phenomena. The polyarthritis of HBV is usually limited to the pre-icteric phase, but patients with chronic active hepatitis or chronic HBV viraemia may have recurrent arthritis.

RHEUMATIC FEVER

Acute rheumatic fever (ARF) refers to a constellation of non-infectious symptoms occurring after a pharyngeal infection with group A streptococci (GAS). Anecdotal evidence suggests that it may also occur in high-risk populations following skin infections with GAS.⁵⁷

Epidemiology

ARF is characterized by inflammation of connective tissue including the joints, subcutaneous tissue, heart and blood vessels. Its prevalence has declined over time in developed countries, but it remains a major public health problem in developing countries, and in the more socially isolated parts of Australasia. The highest documented rates in the world occur in the Aboriginal Australian population and Torres Strait Islander populations of New Zealand and the Pacific Islands.⁵⁸

ARF is primarily a disease of children aged 5–14 years. The annual incidence may reach 350 per 100 000 in Aboriginal children.⁵⁹ However, the polyarthritis of ARF is most commonly seen in adolescents and young adults.

Diagnosis and clinical features

The diagnosis of ARF worldwide is made on the 1944 Jones or more recently World Health Organization major and minor criteria. However, these criteria appear too restrictive for diagnosing ARF in Australian indigenous populations. Therefore, new criteria for use in high- and low-risk populations in Australia have been proposed (see Table 14.3.2).⁶⁰

Table 14.3.2 2005 Australian guidelines for the diagnosis of acute rheumatic fever

	High-risk groups	All other groups
Initial episode of ARF	Two major or one major and two minor manifestations plus evidence of a preceding GAS infection	Two major or one major and two minor manifestations plus evidence of a preceding GAS infection
Recurrent attack of ARF in a patient with known past ARF or RHD	Two major or one major and two minor or three minor manifestations plus evidence of a preceding GAS infection	Two major or one major and two minor or three minor manifestations plus evidence of a preceding GAS infection
Major manifestations	• Carditis, including subclinical evidence of rheumatic valve disease on echocardiogram • Polyarthritis or aseptic monoarthritis or polyarthralgia • Chorea • Erythema marginatum • Subcutaneous nodules

• Carditis, excluding subclinical evidence of rheumatic valve disease on echocardiogram

• Polyarthritis

• Chorea

• Erythema marginatum

• Subcutaneous nodules

ARF, acute rheumatic fever; GAS, group A streptococci; RHD, rheumatic heart disease.

The polyarthritis of ARF is usually the earliest symptom of the disease, and is classically described as migratory affecting several joints in quick succession for a short time, commencing with the large joints of the lower limb then the large joints of the upper limb.⁶¹ Affected joints are painful but objective signs of inflammation such as erythema and swelling are not prominent.

Fever and constitutional symptoms are common. Other important extra-articular major criteria (with polyarthritis) of the disease include the following.⁶¹

Major criteria (with polyarthritis) of acute rheumatic fever

• Carditis: symptomatic pericarditis with pain and/or congestive cardiac failure with breathlessness, new murmurs, cardiomegaly, electrocardiographic evidence of heart block.

• Sydenham’s chorea (St Vitus’ dance): choreiform movements particularly of the face and upper limbs, emotional lability, rarely transient psychosis.

• Subcutaneous Aschoff nodules: firm, painless, mobile nodules near bony prominences on the extensor surfaces of wrists, elbows and knees.

• Rash (Erythema marginatum): occurs in around 5% of ARF. It consists ofblanching ring-like pink macules with a serpiginous edge and central clear portion occurring on the trunk and inner surfaces of the arms and legs, which are not itchy and can come and go for months. They may be slightly raised, but spare the face. The rash may change from hour to hour and may seem to appear, disappear or move rapidly in front of you. It is exacerbated by heat and fades when the patient is cool.

Investigations

Measure antistreptolysin O and antideoxyribunuclease B (anti-DNase B) titres.⁶¹ As these titres can take 6 weeks after infection to peak, interpretation in the acute phase should be cautious, and serial tests should be performed. Note that anti-streptococcal antibody titres are useful in low-risk populations, but are difficult to interpret in high-risk populations due to pre-existing high background titres.⁶² Send a throat swab, although this is positive in less than 10% of high-risk populations. Other important tests include:

• ESR and CRP, which are almost invariably elevated

• FBC, which may demonstrate a leukocytosis and less commonly, a normochromic, normocytic anaemia

• electrocardiography to document the P-R interval

• chest X-ray to look for cardiomegaly or symptomatic cardiac failure.

Synovial fluid aspirate is usually inflammatory with an elevated white cell count, and sterile on microscopy and culture. Radiographs of affected joints generally demonstrate soft tissue swelling only.

Emergency and ongoing management

Emergency management of ARF depends on making the diagnosis, and treating the manifestations. Patients are severely symptomatic, and often require admission for initial observation and management. Request rheumatology and infectious diseases opinions and a neurology opinion if chorea is troublesome. The presence of heart block or, more importantly, frank cardiac failure or acute valvular regurgitation mandate cardiac admission.

The polyarthritis of rheumatic fever is exquisitely responsive to NSAID therapy, particularly aspirin, so much so that failure of NSAID therapy to rapidly relieve symptoms should prompt consideration of an alternative diagnosis.⁶³ Give aspirin at doses of 80–100 mg/kg/day in 4–5 divided doses in adults, usually for 1 to 2 weeks.⁶⁴

Commence antibiotic therapy with phenoxymethylpenicillin 10 mg/kg up to 500 mg orally 12-hourly for 10 days to eradicate streptococcal pharyngitis as soon as possible, after obtaining appropriate diagnostic investigations as detailed above. Commence prophylaxis following resolution of the acute episode in high-risk indigenous communities. Ongoing rheumatology and infectious diseases specialist follow-up is recommended. Note that penicillin reduces the frequency and severity of post-streptococcal rheumatic fever, but has little effect on the course of immune-complex mediated post-streptococcal glomerulonephritis.

Prognosis

Recurrence of ARF commonly occurs within 2 years of the initial attack, despite prophylactic therapy. Most affected connective tissues do not sustain long-lasting damage, with the exception of the heart, which is prone to additive subclinical damage resulting in rheumatic heart disease.⁶⁵

Controversies

1 Role of DMARD therapy in the various causes of acute polyarthropathy.

2 The exact role of HLA-B27 in the pathogenesis of the spondylo-arthropathies.

3 Pathogenetic mechanisms leading to reactive arthropathy.

References

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14.4 Musculoskeletal and soft tissue emergencies

Anthony Tzannes, Anthony F.T. Brown

Essentials

1 Soft tissue injuries may be as debilitating and painful, and take longer to heal, than fractures in the same area.

2 The mechanism of injury and biomechanics predict the soft tissue damage caused.

3 The so-called ‘minor injury’ can be associated with significant and prolonged morbidity that could be permanent if managed incorrectly. Adopting a careful, consistent approach that considers potential pitfalls is important to patient outcome.

4 Exclude potentially serious causes of back pain ‘red flags’ prior to discharging any patient with this presentation.

General evaluation of a soft tissue injury

Assessment

History

Obtain a history of

• the nature of the injury, and when, where and how it was sustained with specific attention to the forces involved

• the possibility of a foreign body, wound contamination and damage to deeper structures

• patient function following the injury

• pain associated with the injury, including time course, nature and aggravating factors/actions

• any crush or shear injury

• current medical conditions and drug therapy

• allergies and tetanus immunization status.

Examination

Examine nerves and tendons for evidence of damage, before infiltrating with local anaesthetic.

Send the patient for X-rays if a radio-opaque foreign body such as metal or glass is suspected, before exploring a wound. Inform the radiographer the nature of the foreign body.

Specific issues with a possible chronic overload injury

• Change in activity/equipment or sudden change in load.

• At what point of activity the pain is felt (before, during, after or a combination).

• History of prior similar injury.

Puncture injuries

Clinical evaluation

This type of injury is caused by stepping on a nail or pin, penetration by a sewing machine needle, or industrial equipment such as a nail gun, high pressure hose or gun. Needlestick and sharps incidents are covered in Chapter 9.10.

Management

Refer all high-pressure gun injuries such as from paint or oil immediately to the appropriate surgical team, even if no apparent damage is seen initially. They will require extensive wound debridement and tissue plane cleaning, however innocuous they seem.

Otherwise, clean the wound with antiseptic and evaluate the need for tetanus prophylaxis and antibiotics. Treat a rusty nail injury to the foot by soaking in iodine in alcohol for 30 min and give amoxicillin 500 mg and clavulanic acid 125 mg one tablet orally tds for 5 days. Instruct the patient to return immediately if signs of infection or gross oedema supervene.

Pretibial lacerations

These are most common in elderly patients, often from trivial trauma tearing a flap of skin, particularly if taking steroids. Ask about general mobility and safety issues at home.

Management

Clean the wound, remove blood clots, trim obviously necrotic tissue and unfurl the rolled edges of the wound to determine actual skin loss. Refer the patient immediately to the orthopaedic or plastic surgery team for consideration of early skin grafting if there is significant skin loss or marked skin retraction preventing alignment of the skin edges.

Otherwise, lay the flap back over the wound and hold in place with adhesive skin-closure strips (Steristrips™). Cover the wound with a single layer of paraffin-impregnated gauze and a cotton-wool and gauze combine pad. Then apply a firm crêpe bandage and instruct the patient to keep the leg elevated whenever possible. Enquire about tetanus immunization status.

Arrange for review and dressing change within 5 days, or earlier if blood or serum has seeped through the wound dressing known as ‘strike-through’, as there is now an increased risk of secondary infection.

Expect the wound edges to heal by granulation tissue and new epidermal tissue laid down at the rate of approximately 1 mm per week. Refer the patient to the orthopaedic or plastic surgery team at this point, if healing is clearly not occurring. Otherwise, arrange follow-up with the GP, plus community nurse input as necessary.

Acute mechanical overload injuries

These include fractures, ligament sprains, muscle strains or tears and tendon ruptures. Many are covered in Section 4.

Classification of ligament sprains/muscle strains

Grade I	Small number of fibres injured, with pain on stressing, but no laxity or loss of strength.
Grade II	Significant number of fibres injured with laxity and or weakness and pain on stressing.
Grade III	Complete tear with gross laxity and no strength.

Management

General principles

The initial management principles are the same for both and include rest, ice, compression and elevation (RICE) and analgesia, usually with a combination of paracetamol 1 g orally qid, plus a non-steroidal anti-inflammatory drug (NSAID) such as ibuprofen 400 mg orally tds (in the absence of significant asthma, peptic ulcer disease and renal impairment).

Ligament sprains

Ligament sprains that are grade I or II are managed with a protective brace or strapping and reduction of, but not cessation of physical activity. Consider grade III sprains for immobilization with a splint or plaster of Paris (POP) cast and/or operative repair if there is gross instability, and warn the patient that they may take up to 3 months or longer to heal. This is of particular relevance to the manual labourer and high-level athlete, although the latter usually has excellent access to physiotherapy and a formulated rehabilitation plan.

Muscle strains

Muscle strains require initial minimization of bruising and haematoma formation by RICE followed by graded return to activity. Physiotherapy may help improve return of function and prevent re-injury, although research is surprisingly limited. Consider complete muscle tears, especially in active individuals, for operative repair, and refer to an orthopaedic specialist. Assess the functional limitations imposed by these injuries, particularly in patients who live alone and or who are elderly and infirm, as loss of independence is likely. Consider the need for community services, respite care or admission until they are able to look after themselves again.

Tendon ruptures

Evaluation

Acute rupture of the supraspinatus tendon, long head of biceps and Achilles tendon are the most common injuries. The extent of the rupture may be complete or partial. Injury may be secondary to an acute event or chronic overload that is often asymptomatic until a tear occurs.

Management

Request an ultrasound to confirm the diagnosis, although magnetic resonance imaging (MRI) is equally or more sensitive and specific depending on which tendons are being imaged, although clearly much less readily available.

Treatment is aimed at the earliest return to normal function, with least likelihood of recurrence. Refer complete tears, particularly in active people, for orthopaedic surgery repair. Manage partial tears conservatively, but they too may have a better outcome if repaired surgically, depending on surgical availability and local hospital guidelines.

Degloving injuries

Evaluation

Degloving injuries are caused by either a shearing or traction force on skin, causing it to be torn from its capillary blood supply. When the skin tears and actually peels off it leaves an obvious exposed open injury.

Closed degloving injuries are harder to diagnose and may only lead to the skin feeling slightly less tethered than prior to injury, a failure to blanch with pressure, poor capillary return and most importantly altered cutaneous sensation. This is most easily and accurately assessed by 2-point discrimination. If 2-point discrimination is normal, a significant degloving injury has not occurred. Pain may or may not be prominent, and/or may relate to an underlying bony injury.

Management

Arrange specialist assessment and admission for all degloving injuries by the appropriate surgical team, usually orthopaedic and or plastic surgery. Keep any degloved skin available, as it may be used as a skin graft.

Do not be tempted to simply replace the skin into its original position and hold it there with sutures or adhesive skin-closure strips (Steristrips™) as this is inadequate. Degloving injuries are also considered as a high-risk wound for tetanus.

Chronic overload (overuse) injuries

Few of these injuries require emergency treatment. However, a general knowledge of these conditions is worthwhile. They develop wherever tissue microtrauma occurs at a rate that exceeds the body’s ability to heal.

Classification

Bony overuse injuries follow a continuum from pain on activity only, through local tenderness, to pain at rest, and loss of function. Many will have led to a stress fracture by the time of presentation to an emergency department (ED).

Other overuse injuries are classified by tissue type and the extent of injury, and are often best diagnosed by the timing of the pain in relation to physical activity. They are further classified by the presence or absence of inflammation.

Classification of chronic overuse syndromes

Grade I	Pain after activity
Grade II	Pain early on and after activity; activity not limited
Grade III	Pain throughout activity, which is limited
Grade IV	Pain at rest.