Epidemiology

Rheumatic heart disease (RHD) is steadily decreasing in the developed world in association with improved standards of living and the availability of penicillin. Amongst developing countries prevalence is variable, with one of the highest prevalences worldwide found in the indigenous Australian communities. A family history of ARF is common, reflecting genetic predisposition as well as environmental influences.

Pathophysiology

The exact pathogenesis of ARF remains unclear. It is postulated that certain virulent strains of Gram-positive Group A β-haemolytic streptococci (Streptococcus pyogenes) invade the pharynx, leading to the production of anti-streptococcal antibodies, which cross-react with host connective tissue.

History

Acute rheumatic fever usually presents in school-age children but may present at any age. A history of pharyngitis several weeks previously is found in 70% of older children, but younger children are less likely to recall a sore throat. Typically, ARF presents with up to a week of high fevers, followed by several weeks of milder temperatures and the appearance of a rash (erythema marginatum). Specific symptoms include migratory joint pain, chorea, and neuropsychiatric manifestations such as abrupt personality change or poor attention span. There may be symptoms of congestive heart failure or non-specific symptoms such as weight loss, fatigue, pallor, headache and abdominal pain.

Examination

The diagnosis of ARF relies upon the identification of specific clinical features. The National Heart Foundation of Australia has developed diagnostic criteria which depend on the stratification of patient risk (Table 5.6.1). High-risk groups are those who live in communities with high rates of ARF or RHD such as Aboriginal and Torres Strait Islanders.

Table 5.6.1 Diagnostic criteria for acute rheumatic fever

High-risk group All other individuals Major manifestations Carditis (including subclinical echocardiograph evidence)
Polyarthritis, aseptic monoarthritis, or polyarthralgia
Erythema marginatum
Subcutaneous nodules
Chorea Carditis (excluding subclinical echocardiograph evidence)
Polyarthritis
Erythema marginatum
Subcutaneous nodules
Chorea Minor manifestations Fever (documented >38°C)
ESR >30 mm hr^–1 or CRP >30 mg L^–1
Prolonged PR interval on ECG Fever (documented >38°C)
ESR >30 mm hr^–1 or CRP
>30 mg L^–1
Prolonged PR interval on ECG
Polyarthralgia or aseptic monoarthritis

Amended from National Heart Foundation of Australia; Diagnosis and management of acute rheumatic fever and rheumatic heart disease in Australia – an evidence-based review. 2006.

An initial episode of ARF may be diagnosed where two major or one major and two minor manifestations are present. The same criteria may be used to diagnose a recurrent episode, which otherwise requires the presence of three minor manifestations. All diagnoses require evidence of preceding Group A streptococcal (GAS) infection.

Erythema marginatum

Erythema marginatum is a distinctive feature of rheumatic fever, but is only found in approximately 10% of patients. Lesions usually begin as small, pink, non-pruritic macules or papules on the trunk or limbs. The lesions gradually spread to develop a raised pink serpiginous edge with central clearing and remain late into the course of illness (Fig. 5.6.1).

Subcutaneous nodules

Subcutaneous nodules are an uncommon but highly specific manifestation of ARF. They are firm, non-tender nodules found over the extensor surface of the elbow, metacarpophalangeal joints, knees, and ankles. Up to three or four can appear in the first weeks of illness and may remain for up to a month.

Sydenham’s chorea

Chorea occurs in up to 30% of patients with ARF, and is postulated to be due to cross-reactivity between anti-streptococcal antibodies and basal ganglia neurones. It presents with jerky, purposeless movement of limbs, speech impairment, involuntary grimacing or emotional lability, and may appear several months after the original GAS infection. Movements may be asymmetric and usually disappear during sleep. Generally symptoms improve in 1–2 weeks and resolve completely over 2–3 months, although the course can be variable. The presence of chorea is sufficient for the diagnosis of ARF without other manifestations, providing differential diagnoses have been excluded.

Laboratory

Imaging

To further evaluate ventricular and valvular morphology and function a chest X-ray and echocardiography are indicated. Echocardiography has an important role in the recognition of carditis, which may be clinically undetectable in up to one half of cases.

Differential diagnosis

Each clinical manifestation of ARF is associated with multiple alternative diagnoses, hence the need for strict diagnostic criteria. Sydenham’s chorea is a diagnosis of exclusion after eliminating other causes of movement disorder such as drug toxicity, systemic lupus erythematosus (SLE), and Wilson’s disease. Erythema marginatum is not specific for ARF, also being found in sepsis, glomerulonephritis and some drug reactions. Subcutaneous nodules are also seen in rheumatoid arthritis. Several systemic inflammatory conditions such as SLE and juvenile arthritis may fulfil all ARF diagnostic criteria and must be excluded.

Acute management

Children who present with features of ARF should be admitted to hospital under a paediatrician for further evaluation and management. Management priorities are as follows:

Prognosis

ARF resolves in most patients by 3 months. Complete spontaneous healing of valvulitis occurs in up to 80% of cases receiving prophylactic antibiotic therapy. Recurrent episodes of rheumatic fever are more common in younger patients and usually occur within 5 years. Prognostic indicators for chronic valve disease include total number of rheumatic fever episodes and time delay between onset of GAS and antibiotics in each instance. Of all patients with initial mitral valve insufficiency, up to 30% have evidence of RHD at follow up. This number increases substantially where aortic valve involvement, congestive heart failure or pericarditis was present at diagnosis.