CHAPTER 151
Rheumatoid Arthritis
Definition
Rheumatoid arthritis is a chronic inflammatory disorder that primarily affects joints but may also have prominent extra-articular features. The arthritis is classically symmetric and affects the peripheral joints. The prevalence of rheumatoid arthritis is approximately 1% in white individuals, and it affects women about 2 to 2.5 times more often than men, which may be related to the effect of sex hormones, such as estrogen, in regulating the immune response [1]. Peak incidence of rheumatoid arthritis is in the third and fourth decades, although the disease affects all ages and individuals from all racial and ethnic groups [2–4]. Classification criteria are available for rheumatoid arthritis and may be helpful in the evaluation of patients (Table 151.1). Many patients with early disease, however, may not fulfill these criteria [5].
Table 151.1
Classification Criteria for Rheumatoid Arthritis*
Criterion | Definition |
Morning stiffness | Morning stiffness in or around the joints lasting at least 1 hour before maximal improvement |
Arthritis of three or more joint areas | Soft tissue swelling or fluid in at least three joints observed by a clinician The 14 possible joints include right and left proximal interphalangeal, metacarpophalangeal, wrist, elbow, knee, ankle, and metatarsophalangeal joints. |
Arthritis of the hand joints | At least one area swollen in a wrist, metacarpophalangeal, or proximal interphalangeal joint |
Symmetric arthritis | Simultaneous involvement of the same joint areas on both sides of the body Involvement of the small joint groups (metacarpophalangeal joints, proximal interphalangeal joints, and metatarsophalangeal joints) is acceptable without absolute symmetry. |
Rheumatoid nodules | Subcutaneous nodules occurring over bone prominences, extensor surfaces, or juxta-articular regions These must be observed by a clinician. |
Serum rheumatoid factor | Abnormal amounts of serum rheumatoid factor by any method for which the result has been positive in < 5% of normal control subjects |
Radiographic changes | Posteroanterior hand and wrist films that demonstrate erosion or unequivocal bone decalcification localized in or most marked adjacent to the involved joints |
* A patient is said to have rheumatoid arthritis if he or she satisfies at least four of the seven criteria. Criteria one through four must have been present for at least 6 weeks.
Symptoms
Rheumatoid arthritis is a systemic disease, and symptoms vary according to the system involved [6–8].
General
Morning stiffness is a prominent feature of rheumatoid arthritis. Unlike the brief stiffness (5 to 10 minutes) that occurs in patients with osteoarthritis, the morning stiffness in rheumatoid arthritis may last for hours. Fatigue and generalized malaise are also common complaints.
Joint
Patients present with joint pain and swelling as well as loss of joint function, which may be due to joint inflammation or structural damage from cartilage destruction and bone erosion. A Baker cyst can develop and cause pain or swelling of the popliteal fossa. If the cyst ruptures, it may cause pain, swelling, and erythema of the calf. If the cricoarytenoid joint is involved, patients may complain of laryngeal pain, hoarseness, or difficulty in swallowing.
Eye
Up to one third of patients will complain of dry eyes (keratoconjunctivitis sicca). These patients may also complain of foreign body sensation, burning, or discharge. Patients with episcleritis will complain of red, painful eyes.
Skin
Patients may note small, painless subcutaneous nodules, mainly over the extensor surfaces. Rheumatoid vasculitis will cause a rash that may lead to ulceration. Patients with vasculitis may also complain of discoloration around the fingertips (digital infarcts).
Neurologic
Numbness and tingling are common symptoms of nerve involvement. Nerve entrapment may result from joint inflammation. The most common site is at the wrist, where median nerve involvement may cause carpal tunnel symptoms. Mononeuritis multiplex is the result of vasculitis and is manifested as weakness, numbness, or tingling in discrete nerve distributions (e.g., femoral, peroneal, or radial nerve, causing proximal leg weakness, footdrop, or wristdrop). Cervical spine instability may lead to myelopathy, causing sensory symptoms and weakness, most commonly in the upper extremities. This can occur in the absence of neck pain in patients with long-standing rheumatoid arthritis.
Cardiac
The incidence and prevalence of coronary artery disease are increased in any type of chronic inflammatory disorder, and this is especially evident in rheumatoid arthritis. Thus patients may present with complaints of chest pain, shortness of breath, diaphoresis, and other symptoms consistent with cardiac ischemia. Prevalence of angina in patients with rheumatoid arthritis may be less because of the relative inactivity. Other cardiac manifestations of rheumatoid arthritis include myocarditis, pericarditis, atrioventricular block, and cardiac rheumatoid nodules. Pericardial involvement is usually asymptomatic.
Pulmonary
Pleural inflammation or nodulosis may produce typical symptoms of pleurisy. Shortness of breath may occur secondary to pleural or interstitial disease.
Physical Examination
All joints are examined for swelling, warmth, effusion, range of motion, and deformity. Fingers, feet, wrists, and knees are most commonly involved. The distal interphalangeal joints are usually spared. In rare cases, patients will present with monarthritis (involvement of a single joint). Rheumatoid nodules are present in about 30% of patients and occur over bone prominences, over extensor surfaces, or in juxta-articular regions [6].
In the hands, early rheumatoid arthritis causes fusiform swelling at the proximal interphalangeal joint. Chronic inflammation may lead to subluxation of the metacarpophalangeal joints with ulnar deviation of the fingers. Damage to collateral ligaments at the proximal interphalangeal joints results in the classic boutonnière (proximal interphalangeal joint flexion and distal interphalangeal joint hyperextension) and swan-neck (proximal interphalangeal joint hyperextension and distal interphalangeal joint flexion) deformities (Figs. 151.1 and 151.2).
Symmetric wrist swelling is usually present. Subluxation results from synovitis and weakening of the ligaments and causes prominence of the ulnar styloid.
Inflammation of the synovial tendon sheath (tenosynovitis) may occur in the flexor or extensor tendons of the fingers. Examination reveals that passive motion is greater than active motion. Crepitus is often felt when the examiner’s hands are placed over the tendon sheaths and the fingers are flexed and extended. If the patient has a trigger finger, placement of one finger over the flexor tendon while the affected finger is flexed and extended will allow palpation of a nodule.
Elbow involvement is common. In early disease, inflammation and effusion cause decreased extension. Effusions can be palpated in the para–olecranon groove. In some cases, there may be pressure on the ulnar nerve. With chronic inflammation and erosion of the cartilage between the radius and ulna, loss of elbow extension and flexion occurs. Rheumatoid nodules are often found over the extensor aspect of the proximal ulna. The olecranon bursa may be enlarged and filled with fluid or nodules.
The shoulder may be involved in rheumatoid arthritis. Effusions are best seen on the anterior aspect of the shoulder below the acromion. Evaluation of rotator cuff strength is important because inflammation of the rotator cuff may result in tendinous destruction. The biceps tendon may rupture, causing a bulge in the biceps when it is flexed against resistance.
The cervical spine may have decreased range of motion or pain with range of motion. Patients with suspected cervical instability should have a thorough neurologic examination, checking for upper motor neuron findings. Patients with cord involvement may demonstrate paresthesias, weakness, or pathologic reflexes. Tingling paresthesias descending the thoracolumbar spine on flexion of the cervical spine are called Lhermitte sign.
The hip joint is deep, limiting evaluation for synovitis and effusion. An inflamed hip will cause groin pain on active and passive range of motion. Patients may walk with an antalgic gait, rapidly taking weight off the affected leg, or shorten their stride length. Pain in the hip may also result from trochanteric bursitis. Application of pressure over the lateral hip region reproduces the pain from the trochanteric bursa. Lateral hip pain and lack of groin pain distinguish trochanteric bursitis from joint inflammation. Iliopsoas bursitis may result in an inguinal mass.
The knee is commonly involved in rheumatoid arthritis. Small effusions can be detected by looking for a “bulge” sign. For the performance of this maneuver, the patient should be lying down. With one hand, the clinician makes an upward stroke to depress the medial synovial pouch. A downward stroke on the lateral aspect of the knee will result in a bulge of the medial pouch if a small effusion is present. A ballottable patella (patellar tap) indicates a larger effusion. Baker cyst occurs as an extension of synovial fluid from the joint cavity. The cyst causes fullness in the popliteal fossa that can be seen when the patient is standing with his or her back facing the clinician. Erythema and swelling of the calf may be seen if the Baker cyst has ruptured. Evaluation for hemorrhage below the malleoli of the ankle (the “crescent” sign) can distinguish this from thrombophlebitis.
The ankle may have synovitis, effusion, or decreased range of motion in the patient with rheumatoid arthritis. Involvement of the hindfoot (subtalar and talonavicular joints) may result in valgus deformity and flatfoot. Metatarsophalangeal joint involvement is common. Synovitis causes pain and fullness with palpation. Hallux valgus deformity is also common. Progressive disease causes dorsal dislocation of the metatarsophalangeal joints and claw toes.
Functional Limitations
Functional limitations depend on the location and severity of joint and extra-articular involvement. There may be limitations or pain with upper extremity movements or lower extremity motions, including gait. Criteria for the assessment of functional status have been established (Table 151.2) and are based on activities of daily living, including self-care (e.g., dressing, feeding, bathing, grooming, and toileting) and vocational (e.g., work, school, and homemaking) and avocational (e.g., recreational and leisure) activities [10].
Table 151.2
Criteria for Classification of Functional Status in Rheumatoid Arthritis
Class I | Able to perform all activities of daily living (self-care, vocational, and avocational) |
Class II | Able to perform self-care and vocational activities, but limited in avocational activities |
Class III |