Abstract
Rheumatoid arthritis (RA) is a chronic, autoimmune, inflammatory arthritis that usually affects the small joints of the hands and feet in a symmetric distribution. Without treatment, RA can cause erosive joint damage and deformity that leads to significant morbidity and disability. In addition to the arthritis, RA is a systemic disease that can involve multiple organ systems, including the skin, lungs, and cardiovascular system. Patients typically present with a polyarthritis affecting the small joints of the hands and feet in a roughly symmetrical fashion. Up to 80% of patients will have positive serological diagnostic testing in the form of rheumatoid factor activity and/or anti-cyclic citrullinated protein antibodies. Plain radiography can be helpful in monitoring progression of the disease. Many advanced therapies have been developed over the last two decades that are effective in treating the inflammation of RA and preventing progression of the disease. Physical and occupational therapy are important adjunctive measures to preserve joint function and quality of life in this population. Surgical consultation is sometimes required to correct deformity and improve pain and function. Medical therapy generally requires monitoring to prevent complications from treatment.
Definition
Rheumatoid arthritis (RA) is a chronic, autoimmune, inflammatory arthritis that usually affects the small joints of the hands and feet in a symmetric distribution. Without treatment, RA can cause erosive joint damage and deformity that leads to significant morbidity and disability. In addition to the arthritis, RA is a systemic disease that can involve multiple organ systems, including the skin, lungs, and cardiovascular system. RA affects about 1% of the adults in the United States and Europe, but rates vary in other populations. For example, Nigerian adults have some of the lowest prevalent RA rates (0.1%), while Pima and Chippewa indigenous populations in the US have among the highest rates (5%). The prevalence of RA in any population increases with age. RA occurs more frequently in women and cigarette smokers.
The American College of Rheumatology has developed a set of criteria to classify patients as having RA, most recently revised in 2010 ( Table 152.1 ). These criteria were validated to appropriately classify patients with RA for clinical study, and serve to update the previous 1987 criteria in an attempt to appropriately classify patients with early RA.
| Criterion | Points |
|---|---|
| Arthritis Joint Distribution | |
| 1 large joint | 0 |
| 2–10 large joints | 1 |
| 1–3 small joints (large joints not counted) | 2 |
| 4–10 small joints (large joints not counted) | 3 |
| >10 joints (at least one small joint) | 5 |
| Serology | |
| Negative RF AND negative ACPA | 0 |
| Low positive RF OR low positive ACPA | 2 |
| High positive RF OR high positive ACPA | 3 |
| Symptom Duration | |
| <6 weeks | 0 |
| >6 weeks | 1 |
| Acute Phase Reactants | |
| Normal CRP AND normal ESR | 0 |
| Abnormal CRP OR abnormal ESR | 1 |
Symptoms
Patients with RA generally present with arthralgias and joint swelling of the small joints of the hands, wrists, and feet in a symmetric pattern. Loss of function is a common complaint among patients with RA, particularly activities requiring fine motor movements (e.g., fastening buttons) or grip strength (e.g., opening jars). Warmth and redness around a joint can occur, but these are more common in other arthritis syndromes, such as gout. Morning stiffness is also a common complaint by patients with RA, typically lasting more than one hour. In addition, since RA is a systemic disease, it is common for patients to have extra-articular features associated with their presentation.
Systemic
Patients with RA can present with nonspecific features of malaise and fatigue. Fevers are uncommon but can occur.
Cutaneous
The most common extra-articular feature of RA is the development of subcutaneous nodules, known as rheumatoid nodules, on the extensor surfaces of joints. Rheumatoid vasculitis is a particularly rare, but potentially devastating cutaneous feature of RA. Rheumatoid vasculitis presents with typical vasculitic eruptions, ranging from purpura to ulceration and infarct.
Ophthalmologic
Patients with RA frequently complain of dry eye and dry mouth, known as keratoconjunctivitis sicca. Episcleritis and scleritis also can in occur with patients with RA, which manifests as red, painful eyes.
Pulmonary
Pleuritis and pleural effusions occur in as many as 20% of RA patients, and may occur early in the course of the disease. Interstitial inflammation and fibrosis usually present with cough and dyspnea and can be life-threatening.
Neurologic
Nerve entrapment secondary to inflammation or deformity is common in RA. Carpal tunnel syndrome (median nerve entrapment) is the most common of these, and presents with sensory loss or paresthesias in the median nerve distribution. A potentially devastating neurologic complication in advanced RA is atlanto-occipital instability or subluxation, which can cause symptoms ranging from radicular pain and paresthesias to myelopathy and death. Mononeuritis multiplex can occur in the setting of rheumatoid vasculitis and causes weakness or paresthesias in single or multiple single nerves (e.g., footdrop or wrist drop).
Cardiac
RA is associated with an increased rate of cardiovascular mortality, secondary to coronary artery disease. Thus, patients with RA should be monitored for symptoms that could be consistent with coronary artery disease, such as substernal chest pain, dyspnea, and diaphoresis. Less commonly, myocarditis, pericarditis, and subsequent arrhythmia can occur in RA. Rarely, RA can cause inflammation along valve rings, causing valvular inflammation, and along the conduction system, resulting in heart block or arrhythmia. Conduction abnormalities can present variably, including dyspnea, chest pain, or syncope.
Physical Examination
The clinician will examine all joints for evidence of synovitis, including swelling, tenderness, warmth, or effusion. The metacarpophalangeal (MCP) joints, proximal interphalangeal (PIP) joints, wrists, knees, and ankles are most commonly involved. Importantly, the distal interphalangeal joints are usually not involved in RA. Rarely, patients will present with a monoarticular arthritis.
Early RA generally presents with swelling and tenderness about the involved joints that is synonymous with activity of the disease. More chronic disease might reveal physical exam signs that correlate with damage from the disease.
Early involvement in the fingers will present with fusiform swelling in the wrists, MCPs, and PIPs. Joint involvement is usually symmetric. Chronic inflammation in the hands or wrists may lead to subluxation of the MCP joints or carpal bones. Wrist subluxation is suggested by a prominent ulnar styloid. Ulnar deviation of the fingers is common in advanced disease. Ligamentous damage at the PIPs can cause the classic boutonnière and swan neck deformities. A boutonnière deformity describes PIP joint flexion and DIP joint hyperextension, while a swan neck deformity describes PIP joint hyperextension and DIP joint flexion ( Figs. 152.1 and 152.2 ). The tendon sheaths of the fingers are also common sites of inflammation in RA. If tenosynovitis is present, then crepitus can be felt by the examiner when the fingers of the patient are slowly flexed and extended. Stenosing tenosynovitis (trigger finger) can occur with more prolonged inflammatory involvement of the tendon sheaths.
The elbow can also be involved in RA. Early disease will cause effusion in the elbow joint, which can be palpated by the clinician in the para-olecranon groove, and is usually accompanied by decreased range of motion. Advanced RA will cause inability to fully extend or flex the elbow, even in passive motion.
The shoulders are also possible sites of inflammation in RA. Active RA is suggested by shoulder effusions, which, if present, are usually visible on the anterior aspect of the joint below the acromion. The rotator cuff and biceps tendon are also important for the clinician to evaluate, since tear or rupture might occur as a result of the chronic inflammation.
The knee is commonly affected in RA and should be evaluated for effusions and Baker’s cysts. Large knee effusions are detectable by ballottement of the patella against the femur. Smaller effusions can be detected by evaluation for the “bulge sign.” With the patient comfortably lying down, the clinician “milks” fluid from the medial patellar pouch superiorly, then subsequently “milks” fluid in the lateral pouch inferiorly. The sign is positive (and thus a small effusion is suggested) if a bulge appears in the medial pouch with the lateral downward stroke. A Baker’s cyst is a cyst in the popliteal fossa that communicates with the joint cavity. If present, a fullness can be palpated in the popliteal fossa.
Involvement of the ankle and subtalar joints may reveal decreased range of motion with dorsi- and plantar-flexion or inversion and eversion. Metatarsophalangeal (MTP) joints may be inflamed, in which case compressing the MTP row may reveal tenderness (a positive “MTP squeeze” sign). Baker’s cysts can rupture, causing swelling in the calf and the ecchymotic “crescent” sign around the medial malleoli of the ankle. More advanced disease might cause hallux valgus deformity or claw and hammer toe deformity. Hindfoot valgus deformity and resultant flatfoot deformity can occur with longstanding disease.
The cervical spine should be examined for decreased range of motion, pain with motion, and impingement phenomenon. Patients with advanced and deforming arthritis elsewhere should have a thorough neurologic examination to evaluate for cervical or atlanto-occipital instability, suggested by paresthesias, weakness, occipital pain, or hyperactive reflexes.
Systemic involvement should also be evaluated during the physical exam. The eyes should be assessed for conjunctival or scleral involvement. The lungs should be auscultated for the fine crackles of interstitial lung disease. A thorough skin exam might reveal rheumatoid nodules on the extensor surfaces of joints or bony prominences or other areas of friction such as the Achilles tendon. These are sometimes difficult to distinguish from the tophi of gouty arthritis.
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