A Review of Rheumatoid Arthritis for the Physician Assistant Exam
The Physician Assistant Exam (PANCE) will expect you to know the different forms of Rheumatoid arthritis (RA). RA is an autoimmune, symmetric polyarticular arthritis that can be severely debilitating — it affects similar joints on both sides of the body.
Rheumatoid arthritis and osteoarthritis are both very common causes of arthritis, although rheumatoid arthritis occurs more often in women than men. When teenagers develop rheumatoid arthritis, they’re diagnosed with juvenile rheumatoid arthritis (JRA).
Rheumatoid arthritis explanation
For testing-taking purposes, you should know some of the diagnostic criteria for rheumatoid arthritis as well as the options for treatment. Diagnostic criteria include the following:
Morning stiffness in the joints, lasting for at least an hour. The time course is important.
The arthritis should be bilateral and symmetrical and affect more than two joints at any one time for more than 6 weeks. Examples can include the metacarpophalangeal joints (MCP) and proximal interphalangeal joints (PIP). The joints are usually swollen and tender.
The test may ask you to differentiate between rheumatoid arthritis and osteoarthritis. Remember that rheumatoid arthritis affects the MCP and PIP but doesn’t usually affect the distal interphalangeal joints (DIP).
Positive lab tests include the anticyclic citrullinated peptide (anti-CCP), which is specific for rheumatoid arthritis. Note that rheumatoid factor, which is commonly ordered in someone suspected of having rheumatoid arthritis, can be negative more than 50 percent of the time.
Classic radiographic findings in someone with rheumatoid arthritis show an erosive arthritis, joint space narrowing, and joint destruction, usually in hand and wrist areas.
People with Caplan’s syndrome have both rheumatoid arthritis and pneumoconiosis. In Caplan’s syndrome, nodules are in the lung. Patients with rheumatoid arthritis can also have rheumatoid nodules, which occur under the skin. Rheumatoid nodules are another diagnostic criterion for rheumatoid arthritis. In addition, boutonniere deformities (flexion of the PIP with DIP hyperextension) as well as swan neck deformities are also found in inflammatory conditions like rheumatoid arthritis.
Treating rheumatoid arthritis involves disease-modifying antirheumatic drugs (DMARDs). Start such medications early, because rheumatoid arthritis is an erosive, inflammatory arthritis that can destroy the joints. Here are the key points about medicines for rheumatoid arthritis:
Prednisone can be given either orally or directly into the joint space. Be wary of prednisone’s numerous major side effects — it has over 25 of them. Big-time side effects include osteoporosis, hyperglycemia, gastritis, psychosis, and avascular necrosis.
Hydroxychloroquine (Plaquenil) is used in mild cases of rheumatoid arthritis. Anyone taking this med needs to have routine ophthalmologic examinations, because it can cause macular degeneration. This drug can also be used to treat mild forms of lupus.
Methotrexate (Rheumatrex) is a very commonly prescribed medication for treating rheumatoid arthritis. It’s an example of an immunosuppressive medication. Methotrexate can cause anemia and can affect liver and kidney function, so follow patients closely with complete blood count, kidney, and liver function tests.
Methotrexate can cause folate deficiency, so a patient who’s taking methotrexate needs folic acid (also known as vitamin B9) replacement.
A class of medications called the biologics, including etanercept (Enbrel) and adalimumab (Humira), are used for severe rheumatoid arthritis. Etanercept works by inhibiting tumor necrosis factor, a potent pro-inflammatory cytokine.
Still’s disease: Juvenile rheumatoid arthritis (JRA)
Juvenile rheumatoid arthritis (JRA, also known as juvenile idiopathic arthritis, or JIA) is the same as Still’s disease. It’s an autoimmune condition that can affect teenagers, with males more affected than females. A quatrad (four things) is associated with Still’s disease:
Joint pain and swelling
Rash on the chest, abdomen, and both upper and lower extremities
You may also see lymphadenopathy and hepatosplenomegaly on physical examination, in addition to an inflamed and generalized rash.
Labs can demonstrate a positive antinuclear antibody (ANA) and positive rheumatoid factor (RF). The rheumatoid factor may not be positive all the time, so a negative rheumatoid factor doesn’t exclude a diagnosis of JRA.
Treatments for juvenile rheumatoid arthritis include steroids, methotrexate (Rheumatrex), and the other disease-modifying antirheumatic drugs. Close follow-up with an eye doctor is also recommended.