Ease Into Prep with a USMLE^® Step 2 CK Question of the Day

The correct answer is B. The patient described has typical symptoms of osteoarthritis, including morning stiffness that resolves, worsening pain with activity, and no evidence of swelling or inflammation. Physical examination findings in osteoarthritis include tenderness to palpation of involved joints without signs of inflammation, joint effusions, crepitus, and osteophytes palpable as bony enlargements along the lateral edge of the joint. Osteoarthritis of the hands manifests with Heberden and Bouchard nodes. Heberden nodes are bony swellings on the distal interphalangeal joints (DIP) and Bouchard nodes are bony growths on the proximal interphalangeal joints (PIP). Osteoarthritis commonly involves the hands, feet, knees, hips, spine, and shoulders. X-ray films of joints with osteoarthritis show joint space narrowing, subchondral sclerosis and cysts, and osteophytes.

Gout (choice A) is a peripheral arthritis that results from the deposition of sodium urate crystals in one or more joints. There is usually a spontaneous onset of pain and inflammation (swelling and redness) with gout. The most common joint involved is the metatarsal-phalangeal joint of the great toe (podagra). Other common sites of gouty arthritis are the ankle, wrist, and knee.

Psoriatic arthritis (choice C) is incorrect. The patient's past medical history for psoriasis does not mean she suffers from psoriatic arthritis. Only 5% of patients who have psoriasis develop psoriatic arthritis, which presents with swelling, redness, and more than 30 minutes of morning stiffness. DIP joint involvement and nail pitting is classic.

Reactive arthritis (choice D), formerly known as Reiter syndrome, usually presents with a history of GI or genitourinary infection, most commonly after Campylobacter jejuni or Chlamydia trachomatis. The classic triad is urethritis, conjunctivitis, and arthritis.

Rheumatoid arthritis (choice E) is also an inflammatory arthritis associated with swelling and redness, morning stiffness lasting longer than 30 minutes, and joint pain that gets better with activity. It usually involves the PIP, MCP, and wrist joints. There may also be constitutional symptoms. An x-ray film may show bony erosions, cysts, osteopenia, joint space swelling, calcifications, and narrowed joint space.