ACP American College of Physicians - Internal Medicine - Doctors for Adults

A 45-year-old woman is evaluated in the office for a 3-month history of pain, stiffness, and swelling of the small joints of the hands and feet. She also has increasing fatigue that has caused her to miss work at least 1 day per week. She has no other medical problems.

On physical examination, the vital signs and general physical examination, including skin examination, are normal. A photograph of one of her hands is shown.

Complete blood count, serum chemistries, and urinalysis are all normal. Erythrocyte sedimentation rate is 44 mm/h.

This patient has symptoms and signs consistent with rheumatoid arthritis. Different joints are variably affected by different disorders. Rheumatoid arthritis and osteoarthritis can both involve the proximal interphalangeal joints of the hands, but metacarpophalangeal joint involvement occurs in rheumatoid arthritis but not typically in osteoarthritis. Distal interphalangeal joint involvement is characteristic of osteoarthritis but not rheumatoid arthritis. Unless a secondary condition, such as trauma, metabolic disorder, or inflammatory arthritis, has already affected the joint, osteoarthritis does not occur in the metacarpophalangeal, wrist, elbow, shoulder, and ankle joints. This patient has erythema and swelling of the metacarpophalangeal joints and loss of function leading to absenteeism from work; these findings are most consistent with rheumatoid arthritis.

Psoriasis is associated with an underlying inflammatory arthritis in up to 30% of patients with skin disease; nail pitting suggests psoriatic arthritis, even in the absence of psoriatic skin lesions. These changes are not present in this patient.

More than 90% of patients with SLE develop joint involvement that can manifest as arthralgia or true arthritis. Joint pain is often migratory and can be oligoarticular or polyarticular and asymmetric or symmetric. Pain typically involves the large and small joints; the wrists and metacarpophalangeal and proximal interphalangeal joints in particular are most commonly affected. The absence of other manifestations of SLE (serositis, cytopenias, kidney disease, rash, photosensitivity) make this diagnosis unlikely.

Key Point

• Rheumatoid arthritis and osteoarthritis can both involve the proximal interphalangeal joints of the hands, but metacarpophalangeal joint involvement occurs in rheumatoid arthritis and not osteoarthritis.