Gout

A 73-year-old man was admitted to the hospital with pain in his hands, feet, and elbows. The patient, an alcoholic, had a 20-year history of hypertension and diabetes. Deformities of the hands (A) and feet had developed during the past 5 years. Tophi were present over both ear lobes. The serum uric acid level was 15 mg/dL. Gouty arthritis, the result of an inflammatory response to monosodium urate (MSU) crystals that are deposited in the joints, was suspected.

Fluid was aspirated from the patient's right elbow and examined by polarized light microscopy. Multiple needle-shaped crystals with strong negative birefringence were seen. Under polarized light, MSU crystals parallel to the line of slow vibration appear brilliant yellow, whereas those at right angles to the line of slow vibration appear brilliant blue; this establishes the diagnosis of gouty arthritis (B).

Polarized light microscopy of joint fluid confirms the diagnosis; it also differentiates gout from pseudogout, in which calcium pyrophosphate dihydrate (CPPD) crystals are deposited in the joints. CPPD crystals yield a weakly positive birefringent result in this evaluation.

Gout usually affects middle-aged men and commonly is associated with obesity, alcoholism, hypertension, renal impairment, and diuretic use. Relapsing episodes of self-limited severe inflammatory arthritis that involves the metatarsophalangeal joints, ankles, and heels occur in the acute form of gout. Tophus formation and bone and joint destruction are seen in the chronic disease. Figure C, taken of a 60-year-old man with symmetric swelling, erythema, warmth, and tenderness of the metacarpophalangeal and proximal interphalangeal joints, shows typical radiographic findings of erosive tophaceous gout.

NSAIDs and colchicine are used to treat acute attacks; hyperuricemia can be controlled with allopurinol. The patient whose hands are pictured in Figure A responded to colchicine. He is now taking allopurinol and is being followed up as an outpatient.