Photoclinic: Gouty Tophus

A 70-year-old man sought medical attention for a white lesion with surrounding erythema on the thumb of his right hand. The lesion had been present for many years and had recently become inflamed and painful. He had no other symptoms. No other areas were affected. His medical history was unremarkable, and he was not taking any medications. The lesion was lanced, and the fluid removed was examined under polarized light microscopy. Analysis revealed negatively birefringent urate crystals, which confirmed the diagnosis of gout. Results of blood tests showed a serum uric acid level of 8.5 mg/dL (normal, 3.5 to 7.2 mg/dL).  Doug Davenport and Samuel G. Poser, MD, of Columbus, Wis, write that primary gout results from a disorder of purine metabolism and/or excretion. The typical presentation is an intense articular inflammation caused by the precipitation of intracellular monosodium urate crystals in synovial fluid. Classically, patients have monarthritis (about 70%); occasionally, polyarthritis is seen. Rarely, nonarticulation sites are involved. This patient was successfully treated with oral colchicine. Certain lifestyle modifications (avoidance of high-purine foods and alcohol in excessive amounts) were suggested. He has had no further thumb discomfort. In some patients, long-term therapy with a serum uric acid–lowering agent, such as probenecid or allopurinol, may be required. NSAIDs (such as indomethacin) and corticosteroids (such as prednisone) can be used in acute settings.