Diagnosis of gout: clinical, laboratory, and radiologic findings.

Acute gouty arthritis typically presents with a sudden and severe exquisitely painful joint, most classically in the first metatarsophalangeal joint (toe). Demonstrating the presence of monosodium urate (MSU) crystals in the joint fluid or tophus has been the gold standard for the diagnosis of gout. However, many physicians do not perform synovial fluid analysis. In the absence of demonstrating the presence of MSU crystals in aspirated joint fluid or tophus, clinical, radiologic, and laboratory criteria are helpful. This article presents an overview of the various classification criteria, clinical presentations, and laboratory and radiologic studies needed to make the diagnosis of gout.