Gout (monosodium urate crystal deposition disease) is a metabolic disorder with recurrent episodes of arthritis which are asymmetric, polyarticular, and affect primarily the lower extremity, and to a lesser extent, hands, wrists and elbows. Men are affected far more frequently than women.

Clinical diagnosis is made from the demonstration of monosodium urate crystals (needle-shaped, negative birefringent), which evoke an acute inflammatory response in skin, subcutaneous tissues and joints. Gout is associated with uric acid overproduction or underexcretion (most common), and is seen in many clinical entities including chronic renal disease, myeloproliferative and hemolytic disorders, thiazide diuretic or alcohol use.

Radiographic features occur late in disease, and include: erosion of intra- or periarticular erosions of bone (often with overhanging edges), preservation of joint space width, periarticular swelling, lack of osteoporosis, and tophi. Secondary osteoarthritic alterations in gouty joints are common, and may obscure disease.

The first metatarsophalangeal joint of the great toe is most commonly affected (“Podogra”), with frequent erosions on medial and dorsal aspects of first metatarsal head, and at tarsometatarsal and intertarsal joints. In chronic tophaceous gout, periarticular monosodium urate deposits create a tophus, a dense mass in soft tissues, that rarely exhibits calcification.