When the patient has no history of gout and is younger than average, concern about a bone tumor is raised. Simply remembering this diagnosis is enough to solve the puzzle, since the usual laboratory and pathological fingings are present and make confirming the diagnosis a simple matter. Gout is an inflammatory arthopathy that occurs as a result of hyperuricemia. It is the most common inflammatory arthritis in men over thirty years old. Hyperuricemia is generally secondary to under-excretion of uric acid.
Uric acid is filtered at the glomerulus and is subject to tubular reabsorption.
Drugs that interfere with tubular handling such as thiazides, cyclosporine, and salicylates can cause a gout crisis. Hyperuricemia is also correlated with obesity, alcohol use, and high protein intake. Gout primarily affects adult men and the peak incidence occurs in the fifth decade. The diagnosis of gout is dependent on the presence of urate cystals in joint fluid and the development of tophi, not the presence of hyperuricemia. The crystals are consumed by neutrophils and then fused with a phagosome in an attempt to digest the crystal.