What is the primary mechanism causing the buildup of uric acid in gout?

The primary mechanism causing the buildup of uric acid in gout is underexcretion of uric acid by the kidneys. This condition leads to hyperuricemia, where serum uric acid levels become elevated due to the kidneys' inability to adequately excrete uric acid. Although gout can be associated with uric acid overproduction in some cases, the majority of patients with gout actually experience underexcretion.

When the kidneys do not eliminate uric acid effectively, the excess uric acid can crystallize and deposit in joint spaces, leading to the acute inflammatory attacks characteristic of gout. This crystallization triggers an inflammatory response, resulting in pain and swelling, particularly in the big toe and other joints.

Dietary factors and genetic predisposition can influence uric acid levels, but they are not the primary mechanisms in the majority of gout cases. Increased dietary intake of purine-rich foods contributes to uric acid levels but does not typically lead to gout on its own unless the kidneys are already struggling to excrete uric acid. Genetic predisposition can play a role in kidney function and uric acid metabolism, but underexcretion remains the central reason for the disease's manifestation.