Metabolic Disorders  
Gouty Tophus

Gouty Tophus

Description : Gout can occur as either inherited or acquired disease. Primary gout is an inherited error of metabolism that results from either an enzymatic defect in purine synthesis or a defect in the renal excretion of uric acid. Acquired gout occurs secondary to disorders that increase the production of uric acid (e.g., myeloproliferative disorders), or which decrease the excretion of uric acid (e.g., chronic renal failure).

Although the presence of tophi in the auricle without manifestation of articular changes is extremely rare, gouty tophi should be considered as one of the potential causes of nodules of the external ear.

Gouty tophi present as painful, skin-covered nodules occurring most frequently on the helix. On palpation, the nodules are gritty, and yellow crystal-like structures may occasionally be seen through the skin.

Clinically, gout usually presents as a painful, swollen osseous joint (most commonly the metatarsophalangeal joint of the great toe) and serum uric acids are elevated. While diet and uricosuric drug therapy may return the serum uric acid levels to normal, the dissolution of previously deposited urate crystals within the tissue does not frequently occur.

In the later stages of gout, deposits of monosodium urate crystals, called tophi, may occur in the subcutaneous tissue. A solitary white, raised, gouty tophus is present on the helix of this patient. The helix is one of the common sites in which tophi develop.

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