| Tophus | |
|---|---|
| Classification and external resources | |
A tophus on the elbow of a middle aged man with chronic gout. |
|
| ICD-9 | 274.0 |
| DiseasesDB | 29389 |
A tophus (Latin: "stone", plural tophi) is a deposit of monosodium urate crystals in people with longstanding high levels of uric acid in the blood. Tophi are pathognomonic for the disease gout. Most people with tophi have had previous attacks of acute arthritis, eventually leading to the formation of tophi.
Tophi form in the joints, cartilage, bones, and other places throughout the body. Sometimes, tophi break through the skin and appear as white or yellowish-white, chalky nodules. Without treatment, tophi may develop on average about ten years after the onset of gout, although their first appearance can range from three to forty-two years. They are more apt to appear early in the course of the disease in people who are older in age. In the elderly population, women appear to be at higher risk for tophi than men.
Although less common, tophi can also form in the kidneys and nasal cartilage.