Gout affecting an 84 year old female patient's big toe. Gout is a disorder of uric acid metabolism by the kidneys. It can result in deposits of monosodium urate crystals in synovial joints and nearby connective tissues. The deposition of crystals causes local inflammatory swellings (tophi) that are extremely painful. Treatment is with anti-inflammatory drugs and changes in diet. This case is a side effect of the diuretic drug furosemide.