IS Case 174: Gout
Imaging Sciences URMC 2008
Publication Date: 2009-05-21
Patient is an 88-year-old male with joint pain.
Classic radiographic findings consistent with gout.
Gout is a common disease caused by hyperuricemia resulting in sodium urate crystal deposition in soft tissues and joints. Hyperuricemia can be caused by overproduction or undersecretion. Overproduction may result from primary causes, mainly enzyme defects in purine synthesis, or from secondary causes such as myelo/lymphoproliferative diseases, hemoglobinopathies, chemotherapy, or alcohol/other drugs. Undersecretion may be primary (idiopathic) from reduced renal excretion of unknown etiology, or secondary from chronic kidney disease, alcohol/drugs, or endocrine disorders. Gout usually affects those from 30-60 years of age, men twenty times more than women, and is most common amongst pacific islanders, less common in Caucasians and African Americans.
Radiographic features include bulky juxtaarticular soft tissue tophi. Calcifications can be seen within tophi 50% of the time. Well marginated sclerotic paraarticular erosions with overhanging edges and preserved joint space are classic radiographic bone findings with gout. The erosions and tophi occur with longstanding disease. Bursitis is common and chondrocalcinosis can also be seen. Any joint may be affected but the most frequent site is the first metatarsal phalangeal joint which results in podagra. Lower extremity joints are affected more than upper extremity joints and small joints more so than big joints.
Diagnosis is made by joint aspiration where negatively birefringent urate crystals can be seen. The synovial fluid shows an inflammatory process with WBC count ranging from 7,000-10,000 x 103 per mL. Urate crystal deposition can also be seen in cartilage and other surrounding tissues. Gout is treated with NSAIDS, primarily indomethacin. Probenicid, colchicine, corticosteroids, and allopurinol are also used. Prevention in gouty attacks relies in avoiding a purine rich diet and alcohol.
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