Alkaptonuric ochronosis: a case report

Alkaptonuric ochronosis is a rare autosomal recessive metabolic disorder resulting in a deficiency of homogentisic acid oxidase (alkaptonuria). Ultimately, this enzyme deficiency enables homogentisic acid to accumulate, become polymerized, and be systemically deposited within various tissues of the body (ochronosis). As the disease progresses, tissue deposition of polymerized homogentisic acid eventually will lead to the progressive degeneration of all affected body systems. There is no definitive cure for alkaptonuric ochronosis, and treatment is aimed at controlling and ameliorating symptoms. Multiple systemic complications occur as a result of alkaptonuric ochronosis. In the skeletal system, cervical, thoracic and lumbosacral degenerative disk disease develops, as do widespread arthritic changes in peripheral and weight-bearing joints. In the respiratory system, dyspnea can develop owing to limited chest excursion as a result of stiffening of cartilage in the chest wall. In the cardiovascular system, coronary and valvular calcification frequently occurs. In the genitourinary system, calculi formation and urine discoloration are chief manifestations. This case report describes a 63-year-old man with alkaptonuric ochronosis who sustained a stress fracture of the left femoral neck, necessitating surgical repair, which was done without complications. An overview of alkaptonuric ochronosis is presented, and anesthetic implications are discussed.