Osteoarticular complications in bismuth encephalopathy.

The authors have observed 59 cases of bismuth encephalopathy between 1972 and 1979. Eight female patients in this group showed osteoarticular lesions confined exclusively to the thoracic vertebrae and the humerus. These lesions included six cases with fractures of the surgical neck of the humerus, bilateral in two patients, three cases with spine fracture, and osteonecrosis of the humeral head in five cases. These lesions were seen predominantly in the severe and chronic myoclonic and convulsive forms of the disease. Intraspongy microfractures due to the intense and repeated myoclonia could explain osteonecrosis. It has been suggested that bismuth facilitates the modification of the bony tissue; however, the evidence remains inconclusive as there are few anomalies of phosphocalcic metabolism.