[Report of a case of Kearns-Sayre syndrome associating with Isaacs-Mertens syndrome].

The patient is a woman who was born in 1936. Her father died of a valvular heart disease and her mother died of apoplexy. She was healthy until 1976 when she noticed stiffness of extremities and so she came to our hospital. At this time, her symptoms disappeared without any specific therapy. In 1979, she entered this hospital because of generalized edema. She was diagnosed as heart failure and treated effectively with frusemide. In 1982, stiffness and gait disturbance aggravated and entered the hospital. At this hospitalization, she was diagnosed as Kearns-Sayre syndrome. After the discharge, she was followed periodically. In May 1983, it was found that she could not abduct and spinate her thumbs. This abnormal hand posture was seen constantly thereafter although the severity of it varied. In April 1985, she was admitted to this hospital because of vomiting and the aggravation of the stiffness. EMG study disclosed spontaneous continuous motor unit discharges. F wave was exaggerated in both frequency and amplitude. The spontaneous activity of the thenar muscle was reduced by blocking the median nerve at the wrist. The patient was administered 250 mg of carbamazepine. Abnormalities of hand posture and EMG were markedly ameliorated by the regimen. We considered that the patient was a rare case of Kearns-Sayre syndrome which was complicated by a syndrome of continuous muscle fiber activity (Isaacs-Mertens syndrome). We speculated that disorders of energy metabolism of motor neurons and inter neurons in the spinal cord might causally relate to spontaneous neuronal discharges.(ABSTRACT TRUNCATED AT 250 WORDS)