Isaacs-Mertens症候群を合併するKearns-Sayre症候群の1例

REPORT OF A CASE OF KEARNS-SAYRE SYNDROME ASSOCIATING WITH ISAACS-MERTENS SYNDROME

　抄録　持続性自発性筋放電およびそれに伴う四肢の筋緊張の亢進と母指のtonicな内転内反を呈するKearns-Sayre症候群の1例を報告した。患者は女性で40歳の頃より間歇的に四肢のこわばりを自覚するようになった。46歳の時にKearns-Sayre症候群と診断された。臨床的には全身の筋萎縮および四肢末梢部の筋緊張亢進と母指の強制的内転内反位がみられた。筋電図上では四肢被検筋全てに持続性自発性放電が認められた。この自発性放電は支配神経のブロックにより抑制された。カルバマゼピンの内服により臨床症状および筋電図所見は軽快した。以上より本例はIsaacs-Mertens症候群を合併したKearns-Sayre症候群と考えられた。またF波が頻度，振幅共に増加していることより自発性放電の発生には脊髄の前角細胞や介在細胞のミトコンドリア異常によるエネルギー代謝障害が関与している可能性が考えられた。

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 extremi-ties and so she came to our hospital. At thistime, 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 frosemide. 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 supinate her thumbs. This abnormal hand posture was seen constantly there-after 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 mo-tor 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 con-sidered that the patient was a rare case of Kearns-Sayre syndrome which was complicated by a syn-drome 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.