両側視床梗塞による痴呆からakinetic mutismに移行した1症例

A CASE REPORT OF THE INFARCTlON OF THE BILATERAL THALAMUS AND THE MIDBRAIN

　抄録　両側性の視床病変により痴呆を呈する例のあることはよく知られているが，梗塞による視床性痴呆の報告は本邦では未だ少なく，調べえた限りでは2例のみである。うち1例はCT所見のみであり，他の例は罹患動脈がわれわれの例とは異なる。症例は63歳男子。右延髄梗塞に罹患後約7カ月目に昏睡に陥り，1〜2日後に意識レベルが回復した時には極端な寡黙と俳徊，弄便などの異常行動および右動眼神経麻痺を呈した。異常行動はその後次第に鎮静し好褥状態を示すようになり，末期にはakinetic mutismの状態となった。病理学的には両側視床の束旁核，正中中心核および左内髄板を主座とする軟化巣がみられた。本例の臨床症状の経過は両側視床に発生した梗塞巣が呼吸器感染による低酸素血症や脱水のために次第に拡大し，中脳と視床の境界部に伸展してゆく過程に対応したものと考えた。

A 63 years old man was admitted because of coma of 24 hours duration. He had a history of infarction of the medulla oblongata 7 months earlier. On admission he was unconscious and had right oculomotor nerve palsy. To a painful stim-ulus, he responded with only a slight body move-ment. On the CT scan, low density areas were seen in the bilateral thalamus and the midbrain. In the next day he recovered from coma and abnormal behaviors appeared such as wondering in the ward, touching other patient's face and manipulating his stool. Verbal expression was extremely poor. Chlorpromazine was needed to supress abnormal behaviors. Thereafter, abnormal behaviors gradually subsided and by the 23 hospital day he became bedridden even when chlorpromazine was withdrawn. At that time, he said only "yes" or "no" in response to questions and only few spontaneous movements were obser-ved. From the 40 hospital day he suffered from pneumonia and gradually sank into the state of akinetic mutism. He died on the 50 hospital day.

Pathologically, infarctions destroyed the n. parafascicularis, n. centromedianus and the intra-laminar nuclei in the left thalamus, n. parafa-scicularis and a part of n. centromedianus in the right. In the medulla oblongata, right n. ambiguus and reticular formation were destroyed. Both thalamic lesions extended posteriorly to unite with the midbrain lesion.

It was considered that the bilateral thalamic infarctions corresponded to the demential beha-viors in the early phase of the clinical course and gradual posterior extention of the lesion toward the midbrain corresponded to the transition to the state of akinetic mutism.