片麻痺で発症し重症化した脳底動脈血栓症—Herald hemiparesisの2例

The Early Hemiparesis of Stroke in Evolution of Basilar Artery : Case Report

　脳底動脈のstroke in evolutionが片麻痺で発症することがあるとの認識は，抗凝固療法の開始を判断するのに重要である。Fisherはこの片麻痺をherald hemiparesisと呼び臨床的注意を喚起している。我々は，71歳と76歳の2例を報告した。症例1はヘパリンを使用したがlocked-in状態に陥り，症例2は抗凝固療法を開始することなく急速に昏睡となり不幸な転帰をとった。両例とも片麻痺とともに強い構音障害を認め，1例では脳幹局在徴候の出現と前後して非麻痺側の下肢にミオクローヌス様の不随意運動が認められた。Herald hemiparesisの早期診断はしばしば困難であるが，高度の構音障害とミオクローヌスの出現は特徴的で診断的意義を有すると考えられる。

In basilar artery thrombosis, hemiparesis without obvious brainstem signs may precede the tetra-plegia with coma or a locked-in state. This premoni-tory hemiparesis was called as "herald hemiparesis" by Fisher (1988). Its early detection is important because immediate anticoagulant therapy may pre-vent its evolution. We reported two patients with such hemiparesis. The first case was a 71-year-old diabetic and hypertensive man who was admitted because of right hemiparesis, dysarthria and de-creased spontaneous speech. Initially, his symptoms looked like those of a left cerebral lesion. CT scans revealed no fresh cerebrovascular lesion. A few hours later, a myoclonic movement appered in his left lower limb, and right MLF syndrome developed. We thought he had basilar artery thrombosis and we started intravenous administration of heparin. But he developed tetraplegia with locked-in state.The second case was a 76-year-old diabetic and hypertensive man with a confusional state, right hemiparesis, dysarthria and conjugate gaze devia-tion to left. After admission, he rapidly became comatose and developed respiratory arrest. CT scans revealed low density areas in the brainstem, cerebellum and the occipital lobe. He died ten days later.

Early detection of herald hemiparesis is by no means easy. However, severe dysarthria and myo-clonic jerks in a patient with hemiparesis should be considered as warning signs to indicate the herald hemiparesis with subsequent severe brainstem infarction.