手掌・口症候群を呈した橋梗塞の1剖検例

CHEIRO-ORAL SYNDROME WITH PONTINE INFARCT:REPORT OF A CASE

　抄録　手掌・口症候群をもって発症，十数時間のうちに"Locked-in"syndromeに陥った橋梗塞の1部検例を報告し，橋の虚血性病変による手掌・口症候群の発現機序について考察した。症例は心筋梗塞の既往をもつ41歳男性で，突然のめまいとともに左手掌と左側口唇のしびれ感が出現し，同部位に触覚低下を認めたため入院した。入院時のCTでは異常を認めず，経過観察していたところ，手掌・口症候群出現後十数時間のうちに"Locked-in"syndromeの状態となった。発病後9日目のCTで橋の梗塞巣を確認し，保存的治療を続けていたが，肺炎等の合併症により第58病日に死亡した。剖検の結果，脳底動脈の末梢2／3は器質化した血栓により完全閉塞していた。またこれに伴い，橋底部を主病巣とし一部橋被蓋腹内側部にも達する梗塞巣が認められた。大脳および視床には病変を認めなかった。手掌・口症候群の責任病巣としては，内側毛帯内側部と三叉神経毛帯腹側路が近接する橋被蓋腹内側部が考えられた。特にこの部位は脳底動脈から直接分岐するparamedian branchの灌流域の末梢部にあたり，虚血に陥りやすく，かつ手掌や口唇は感覚閾値が低いため，橋梗塞の初発症状として手掌・口症候群を呈したものと考えられた。

A case of cheiro-oral syndrome presumably due to brain stem infarction was reported. A 41-year-old man suddenly experienced the numbness of the palm and the lips on the left side at 2 p. m. March 30, 1982 and was admitted to our clinic at 5p. m. on that day. Neurological examination on admission revealed hypesthesia of the palm and the lips on the left side, but pain and temperature sensibilities were preserved. Neither astereognosia nor extinction phenomenon was there. CT scan showed no abnormal findings. At 9 p. m. his speak-ing became somewhat obscure and he became unable to swallow fluid. And after ten hours or so, he became quadriplegic, anarthric and lost almost all voluntary movement below the eye, while his consciousness was preserved ("Locked-in" syndrome). CT scan taken on the 9 th hospital day revealed brain stem infarction. He expired on the 58 th hospital day because of the exacerbation of pneumonia.

At autopsy both vertebral arteries and basilar artery were markedly sclerotic. The rostral two-thirds of the basilar artery was occluded by orga-nized thrombus. The serial microscopic sections through the midbrain and the medulla oblongata showed extensive infarction of the basis pontis. The tegmentum pontis remained free, except that a small offshoot of the infarct reached into the medial part of the medial lemniscus. The cere-brum, the thalamus, and the cerebellum were gross-ly normal.

From anatomical viewpoint, the ventral second-ary ascending tract of the trigeminal nerves carry-ing discriminatory tactile sensibility from the face is in the vicinity of the medial part of the medial lemniscus in the ventromedial portion of the pontine tegmentum, and this area is peripheral portion supplied by the paramedian branches of the basilar artery.

In basilar artery thrombosis, it is said that thrombosis begins at small branches such as para-median or short circumferential branches and later extends into the trunk of basilar artery. Therefore it is supposed that at the beginning of his disease the ventromedial portion of the pontine tegmen-tum of the right side became first ischemic, which was manifested symptomatically by numbness of the palm and the lips on the left side. It is sug-gested that cheiro-oral syndrome might be ascrib-ed to brain stem lesion besides cerebral or thalamic one, and that this syndrome could be a warning sign of thrombosis of the basilar artery.