運動障害を伴う孤発性三叉神経症を呈した橋被蓋部梗塞の1例

Isolated Trigeminal Neuropathy Involved with Motor Dysfunction due to Small Infarction in the Pontine Tegmentum

はじめに

　三叉神経障害を生じ得る脳幹梗塞の多くはroot entry zone近傍であり，橋被蓋部の梗塞によるものは少ない^1－10）。さらに，孤発性三叉神経障害は疼痛，感覚障害を生じるが，三叉神経運動核の障害を伴った孤発性三叉神経障害の報告は過去に1例のみである^4）。今回われわれは橋被蓋の微小な梗塞による三叉神経運動核の障害によると考えられる明らかな片側開口障害を生じた例を経験したので，脳幹病変による三叉神経障害について文献的考察を加え報告する。

Abstract

　We present a case of isolated trigeminal neuropathy involved with motor dysfunction due to a small infarction in the pontine tegmentum.　A 70-year-old man presented with sudden numbness around the left mouth accompanied by maxillary pain.　Neurological examinations revealed jaw deviation to the left when opening the mouth, but no other abnormal findings including those of the cranial nerves were detected.　X-rays indicated hypomobility of the left temporomandibular joint, and diffusion-weighted magnetic resonance imaging (MRI) revealed a small infarction in the left pontine tegmentum.　Unilateral limitation of the temporomandibular joint movement, numbness, and pain in the territory of the left trigeminal nerve resolved within 2 months.　This case suggests that a small infarction in the pontine tegmentum can simultaneously cause trigeminal neuralgia and masticatory muscle weakness with no other symptoms and signs.　MRI, especially diffusion-weighted imaging, should be considered for patients with isolated trigeminal neuropathy.

(Received: December 22,2009,Accepted: March 23,2010)