Garcin症候群様の一側脳神経麻痺を呈した脳幹脳炎の1例

Unilateral Multiple Cranial Nerve Palsies Mimicking Garcin Syndrome as an Atypical Symptom of Brainstem Encephalitis:A Case Report

要旨　亜急性の一側性の多発性脳神経麻痺を呈した56歳の男性を経験した。左側顔面のしびれおよび左側咽頭麻痺による嚥下障害で発症し，経過中に左側の前庭神経麻痺，眼球運動障害，右側眼球内転障害および軽度の意識障害の出現をみた。血液，髄液，頭部MRIなどの諸検査はすべて正常であった。ステロイドパルス療法およびガンマグロブリン大量療法は奏効しなかったが，約3カ月の経過で自然軽快した。意識障害が認められた点やblink reflexの所見から，古典的Bickerstaff型脳幹脳炎を疑ったが，Garcin症候群類似の一側性多発神経麻痺を呈した経過は特異であり，その病態には液性免疫以外の機序も関与している可能性が考えられた。

We report a 56-year-old Japanese man who was admitted because of dysphagia and left side facial dysesthesia. On admission, his general conditions were unremarkable. Neurological examination revealed that he was alert and well oriented. He exhibited left-side cranial nerve involvement such as the trigeminal（sensory and motor）, glossopharyngeal and potential vagal nerve palsy. He exhibited neither long-tract signs, such as motor weakness, sensory disturbance in his extremities and pathological reflex, nor ataxia. By a few days after admission, his symptoms had worsened. Vertigo and diplopia appeared, and his consciousness level became drowsy. Bilateral third and sixth nerves, left fourth, fifth, eighth, ninth and tenth nerves were involved. Results of laboratory tests and CSF studies were within normal. Results of examination of the skull base X-ray and MRIs of the brain were normal. Administration of corticosteroid and intravenous administration of a high dose of γ-globulin were not effective. His symptoms gradually recovered three months after admission. Based on clinical symptoms and results of physiological examination, i. e., an involvement of his consciousness and abnormal findings in blink reflex test that suggest involvement of the brainstem, he was diagnosed as having brainstem encephalitis. Although the exact pathophysiological mechanisms were unclear, it is clinically important to note that an atypical brainstem encephalitis may present a subacute progressive appearance of unilateral multiple cranial nerve palsies mimicking Garcin syndrome.