抗GQ1b抗体陽性の小脳失調を伴わない感染後急性外眼筋麻痺の2症例

Two cases of post-infectious acute ophthalmoparesis without ataxia associated with anti-GQ1b IgG antibodies

　34歳男性と28歳女性が複視で受診した。先行感染は，1例には10日前に上気道感染が，もう1例には8日前に下痢がみられた。2例とも眼瞼下垂と瞳孔異常を伴わない外眼筋不全麻痺があった。小脳失調と腱反射異常はなかった。血糖，血清の乳酸とピルビン酸，甲状腺機能，脳脊髄液は正常範囲であった。脳の磁気共鳴画像（MRI）所見には異常がなかった。両症例とも抗アセチルコリン受容体抗体は陰性であった。血清の抗GQ1blgGが強陽性であり，「抗GQ1b抗体陽性の小脳失調を伴わない感染後急性外眼筋麻痺」と診断した。眼症状は，それぞれ4か月後と50日後に自然寛解した。本疾患は，片眼性のものを含み過去に46例の報告があり，Fisher症候群の不全型ないしGuillain-Barré症候群の亜型であると考えられている。

A 34-year-old man and a 28-year-old woman resented with diplopia. One case had upper respi-ratory infection 10 days before and the other had diarrhea 8 days before. Both cases showed bilateral paresis of extraocular muscles without blepharoptosis or pupillary abnormalities. Both had no cerebellar ataxia with preserved tendon reflexes. Their blood sugar, serum lactate and pyruvate, thyroid functions, and cerebrospi-nal fluid were within normal ranges. Magnetic resonance imaging (MRI) of the brain showed normal findings in both. Both were negative for anti-acetylcholine receptor. Serum anti-GQ1b IgG antibodies were strongly positive, leading to the diagnosis of “post-infectious acute ophthalmoparesis without ataxia assosiated with anti-GQ1b IgG antibody”. The ocular lesions spotaneously resolved after 4 months in one and 50 days in the other. There are 46 cases of this disease in literature, including cases of unilateral ocular involvement. It is considerd to be an abortive type of Fisher syndrome or a variant of Guillain-Barre syndrome.