高度な味覚障害を呈した中間神経痛の1例

A case of intermediate nerve neuralgia presenting with severe taste disorder

中間神経痛とは，外耳道痛を主症状とし，痛みは頭頂後頭領域に放散し，時に流涙・唾液過多・味覚異常を伴う脳神経ニューロパチーであり，三叉神経痛，舌咽神経痛との鑑別に苦慮するまれな疾患である。今回我々は，右外耳道に発作性電撃痛のほかに味覚障害を強く訴え，3次元magnetic resonance cisternogram/magnetic resonance angiogram fusion image（3D-MRC/MRA）にて，顔面神経―前庭聴神経に対する血管による高度な圧迫を確認，中間神経痛と診断し，微小血管減圧術を行い，外耳道痛，味覚障害の著明な改善を認めた1例を経験したので，中間神経痛における味覚障害の発現機序，診断・治療について検討を加え報告する。

Intermediate nerve neuralgia is a cranial neuropathy characterized by paroxysmal pain in the external auditory canal accompanied by lacrimation, hypersalivation, and dysgeusia. In diagnosis of intermediate nerve neuralgia, the efficacy of three-dimensional magnetic resonance cisternography/magnetic resonance angiography（3D MRC/MRA）fusion imaging was discussed. A 68-year-old woman presented to hospital with complaints of paroxysmal electric shock pain in right external auditory canal, tinnitus, and dysgeusia. 3D-MRC/MRA indicated vascular compression for right facial and vestibulocochlear nerves and we suspected intermediate nerve neuralgia. Microvascular decompression（MVD）was performed and improvment in symptoms was observed immediately. 3D MRC/MRA fusion image can be used for decision making of surgery for intermediate nerve neuralgia.