急性小脳失調症に末梢性顔面神経麻痺が遅発性に続発し水痘・帯状疱疹ウイルス抗体価高値を示した1例

抄録

　A 51-year-old immunocompetent woman presented with slight fever, cough and general fatigue. After 4 days, she developed slight headache, spontaneous rotatory vertigo, nausea and vomiting. Subsequently, she gradually developed unsteadiness of gait. Two weeks after the onset of vertigo, she visited the outpatient clinic of our university hospital. Neurologic examination revealed a wide-based gait, predominantly right-sided upper/lower limb ataxia, and right dysdiadochokinesia. On cranial nerve examination, she was found to have right peripheral facial nerve palsy, which she had not recognized before. She had neither rash nor pain in her auricles. Brain MRI was normal. Laboratory data showed positive results for serum anti-varicella zoster virus (VZV) IgG, but negative results for IgM. The findings of electronystagmography (ENG) were as follows; 1) ataxic nystagmus with irregular amplitudes and frequencies on lateral gaze; 2) eye position of slow-phase nystagmus with a negative exponential time course (decreasing velocity), reflecting an unsustained eye position signal caused by an impaired neural integrator; 3) impaired smooth pursuit; 4) reduced optokinetic nystagmus; 5) impaired caloric nystagmus. These findings suggested disturbances of both the neural integrator and velocity storage systems, in addition to cerebellar (flocculus, paraflocculus) dysfunction. As for the pathophysiological mechanisms underlying the disturbances of both the neural integrators, we suspected VZV involvement of the peripheral vestibular nerve, in addition to right peripheral facial nerve involvement, rather than lesions of the brainstem (MVN, NPH). Cerebellitis associated with VZV is very rare in adults. Furthermore, it would be emphasized that it is very rare for peripheral facial palsy to be followed by cerebellitis two weeks later in cases of VZV involvement.