Vernet Syndrome by Varicella-Zoster Virus
32-year-old man with left shoulder weakness was consulted to our department for an electrodiagnostic study. This patient had been admitted to the department of otolaryngology in our hospital due to sore throat, left earache, hoarseness, and swallowing difficulty, which developed three weeks before the study. On admission, vesicular rashes on the patient's left ear were detected (). Speech audiometry, the stapedial reflex test, tympanometry, the auditory brainstem response threshold test, and the pure tone test were all normal. Laryngoscopy showed that his left vocal cord was hypomobile (). On neurological examination, he showed impaired gag reflex on the left side and deviation of the uvula to the right side (). There was no impairment of facial sensation and motion, no tongue deviation or nystagmus. He had no particular underlying disease. Records revealed that twenty years ago, the patient had tympanoplasty in his left ear due to injury by trauma.\nSerological tests showed negative results for herpes simplex virus immunoglobulin M, and positive results for herpes simplex virus immunoglobulin G, and varicella-zoster virus immunoglobulin G and M. These findings were consistent with acute varicella-zoster virus infection. Magnetic resonance imaging (MRI) of the temporal bone revealed no nodular lesions in the left jugular foramen, and there was no evidence of a brainstem lesion (). A computed tomography scan of the neck revealed asymmetry of the jugular foramina, and there was no evidence of upper respiratory infection ().\nOn the day of the electrodiagnostic study, atrophy of the left trapezius muscle was observed. The left scapula was displaced more laterally, compared to the right one, and an inferior angle of the left scapula was rotated internally. The winged scapula became more prominent with shoulder flexion, and manual muscle tests showed decreased muscular strength of Medical Research Council (MRC) grade 3 in left shoulder abduction and MRC grade 4 in left shoulder flexion. There was no limitation in the active or passive range of motion of the left shoulder, and there was no impairment of sensation in the neck and both upper extremities. Moreover, deep tendon reflexes of the upper extremities were normal.\nDuring the motor nerve conduction study, amplitudes of compound muscle action potentials in the left spinal accessory nerve recorded from the left upper and mid trapezius muscles were absent. The amplitude of compound muscle action potential recorded from the lower trapezius muscles decreased to 0.4 mV on the left side compared to 2.8 mV on the right side. The distal latency of compound muscle action potential recorded from the lower trapezius muscles was delayed by 6.55 ms on the left side compared to 4.75 ms on the right side ().\nNeedle electromyography showed increased insertional activities in the left sternocleidomastoideus, abnormal spontaneous activities at rest and reduced interferential patterns on maximal volition in the left trapezius muscles. However, there were no abnormal spontaneous activities at rest in the muscles of the tongue, face, cervical spine, and left upper extremity. Based on these findings, the patient was diagnosed with Vernet syndrome, involving the left ninth, tenth, and eleventh cranial nerves, attributable to varicella-zoster virus.\nAcyclovir, an antiviral drug, was administered intravenously with a dose of 250 mg, three times a day, for five days. The patient was then orally given 250 mg of famciclovir, three times a day, for the next four days. He also underwent physical therapy at an outpatient clinic. After three months, the left earache (otalgia) and shoulder pain subsided. According to the follow-up manual muscle test (MRC), the left upper extremity showed a marked improvement-left shoulder abduction grade 4 and left shoulder flexion grade 5.