The 3rd Cranial Nerve Palsy due to Posterior Communicating Artery Aneurism Mimicking Acute Vestibulopathy (Vestbular Neuritis)

Abstract

We present a 66-year old woman complaining of dizziness and vomiting for the previous three days. Her symptoms were quite similar to vestibular neuritis except for mild headache. Spontaneous nystagmus recording, head shake test, and slow harmonic acceleration results were also similar to vestibular neuritis. But the caloric test was not consistent with the chair test results. During the neurologic examination, ptosis, mydriasis, and the diplopia in the left eye were detected, which was indicative of central organic pathology. Bilateral posterior communicating artery aneurysm that was compressing the left oculomotor nerve was detected by CT angiography. A careful and precise neurologic examination should never be neglected when examining a dizzy patient. It was also noticeable that, acute third nerve palsy may present as intermittent saccades which mimic spontaneous nystagmus in vestibular neuritis. Korean J Otorhinolaryngol-Head Neck Surg 2009;52:784-8 Key WordsZZOculomotor nerve·Aneurysm·Posterior communicating artery aneurysm.