Neuroimaging for Isolated Sixth Nerve Cranial Neuropathy

Abstract

An acute neurologically isolated sixth nerve palsy in an adult over age 50 with vasculopathic risk factors is most commonly due to microvascular ischemia. Traditionally, clinical recommendation has been to defer immediate neuroimaging in favor of “watchful waiting” anticipating spontaneous recovery of the ocular motor palsy, as imaging is usually unrevealing. However, this approach may result in a missed or delayed diagnosis of an alternative, potentially (or perceived) life threatening or treatable cause of sixth nerve palsy, such as a space occupying mass or infarction. This chapter reviews the causes of isolated sixth nerve palsy, current guidelines for diagnostic evaluation, and the studies on the yield of neuroimaging for this condition.