Isolated Oculomotor Nerve Palsy in a Young Adult: An Unexpected Diagnosis of HIV.

Neurological manifestations of human immunodeficiency virus (HIV) infection are diverse and may occasionally present in the initial manifestation of the disease. Isolated cranial nerve palsies are uncommon and can pose a diagnostic challenge, particularly in young adults without known immunodeficiency. We report the case of a 31-year-old man who presented with headache, left eyelid ptosis, and binocular diplopia. Examination revealed an isolated left oculomotor nerve palsy with pupillary involvement. Neuroimaging excluded compressive and vascular causes, and cerebrospinal fluid (CSF) analysis demonstrated an inflammatory profile. An extensive diagnostic workup was otherwise negative, and further evaluation revealed previously undiagnosed early-stage HIV infection. Antiretroviral therapy was initiated, leading to complete neurological recovery at three-month follow-up. This case highlights that isolated oculomotor nerve palsy may represent an early neurological manifestation of HIV infection and underscores the importance of considering HIV testing in unexplained cranial nerve palsies.