Diplopia and Ataxia in a Heavy Smoker

A64-year-oldmanwith coronary artery disease and an 80 pack-year smoking habit presented with 2 weeks of gait instability leading to frequent falls and 8weeks of vertigo and double vision. He reported unintentional weight loss without fevers or decreased appetite. He denied any history of alcohol abuse. Medications includedmetoprolol and aspirin.Onexamination, he was alert and oriented and vital signs were normal; body mass index was 24. Neurologic examination revealed right eyeheterotropia andnasal upshoot indicative of a fourth cranial nerve palsy (Figure 1A), left ptosis, flatteningof the rightnasolabial fold (Figure 1B), andbilateral restrictedupgazeandataxia (Video). Strengthand reflexeswerepreserved.Results of abasicmetabolic panel andcomplete blood cell count were normal. Screening for human immunodeficiency virus, Lyme disease, anddrugusewasnegative. Contrast-enhancedmagnetic resonance imaging (MRI) of the brain was unremarkable. Cerebrospinal fluid (CSF) sampling revealed elevated protein (75 mg/dL [reference range, 10-42]), lymphocyte predominant pleocytosis (21-66 cells/uL [reference range, 0-11]), and oligoclonal bands (OCBs). Pleural thickening was seen on routine chest radiography; chest computed tomography (CT) revealedmediastinal lymphadenopathy, subcentimeterpulmonarynodules, andcalcifiedpleural plaques. Video at jama.com