Isolated Ipsilateral Hemiparesis From a Pyramidal Decussation Infarct: A Rare Case Confirmed by Magnetic Resonance Imaging

A 38-year-old male smoker with chronic hypertension, anxiety secondary to alcohol withdrawal, chronic alcohol use, and a history of noncompliance with prescribed medications presented with 2 weeks of progressive left-sided weakness, numbness, dizziness, and gait instability. He also reported a month-long history of facial drooping that had not been formally evaluated. Brain magnetic resonance imaging revealed a small acute/subacute infarct in the left posterolateral cervicomedullary junction, at the level of the pyramidal decussation, which produced ipsilateral motor and sensory symptoms. This is a rare presentation of a stroke causing purely ipsilateral neurologic deficits and served as an important reminder of neurologic anatomy caudal to the pyramidal decussation.