To highlight the neuroanatomical localization of central-type facial nerve palsy in lower brainstem lesions.

A 77-year-old man presented to the emergency room (ER) with a 2-hour history of lightheadedness, blurry vision, and ataxia after defecation. He was adherent to apixaban prescribed for atrial fibrillation. Examination revealed orthostatic hypotension without neurologic deficits. CT head and MRI brain were negative for stroke so patient was discharged home. The following day, he developed dysarthria, diplopia, nausea, numbness and weakness of the left face, and left hemiparesis.  

He presented to the ER two days later with binocular horizontal diplopia, left central-type facial nerve palsy, left hemiparesis, left hemihypesthesia, and ataxia. CTA of head and neck revealed high-grade focal stenosis of proximal basilar artery. Repeat MRI brain showed restricted diffusion in the right ventromedial inferior pons and superior medulla with corresponding T2/FLAIR hyperintensity.  Echocardiography was normal.

His deficits improved and he was discharged home on aspirin and apixaban after four days on admission.

Our patient had an infarction caudal to the right facial nucleus and presented with contralateral central-type facial palsy with other features of inferior medial pontine/superior medial medullary stroke, emphasizing the complexity of the neural pathways that supply facial muscles.

Our report supports the hypothesis of medullary loops of cortico-facial tracts supplying the contralateral lower face, enlightening clinicians faced with the mystery of unexpected central-type facial nerve palsy in patients with caudal brainstem stroke.