title: A case of dorsolateral pontine infarct: Description of a new vascular alternating syndrome.
abstract: BACKGROUND
  Inferolateral pontine infarcts are well-described lesions of the anterior inferior cerebellar artery territory with a wide variety of clinical presentations. We report the case of isolated unilateral hearing loss and contralateral sensation of coldness due to a dorsolateral lower pontine infarct.
  
  
  METHODS
  We describe the case of a 48-year-old female patient who developed isolated selective high-frequency hearing loss on the left side, and contralateral hemibody sensation of coldness. MRI showed a left-sided dorsolateral lower pontine ischemic lesion. A subsequent angiogram revealed the lesion to result from the spontaneous dissection of a long circumferential branch of the basilar artery.
  
  
  CONCLUSIONS
  To our knowledge, this is the first reported case of a vascular alternating syndrome consisting of isolated ipsilateral hearing loss and contralateral thermal dysesthesia from a dorsolateral lower pontine infarct. Occlusion of a long perforating branch of the basilar artery and consequent posterolateral lower pontine infarct may result in an alternating syndrome with subtle clinical symptoms. Knowledge of this type of syndrome may direct physicians towards the diagnosis of a dorsolateral lower pontine infarct, despite vague clinical complaints.
authors.affiliation: Department of surgery, division of neurosurgery, hôpital Notre-Dame, centre hospitalier de l'université de Montréal (CHUM), 1560, rue Sherbrooke-Est, H2L 4M1 Montréal, QC, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Obaid
authors.affiliation: Department of surgery, division of neurosurgery, hôpital Notre-Dame, centre hospitalier de l'université de Montréal (CHUM), 1560, rue Sherbrooke-Est, H2L 4M1 Montréal, QC, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Magro
authors.affiliation: Service de neurochirurgie, CHU de la Cavale, l, Tanguy-Prigent, 29200 Brest, France.
authors.forename: R
authors.initials: R
authors.lastname: Seizeur
authors.affiliation: Department of surgery, division of neurosurgery, hôpital Notre-Dame, centre hospitalier de l'université de Montréal (CHUM), 1560, rue Sherbrooke-Est, H2L 4M1 Montréal, QC, Canada. Electronic address: michel.bojanowski.chum@ssss.gouv.qc.ca.
authors.forename: M W
authors.initials: MW
authors.lastname: Bojanowski
mesh_terms: D000784:Aortic Dissection / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D020526:Brain Stem Infarctions / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D002533:Cerebral Angiography / Q000379:methods; D003128:Coma / Q000209:etiology; D004292:Dominance, Cerebral; D004630:Emergencies; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology* / Q000503:physiopathology; D046088:Hearing Loss, Unilateral / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D006849:Hydrocephalus / Q000000981:diagnostic imaging / Q000209:etiology; D002532:Intracranial Aneurysm / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D008875:Middle Aged; D011149:Pons / Q000098:blood supply* / Q000503:physiopathology; D012678:Sensation Disorders / Q000209:etiology* / Q000503:physiopathology; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000209:etiology; D013577:Syndrome; D014715:Vertebrobasilar Insufficiency / Q000209:etiology / Q000503:physiopathology
keywords: Alternating syndrome; Anévrisme; Artère basilaire; Basilar artery; Infarctus; Long circumferential branch aneurysm; Longue branche circonférentielle; Pontine infarct; Protubérance; Syndrome alterne