title: Vertebrobasilar artery dissection presenting with simultaneous subarachnoid hemorrhage and brain stem infarction: case report.
abstract: BACKGROUND
  Intracranial dissecting aneurysms have been associated with subarachnoid hemorrhage (SAH) or cerebral ischemia. We encountered a patient presenting with simultaneous subarachnoid hemorrhage and brainstem infarction caused by a dissecting aneurysm of the vertebrobasilar artery, which was diagnosed by magnetic resonance imaging (MRI) but did not show abnormal findings on cerebral angiography.
  
  
  METHODS
  A 55-year-old man had sudden onset of headache and left abducens palsy. Computed tomography revealed a subarachnoid hemorrhage localized in the left prepontine cistern and the left cerebellomedullary fissure. Cerebral angiography showed neither a saccular aneurysm nor fusiform dilatation causing the subarachnoid hemorrhage. MRI demonstrated a small infarction in the left dorsal pons, and an intramural hematoma of the left vertebral artery and lower basilar artery.
  
  
  CONCLUSIONS
  This is a rare case of a vertebrobasilar dissecting aneurysm that simultaneously caused both SAH and brain stem infarction. MRI should be performed in the acute phase of SAH of unknown origin to determine the possible coexistence of a dissecting aneurysm, as occurred in this case.
authors.affiliation: Department of Neurosurgery, Aomori Prefectural Central Hospital, 2-1-1 Higashi-tsukurimichi, Aomori, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Murakami
authors.forename: Noboru
authors.initials: N
authors.lastname: Takahashi
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Matsumura
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Umezawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Midorikawa
authors.forename: Michiharu
authors.initials: M
authors.lastname: Nishijima
mesh_terms: D000784:Aortic Dissection / Q000150:complications* / Q000175:diagnosis; D001488:Basilar Artery / Q000000981:diagnostic imaging / Q000473:pathology; D020526:Brain Stem Infarctions / Q000175:diagnosis / Q000209:etiology*; D002533:Cerebral Angiography; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000209:etiology*; D014057:Tomography, X-Ray Computed; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000473:pathology