title: Interhemispheric subdural hematoma caused by a ruptured internal carotid artery aneurysm: case report.
abstract: BACKGROUND
  Interhemispheric subdural hematoma (ISH) usually occurs after head trauma; nontraumatic ISH is extremely rare.
  
  
  METHODS
  The authors describe a 62-year-old male presenting with severe headache and ptosis on the left side. Computed tomography (CT) and magnetic resonance imaging disclosed a hematoma in the interhemispheric subdural space without subarachnoid hemorrhage. Cerebral angiography revealed an aneurysm arising from the left internal carotid-posterior communicating artery (IC-PC) junction. The patient underwent emergency clipping of the aneurysm and was discharged without neurological deficit.
  
  
  CONCLUSIONS
  Ruptured aneurysms resulting in ISH without subarachnoid hemorrhage have been reported in only a few cases; this is the second case to describe the association of a ruptured IC-PC aneurysm with an ISH. The etiology of ISH formation due to ruptured aneurysms and the diagnosis are discussed.
authors.affiliation: Departments of Neurosurgery, Tsukuba Memorial Hospital, Tsukuba, Ibaraki, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Ishikawa
authors.forename: K
authors.initials: K
authors.lastname: Sugimoto
authors.forename: K
authors.initials: K
authors.lastname: Yanaka
authors.forename: S
authors.initials: S
authors.lastname: Ayuzawa
authors.forename: M
authors.initials: M
authors.lastname: Iguchi
authors.forename: T
authors.initials: T
authors.lastname: Moritake
authors.forename: E
authors.initials: E
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Nose
mesh_terms: D017542:Aneurysm, Ruptured / Q000175:diagnosis* / Q000601:surgery; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D002533:Cerebral Angiography; D007839:Functional Laterality; D006408:Hematoma, Subdural / Q000209:etiology* / Q000601:surgery; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D014057:Tomography, X-Ray Computed