title: Chronic hydrocephalus in elderly patients following subarachnoid hemorrhage.
abstract: BACKGROUND
  With the aging of the population, surgery for ruptured intracranial aneurysms is increasing among the elderly. We sought to clarify the characteristics of chronic hydrocephalus following aneurysmal subarachnoid hemorrhage (SAH) in elderly patients.
  
  
  METHODS
  Of the 576 surgically treated patients, 289 were aged 59 years or younger, 169 were 60 to 69, and 118 were 70 years or older. The relationship between chronic hydrocephalus and the causative factors was analyzed for each age group.
  
  
  RESULTS
  Of the 576 patients, chronic hydrocephalus was observed in 215 (37%), with the incidence increasing significantly with age (p < 0.001) and being the highest in the oldest age group. In elderly patients, the incidence of chronic hydrocephalus was relatively high, even after mild SAH. The incidence of chronic hydrocephalus was high regardless of age in patients with severe SAH, such as in those with H&H grades III-IV, SAH grades III-IV, acute hydrocephalus, symptomatic vasospasm, and intraventricular hemorrhage, and in those with vertebro-basilar artery aneurysms.
  
  
  CONCLUSIONS
  In the elderly, the incidence of chronic hydrocephalus following SAH was significantly higher than in younger patients, even after mild SAH. In elderly patients, careful observation and individualized treatment are necessary even if SAH is mild.
authors.affiliation: Department of Neurosurgery, Shimane Prefectural Central Hospital, Izumo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yoshioka
authors.forename: T
authors.initials: T
authors.lastname: Inagawa
authors.forename: Y
authors.initials: Y
authors.lastname: Tokuda
authors.forename: F
authors.initials: F
authors.lastname: Inokuchi
mesh_terms: D000368:Aged; D002423:Cause of Death; D002908:Chronic Disease; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology* / Q000503:physiopathology; D015994:Incidence; D002532:Intracranial Aneurysm / Q000150:complications*; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000209:etiology / Q000401:mortality