title: Normal pressure "herniation".
abstract: BACKGROUND
  Hydrocephalus with normal intracranial pressure has rarely been reported to result in herniation.
  
  
  METHODS
  Case report.
  
  
  RESULTS
  A 52-year-old man became acutely comatose with extensor posturing and ventriculomegaly 17 days after experiencing a primary ventricular hemorrhage. An external ventricular drain revealed normal intracranial pressure. After 24 hours without improvement with the drain set at a level of 5 mm H2O, negative-pressure siphoning (50 mL of cerebrospinal fluid [CSF] removed) reduced ventricular size and led to dramatic clinical recovery.
  
  
  CONCLUSIONS
  Normal pressure hydrocephalus can result in delayed brainstem herniation after ventricular hemorrhage. CSF siphoning in these patients can reverse the syndrome.
authors.affiliation: Department of Neurology, Columbia-Presbyterian Medical Center, New York, NY, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Pratt
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Mayer
mesh_terms: D000208:Acute Disease; D002557:Cerebrospinal Fluid Shunts; D004677:Encephalocele / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D020300:Intracranial Hemorrhages / Q000150:complications* / Q000000981:diagnostic imaging / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011859:Radiography