Pseudo-subarachnoid hemorrhage: a rare neuroimaging pitfall

Can J Neurol Sci. 1999 Feb;26(1):57-9.


Objective: We report an unusual case of the CT appearance of diffuse subarachnoid hemorrhage in a patient with anoxic encephalopathy, a situation which neurosurgeons, neurologists, and neuroradiologists should be aware of.

Clinical presentation: A young man collapsed unconscious in jail after abusing an unknown quantity and variety of drugs. CT scan showed a picture compatible with diffuse subarachnoid hemorrhage.

Intervention: As the patient had a Glasgow Coma Score of 3 no heroic intervention was undertaken. An autopsy performed 40 hours after the initial ictus and 24 hours after death revealed no evidence of subarachnoid hemorrhage but gross and microscopic evidence of anoxic encephalopathy.

Conclusion: Anoxic encephalopathy can mimic diffuse subarachnoid hemorrhage on CT.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Coma / chemically induced
  • Coma / diagnostic imaging
  • Diagnosis, Differential
  • Drug Overdose
  • Glasgow Coma Scale
  • Humans
  • Hypoxia, Brain / diagnostic imaging
  • Hypoxia, Brain / pathology
  • Male
  • Subarachnoid Hemorrhage / diagnostic imaging*
  • Subarachnoid Hemorrhage / pathology
  • Substance-Related Disorders / complications
  • Tomography, X-Ray Computed