Pseudo-subarachnoid hemorrhage: a rare neuroimaging pitfall

Objective: We report an unusual case of the CT appearance of diffuse subara chnoid hemorrhage in a patient with anoxic encephalopathy, a situation whic h neurosurgeons, neurologists, and neuroradiologists should be aware of. Cl inical presentation: A young man collapsed unconscious in jail after abusin g an unknown quantity and variety of drugs. CT scan showed a picture compat ible with diffuse subarachnoid hemorrhage. Intervention: As the patient had a Glasgow Coma Score of 3 no heroic intervention was undertaken. An autops y performed 40 hours after the initial ictus and 24 hours after death revea led no evidence of subarachnoid hemorrhage but gross and microscopic eviden ce of anoxic encephalopathy. Conclusion: Anoxic encephalopathy can mimic di ffuse subarachnoid hemorrhage on CT.