Pseudo-subarachnoid hemorrhage of the head diagnosed by computerized axial tomography: a postmortem study of ten medical examiner cases.

In this report, we describe ten cases of pseudo-subarachnoid hemorrhage on computer axial tomography (CT) scan of the head. A pseudo-subarachnoid hemorrhage is a false positive finding by CT of the head in which the scan is interpreted as being positive for a subarachnoid hemorrhage not substantiated by subsequent neuropathologic findings. This study is a retrospective review of postmortem cases brought into the Office of the Chief Medical Examiner for the State of Maryland over a three-year period (from 1997 to 2000). We compared the clinician's impression of the CT scan with the postmortem neuropathology. The clinical diagnosis of subarachnoid hemorrhage was based on misinterpretation of non-contrast CT scans of the head. In six of the ten cases, the reading was performed by a radiologist and in four cases by nonradiologist physicians (emergency room physician, neurologist, or neurosurgeon). All the patients survived between a few hours to a few days after being admitted to the hospital. For most of the cases (80%), the neuropathology showed hypoxic/ischemic encephalopathy. The most common cause of death (four out of ten cases) was narcotic intoxication. This report is submitted so that clinicians and pathologist become more familiar with this entity.