A 25 year old male college student presents to the ER with complaint of sudden severe headache with an episode of vomiting. On exam he looks uncomfortable but is neurologically normal, that is, he is awake, oriented fully, moving arms and legs without weakness or neglect. Pupils are 3 mm and reactive. A head CT is ordered:
The verbal report is “normal,” and he is discharged home.
One week later the same patient arrives at the ER by ambulance, non arousable, with decerebrate (extensor) posturing to deep pain stimulus, no verbalizations, and non reactive pupils measuring 5 mm. A CT scan is again ordered:
This devastating subarachnoid hemorrhage was preceded a week earlier by a tiny bleed in the region of the left posterior cerebral artery, a hemorrhage so small in fact that is was not identified on the radiologist’s formal reading. The patient experienced a sentinel headache that heralded the aneurysm rupture that took his life a week later. In the case of a suspected subarachnoid hemorrhage with a negative head CT, consider lumbar puncture to look for RBCs or xanthochromia in the CSF.