Sentinel Headache: Subarachnoid Hemorrhage

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:

Sudden, severe headache

Sudden, severe headache

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:

Devastating subarachnoid hemorrhage

Devastating subarachnoid hemorrhage

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.  

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When to get a CT Head

When to get a head CT?

How do you know when to order a head CT? A patient presents with headache or confusion: should you get a scan now? Here is a mnemonic that can help you know when to get a head CT on a patient with neurological symptoms.

SCAN – NOW. Get a CT Head if . . .

Seizure: new onset seizure

Confusion, or any change in mental status

Acute onset: a “new and different” headache

Nuchal rigidity: the stiff neck of meningitis or subarachnoid hemorrhage

Neuro deficit: any focal neuro change, like unequal pupils or pronator drift

Optic papilledema: a sign of increased intracranial pressure

Worrisome history: like malignancy, anticoagulants, or prior bleed or known lesion

For the patient with complaint of headache, always ask, “Is this the same old headache that’s bothered you so long … or IS THIS NEW AND DIFFERENT?” The “new and different headache” needs a CT.

For the headache patient, always perform a funduscopic exam, looking for optic papilledema, a sign of increased intracranial pressure. Every headache workup needs a funduscopic exam!

Nuchal rigidity is a classic sign of meningitis and is caused by the irritation of the meninges caused by bacteria and white blood cells in the CSF. This irritation is heightened by flexion of the neck, as the meninges are stretched. In a subarachnoid hemorrhage, red blood cells in the CSF cause a similar irritation of the meninges, aggravated by neck flexion. This nuchal rigidity is also associated with Kernig’s sign and Brudzinski’s sign. Any patient with headache and nuchal rigidy requires an immediate CT of the head. (And in the presence of acute illness or fever suggesting meningitis, immediate administration of antibiotics, even before the diagnostic workup is completed.)