Intracranial Hemorrhage: The Daily PANCE Blueprint
A 44-year-old woman presents to the emergency department with the sudden onset of the “worst headache of my life” while bending over to pick up a box. She reports associated nausea but no focal neurologic deficits. A non-contrast head CT performed within 3 hours of symptom onset is negative. What is the next best step?
A. CT Angiogram of the head
B. Lumbar puncture
C. MRI of the brain
D. Administer sumatriptan
E. Repeat CT in 24 hours
Answer and topic summary
The answer is B. Lumbar puncture.
A thunderclap headache is considered a subarachnoid hemorrhage (SAH) until proven otherwise. Non-contrast head CT is the initial test of choice; however, its sensitivity decreases after the first 6 hours from onset. If CT is negative yet suspicion remains high, a lumbar puncture is performed to look for xanthochromia (yellow discoloration of CSF from RBC breakdown), which confirms blood in the subarachnoid space. LP is both definitive and immediate, allowing diagnosis without dangerous delays. Once SAH is confirmed, further imaging (CTA or MRA) is performed to identify the source, often a ruptured berry aneurysm.
Memory aid: Think “CT then LP — See The Leak” → CT rules in the bleed early, LP finds it when CT misses.
Incorrect answer explanations:
- CT Angiogram of head – Useful to locate aneurysm after SAH diagnosis, not as the next step after a negative CT with high suspicion.
- MRI of the brain – More sensitive for other pathologies, but LP is the gold standard for excluding SAH after negative CT.
- Administer sumatriptan – Treats migraines; contraindicated in possible SAH due to vasoconstrictive effects.
- Repeat CT in 24 hours – Delays diagnosis and risks rebleeding; LP gives a definitive answer immediately.
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Covered under ⇒ PANCE Blueprint Neurology ⇒ ⇒
Also found on the PAEA Emergency Medicine Rotation EOR topic list
