[ Neurosurgery ] SAH 2

PCOM aneurysm – compression effect

CN3 palsy.

MCA bifurcation aneurysm – effect

Hemiparesis and aphasia.

Basilar tip aneurysm – significance and effect

Most common posterior circulation aneurysm, causing brainstem compression and coma.

PCA aneurysm – compression effect

May compress CN3 (CN3 palsy).

Berry aneurysm – clinical presentations

Rupture (most common, 95 to 97%, presenting as SAH), mass effect (headache, CN palsies), or incidental.

SAH headache – features

Sudden and severe (worst headache of life), thunderclap reaching maximum intensity in under 1 minute.

SAH – loss of consciousness

Common (about 50%), transient or prolonged.

SAH – meningeal signs

Neck stiffness and photophobia.

SAH – other clinical features

Focal deficits (CN palsies, hemiparesis), seizures, and raised ICP (Cushing triad with reactionary HTN).

Sentinel hemorrhage – definition

A small leak from the aneurysm days to weeks before major rupture, causing a warning headache.

SAH – best initial test

Non-contrast CT (positive in 95 to 98%).

CT in SAH – sensitivity over time

High within 6 to 12 hours, drops after 24 to 48 hours.

CT in SAH – findings

Hyperdense blood within CSF spaces, and the death star sign (blood in the cisterns).

CT in SAH – other assessments

ICH and/or IVH, and amount of cisternal blood (Fisher grade, predicts vasospasm).

Lumbar puncture in SAH – role

Most sensitive test, done when CT is negative, best at least 6 to 12 hours after onset (not sensitive acutely).

Xanthochromia – significance and timing

Most important LP finding: yellow CSF from RBC breakdown, appears after 6 hours, almost always present after 12 hours, persists up to 2 weeks.

3 tube test – purpose

Distinguishes SAH from a traumatic tap.

DSA in SAH – role

Confirmatory test and gold standard for aneurysm detection.

DSA in SAH – technique

4-vessel angiography (2 ICA and 2 vertebral), 3 views per vessel, with 3D views assessing size, shape, and neck-to-fundus ratio.

WFNS grading – basis

Clinical grading system based mainly on GCS