Brain (CNS)
Subarachnoid Hemorrhage
지주막하출혈
Acute bleeding into subarachnoid space, usually from ruptured aneurysm
- How common
- ~9 per 100,000/year
- Typical age
- Ages 40-60
What is it?
Rupture of saccular aneurysm at arterial bifurcation → high-pressure bleed into subarachnoid space → raised ICP, vasospasm, hydrocephalus.
Commonly affected: Circle of Willis (ACoA, PCoA, MCA, basilar)
How it develops
- Aneurysm formationBifurcation wall weakness (HTN, smoking, genetics)
- RuptureOften during exertion/Valsalva
- SAHBlood spreads through CSF spaces
- Vasospasm/rebleedingVasospasm days 4-14; rebleeding peaks first 24 h
Symptoms
- Thunderclap headacheWorst headache of life, peaks in seconds
- Decreased LOC/seizureIn severe SAH
- Vomiting/nauseaFrom raised ICP
- Neck stiffnessMeningeal irritation
- Cranial nerve palsyCN III palsy with PCoA aneurysm
How it is examined
- Hunt-Hess gradeGrades 1-5, clinical severity
- WFNS gradeGCS + motor deficit
- FundoscopyTerson syndrome (vitreous bleed)
Imaging
Non-contrast CT (100% sensitive within 6 h).
- Hyperdense blood in basal cisterns
- Sylvian fissure blood
- Intraventricular blood
If CT negative + high suspicion, LP for xanthochromia; CTA/DSA finds aneurysm.
- Xanthochromia (after 12 h)
- CTA/DSA shows aneurysm location/size
Non-surgical care
- Rebleeding preventionSBP <140-160 mmHg, bed rest
- Nimodipine 60 mg q4h21 days - reduces vasospasm mortality
- EuvolemiaAvoid hypovolemia, isotonic fluids
- Seizure prophylaxisShort-course levetiracetam
- Transcranial DopplerDetects vasospasm early
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Confirmed aneurysm, treat within 24-72 h
Procedures that may be discussed
- Endovascular coiling (preferred per ISAT)
- Microsurgical clipping
- EVD for hydrocephalus
- Endovascular verapamil/balloon angioplasty for vasospasm
Outlook
30-day mortality 35-40%. One-third of survivors have permanent disability. Rebleeding mortality 80%.