Thunderclap 'worst headache of life', meningismus
ABCDE A-B-C, protect airway if ↓GCS; analgesia, BP control; nimodipine; urgent CT + neurosurgery.
Calculators: gcs
First: Head CT without contrast (max sensitivity early — blood settles to base)
If CT negative → LP looking for xanthochromia
Then: CT angiography → coil or clip the aneurysm
Prevent vasospasm: Nimodipine 60 mg PO q4h ×21 d; control BP
Order set Non-contrast CT head LP if CT negative (xanthochromia) CT angiography Nimodipine BP control Escalate / ICU ↓GCS / high Hunt-Hess grade Hydrocephalus, rebleed, vasospasm Needs neurosurgery / coiling Criteria Admit All SAH
ICU ↓GCS, high grade, hydrocephalus, vasospasm risk
Intubate ↓GCS / airway protection
Discharge Aneurysm secured, neurologically stable, vasospasm window passed
Clinical detail — differentials, red flags, pitfalls, disposition Red flags Thunderclap headache ↓GCS Focal deficit Differentials Migraine Meningitis Venous sinus thrombosis Common mistakes Missing CT-negative SAH (skipping LP) Not starting nimodipine Disposition & follow-up Neurosurgery/coiling; monitor for vasospasm/hydrocephalus.
Discharge package Medications Nimodipine course; analgesia
Follow-up Neurosurgery; vascular imaging
Warning symptoms Severe headache, neuro deficit, seizures
💊 Treatment detail — doses & preparation Nimodipine CCB (SAH vasospasm)
Dose 60 mg PO/NG q4h ×21 days — every SAH
Preparation 30 mg tablets or NG solution; give on schedule (vasospasm window)
Monitor BP — hypotension worsens perfusion; do not stop early
Labetalol IV IV α+β-blocker
Dose 20 mg IV over 2 min, repeat 20–80 mg q10 min (max 300 mg) or 0.5–2 mg/min infusion
Preparation 200 mg in 160 mL (1.25 mg/mL) for infusion; boluses undiluted (5 mg/mL vial)
Monitor Avoid in asthma/decompensated HF; postural hypotension
Mannitol 20% osmotic diuretic (ICP)
Dose 0.25–1 g/kg IV bolus over 10–20 min for ICP crisis
Preparation 20% (200 mg/mL) 500 mL bag via filter needle (crystals); may repeat q6–8h
Monitor Serum osmolality (keep <320), Na⁺, volume; effect wanes after 48 h
Levetiracetam antiepileptic
Dose Status: 60 mg/kg IV (max 4500 mg) over 15 min; maintenance 500–1500 mg BD
Preparation 500 mg/5 mL vial in 100 mL NS over 15 min; PO tablets/solution 1:1 conversion
Monitor Mood/behaviour changes; minimal interactions
📖 AHA-ASA aneurysmal SAH Reviewed July 2026