Subarachnoid Hemorrhage: Investigation, Treatment, and Drug Management
Diagnostic Investigation
For patients presenting with acute severe headache, immediate non-contrast head CT is the first-line investigation, followed by lumbar puncture if CT is negative and clinical suspicion remains high. 1
Imaging Protocol
Within 6 hours of symptom onset: High-quality non-contrast head CT on a modern scanner interpreted by a board-certified neuroradiologist has approximately 95% sensitivity and can reasonably exclude SAH without further testing if negative and the patient has no neurological deficits 1
Beyond 6 hours or with neurological deficits: Non-contrast head CT followed by lumbar puncture with spectrophotometric analysis for xanthochromia is mandatory if CT is negative, as this combination achieves 100% sensitivity 1
Vascular imaging: Once SAH is confirmed, digital subtraction angiography (DSA) remains the gold standard for identifying the aneurysm source, though CT angiography (CTA) is reasonable as initial vascular imaging and may guide treatment decisions 1, 2
If initial angiography is negative: Repeat DSA should be performed days to weeks later (typically 1-6 weeks), as the yield for detecting an aneurysm is 10% 1
Critical Pitfall
The Ottawa SAH Rule may help identify high-risk patients, but its specificity is only 14%, meaning many patients will still require imaging 1. Do not rely on clinical rules alone to exclude SAH.
Treatment Approach
Patients with confirmed aneurysmal SAH require immediate transfer to a specialized neurovascular center with both endovascular and neurosurgical capabilities, and the ruptured aneurysm should be secured within 24-48 hours to prevent rebleeding. 2, 1
Aneurysm Repair Strategy
For good-grade anterior circulation aneurysms amenable to both techniques, endovascular coiling is recommended over surgical clipping to improve 1-year functional outcomes. 1
Posterior circulation aneurysms: Coiling is strongly preferred over clipping (relative risk of death/dependency 0.41,95% CI 0.19-0.92) 1
Large intraparenchymal hematoma with depressed consciousness: Emergency surgical clot evacuation with concomitant aneurysm clipping should be performed immediately, as this reduces mortality from 80% to 27% 1
Age considerations:
Wide-neck or fusiform/blister aneurysms: Stent-assisted coiling or flow diverters are reasonable when primary coiling or clipping is not feasible 1
Critical Pitfall
Avoid stents or flow diverters in acute ruptured saccular aneurysms amenable to primary coiling or clipping, as dual antiplatelet therapy significantly increases hemorrhagic complications, particularly ventriculostomy-related bleeding. 1
Medical Management and Drug Therapy
Nimodipine 60 mg orally every 4 hours for 21 days is the only medication proven to improve functional outcomes and must be initiated immediately upon diagnosis. 1, 3
Nimodipine Administration
Dosing: 60 mg every 4 hours for 21 days, started as early as possible 3
Mechanism: Highly lipophilic calcium channel blocker that crosses the blood-brain barrier, preventing delayed cerebral ischemia (not by relieving angiographic vasospasm, but through neuroprotective mechanisms) 3
Evidence: Reduces severe deficits due to vasospasm and improves good recovery rates, particularly in Hunt and Hess Grades IV-V patients (25.3% vs 10.9% good recovery compared to placebo) 3
Hepatic impairment: Reduce dose in cirrhotic patients, as bioavailability doubles due to reduced first-pass metabolism 3
Administration timing: Give on empty stomach when possible, as food reduces peak concentration by 68% and bioavailability by 38% 3
What NOT to Use
Routine statin therapy and intravenous magnesium are not recommended, as they have not demonstrated benefit in preventing delayed cerebral ischemia. 1
Management of Delayed Cerebral Ischemia
If symptomatic delayed cerebral ischemia develops, elevate blood pressure and maintain euvolemia to reduce progression and severity. 1
Avoid prophylactic measures: Do not perform prophylactic hemodynamic augmentation (triple-H therapy) or hypervolemia, as these increase iatrogenic complications without proven benefit 1
Monitoring: Serial transcranial Doppler should be performed at least daily for 14 days to detect vasospasm 4
Blood pressure targets: Adjust mean arterial pressure to ensure adequate cerebral perfusion pressure only when vasospasm or increased intracranial pressure is documented 4
Critical Care Considerations
Triage: Transfer all SAH patients to high-volume centers with neurovascular teams and neurointensive care units, as hospital volume strongly correlates with outcomes 1
Invasive monitoring: Consider in high-grade SAH patients with limited neurological examination 1
Hydrocephalus management: External ventricular drainage or intraparenchymal pressure monitoring is recommended for detecting increased intracranial pressure 4
Avoid hyperoxia: While preventing hypoxia is critical, hyperoxia causes vasoconstriction and decreased cardiac output 1
Medical Complications
Medical (non-neurologic) complications occur in 40% of patients and account for 23% of deaths—equal to deaths from rebleeding or vasospasm individually 5. The most common life-threatening complications are:
- Pulmonary edema (23% overall, 6% severe), with increased frequency on days 3-7 and around surgery 5
- Cardiac arrhythmias (30% any rhythm disturbance, 5% life-threatening), peaking on the day of or after aneurysm surgery 5
- Renal dysfunction (7%), often associated with antibiotic therapy 5
Long-Term Follow-Up
Cerebrovascular imaging after treatment and subsequent monitoring are essential for detecting aneurysm remnants, recurrence, or regrowth, as well as identifying de novo aneurysms in younger patients or those with family history. 1
Rehabilitation: Multidisciplinary assessment for physical, cognitive, and behavioral deficits should begin early, as these persist in the majority of survivors 1
Common persistent deficits: Executive dysfunction, short-term memory impairment, anxiety, depression, and fatigue are more common than focal neurological deficits 1