What is the initial management for a patient with a subarachnoid hemorrhage (SAH) on computed tomography (CT) scan?

Initial Management of Subarachnoid Hemorrhage on CT Scan

Once SAH is confirmed on CT scan, immediately secure the airway if needed, transfer the patient to a high-volume center with neurosurgical and endovascular capabilities, initiate oral nimodipine 60 mg every 4 hours, control blood pressure to prevent rebleeding while maintaining cerebral perfusion, and proceed urgently with vascular imaging (CTA or DSA) to identify the aneurysm source for definitive treatment within 24 hours. 1

Immediate Stabilization and Transfer

• Transfer to a specialized center with neurosurgical experience managing aneurysms using both endovascular and surgical techniques, as low-volume hospitals (<10 cases/year) should transfer to high-volume centers (>35 cases/year) with multidisciplinary neuro-intensive care services 1, 2
• Assess neurological status using validated scales (Hunt and Hess or World Federation of Neurological Surgeons grade) as this is the most useful indicator of outcome 1
• Secure the airway in patients with decreased level of consciousness (Hunt and Hess grades IV-V) to protect against aspiration and maintain oxygenation 3

Blood Pressure Management

• Control hypertension carefully using titratable agents to balance the competing risks of rebleeding versus maintaining adequate cerebral perfusion pressure 1
• Target systolic blood pressure <160 mmHg, as values above this threshold are associated with increased rebleeding risk 2
• Avoid aggressive blood pressure reduction that could compromise cerebral perfusion in the setting of elevated intracranial pressure 1

Pharmacological Neuroprotection

• Administer oral nimodipine 60 mg (two 30 mg capsules) every 4 hours immediately and continue for 21 consecutive days 1, 4
• Nimodipine improves neurological outcomes (not by preventing vasospasm per se, but through neuroprotective mechanisms) and has been shown to reduce severe deficits and improve good recovery rates, particularly in poor-grade SAH patients 4
• If the patient cannot swallow, extract capsule contents with an 18-gauge needle into an oral syringe labeled "Not for IV Use" and administer via nasogastric tube with 30 mL saline flush 4
• Never administer nimodipine intravenously as this can cause life-threatening hypotension 4

Vascular Imaging to Identify Aneurysm Source

• Proceed immediately with CT angiography (CTA) to identify the bleeding source, as CTA has 96.5% sensitivity and 88% specificity for aneurysms overall 2, 5
• CTA is particularly useful for triaging patients to endovascular coiling versus surgical clipping, with 95.7% of patients able to proceed to treatment based on CTA alone 5
• If CTA is negative but SAH is confirmed, perform digital subtraction angiography (DSA) with 3D rotational angiography, which has >98% sensitivity and specificity for detecting aneurysms 2
• Be aware that CTA has limited sensitivity (61%) for aneurysms <3 mm, necessitating DSA in cases with diffuse SAH pattern but negative CTA 1, 2

Aneurysm Repair Timing and Modality

• Secure the aneurysm within 24 hours of presentation (ideally <24 hours from ictus) to reduce rebleeding risk, which carries 70-90% mortality 1, 2
• The rebleeding risk is highest in the first 24 hours, with early treatment (<24 hours vs >24 hours) showing clear outcome benefit 1
• For aneurysms amenable to both clipping and coiling, endovascular coiling should be considered first based on randomized trial data showing better outcomes 1
• Posterior circulation aneurysms particularly benefit from coiling over clipping (RR 0.41 for death or dependency) 1
• Complete obliteration of the aneurysm is the goal whenever technically feasible to prevent rebleeding 1

Critical Care Monitoring

• Admit to a dedicated neurological intensive care unit for multimodal neuromonitoring 3
• Monitor for acute hydrocephalus, which should be managed with cerebrospinal fluid drainage (external ventricular drain or lumbar drain) 1
• Maintain euvolemia and normal circulating blood volume to prevent delayed cerebral ischemia (DCI) 1
• Monitor closely for delayed cerebral ischemia (typically days 4-14), which occurs in up to 30% of patients 3

Common Pitfalls to Avoid

• Do not delay aneurysm treatment beyond 72 hours unless there are compelling contraindications, as the risk of rebleeding remains elevated throughout the first two weeks 1
• Do not use prophylactic hypervolemia or triple-H therapy (hypertension, hypervolemia, hemodilution) as this is no longer recommended; maintain euvolemia instead 1
• Do not use antifibrinolytic agents routinely in the pre-treatment period without careful consideration of risks versus benefits 1
• In patients with large intracerebral hematoma causing mass effect, emergency surgical evacuation may be needed before or concurrent with aneurysm repair 1