What are the immediate diagnostic and treatment priorities for a patient with suspected subarachnoid hemorrhage?

Immediate Management of Suspected Subarachnoid Hemorrhage

For suspected subarachnoid hemorrhage, immediately obtain a noncontrast head CT, followed by lumbar puncture if CT is negative but clinical suspicion remains high, then proceed urgently to CT angiography once SAH is confirmed, initiate oral nimodipine 60 mg every 4 hours, control blood pressure to systolic <160 mmHg with titratable agents, and arrange emergent transfer to a high-volume neurosurgical center for aneurysm repair within 24 hours. 1, 2, 3

Diagnostic Priorities

Initial Imaging

• Perform noncontrast head CT immediately as the first diagnostic test, which has 98.7-100% sensitivity within 6 hours of symptom onset 2, 3
• The sensitivity of CT declines significantly after 6 hours, dropping to approximately 93% at 24 hours 2, 3
• If a third-generation or higher CT performed within 6 hours is read as normal by an experienced neuroradiologist, lumbar puncture may not be required 4

Lumbar Puncture Indications

• Perform lumbar puncture when CT is negative but clinical suspicion remains high, particularly if CT was performed >6 hours after symptom onset or was not interpreted by an experienced neuroradiologist 4, 2, 3
• Analyze cerebrospinal fluid by spectrophotometric analysis for xanthochromia, which has 100% sensitivity and 95.2% specificity when performed 12 hours to 2 weeks after symptom onset 2, 3
• A common pitfall is skipping lumbar puncture after negative CT beyond 6 hours from onset—this must be avoided as CT sensitivity declines substantially 2

Vascular Imaging

• Proceed immediately with CT angiography (CTA) once SAH is confirmed to identify the bleeding source, as CTA has 96.5% sensitivity and 88% specificity for aneurysms overall 1, 2, 3
• Be aware that CTA has only 61% sensitivity for aneurysms <3 mm 1, 2, 3
• 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 1, 2, 3
• Do not delay CTA to "stabilize" the patient—vascular imaging is an integral component of emergency evaluation and directly influences immediate management 3

Treatment Priorities

Blood Pressure Management

• Control systolic blood pressure to <160 mmHg using titratable agents to balance the competing risks of rebleeding versus maintaining adequate cerebral perfusion pressure 4, 1, 2
• Avoid aggressive blood pressure reduction that could compromise cerebral perfusion in the setting of elevated intracranial pressure 1
• Hypertension above 160 mmHg is associated with increased rebleeding risk 1, 3

Pharmacological Neuroprotection

• Administer oral nimodipine 60 mg every 4 hours immediately and continue for 21 consecutive days, as this is the only treatment proven in adequate clinical trials to improve neurological outcomes 4, 1, 2
• Note that nimodipine improves outcomes but does not prevent cerebral vasospasm 4
• In dysphagic patients, nimodipine may be given by enteral tube 4

Urgent Transfer and Aneurysm Repair

• Transfer patients immediately to a high-volume center (>35 SAH cases per year) with neurosurgical and endovascular capabilities and multidisciplinary neuro-intensive care services 4, 1, 5
• Low-volume hospitals (<10 SAH cases per year) should arrange early transfer 4
• Secure the aneurysm within 24 hours of presentation to reduce rebleeding risk, which carries 70-90% mortality 4, 1, 3
• The risk of rebleeding is 3-4% in the first 24 hours (possibly higher), with the highest risk occurring within 2-12 hours after initial hemorrhage 4, 1

Aneurysm Repair Modality

• For aneurysms amenable to both clipping and coiling, endovascular coiling should be considered first based on randomized trial data showing better outcomes 4, 1
• Posterior circulation aneurysms particularly benefit from coiling over clipping (relative risk 0.41 for death or dependency) 1
• Complete obliteration of the aneurysm is the goal whenever technically feasible 4, 1
• The decision should be made by a multidisciplinary team including cerebrovascular neurosurgeons, endovascular specialists, and neurointensivists 4, 5

Critical Care Monitoring

Neurological Assessment

• Rapidly assess neurological status using validated scales such as Hunt and Hess or World Federation of Neurological Surgeons grade, as initial clinical severity is the most useful indicator of outcome 4, 1
• Monitor closely for neurological deterioration, which may indicate rebleeding, hydrocephalus, or delayed cerebral ischemia 5, 6

Hydrocephalus Management

• Manage acute symptomatic hydrocephalus with cerebrospinal fluid drainage using external ventricular drain or lumbar drainage depending on the clinical scenario 4, 1, 2
• Hydrocephalus can cause gradual obtundation in the first hours or days 7

Volume Status

• Maintain euvolemia and normal circulating blood volume to prevent delayed cerebral ischemia 4, 1, 2
• Do not use prophylactic hypervolemia or triple-H therapy, as this is no longer recommended 1

Common Pitfalls to Avoid

• Do not dismiss negative CT in high-risk presentations—patients with thunderclap headache, photophobia, neck stiffness, or exertional onset require full workup including lumbar puncture regardless of CT findings 2, 3
• Do not rely on CTA alone if diffuse SAH pattern is present but CTA is negative—proceed to DSA due to limited sensitivity for small aneurysms 1, 2, 3
• Do not delay aneurysm treatment beyond 72 hours unless there are compelling contraindications, as rebleeding risk remains elevated throughout the first two weeks 1
• Do not skip aspirin administration—in acute stroke patients, aspirin should be given immediately after brain imaging excludes intracranial hemorrhage, but this does NOT apply to SAH patients where aspirin is contraindicated until after aneurysm repair 4
• Do not use antifibrinolytic agents routinely in the pre-treatment period without careful consideration of risks versus benefits 1