What is the presentation and treatment for subarachnoid hemorrhage?

Subarachnoid Hemorrhage: Presentation and Treatment

Clinical Presentation

Subarachnoid hemorrhage classically presents with sudden-onset severe headache described as "the worst headache of my life," occurring in approximately 80% of patients who can provide a history. 1

• The headache reaches maximal intensity immediately and may be preceded by a warning or sentinel headache in 10-43% of cases 1
• Associated symptoms include neck pain or stiffness, nausea, vomiting, photophobia, and altered mental status 1, 2, 3
• Neurological status at presentation is the strongest predictor of outcome and should be rapidly assessed using validated grading scales 4, 5

Diagnostic Approach

Non-contrast head CT is the first-line diagnostic test with 98-100% sensitivity within 12 hours of symptom onset, declining to 93% at 24 hours. 4, 1

• If CT is negative or inconclusive but clinical suspicion remains high, lumbar puncture for cerebrospinal fluid analysis is necessary to evaluate for xanthochromia, which has nearly 100% sensitivity when performed >6-12 hours after symptom onset 1
• Once SAH is confirmed, proceed immediately to cerebrovascular imaging (CT angiography or digital subtraction angiography) to identify the bleeding source 4, 6, 1
• High-quality CTA is initially preferable to catheter angiography for investigating the cause of hemorrhage 6

Immediate Management and Transfer

Patients with subarachnoid hemorrhage should be transferred immediately to high-volume centers (>35 SAH admissions per year) with experienced cerebrovascular surgeons, endovascular specialists, and dedicated neurocritical care units, as this significantly reduces mortality from 39% to 27%. 4, 7

Blood Pressure Control

• Maintain systolic blood pressure below 160 mmHg using titratable agents to prevent rebleeding prior to aneurysm securing 1

Prevention of Rebleeding

• The risk of rebleeding is 15% within the first 24 hours with 70% mortality for those who rebleed 5, 4
• Early aneurysm treatment should be performed within 24-48 hours to reduce rebleeding risk 5, 4, 6

Aneurysm Securing

For aneurysms amenable to both surgical clipping and endovascular coiling, endovascular coiling should be considered as the preferred approach based on superior outcomes in randomized trials. 5, 4, 6

• The goal of initial treatment is complete obliteration whenever feasible to substantially reduce risks of both rebleeding and retreatment 5
• For posterior circulation aneurysms, coiling demonstrates significant benefit over clipping with a relative risk of 0.41 (95% CI, 0.19-0.92) for death or dependency 5
• If complete obliteration is not feasible, partial treatment aimed at securing the putative rupture site during the acute phase is reasonable, with retreatment typically within 1-3 months 5

Medical Management

Administer oral nimodipine 60 mg every 4 hours for 21 consecutive days starting within 96 hours of hemorrhage onset to improve neurological outcomes. 5, 4, 8

• Nimodipine is one of only two treatments (along with endovascular aneurysm repair) based on high-level evidence for SAH 5
• The medication reduces the severity of neurological deficits resulting from vasospasm 8
• Do not administer nimodipine intravenously or by other parenteral routes 8
• If the capsule cannot be swallowed, extract contents with an 18-gauge needle and administer via nasogastric tube with 30 mL normal saline 8

Fluid Management

• Maintain euvolemia and normal circulating blood volume through goal-directed fluid management 4, 1
• Avoid prophylactic hypervolemia as it does not improve outcomes and may be harmful 4, 1

Management of Complications

Delayed Cerebral Ischemia (DCI)

• For symptomatic DCI, induce hypertension as first-line therapy unless baseline blood pressure is already elevated or cardiac status precludes it 4, 2, 3
• Volume expansion and induced hypertension are the only measures proven effective for treatment of delayed cerebral ischemia 3

Acute Hydrocephalus

• Place external ventricular drainage urgently for acute symptomatic hydrocephalus, which is a common and life-threatening complication 4, 3

Antifibrinolytic Therapy

• Short-term tranexamic acid or aminocaproic acid is reasonable to reduce early rebleeding risk in patients with significant delay to aneurysm obliteration and no medical contraindications 4

Monitoring and Follow-up

• Provide care in a dedicated neurocritical care unit with continuous monitoring for neurological deterioration, intracranial pressure changes, and systemic complications 4, 7
• Initiate venous thromboembolism prophylaxis once the aneurysm is secured 1
• Maintain effective glycemic control with strict hyperglycemia management while avoiding hypoglycemia 1
• Perform delayed follow-up vascular imaging with strong consideration for retreatment if clinically significant remnants are identified 4

Common Pitfalls to Avoid

• Do not delay transfer to a high-volume center - mortality is significantly higher at low-volume centers 4
• Do not induce hypervolemia prophylactically - this outdated practice (triple-H therapy) is associated with excess morbidity 5, 4
• Do not use prophylactic anticonvulsants routinely - guidelines recommend against this practice despite slow adoption 5
• Do not miss SAH in patients with thunderclap headache and negative CT - always perform lumbar puncture if clinical suspicion remains high 1