What is the management plan for a patient with diffuse subarachnoid hemorrhage?

Management of Diffuse Subarachnoid Hemorrhage

Patients with diffuse subarachnoid hemorrhage require immediate transfer to a high-volume center (>35 SAH cases/year) with dedicated neurocritical care, experienced cerebrovascular surgeons, and neurointerventional specialists, as this reduces mortality from 39% to 27%. 1, 2

Immediate Diagnostic Workup

For diffuse SAH specifically, digital subtraction angiography (DSA) is mandatory regardless of CTA results, as small aneurysms or vascular lesions may not be detected on CTA due to spatial resolution limitations. 1 Diffuse basal cistern and sylvian fissure hemorrhage patterns carry higher risk for underlying aneurysm compared to focal cortical SAH. 1

• Non-contrast head CT should be obtained immediately (98-100% sensitivity within 12 hours, declining to 93% at 24 hours). 2, 3
• CTA should follow once SAH is confirmed, but DSA remains the gold standard for evaluating cerebrovascular anatomy and aneurysm geometry in diffuse SAH. 1

Acute Stabilization and Monitoring

Care must be provided in a dedicated neurocritical care unit by a multidisciplinary team including neurosurgeons, neurointerventionalists, and neurointensivists. 1, 2

• Rapidly assess neurological status using validated grading scales (Hunt-Hess or World Federation of Neurological Surgeons), as initial clinical severity is the strongest predictor of outcome. 1, 2, 3
• Control blood pressure with titratable agents to balance rebleeding risk against maintaining cerebral perfusion pressure. 3
• Ultraearly rebleeding risk is 15% within the first 24 hours (70% occurring within 2 hours), with high mortality rates. 1, 3

Definitive Aneurysm Treatment

Early aneurysm obliteration should be performed urgently to reduce rebleeding risk. 2, 3 The risk of rebleeding increases with time: 5.7% at 0-3 days, 9.4% at 4-6 days, and 21.5% at 15-32 days if untreated. 3

• For aneurysms amenable to both surgical clipping and endovascular coiling, endovascular coiling is the preferred approach based on superior functional outcomes in randomized trials. 2, 3, 4
• Complete obliteration should be achieved whenever possible; partial treatment to secure the rupture site followed by delayed definitive treatment is reasonable if complete obliteration is not immediately feasible. 3, 4

Medical Management

Administer oral nimodipine 60 mg every 4 hours for 21 consecutive days, starting within 96 hours of hemorrhage onset. 2, 3, 4, 5 This improves neurological outcomes, though it does not prevent vasospasm itself. 3, 5

• If the patient cannot swallow, extract capsule contents using an 18-gauge needle and administer via nasogastric tube with 30 mL normal saline flush, using a syringe labeled "Not for IV Use." 5
• Never administer nimodipine intravenously, as this causes life-threatening hypotension. 5
• Reduce dose to 30 mg every 4 hours in patients with hepatic cirrhosis due to increased bioavailability. 5

Prevention and Management of Delayed Cerebral Ischemia (DCI)

Maintain euvolemia and normal circulating blood volume through goal-directed fluid management; avoid prophylactic hypervolemia as it does not improve outcomes and may be harmful. 2, 4

• For symptomatic DCI, induce hypertension as first-line therapy unless baseline blood pressure is already elevated or cardiac status precludes it. 2, 3, 4
• Prophylactic hemodynamic augmentation should be avoided in asymptomatic patients at risk for DCI. 4
• Transcranial Doppler monitoring can detect vasospasm, with Lindegaard ratios of 5-6 indicating severe spasm requiring treatment. 4

Management of Acute Complications

Place external ventricular drainage urgently for acute symptomatic hydrocephalus, which is a common and life-threatening complication. 2, 3, 4

• Recent evidence suggests that when preoperative ventriculostomy is followed by early aneurysm treatment, rebleeding risk is not increased. 1
• Emergency reversal of anticoagulants should be performed if the patient is anticoagulated. 4

Additional Considerations

• 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. 2
• Venous thromboembolism prophylaxis should be initiated once the aneurysm is secured. 4
• Avoid phenytoin for seizure prophylaxis as it is associated with excess morbidity and mortality. 4
• Avoid routine use of statins, intravenous magnesium, and endothelin antagonists as they have not been shown to improve outcomes. 4

Follow-up Imaging

Perform immediate post-treatment cerebrovascular imaging to identify aneurysm remnants or recurrence. 3, 4 Delayed follow-up vascular imaging should be performed with strong consideration for retreatment if clinically significant remnants are identified. 2, 4

Common Pitfalls

• Do not rely on CTA alone for diffuse SAH—DSA is mandatory as it may reveal aneurysms missed on CTA. 1
• Medical complications (cardiac arrhythmias, pulmonary edema, hepatic/renal dysfunction) contribute equally to mortality as rebleeding or vasospasm individually, requiring meticulous monitoring. 6
• Cardiac arrhythmias and pulmonary edema increase on the day of or day after aneurysm surgery, necessitating heightened vigilance during this period. 6