What should interns know about managing subarachnoid hemorrhage in patients?

What Interns Should Know About Subarachnoid Hemorrhage

Recognize the Presentation Immediately

The classic presentation is sudden-onset "worst headache of my life" reaching peak intensity within seconds to minutes—this occurs in 80% of patients who can give a history and should trigger immediate action. 1

Key clinical features to identify:

• Headache (present in 74% of cases) with maximal intensity within 1 hour 1
• Nausea/vomiting (77% of cases) 1
• Brief loss of consciousness (53% of cases) 1
• Neck stiffness/nuchal rigidity (35% of cases) 1
• Photophobia and focal neurological deficits including cranial nerve palsies 1

Critical pitfall: Up to 43% of patients report sentinel (warning) headaches 2-8 weeks before major rupture—dismissing these increases rebleeding risk 10-fold. 2 Misdiagnosis occurs in 12% of cases, with failure to obtain neuroimaging being the most common error. 2

Immediate Diagnostic Algorithm

Within 6 hours of symptom onset: Non-contrast head CT has 98.7-100% sensitivity and is sufficient to exclude SAH when interpreted by experienced radiologists. 1, 3

After 6 hours but within 5-7 days: CT sensitivity declines (93% at 24 hours, 57-85% at 6 days), requiring lumbar puncture if CT is negative but clinical suspicion remains high. 1

Lumbar puncture technique: Must be performed >6-12 hours after symptom onset to demonstrate xanthochromia (sensitivity 100%, specificity 95.2%). 1

If high concern persists with negative/inconclusive CT angiography: Digital subtraction angiography is indicated. 4

Airway and Hemodynamic Management

Intubation protocol: If altered consciousness, inability to protect airway, or respiratory compromise develops, use rapid sequence intubation with specific attention to preoxygenation, pharmacological blunting of reflex dysrhythmia, and avoiding blood pressure fluctuations. 4 Follow with nasogastric/orogastric tube placement to reduce aspiration risk. 4

Blood pressure targets for unsecured aneurysm: Maintain systolic BP <160 mmHg using titratable agents (nicardipine, labetalol, or clevidipine) to prevent rebleeding while avoiding severe hypotension and BP variability. 4, 1 A retrospective study showed 17% rebleeding rate when systolic BP >150 mmHg within 24 hours. 4

Critical warning: Avoid hypervolemia—it is potentially harmful and does not improve outcomes. 4, 5

Neurological Assessment and Grading

Document severity using an accepted grading scale (Hunt and Hess, Fisher, Glasgow Coma Scale, or World Federation of Neurological Surgeons Scale) for prognosis and triage. 4 Record age, preexisting hypertension, time of admission after SAH, and admission blood pressure—all influence prognosis. 4

Essential Pharmacological Management

Nimodipine 60 mg orally every 4 hours for 21 days is the ONLY Class I, Level A recommendation and must be started within 96 hours of symptom onset for improved neurological outcomes. 4, 6 This is FDA-indicated for reducing incidence and severity of ischemic deficits regardless of Hunt and Hess grade. 6

Critical administration warning: NEVER administer nimodipine IV—this has resulted in death, cardiac arrest, cardiovascular collapse, and severe hypotension. 6 If patient cannot swallow, extract capsule contents with 18-gauge needle into oral syringe labeled "Not for IV Use" and administer via nasogastric tube with 30 mL normal saline flush. 6

Pain management: Oral acetaminophen is the foundation for SAH-associated headache. 1, 5 Avoid routine opioids—their efficacy is disappointingly poor with median pain reduction of only -1 point on numeric rating scale. 5

Seizure prophylaxis: Seizures occur in up to 20% of patients, most commonly in first 24 hours. 1 However, phenytoin for seizure prevention is associated with excess morbidity and mortality. 4

Rebleeding Prevention

The highest risk period is the first 24 hours (3-4% rebleeding rate). 1, 2 Bedrest alone does not reduce rebleeding risk but may be included as part of broader treatment strategy. 4

Antifibrinolytic therapy: Routine use is not useful and not recommended. 4

Anticoagulation reversal: If patient is anticoagulated, perform emergency reversal immediately. 4

Transfer and Definitive Management

Transfer immediately to high-volume centers (>35 aSAH cases/year) with neurocritical care services and both neuroendovascular and cerebrovascular surgeons available. 4, 2 Care should be provided in neurocritical care unit by multidisciplinary team. 4

Aneurysm securing: Ruptured aneurysms should be evaluated by both endovascular and neurosurgical specialists. 4 For good-grade aSAH from anterior circulation aneurysms equally suitable for both modalities, primary coiling is preferred over clipping to improve 1-year functional outcome. 4 For posterior circulation aneurysms amenable to treatment, coiling is preferred. 4

Emergency clot evacuation is recommended for salvageable aSAH with large intraparenchymal hematoma. 4

Complications to Monitor

Delayed cerebral ischemia (DCI): Prophylactic hemodynamic augmentation should NOT be performed in patients at risk. 4 Once aneurysm is secured and if DCI develops, induce hypertension unless baseline BP already elevated or cardiac status precludes it. 2

Hydrocephalus: Perform urgent CSF diversion for acute symptomatic hydrocephalus using bundled protocol. 4 Permanent CSF diversion is recommended for chronic symptomatic hydrocephalus. 4

VTE prophylaxis: Once aneurysm is secured, use VTE prophylaxis. 4

Mechanical ventilation: If required, use standardized ICU care bundles. 4

Drug Interactions to Avoid

Strong CYP3A4 inhibitors are contraindicated with nimodipine (clarithromycin, telithromycin, HIV protease inhibitors, ketoconazole, itraconazole, voriconazole, nefazodone). 6 Grapefruit juice must be avoided—effects last at least 4 days after last ingestion. 6

Strong CYP3A4 inducers should generally not be administered (rifampin, carbamazepine, phenobarbital, phenytoin, St. John's Wort) as they significantly reduce nimodipine efficacy. 6

Bottom Line for Interns

Your primary responsibilities are: (1) Recognize the presentation and obtain immediate non-contrast head CT, (2) Maintain systolic BP <160 mmHg with titratable agents, (3) Start nimodipine 60 mg PO every 4 hours within 96 hours, (4) Arrange immediate transfer to neurocritical care center, and (5) Never give nimodipine IV. 4, 1, 6 The first 24 hours carry the highest rebleeding risk—time is brain. 1, 2