Headache Course in Subarachnoid Hemorrhage
Clinical Presentation
Headache in subarachnoid hemorrhage typically presents as sudden-onset, severe pain reaching maximal intensity within 1 hour, described as "the worst headache of my life" by 80% of patients, and is present in 74% of confirmed cases. 1, 2
Characteristic Features
- Onset pattern: The headache reaches peak intensity immediately or within seconds to minutes, distinguishing it from other headache types 1
- Associated symptoms occur in the majority of patients:
Warning/Sentinel Headaches
Sentinel bleeds occur in 10-43% of patients within 2-8 weeks before major rupture and represent a critical diagnostic opportunity. 3, 4
- The sentinel headache is typically milder than the major rupture but may last several days 1
- Nausea and vomiting may occur, but meningismus is uncommon with sentinel hemorrhage 1
- Recognizing sentinel bleeds before catastrophic rupture is lifesaving, as misdiagnosis increases the likelihood of death or disability nearly 4-fold 1, 3
Diagnostic Pitfalls
Misdiagnosis occurs in 12% of cases, with failure to obtain non-contrast head CT being the most common error. 1, 3
- SAH accounts for only 1% of all headaches evaluated in emergency departments, requiring high clinical suspicion 1
- Individual findings occur inconsistently, and headache type is sufficiently variable that classic presentations are not universal 1
- Up to 12% of patients die before receiving medical attention 1
Diagnostic Workup
Imaging Timeline
For patients presenting within 6 hours of headache onset with no new neurological deficits, a negative high-quality non-contrast head CT interpreted by a fellowship-trained neuroradiologist is sufficient to exclude SAH (sensitivity 98.7%, missing <1.5 in 1000 cases). 1
- CT sensitivity remains very high (close to 100%) in the first 3 days after SAH 1
- Sensitivity declines to 93% at 24 hours and 57-85% at 6 days 1
- After 5-7 days, lumbar puncture is required to demonstrate xanthochromia 1
Lumbar Puncture Indications
If CT is negative or nondiagnostic but clinical suspicion remains high, lumbar puncture for xanthochromia evaluation should be performed >6-12 hours after symptom onset (sensitivity 100%, specificity 95.2%). 1
Ottawa SAH Rule Application
The Ottawa SAH Rule identifies patients requiring additional investigation when presenting with severe headache reaching maximum intensity within 1 hour. 1
Criteria requiring workup (any one present):
- Age ≥40 years 1
- Neck pain or stiffness 1
- Witnessed loss of consciousness 1
- Onset during exertion 1
- Thunderclap headache (instantly peaking pain) 1
- Limited neck flexion on examination 1
Headache Management
First-Line Therapy
Oral acetaminophen should be administered to all patients with SAH-associated headache as the foundation of pain management. 2
Blood Pressure Control
Systolic blood pressure should be maintained below 160 mmHg using titratable agents (nicardipine, labetalol, or clevidipine) to prevent rebleeding while managing headache. 2, 4
- Avoid hypervolemia, which increases complications without improving outcomes 2, 4
- Maintain euvolemia rather than hypervolemia 4
Nimodipine Administration
Nimodipine 60 mg every 4 hours for 21 days should be administered to all SAH patients for improved neurological outcomes, with potential secondary benefits for headache management. 2
Persistent Post-SAH Headache
Consider headache specialist referral for patients with persistent post-SAH headache after discharge. 2, 4
- Persistent headaches decrease quality of life and have multimodal pathophysiology 5
- Rapid reduction of opioid medications is recommended if not effective 5
- Consider multimodal pain control strategies including nerve blocks 5
Critical Management Priorities
Early neurosurgical or endovascular intervention is critical to prevent rebleeding, which carries the highest risk in the first 24 hours (3-4% rebleeding rate). 3