EBQ:Perry Subarachnoid Haemorrhage Study

incomplete Journal Club Article

Perry JJ et al. "High risk clinical characteristics for subarachnoid haemorrhage in patients with acute headache: prospective cohort study". BMJ. 2010. 28(341):c5204.
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Clinical Question

What is the sensitivity of non-contrast head CT for detecting spontaneous subarachnoid hemorrhage (SAH), when performed on a third-generation CT scanner within 6 hours of headache onset?

Conclusion

Third-generation non-contrast head CT is highly sensitive for detecting spontaneous SAH when performed within 6 hours of headache onset and interpreted by a radiologist experienced in reading head CT.

Major Points

Within 6 hours of headache onset, CT had:

Sens = 100% (95% confidence interval: 97%-100%)

Spec = 100% (99.5%-100%)

For all patients studied, CT had:

Sens = 92.9% (89%-95.5%)

Spec = 100% (99.9%-100%)

Population

Inclusion Criteria

• >15 years old
• Acute headache reaching peak intensity within one hour
• Normal neurologic exam
• CT ordered by the treating physician to rule out SAH

Exclusion Criteria

• Focal neurologic deficits
• Papilledema
• History of SAH
• History aneurysm
• Previous VP shunt
• Brain neoplasm
• Onset of headache >14 days ago
• Recurrent headache (≥3 similar)
• Transfer with confirmed diagnosis of SAH