Clinical decision rule for decreasing unnecessary CT / LP to evaluate for subarachnoid hemorrhage (SAH) in patients with headaches who have none of the following.
- Age > 40 years old
- Neck pain or stiffness
- Witnessed loss of consciousness
- Onset during exertion
- Thunderclap (immediately peaking)
- Limited neck flexion on physical exam
Inclusion criteria:
- Age > 15 years old
- Nontraumatic
- severe headache peaking within 1 hr of onset
Exclusion criteria:
- Neurologic deficits
- Previous aneurisms
- History of brain tumor(s)
- History of recurrent headaches (≥ 3 episodes within 6 months)
Sensitivity: 100% (n=1826, 132 SAH)
Specificity: 15%
NPV: 100%
(-) LR: 0.024
Perry JJ et al. Clinical Decision Rules to Rule Out Subarachnoid Hemorrhage for Acute Headache. JAMA. 2013; 310(12): 1248-1255.