Objectives: There is little evidence guiding physicians in the evaluation of acute headache to rule out nontraumatic subarachnoid hemorrhage (SAH). The authors assessed emergency physicians in: 1) their pretest accuracy for predicting SAH, 2) their comfort with not ordering either head computed tomography (CT) or lumbar puncture (LP) in patients with acute headache, and 3) their comfort with not ordering head CT before performing LP in patients with acute headache.
Methods: This two-and-a-half-year prospective cohort study was conducted in three tertiary care university emergency departments with 51 emergency physicians. Consecutive patients more than 15 years of age with a nontraumatic, acute headache (onset to peak headache less than one hour) and normal results on neurologic examination were enrolled. Patients known to have cerebrospinal fluid shunt, aneurysm, or brain neoplasm, and patients with recurrent headaches of the same intensity/character as their current headache were excluded. Physicians recorded their pretest probability for SAH and their comfort with performing either no tests or an LP without first obtaining head CT.
Results: The authors enrolled 747 patients (mean age 42.8 years; 60.1% female; 77.0% their worst headache; 83.4% had CT and/or LP), including 50 (6.7%) with SAHs. Physicians reported being "uncomfortable" or "very uncomfortable" with performing no test in 75.4% of cases and being "uncomfortable" or "very uncomfortable" with performing LP without CT in 49.6% of cases. The area under the receiver operating characteristic (ROC) curve for SAH was 0.85 (95% CI = 0.80 to 0.91).
Conclusions: Physicians were able to moderately discriminate SAH from other causes of headache before diagnostic testing.