CJEM Articles: subarachnoid hemorrhage

Objective: Patients with acute headache often undergo com puted tomography (CT) followed by a lumbar puncture to rule out subarachnoid hemorrhage. Our international study exam ined current practice, the perceived need for a clinical deci sion rule for acute headache and the required sensitivity for such a rule.

Methods: We approached 2100 emergency physicians from 4 countries (Australia, Canada, the United Kingdom and the United States) to participate in our survey by sampling the membership of their emergency associations. We used a modified Dillman technique with 3-5 notifications and a prenotification letter employing a combination of electronic mail and postal mail. Physicians were questioned about neu rologically intact patients who presented with headache. Analysis included both descriptive statistics for the entire sample and stratification by country.

Results: The total response rate was 54.7% (1149/2100). Respondents were primarily male (75.5%), with a mean age of 42.5 years and a mean 12.3 years of emergency depart ment (ED) experience. Of the physicians who responded, 49.5% thought all acute headache patients should be investi gated with CT and 57.4% felt CT should always be followed by lumbar puncture. Of the respondents, 95.7% reported they would consider using a clinical decision rule for patients with acute headache to rule out subarachnoid hemorrhage. Respondents deemed the median sensitivity required by such a rule to be 99% (interquartile range 98%-99%). Approxi mately 1 in 5 physicians suggested that 100% sensitivity was required.

Conclusion: Emergency physicians report that they would welcome a clinical decision rule for headache that would determine which patients require costly or invasive tests to rule out subarachnoid hemorrhage. The required sensitivity of such a rule was realistic. These results will inform and inspire the development of clinical decision rules for acute headache in the ED.

Objectives: This study evaluated the incidence of subarachnoid hemorrhage (SAH) and the use of computed tomography (CT) and lumbar puncture (LP) in a cohort of emergency department (ED) patients with acute headache.
Methods: Health records from a tertiary care ED were used to identify all patients over 15 years of age who presented with headache over a 10-month period. Patients were excluded if they had been referred with confirmed SAH or if they had recurrent headache, head trauma, decreased level of consciousness or new neurologic deficits. Outcome measures included ED diagnosis, use of CT or LP, and ED length of stay. Analysis included descriptive statistics, 95% confidence intervals (CIs) and analysis of variance for length of stay.
Results: The mean age of the 891 patients was 41.9 years. Ten (1.1%) of the patients had SAH, 313 (35.1%) underwent CT, and 85 (9.5%) underwent LP. Only 9 (2.9%) of the CT scans and 2 (2.4%) of the LPs were positive for SAH. Of the 296 patients with normal CT results, 232 (78.4%) did not undergo subsequent LP. The mean length of stay was 4.0 hours (95% CI, 3.8-4.1) if no diagnostic testing was performed, 5.0 hours (95% CI, 4.7-5.4) if CT was performed and 7.1 hours (95% CI, 6.3-7.9) if LP was performed (p = 0.001).
Conclusions: Diagnostic testing was associated with substantially prolonged lengths of stay. CT and LP had low diagnostic yields, which suggests the need for a clinical decision rule to rule out SAH in ED patients with acute headache.