One of three rules might eliminate unnecessary evaluation of patients with acute headache.
Because subarachnoid hemorrhage (SAH) is a potentially devastating cause of acute headache, many patients with acute headache undergo extensive testing (e.g., computed tomography [CT], lumbar puncture) to rule it out. In this 5-year multicenter prospective Canadian study that involved nearly 2000 neurologically intact adults who presented with acute (peaking within 1 hour) nontraumatic headache, investigators sought to identify clinical characteristics that predicted SAH.
Overall, 130 patients had SAH. Sixteen clinical characteristics were associated significantly with SAH and were used to create three possible clinical decision rules:
- Rule 1: age >40, complaint of neck pain or stiffness, witnessed loss of consciousness, onset of headache with exertion.
- Rule 2: arrival by ambulance, age >45, vomiting at least once, diastolic blood pressure >100 mm Hg.
- Rule 3: arrival by ambulance, systolic blood pressure >160 mm Hg, complaint of neck pain or stiffness, age 45–55.
Although these decision rules are promising, they must be validated in other populations before they are used routinely; indeed, the authors note that a prospective validation study is under way. But, in the meantime, the findings provide guidance: Patients who present with nontraumatic headaches that peak within 1 hour and who have any of the clinical characteristics mentioned in the rules above should be assessed carefully for SAH. As the authors note, validated rules "could allow clinicians to be more selective and accurate when investigating patients with headache" and lower use of CT and lumbar puncture.
Paul S. Mueller, MD, MPH, FACP
Published in Journal Watch General Medicine November 9, 2010
Citation(s): Perry JJ et al. High risk clinical characteristics for subarachnoid haemorrhage in patients with acute headache: Prospective cohort study. BMJ 2010 Oct 28; 341:c5204. (http://dx.doi.org/10.1136/bmj.c5204)