UMEM Educational Pearls

Category: Neurology

Title: Acute Nontraumatic Headache: CT/LP or Not?

Keywords: ACEP, SAH, imaging, nonopioid, CTA, LP (PubMed Search)

Posted: 9/25/2019 by WanTsu Wendy Chang, MD
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  • The ACEP clinical policy on the evaluation and management of acute nontraumatic headache in the ED was recently updated.
  • Similar to prior policies, it focuses on the diagnosis of subarachnoid hemorrhage (SAH) due to the disproportionate amount of literature in comparison to other high risk etiologies.
  • In summary:

    1. Are there risk-stratification strategies that reliably identify the need for emergent neuroimaging?
      • The Ottawa SAH Rule has a high sensitivity but low specificity for patients presenting with a normal neurological exam and peak headache intensity within 1 hour of symptom onset (Level B recommendation).
      • Caution in application of this rule, as use in the incorrect population may increase unnecessary testing.
    2. Are nonopioids preferred to opioids for treatment of acute primary headache?
      • Preferentially use nonopioid medications in the treatment of acute primary headaches in ED patients (Level A recommendation).
      • Consider discharge medication and education to reduce headache recurrence and repeat ED visit.
    3. Does a normal noncontrast head CT performed within 6 hours of headache onset preclude the need for further diagnostic workup for SAH?
      • Noncontrast head CT using at least a 3rd generation scanner performed within 6 hours of headache onset can be used to rule out nontraumatic SAH (Level B recommendation).
      • If clinical suspicion remains high despite the negative noncontrast head CT, further evaluation may be pursued.
    4. In a patient who is still considered to be at risk for SAH after a negative noncontrast head CT, is CTA as effective as LP to rule out SAH?
      • Use shared decision making to select the best modality for each patient after weighing the potential for false-positive CTA and the pros/cons associated with LP (Level C recommendation).
  • This clinical policy does not address the evaluation of other potential etiologies for acute headache, including in the pregnant woman and postpartum woman. 


Godwin SA, Cherkas DS, Panagos PD, et al. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with acute headache. Ann Emerg Med 2019;74(4):e41-74. 


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