ACEP CLINICAL POLICY - CRITICAL ISSUES IN THE EVALUATION AND MANAGEMENT OF ADULT PATIENTS PRESENTING TO THE EMERGENCY DEPARTMENT WITH ACUTE HEADACHE

While clinical policy does not necessarily establish a standard of care, it is important to know where your organization stands on key clinical questions.  This American College of Emergency Physicians clinical policy summary focuses on the evaluation and management of adult patients presenting to the emergency department with acute, nontraumatic headache.  It focuses on five critical questions: (1) Does a response to therapy predict the etiology of an acute headache? (2) Which patients with headache require neuroimaging in the Emergency Department? (3) Does lumbar puncture need to be routinely performed on ED patients being worked up for nontraumatic subarachnoid hemorrhage whose noncontrast brain computed tomography (CT) scans are interpreted as normal? (4) In which adult patients with a complaint of headache can a lumbar puncture be safely performed without a neuroimaging study? (5) Is there a need for further emergent diagnostic imaging in the patient with sudden-onset, severe headache who has negative findings in both CT and lumbar puncture? 

Edlow, J. et al.  Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Acute Headache. Annals of Emergency Medicine.  Ann Emerg Med. 2008;52:407-436.


1.  For patients presenting to the emergency department (ED) with acute, non-traumatic headache, does response to therapy predict the etiology of an acute headache?

 https://simple.wikipedia.org/wiki/Intravenous_therapy

https://simple.wikipedia.org/wiki/Intravenous_therapy

  • Level A- None specified
  • Level B- None specified
  • Level C- Pain response to therapy should not be used as the sole diagnostic indicator of the underlying etiology of an acute headache

Though there are many different mechanisms that can cause headache (dilation of intracranial arteries, compression of cranial nerves, raised intracranial pressure, etc.), the end result is the release of numerous peptides causing "neurogenic inflammation."  Most of our current headache medications (eg. dihydroergotamine, prochlorperazine, and metoclopramide) target this inflammatory process by acting as an agonist to the serotonin 5-HT receptor.  Therefore, it is possible for a variety headaches to get some relief from our headache medications.  The only published data about response to pain medications as an indicator of underlying headache etiology is limited to case reports and case series.

Take Home Point: Don't put much stock in a patient’s response to pain medication as an indicator for the headache etiology.


2.  Which patients require neuroimaging in the ED?

 https://commons.wikimedia.org/wiki/File:SubarachnoidP.png

https://commons.wikimedia.org/wiki/File:SubarachnoidP.png

  • Level A- None specified
  • Level B- Patients presenting to the ED with headache and abnormal neurologic exam (focal deficit, altered mental status) should undergo an emergent CT brain. Patient presenting with a new onset severe headache should undergo an emergent CT. HIV positive patients with a new headache should be considered for an emergent neuroimaging study.
  • Level C- Patients who are older than 50 years and present with a new type of headache should be considered for an urgent neuroimaging study

Headache patients with abnormal findings on neurologic exam had a three fold increase in having a positive finding on head CT [1]. This is not surprising, and I don’t think that we are going to let patients with a headache and focal deficit go without imaging.

In general, the descriptors "sudden onset headache" and "worst headache of life" have been associated with a higher incidence of serious pathology in literature. The best data (according to ACEP) put the likelihood of serious pathology in these patients between 10-15%[2-5]. They recommend that patient with these headache descriptors undergo neuroimaging/LP to evaluate for SAH.

Patients with HIV are more likely to have space occupying lesions causing their headache. The clinical policy identifies four factors that increase risk of having a space occupying lesion: 1) New seizure, 2)  Altered mental status, 3) Headache different in character from previous, 4) Headache lasting longer than three days.  The presence of one or more of these findings identified all patients with focal lesions[6].


Patients older than 50 with a new type headache were more likely to receive a pathologic diagnosis (OR of 3.3, CI 1.2-9.3) than those under 50 years old [7]. This does not mean emergent imaging in all patients with headache older than 50, but you should think about their ability to follow up with a primary provider and consider calling their PCP to arrange for imaging.


Take home: Image patients with a headache and focal neurologic deficit. Descriptors like the "worst headache of life" and "sudden onset headache" are red flags for subarachnoid hemorrhage. Patients with HIV and new headache should be imaged. Patients > 50 y/o with new headache should have imaging in the ED or close follow up arranged.


3.  Does a lumbar puncture need to be routinely performed on ED patients being worked up for nontraumatic subarachnoid hemorrhage whose noncontrast brain CT scan are interpreted as normal?

 https://commons.wikimedia.org/wiki/File:Meningitis_-_Lumbar_puncture.jpg

https://commons.wikimedia.org/wiki/File:Meningitis_-_Lumbar_puncture.jpg

  • Level A- None specified
  • Level B- In patients presenting to the ED with sudden onset, severe headache and a negative noncontrast head CT, LP should be performed to rule out SAH.
  • Level C- None specified

CT scan has been shown in a number of studies to be very sensitive for detecting SAH within 6 hours of headache onset. These studies have brought into question whether or not an LP is needed if a CT is performed within 6 hours. Depending on who you ask, you will get a different answer to this question. The ACEP clinical policy (albeit written in 2008 and not updated since) states that in all patients for which you are concerned for SAH who have a negative CT scan, a lumbar puncture should be performed to further evaluate for SAH.

Take Home:  Perform a lumbar puncture in patients in whom you are concerned for SAH but have a negative CT scan.


4.  In which adult patients with a complaint of headache can a lumbar puncture be safely performed without a neuroimaging study?

  • Level A- None specified
  • Level B- None specified
  • Level C- Adult patients with a headache and signs of increased ICP (papilledema, absent venous pulsations on fundoscopy, AMS, focal neurologic deficit, signs of meningeal irritation) should undergo a neuroimaging study prior to a lumbar puncture. In the absence of clinical findings suggestive of increased ICP, a lumbar puncture can be safely performed without obtaining a neuroimaging study.

There have been case reports and case series over the past 100 years of patients with increased ICP herniating following lumbar puncture. In the few case series that have been reported, all patients who herniated had examination findings of increased ICP. One small study from Duke found that an emergency physician’s clinical impression had the highest predictive value in determining who had a contraindication to lumbar puncture [8]. There is not much else in the literature looking at this question.

Take Home: If a patient has an abnormal neurologic exam (AMS, focal deficit, signs of meningeal irritation, papilledema) get a CT scan prior to performing an lumbar puncture.


5.  Is there a need for further emergent diagnostic imaging in the patient with sudden onset, severe headache who has negative findings on both CT and lumbar puncture?

  • Level A- None specified
  • Level B- Patients with a sudden onset, severe headache who have negative findings on head CT, normal opening pressure, and negative CSF analysis do not need emergent angiography and can be discharged from the ED with follow up recommended.
  • Level C- none specified

It has been suggested that a lumbar puncture performed prior to 12 hours before symptom onset may give false negative results either because blood has not diffused down or there has not been enough time to allow xanthochromia to appear. Multiple studies have shown that all patients undergoing LP, regardless of time from symptom onset, have RBCs in the lumbar theca. Some people believe that performing CTA after a negative noncontrast study and lumbar puncture is necessary to further evaluate for aneurysms. Multiple studies have looked at morbidity and mortality rates in patients that were worked up for SAH and had a negative CT and lumbar puncture – not one of the patients in any of these studies had SAH in the follow up period (which ranged from 6 months to 3 years)[9-11]. There has been one study looking at CTA as an adjunct to our normal SAH workup – 6 were found to have aneurysms. Of these 6, 3 had positive lumbar punctures, one ended up being a false positive, and one patient declined surgery and remained asymptomatic [12]. Using CTA to diagnose SAH in the ED has not been proven but merits additional study.

Take Home: Currently there is no role for CTA in the workup for SAH if a patient has a negative noncontrast CT head and lumbar puncture.

 

Written by Kevin Kelleher, MD

Edited and Posted by Jeffrey A. Holmes, MD


References

1.  US Headache Consortium. Evidence-based guidelines in the primary care setting: neuroimaging in patients with nonacute headache. American Academy of Neurology, 2000. Available at: http://www.aan.com. Accessed January 1, 2001.

2.  Linn FHH, Wijdicks EFM, van der Graaf Y, et al. Prospective study of sentinel headache in aneurysmal subarachnoid haemorrhage. Lancet. 1994;344:590-593. 36.

3.  Wijdicks EF, Kerkhoff H, van Gijn J. Long-term follow-up of 71 patients with thunderclap headache mimicking subarachnoid haemorrhage. Lancet. 1988;2:68-70.

4.  Landtblom AM, Fridriksson S, Boivie J, et al. Sudden onset headache: a prospective study of features, incidence and causes. Cephalalgia. 2002;22:354-360.

5.  Morgenstern LB, Luna-Gonzales H, Huber JC Jr, et al. Worst headache and subarachnoid hemorrhage: prospective, modern computed tomography and spinal fluid analysis. Ann Emerg Med. 1998;32:297-304.

6.  Rothman RE, Keyl PM, McArthur JC, et al. A decision guideline for emergency department utilization of noncontrast head computed tomography in HIV-infected patients. Acad Emerg Med. 1999;6: 1010-1019.

7.  Goldstein JN, Camargo CA Jr, Pelletier AJ, et al. Headache in United States emergency departments: demographics, work-up and frequency of pathological diagnoses. Cephalalgia. 2006;26: 684-690.

8. Gopol AK, Whitehouse JD, Simel DL, et al. Cranial computed tomography before lumbar puncture: a prospective clinical evaluation. Arch Intern Med. 1999;159:2681-2685.

9.  Perry JJ, Spacek A, Forbes M, et al. Is the combination of negative computed tomography result and negative lumbar
puncture result sufficient to rule out subarachnoid hemorrhage? Ann Emerg Med. 2008;51:707-713.

10.  Landtblom AM, Fridriksson S, Boivie J, et al. Sudden onset headache: a prospective study of features, incidence and causes. Cephalgia. 2002;22:354-360.

11.  Linn FHH, Wijdicks EFM, van der Graaf Y, et al. Prospective study of sentinel headache in aneurysmal subarachnoid haemorrhage.  Lancet. 1994;344:590-593.

12.  Carstairs SD, Tanen DA, Duncan TD, et al. Computed tomographic angiography for the evaluation of aneurysmal subarachnoid hemorrhage. Acad Emerg Med. 2006;13:486-492.