Headache has been cited as the fourth most common reason for visits to the emergency department (ED), with an estimated 4 million people in the United States presenting to the ED each year with this complaint.1,2 Although most cases are due to primary headache disorders and ultimately determined to be benign, the consequences of more serious pathology, which accounts for approximately 4% of ED headaches, can be catastrophic, highlighting the importance of accurate diagnosis in this setting.3

Thus, “identifying life-threatening secondary causes of headache — which may be broadly categorized into structural, infectious, and vascular causes — is the primary focus of evaluation in the ED,” because they are associated with high mortality and morbidity, according to a 2019 paper by Murtaza Akhter, MD, assistant professor in the Department of Emergency Medicine at the University of Arizona College of Medicine, Phoenix, and colleagues.3

Screening and Diagnosis

Clinicians should look for red flags that “screen for emergent headaches hiding behind a normal neurologic examination — primarily and classically [intracranial hemorrhage] or meningitis, but also including encephalitis, intracranial abscess, and central venous thrombosis,” the authors wrote.3 Red flags for meningitis, for example, include fever and recent antibiotic use, whereas red flags for elevated intracranial pressure include focal neurological deficits, syncope, seizure, and an immunocompromised state or cancer history.

A thorough history and exam may indicate the need for additional testing, such as neuroimaging or serum or cerebrospinal fluid analysis, although 80% of patients require no further testing.3 If the neurological exam is normal, the risk for malignant pathology decreases from 1 in 20 to 1 in 40.3 Imaging tests may include noncontrast computed tomography (CT) in cases of suspected intracranial hemorrhage, magnetic resonance imaging scans to assess for acute ischemic injury or posterior fossa pathology, CT or magnetic resonance venography for suspected cerebral venous thrombosis, and angiography for suspected dissection or aneurysm.

Being aged >50 years is associated with a substantially greater risk for secondary headache; for example, 10 times higher in a 75-year-old patient vs a 50-year-old patient.4 “This actually supports the practice of scanning practically every patient >75 years old with an undifferentiated headache, given that their risk far exceeds the average risk for patients selected for imaging,” stated Akhter et al.3

Some experts have suggested that the use of CT for headache diagnosis in the ED could be reduced through quality improvement efforts. In a 2018 study, Daniel G. Miller, MD, clinical associate professor of emergency medicine at the University of Iowa, and colleagues observed a 9.6% reduction in such imaging after providers reviewed data regarding their own head CT ordering practices.5 There was no difference in the proportion of death (P =.337) or missed intracranial diagnosis (P =.312) associated with this reduction in CT use.

In their overview of diagnostic and treatment strategies for headaches in the ED, Akhter et al included a special focus on acute meningitis, subarachnoid hemorrhage (SAH), and acute angle-closure glaucoma as potential etiologies.

Meningitis. Although the most specific signs of meningitis are Kernig’s sign (98%), Brudzinski’s sign (98%), and jolt accentuation (82%), their low sensitivities may warrant cerebrospinal fluid analysis “even with a nonfocal neurologic exam without meningeal signs if the history is not adequately reassuring,” Akhter et al wrote.3 Research findings have shown that 77% of patients with meningitis had nonfocal neurologic exams and 30% of patients had no objective neck stiffness.3

“The most reassuring constellation is the complete absence of the triad of fever, neck stiffness, and altered mental status,” the authors noted, as 99% to 100% of patients with meningitis will present with at least 1 of these symptoms.3,6 The presence of any 1 of these signs, however, may necessitate additional workup.

SAH. Approximately 90% and 50% of aneurysmal SAHs present with nonfocal neurologic exams and normal mentation, respectively. “In the absence of focal neurologic findings, the most predictive historical factors to suggest SAH are age >50, sudden onset [Editor’s Note: 97% sensitive for SAH], association with Valsalva or exertion, neck stiffness, first-degree relative(s) with SAH, and history of unconsciousness.”3

Noncontrast CT followed by lumbar puncture represents the current gold standard workup for SAH evaluation; this approach has been found to have 100% sensitivity.7 Various studies have examined less invasive alternatives to lumbar puncture that may be used in patients for whom lumbar puncture is contraindicated. CT angiography was determined to be a reasonable alternative for these patients.3

Acute angle-closure glaucoma. The presentation of acute angle-closure glaucoma, which can include abrupt-onset headache, intense eye pain, vision loss, nausea, and vomiting, may overlap with that of several other diagnoses, such as SAH or cluster headache.3 This can be precipitated by pupillary dilation, which “increases contact between the iris and the lens, acutely closing the angle between the peripheral iris, trabecular meshwork, and cornea, and resulting in a precipitous increase in intraocular pressure,” as explained in the 2019 paper.3

Physical exam findings may include a “red eye with a fixed and mid-dilated pupil, corneal clouding, and a shallow anterior chamber. A measurement of intraocular pressure in the range of 60-90 mm Hg (10-20 mm Hg being normal) is diagnostic of this condition.”3

Neurology Advisor interviewed Dr Akhter and Dr Miller to learn more about managing headache in the ED.

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Neurology Advisor: What are some of the challenges in diagnosing headache in the ED, and how is this typically approached?

Dr Akhter: The main challenge is basically the same as with any complaint in the ED. Namely, is it a life-threatening condition or not? The first step, as always, is to do a thorough history and physical. If something is found that is potentially concerning, then you have to consider next steps to look for said dangerous things.

Dr Miller: One of the main challenges to assessing headaches in ED patients is that the causes of headache are numerous and range from the benign to life-threatening, and the presentations of different conditions have such significant overlap that they can be difficult to differentiate from one another. As an emergency physician (EP), I have cared for several patients with aneurysmal SAH who “looked fine” at the time of their presentation. This can lead practicing clinicians to order advanced imaging on a high percentage of headache evaluations for fear of missing a devastating disease, but this search for a needle in a haystack is low-yield and exposes many patients to expensive testing and radiation exposure.

I suspect that a key feature of our intervention’s success was that it was individualized to the physicians.5 Our study looked at 2 sequential interventions. The first was a general approach of educating EPs about indications for imaging in headache, and this did not yield a significant change. The second intervention helped each EP to analyze her or his own practice patterns, and it was only after this individualized approach that we found brain imaging rates declined by about 10% without any associated increase in missed diagnoses.

Neurology Advisor: What are common treatment approaches for headache in this setting?

Dr Akhter: Treatment completely depends on what you think is causing the headache. If hemorrhagic stroke is causing the headache, for example, the treatment is very different than if there is, say, a tension headache causing the pain. The first thing is to rule out a life-threatening emergency. For analgesia per se, a variety of treatments can be used. One popular approach is the “migraine cocktail,” regardless of whether the cephalgia is truly a migraine or not.

Dr Miller: Although we select specific approaches that are tailored to each individual’s presentation, parenteral antidopaminergic medications are a mainstay of therapy. These are quite safe and generally well-tolerated. As most ED patients have already failed therapies that are available in the home setting, those steps are less often used in the ED. Opiates do not offer a benefit over these therapies, and there are obvious down sides to their use, so most EPs work hard to avoid opiates for the treatment of nontraumatic headache.

Neurology Advisor: What are other relevant recommendations for clinicians?

Dr Akhter: Remember, you are the front line. Neurologists and television commercials say all sorts of scary things, but you … are the actual physician who has to parse out the benign causes from the life-threatening ones. Also, a pro tip: A headache that is not sudden onset, literally thunderclap, is virtually never a SAH.

Dr Miller: In my personal clinical experience, I have found that patients presenting to the ED have 2 concerns that both need to be addressed: They want symptom control, and they are concerned that they might have a life-threatening cause of headache. Clinicians who fail to address both of these concerns are setting themselves up for a failed encounter, typically in the form of repeat visits, low patient satisfaction, or both. Often, an open discussion about the patient’s fears is a more effective means of reassurance than the ordering of expensive tests in the absence of explicitly acknowledging the patient’s fears.

Neurology Advisor: What further research is needed in this area?

Dr Akhter: A ton more research is needed. For one, we need to be able to more specifically, as well as sensitively, diagnose headaches that are present as a result of stroke. Transient ischemic attack can cause a headache and may not present with any other findings on exam or imaging, and therefore is very hard to catch. It would also be great to have a sensitive and specific marker for migraines as opposed to other neurological conditions. Speaking of migraines, more research is needed on better treatments, considering that these are extremely painful conditions and can really degrade a person’s quality of life.

Other points: If any physicians reading this decide to go into academia, consider working with me on the Holy Grail: the troponin of transient ischemic attack. Imagine how much the chest pain workup has changed since the use of troponin, and how different the workup of headache and stroke could be with a similarly sensitive and specific marker.

Dr Miller: The Ottawa Subarachnoid Hemorrhage rule has shown promise, but it cannot rule out SAH in patients older than 40 years.7 With an aging population, it would be beneficial to have a clinical decision rule that can safely exclude SAH in patients older than 40 years.

References

1. Zodda D, Procopio G, Gupta A. Evaluation and management of life-threatening headaches in the emergency department. Emerg Med Pract. 2019;21(2):1-20.

2. Friedman BW. Chapter 21 – presentation of headache in the emergency department and its triage.  In: Diamond S, ed. Headache and Migraine Biology and Management. Bronx, NY: Academic Press; 2015;267-276.

3. Filler L, Akhter M, Nimlos P. Evaluation and management of the emergency department headache. Semin Neurol. 2019; 39(1):20-26.

4. Goldstein J, Camargo C, Pelletier A, Edlow J. Headache in United States emergency departments: demographics, work-up and frequency of pathological diagnoses. Cephalalgia. 2006;26(6):684-690.

5. Miller DG, Vakkalanka P, Moubarek ML, Lee S, Mohr NM. Reduced computed tomography use in the emergency department evaluation of headache was not followed by increased death or missed diagnosis. West J Emerg Med. 2018;19(2):319-326.

6. Attia J, Hatala R, Cook DJ, Wong JG. Does this adult patient have acute meningitis? JAMA. 1999;282(2):175-181.

7. Perry JJ, Stiell IG, Sivilotti ML, et al. Clinical decision rules to rule out subarachnoid hemorrhage for acute headache. JAMA. 2013;310(12):1248-1255.