Michael Eller; Peter J Goadsby


Expert Rev Neurother. 2013;13(3):263-273. 

In This Article

Headache & Red Flags in the Emergency Department

MRI in primary headache is a clinical decision typically considered in an ambulant setting. This outpatient clinical context has been emphasized in this paper. Of course, many people will present to a hospital, particularly when symptoms begin. The use of red flags is equally apposite in this setting. While a comprehensive review of the diagnostic work-up of headache in the emergency department (ED) and subsequent management is beyond the scope of this paper, it is worth highlighting the following two points: almost any condition can manifest with the symptom of headache and most people presenting to the ED with this complaint will be discharged with a primary headache diagnosis.[50]

People may present to the ED with the primary complaint of headache for a variety of reasons, not always explicit. These range from concern about the cause of their headache to acquiring a prescription for migraine treatment. Headache accounted for 2.2% of all adult visits to the ED in the USA from 1991 to 2002 (2.1 million/year). From data derived from a representative sample, a total of 14% underwent imaging, typically CT. A benign diagnosis was made in 98% of the patients, of which 63.5% had migraine. A pathological diagnosis was made in 2% of the patients, and was more frequent in older patients: ischemic stroke and transient ischemic attack in 0.8%, intracranial hemorrhage and SAH in 0.6%, meningitis and encephalitis in 0.5%, and other diagnosis seen in 0.2%.[50] While MRI will often have a place in the work-up of these and other pathological diagnoses, any specifics, such as the use of MRI in the diagnosis of stroke, are beyond the scope of this article.

Diagnosis among headache presentations begins with the dichotomy of a primary versus secondary condition, and largely follows the contours of the ICHD. This is often a straightforward decision. In one study of emergency medicine investigators, there was a high level of interobserver agreement on secondary headaches (94%) and primary headaches (91%).[51] Of course this diagnostic decision can also represent one of the thorniest in medicine. Red flags, expounded in Box 1, are a useful strategy to help diagnose secondary headache regardless of the clinical context, and will often call for an emergent or elective MRI brain scan to help make a definitive diagnosis.