Low-to-moderate frequency headaches of long duration include episodic migraine and episodic tension-type headache. The main pain features of tension-type headache are bilateral location, non-pulsating quality, mild to moderate intensity, and lack of aggravation by routine physical activity. The pain is not accompanied by nausea or vomiting, although either photophobia or phonophobia (but not both) may occur (Headache Classification Committee of the International Headache Society 2013). Even though episodic tension-type headache is the most prevalent primary headache disorder in the population, it is not a frequent cause of medical visits.
Migraines are the most common acute headaches seen in the emergency department, by far more frequent than secondary headaches (Friedman and Grosberg 2009). Migraine attacks in the acute care setting are usually severe, throbbing, and associated with nausea, photophobia, or phonophobia. If the attack is severe, the patient may be prostrate and pale, sometimes vomiting. Although unilaterality of pain is a diagnostic criterion, it may be bilateral. It is not necessary to investigate a typical attack. However, migraine-like attacks not responsive to treatment and requiring prolonged observation (longer than 12 hours) should be investigated.
Presentations other than typical migraine with or without aura are more common in the emergency department than in other settings. Migraine with brainstem aura is a subtype characterized by at least 2 of the following aura symptoms, all fully reversible: dysarthria, vertigo, tinnitus, decreased hearing, double vision, ataxia, and decreased level of consciousness. The headache fulfills criteria for migraine (Headache Classification Committee of the International Headache Society 2013).
Hemiplegic migraine is the first migraine syndrome to be linked to a specific set of genetic polymorphisms (Stillman 2009). This is migraine with aura, except that the aura includes some degree of motor weakness (hemiparesis) and may be more prolonged than 60 minutes (up to 24 hours). In familial hemiplegic migraine, at least 1 first-degree relative has had similar attacks (also meeting these criteria). Cerebellar ataxia occurs in 20% of familial hemiplegic migraine sufferers. Headaches that otherwise meet these criteria but present without family history of the disorder are classified as sporadic hemiplegic migraine. Unless patients already have a diagnosis of hemiplegic migraine (and were, therefore, previously investigated), additional investigation is necessary.
Status migrainosus refers to an attack of migraine with a headache phase that lasts longer than 72 hours. The pain and associated symptoms are debilitating, by definition.
Persistent aura without infarction is diagnosed when aura symptoms, otherwise typical of past attacks, persist for more than one week, and investigation shows no evidence of infarction. It is an unusual but well-documented complication of migraine that is now included in the International Headache Society classification.
Migrainous infarction is an uncommon occurrence. One or more otherwise typical aura symptoms persist beyond 1 hour, and neuroimaging confirms ischemic infarction. Strictly applied, these criteria distinguish this disorder from other causes of stroke, which must be excluded. The neurologic deficit develops during the course of an apparently typical attack of migraine with aura and exactly mimics the aura of previous attacks (Headache Classification Committee of the International Headache Society 2013).