Headache is one of the most common presentations in clinical neurology - and potentially, one of the most confusing, unless approached systematically.
Fortunately, many of the headache disorders conform to a specific cluster of characteristics, which can often be identified clinically. Thus, a careful history and examination is key to an accurate diagnosis.
In this patient, the headache is severe and pulsating, with associated nausea and photophobia; note also the presence of a scintillating scotoma, indicating the presence of a visual aura.
The above cluster of findings is almost pathognomonic of a (typical) migraine with a visual aura, as based on the classification outlined by the International Headache Society (IHS).
Migraine is a clinical diagnosis; the U.S. Headache Consortium does not recommend routine investigation of these patients.
Current guidelines recommend the use of migraine specific agents (such as triptans) in individuals with a severe headache; antiemetics should
also be administered in view of the nausea.
Propranolol is used for prophylaxis of migraine, and has no place in the acute setting. Oxygen is a therapeutic option in individuals with cluster headaches.
Migraine is a primary headache disorder characterized by recurrent episodes of headache, each lasting from 4 to 72 hours; in the Global Burden of Disease Survey conducted in 2010, it was ranked as the 3rd most prevalent disorder, and the 7th highest specific cause of disability worldwide.
Migraine has two major subtypes: migraine without aura, and migraine with aura. The remainder of this text focuses on migraine with (typical) aura, which is the type most frequently encountered in clinical practice.
The migraine headache is classically unilateral, throbbing, and moderate to severe in intensity. It builds up over a few hours and may become diffuse over time. Nausea and vomiting are frequently associated symptoms.
The aura can be visual or sensory, or it may involve speech and/or language symptoms. Note that visual auras often present as a fortification spectrum, i.e. a zigzag figure near the point of fixation. In some cases, a scotoma without positive phenomena may occur.
The pathophysiological mechanism underlying migraine with aura is termed 'the cortical spreading depression of Leão'.
The starting event is a brief excitation of the occipital cortical neurons, which then initiates a depolarization wave that travels across the cortex at a rate of 3 to 5 mm/min, giving rise to the aura; prolonged neuronal depression results afterwards.
This sequence of events is followed by a reduction in the regional cerebral blood supply, giving rise to the characteristic headache.
Many factors trigger migraine; e.g stress, hormonal changes, smoking, certain medications and food, exposure to bright light and strong odours. Migraine also has a genetic component, with a significantly increased risk among first degree relatives.
The clinical criteria for the diagnosis of migraine with typical aura are described in the International Classification of Headache Disorders (ICHD); at the time of writing, the 3rd edition (released in 2013) is the most current version.
The diagnostic criteria consist of the following:
A) At least two attacks fulfilling criteria B and C below.
B) Aura consisting of visual, sensory and/or speech/ language symptoms, each fully reversible, but no motor, brainstem or retinal symptoms.
C) At least two of the following four characteristics:
at least one aura symptom spreads gradually over 5 minutes, and/or two or more symptoms occur in succession. each individual aura symptom lasts 5-60 minutes. at least one aura symptom is unilateral. the aura is accompanied, or followed within 60 minutes, by headache. D) Not better accounted for by another ICHD-3 diagnosis, and a transient ischemic attack has been excluded.
The diagnosis is usually evident after a careful history alone, although there are rare secondary mimics including carotid arterial dissection, arteriovenous malformations and seizures.
Note that further investigations should be carried out only if the history and examination is suggestive of a secondary cause.
Several measures have been identified for the successful acute and long term treatment of migraine.
Non-pharmacological measures include patient education on avoiding trigger factors, identifying the headache early in its course, and stress reduction and relaxation where applicable.
It is also essential to engage patients in their own management, and to tailor treatment according to their individual needs.
The US Headache Consortium has several recommendations on the pharmacological management of migraine.
Headaches of mild to moderate severity may be managed with NSAIDs and combination analgesics, i.e. acetaminophen, aspirin and caffeine.
More severe headaches warrant the use of migraine specific agents such as triptans and ergotamine; combination analgesics may be used if the patient has shown a previous response.
Opiates may also be used in selected patients.
Note that acetaminophen alone is not recommended as a specific treatment option for migraine; it has only been found to be effective in combination, as stated above.
Antiemetics should be used in patients with concomitant nausea and vomiting.
Topiramate or propranolol should be prescribed for the prophylaxis of patients with frequent, disabling symptoms.
Although migraine is a chronic condition, remission is known to occur, especially with advancing age.
1. Migraine is a clinical diagnosis. Routine investigations are usually unnecessary.
2. Acetaminophen alone is not recommended as a specific treatment option for migraine.
3. In patients with no contraindications, Triptans are a good first choice for termination of a severe migrainous headache.