A migraine with predominant brainstem aura symptoms is known as a basilar migraine. Bickerstaff first described it in 1961. Other names for it are basilar artery migraine, basilar-type migraine, brainstem migraine, vertebrobasilar migraine, and Bickerstaff migraine. It was named basilar migraine because it was thought to be caused by spasm of the basilar artery. However, there is no proven evidence of vascular pathology for a basilar migraine, and it is now believed to be due to the firing of nerves in the brainstem. It is now recognized as a subtype of migraine with aura and is preferably called "migraine with brainstem aura."
Aura refers to short-lived sensory symptoms experienced just before or during the acute migraine episode. About one-fourth of all migraine patients experience typical aura symptoms. A migraine with brainstem aura (a basilar migraine) is a rare subtype of a migraine with aura that presents with symptoms originating from brainstem or both cerebral hemispheres at the same time.
Exact etiology of migraine with brainstem aura is not known. Like other types of migraine, environmental factors play a role. The genetic role is suggested, but no definite linkage has been found yet. Common triggers (like in other types of a migraine) include strong smells, loud noises, weather changes, excessive sleep, lack of sleep, increased stress, intense physical exertion, oral contraceptives, foods like cheese, alcohol, caffeine, and certain food preservatives like monosodium glutamate (MSG).
Actual prevalence and incidence are unknown. It is more common in females than in males. It can occur at all ages but is more common in adolescence and young adults. The age of onset is usually 7 to 20.
Basilar migraine was initially thought to have vascular pathology caused by short-term spasms of the basilar artery. However, the vascular hypothesis could not be proved, and it is now believed that like other migraine types, the basilar migraine is related to nerves.
Basilar migraine is now believed to be a type of migraine with aura. The aura is a result of cortical spreading depression, which is a self-propagating wave spreading across the cerebral cortex due to the depolarization of neurons and glia. Location of aura symptoms in a basilar migraine is brainstem or both occipital hemispheres; whereas, in migraine with typical aura, it mainly involves a unilateral hemisphere.
There is little data regarding the genetic basis of a basilar migraine. Basilar type aura may be triggered by genes involved in migraine with a typical aura. Some reports suggest that FHM gene may be involved in a basilar migraine without hemiplegia. However, no definitive genetic linkage is identified.
History and Physical
Brainstem aura symptoms include vertigo, dysarthria, diplopia, tinnitus, impaired hearing, lack of coordination, confusion, and sometimes loss of consciousness. The most common symptom is vertigo. Most patients also have typical aura symptoms like photopsia, loss of vision, paresthesia, speech, and language problems like word-finding difficulty, language comprehension, and difficulty reading. Some patients may have associated anxiety and hyperventilation which can lead to misdiagnosis. All aura symptoms are completely reversible. Aura symptoms can last a few minutes to an hour followed by an occipital headache that may last hours to days. Rarely, migraine with brainstem aura occurs without a headache. Prodromal symptoms of migraine-like mood swings, irritability, tiredness, nausea, and neck pain should not be confused with aura symptoms. There are no motor or retinal symptoms in migraine with brainstem aura and symptoms like weakness, paralysis, loss of vision in one eye should prompt evaluation for an alternate diagnosis.
Symptoms can be very frightening especially when they occur the first time or until a definite diagnosis is made. Symptoms of brainstem aura can mimic some serious diseases like stroke, tumors, and infections, so it is important to seek medical attention the first time or if there is any change in symptom severity and frequency. Symptoms of migraines with brainstem aura are usually more frightening than harmful, as they are completely reversible.
The International Classification of headache disorders outlined the following criteria for the diagnosis of basilar migraine.
- (A) Symptoms not attributed to another disorder
- (B) At least 2 attacks that fulfill criteria C, D, or E
- (C) Aura with more than one of the following symptoms: dysarthria, vertigo, tinnitus, hearing impairment, diplopia, ataxia, decreased level of consciousness, bilateral paresthesia, with no motor or retinal symptoms and completely reversible symptoms
- (D) At least one of the following: At least 1 aura symptom occurring gradually over 5 minutes or more and/or 2 or more symptoms occurring in succession over 5 minutes or more, each aura symptom lasts more than 5 minutes, but less than 60 minutes, at least 1 aura symptom is unilateral
- (E) Migraine without aura begins during the aura or within 1 hour.
Brain imaging like MRI head, MRA head, or CT angiography is usually indicated to rule out other pathologies like stroke, AV malformations, and tumors. EEG is indicated to rule out seizures especially when there is confusion and decreased the level of consciousness. Rarely, 24-hour Holter monitoring is required to rule out arrhythmias.
- A basilar migraine can mimic a hemiplegic migraine and migraine with typical aura.
- Other differentials that should be excluded before a clinician makes a definite diagnosis of a basilar migraine include Meniere disease, vestibular disease, transient ischemic attack (TIA), stroke, brainstem atrioventricular (AV) malformation, tumors, and meningitis.
Brainstem aura migraine is often more disabling than migraine without aura and migraine with typical aura, because of increased severity and longer duration of symptoms. The frequency of brainstem aura decreases with age, and they often evolve in more typical patterns with age.
Migraines with aura have a slightly higher risk of stroke than migraine without aura; however, there is no evidence that migraine with brainstem aura has a higher risk of stroke than migraine with typical aura.
Smoking and the use of estrogen contraceptives further increase the risk of stroke, and risk factor modification should be reinforced to all patients.
The patients can sustain falls if they suddenly lose consciousness as a part of the aura.
Deterrence and Patient Education
The pharmacist should educate the patient on the best medications to manage the headache. In addition, nausea and vomiting also require treatment. Patients need to understand that compliance with these agents is needed for the resolution of the headache. Because the headache is difficult to manage once it has started, prevention is key. The pharmacist and the primary care clinician should encourage the patient to make changes in lifestyle and avoid the triggers. A headache journal should be kept to track the symptoms and triggers. A healthy diet, regular exercise, adequate sleep, and stress relief can lower the risk of basilar migraine. Even setting a mealtime is necessary as skipping meals can trigger a basilar migraine. Finally, patients need to be educated that reliance on natural substances and herbs may not be wise as there is little evidence that these products can produce pain relief.
Enhancing Healthcare Team Outcomes
Basilar migraines are challenging to diagnose and treat. They require an interprofessional team of a neurologic headache specialist, nurse experienced with headache management and patient education, and pharmacist to assist with medication management to obtain the best results. Unlike the traditional migraine, basilar migraine does respond to over the counter NSAIDs and hence patient education is vital. It is important to speak to a headache specialist before trying natural alternatives. Open communication between the clinicians and the neurologist is vital to ensure that the patient is receiving the accepted standard of care. [Level V]