Migraines are a common neurological condition characterized by severe headaches, often accompanied by other symptoms like sensitivity to light and sound. These debilitating attacks can significantly impact daily life for those who experience them. Brainstem migraine is a distinct form, presenting with specific neurological features that set it apart.
Understanding Brainstem Migraine
Brainstem migraine, previously known as basilar-type migraine, is a recognized subtype of migraine with aura. The International Classification of Headache Disorders (ICHD-3) defines it as a migraine with aura symptoms clearly originating from the brainstem, without motor weakness. This condition is relatively rare, affecting about 1.5% of individuals with headaches and 6.6% to 10% of those who experience migraine with aura.
The brainstem is a lower part of the brain that connects the cerebrum with the spinal cord and cerebellum, playing a role in many basic functions like breathing, heart rate, and consciousness. Cortical spreading depression (CSD), a wave of neural activity, is thought to be the underlying mechanism for migraine with brainstem aura, similar to typical visual aura. In brainstem migraine, this CSD is believed to originate in the brainstem or in both cerebral hemispheres simultaneously, leading to symptoms that manifest on both sides of the body. The previous belief that the basilar artery was the cause of these attacks, suggesting short-term narrowing or spasm, has since been disproven.
Recognizing the Symptoms
Brainstem migraine attacks are characterized by a range of transient neurological symptoms that arise from brainstem dysfunction. These symptoms develop gradually, lasting between 5 to 60 minutes, and are fully reversible. They may occur before or alongside the migraine headache itself.
Common symptoms include vertigo. Dysarthria is also frequently observed. Other manifestations can include tinnitus, hypacusis, and diplopia. Individuals may also experience ataxia or a decreased level of consciousness, sometimes resembling sleep from which they can be easily aroused. These attacks do not involve motor weakness or retinal symptoms like vision changes in only one eye; such symptoms would indicate different migraine subtypes.
Diagnosing Brainstem Migraine
Diagnosing brainstem migraine primarily relies on a thorough clinical evaluation, including a detailed medical history and a neurological examination. Healthcare professionals look for at least two attacks that meet the specific diagnostic criteria outlined by the ICHD-3. These criteria include the presence of at least two fully reversible brainstem symptoms, without any motor weakness or retinal symptoms.
Diagnosis also rules out conditions like stroke, transient ischemic attack (TIA), seizures, or other cerebrovascular diseases. Imaging studies like an MRI may be performed to exclude these other causes, although the imaging results are normal in cases of brainstem migraine. An electroencephalogram (EEG) may also be conducted to rule out seizure disorders.
Treatment and Management
Treatment for brainstem migraine aims to manage acute attacks and implement preventive strategies to reduce their frequency and severity. Acute treatment involves nonsteroidal anti-inflammatory drugs (NSAIDs) combined with anti-nausea medications like phenothiazine. While triptans and ergotamines were historically avoided due to concerns about their vasoconstrictive effects and a disproven theory of basilar artery involvement, recent research suggests they may be safe options for acute treatment.
For prevention, medications include topiramate, verapamil, and lamotrigine. Newer treatments, CGRP inhibitors like atogepant and rimegepant, and lasmiditan, are available for acute and preventive management. Lifestyle modifications are beneficial, including identifying and avoiding specific triggers, maintaining a regular sleep schedule, managing stress, and engaging in regular exercise.