Migraine is a neurological disorder that extends beyond a simple, severe headache. While many people experience the classic pattern of a headache preceded by sensory disturbances, others encounter less common presentations. These “migraine variants” are conditions where the neurological symptoms, known as aura, are the dominant feature, often occurring without the head pain typically associated with a migraine attack. Understanding these distinct patterns is important because the symptoms can be alarming and often mimic other serious medical events.
Defining Atypical Migraine Presentations
A migraine variant is a clinical term for a migraine attack where the neurological symptoms are atypical in their duration, type, or relationship to the headache phase. These presentations are classified by the International Classification of Headache Disorders (ICHD-3) as specific subtypes of migraine with aura. The core difference is that the transient neurological deficits, or aura, become the primary feature of the episode. This classification includes episodes where the aura is unusually prolonged or where the headache phase is entirely absent. The underlying mechanism for aura is Cortical Spreading Depression (CSD), a slow wave of electrical and chemical change that moves across the brain’s surface.
Sensory and Visual Variants
One of the most common atypical presentations is Migraine Aura without Headache, often referred to as a “silent migraine” or acephalgic migraine. In this variant, the characteristic aura symptoms occur, but the head pain phase is missing. Symptoms commonly include visual disturbances, such as flashing lights, zigzag lines, or temporary blind spots (scotomas). Sensory aura can also occur without a headache, presenting as tingling or numbness (paresthesia) that gradually spreads across one side of the face, hand, or arm. These symptoms typically last between five and 60 minutes, mirroring the duration of a typical aura.
Another distinct visual variant is Retinal Migraine, characterized by repeated attacks of temporary vision loss or blindness in only one eye. Unlike typical migraine aura, retinal migraine is monocular. This temporary vision loss is believed to be caused by a temporary narrowing of blood vessels supplying the retina. The visual disturbance in the single eye may involve flickering lights or a blind spot, usually resolving completely within an hour.
Variants Affecting Motor Function and Brainstem
Variants involve motor weakness or symptoms originating from the brainstem. Hemiplegic Migraine (HM) is a rare but serious subtype characterized by temporary paralysis or weakness (hemiparesis) on one side of the body. This motor weakness is always associated with other aura symptoms, such as sensory, visual, or speech difficulties, and can last from a few hours up to several days. Hemiplegic migraine is categorized as either Familial (FHM) or Sporadic (SHM). FHM is diagnosed when a patient has at least one first- or second-degree relative who also experiences attacks with motor weakness.
Migraine with Brainstem Aura, formerly known as Basilar Migraine, involves symptoms that originate from the brainstem area. Diagnostic criteria require at least two fully reversible symptoms:
- Vertigo
- Slurred speech (dysarthria)
- Double vision (diplopia)
- Ringing in the ears (tinnitus)
- Unsteadiness (ataxia)
These symptoms are often accompanied by a headache, but this variant does not include motor weakness or retinal symptoms.
Clinical Identification and Management
The primary challenge in managing migraine variants is the necessity of a differential diagnosis, as the symptoms often mimic life-threatening conditions. Transient neurological deficits, especially motor weakness or speech difficulty, must first be investigated to rule out stroke, transient ischemic attack (TIA), or epilepsy. This process typically involves neuroimaging (MRI or CT scan) and sometimes an electroencephalogram (EEG) to exclude a structural cause or seizure activity.
Once a migraine variant is identified, management focuses on acute treatment and prevention. Acute medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen, are used for pain relief. However, in variants like Hemiplegic Migraine, triptans are generally avoided due to concerns about vascular constriction. Preventative therapy, using medications like beta-blockers or anti-epileptic drugs, is recommended for patients with frequent or severe attacks to reduce the frequency and intensity of episodes.