A typical migraine involves a moderate to severe throbbing headache, usually on one side of the head, often accompanied by sensitivity to light and sound, and nausea. An aura, a temporary neurological disturbance, may precede the pain, typically featuring visual changes like zigzag lines or flashing lights. An atypical migraine deviates from this standard presentation by featuring unusual or prolonged symptoms, non-headache manifestations, or neurological features that mimic serious conditions. The term “atypical” is an informal but widely used way to categorize these complex presentations, which do not fit neatly into standard diagnostic criteria. This category includes attacks where the primary symptom is not a headache, or where neurological deficits are severe or long-lasting.
Defining the Atypical Presentation
Migraines are labeled “atypical” when their characteristics deviate significantly from the common profile of a four-phase attack that includes a headache. This often involves a focus on the aura phase, where the neurological symptoms are the most prominent part of the episode. A primary example is Migraine Aura Without Headache, sometimes called “silent migraine” or “acephalgic migraine.” In these episodes, a person experiences the visual disturbances, numbness, or difficulty speaking of an aura, but the expected throbbing head pain never develops.
The aura itself can also be atypical by being prolonged, lasting longer than the typical one-hour duration, or by involving symptoms not typically associated with a standard migraine. These presentations may include sensory changes like tingling that spreads slowly from the hand up the arm, or temporary weakness affecting one side of the body. The neurological symptoms in an atypical migraine are temporary and fully reversible, but they can severely disrupt daily life.
Atypical presentations are often characterized by symptoms that affect areas outside of the head, such as the inner ear or the visual system. Vestibular symptoms, including a sensation of spinning or unsteadiness, are common in these complex attacks. Some atypical migraines may feature autonomic symptoms like nasal congestion, facial flushing, or eyelid drooping, suggesting a broader involvement of the nervous system.
Recognized Syndromes of Atypical Migraine
The category of atypical migraine includes several specific, recognized syndromes defined by their distinct and complex neurological symptoms. These conditions are classified under the broader umbrella of migraine with aura, but their unique features set them apart from the more common visual aura.
Vestibular Migraine
Vestibular migraine is a condition where the primary complaint is not headache, but episodes of dizziness, vertigo, or a sense of unsteadiness. Vertigo, the sensation of spinning or moving when standing still, can last from a few minutes up to 72 hours. People with this syndrome may also experience a reduced tolerance for quick head movements, or a feeling of pressure or fullness in the ear. While a headache may be present during the attack, it is often absent or a minor symptom, making the vertigo the most prominent feature. The diagnostic criteria require at least five episodes of moderate to severe vestibular symptoms and a history of migraine symptoms.
Hemiplegic Migraine
Hemiplegic migraine is a rare form of migraine aura characterized by temporary weakness or paralysis on one side of the body. The motor weakness can affect the face, arm, or leg, and typically occurs during the aura phase, before or during the headache. This one-sided weakness can be accompanied by other neurological symptoms, such as speech difficulties, confusion, or sensory changes like tingling.
This syndrome is classified into two types: familial hemiplegic migraine (FHM) and sporadic hemiplegic migraine (SHM). FHM is diagnosed when at least one first- or second-degree relative has experienced aura with motor weakness, and it is often linked to genetic mutations in genes like CACNA1A or ATP1A2. SHM refers to cases where there is no known family history of the condition.
Retinal/Ocular Migraine
Retinal migraine, also known as ocular migraine, is distinguished by temporary visual disturbances or total vision loss that affects only one eye. The visual symptoms, which can include flashing lights, zigzag lines, or a blind spot called a scotoma, usually last between 10 and 20 minutes. The visual changes are monocular, which differentiates it from the typical migraine aura that affects the visual field of both eyes. The headache phase, which can be moderate to severe, often begins during or within an hour of the visual symptoms subsiding. While the visual loss is typically brief and reversible, a full medical evaluation is necessary to rule out more serious causes of monocular vision changes.
Diagnosis and Differential Considerations
Diagnosing an atypical migraine requires ruling out other, often life-threatening, neurological conditions that share similar symptoms. The stroke-like presentation, such as one-sided weakness, difficulty speaking, or sudden vision loss, means doctors must first consider a transient ischemic attack (TIA) or an ischemic stroke. Unlike the gradual onset of a migraine aura, symptoms of a TIA or stroke typically begin abruptly.
To exclude these vascular events, a healthcare provider will often order neuroimaging tests, such as a brain magnetic resonance imaging (MRI) and a magnetic resonance angiography (MRA). These scans help visualize the brain tissue and blood vessels, confirming the absence of blockages or damage indicative of a stroke. Patient history is also important, as a history of recurrent, self-resolving neurological deficits points toward an atypical migraine.
The differential diagnosis must also consider seizure disorders, which can present with postictal paralysis or other focal neurological deficits. The physician must analyze the progression of symptoms, as migraine aura symptoms tend to spread gradually over several minutes, while a stroke-related deficit is usually sudden. The definitive diagnosis of an atypical migraine is generally made by exclusion.