What Are the Symptoms?
Hemiplegic migraines normally begin in youth, with average onset at 12 years old for familial cases and 17-21 years old for sporadic migraines. In general, this type of migraine often appears to spontaneously resolve with age.
Some common features of hemiplegic migraine include:
- Infrequent attacks: An average of 2-4 per year.
- Complex, prolonged aura symptoms, always including motor weakness on one side of the body, such as difficulty moving the hand, leg or face. Symptoms often start in the hand and gradually spread to the arm and face. These symptoms often last much longer than typical aura symptoms; although they usually resolve within 72 hours, they may occasionally last weeks.
- Muscle weakness typically associated with at least one other aura symptom, including sensory (in 98% of people experiencing the attack): numbness or a prickly sensation in the face, arms and legs; visual (89%): a bright light directly in the field of vision, double vision, flashing lights, and bright, shimmering, jagged lines; speech (79%): inability to understand or express speech; and/or basilar (70%): dizziness, double vision, and lack of coordination.
A person with hemiplegic migraine may display all major aura symptoms, as well as typical migraine headache symptoms: throbbing or pulsating pain on one side of the head, sensitivity to light, sound, and sometimes smell and touch, nausea and vomiting.
What Causes It?
Certain triggers seem to be specific to hemiplegic migraine, and can include mild head trauma or insertion of a cerebral angiography catheter.
Other common triggers for hemiplegic migraine — these seen in other types of migraine as well — include exercise and emotional stress.
People with hemiplegic migraine don’t appear to be hypersensitive to calcitonin gene-related peptides, known to be highly involved in most typical migraines. However, research shows that FHM is 50% heritable; that is, half the risk of getting it comes from a person’s genes, rendering their brain sensitive to attacks from environmental triggers and life events.
How Is It Diagnosed?
To diagnose hemiplegic migraine, healthcare professionals identify characteristic symptoms, take a detailed patient history, and perform a thorough clinical evaluation, and may conduct specialized testing, such as brain imaging and molecular genetic tests.
In general, affected people must have two episodes of migraine with aura that create temporary muscle weakness on one side of the body (hemiplegia), in conjunction with at least one other type of aura symptom. To diagnose FHM, the individual must have at least one close relative with the disorder.
How Is It Treated?
Hemiplegic migraine requires an immediate consultation with a doctor for a proper diagnosis. Because it is relatively rare, it is mostly managed in the same way as typical migraine with aura. Since attacks are relatively infrequent, many patients prefer to take medication only if and when an attack begins.
Recommended medication may include verapamil, a calcium ion channel blocker, for individuals with frequent or prolonged aura; topiramate, an anti-seizure medication, or amitriptyline, an antidepressant, if headache pain predominates; or acetazolamide if there is a family history of hemiplegic migraine.