Hemiplegic Migraine: Definition and Diagnostic Criteria
Hemiplegic migraine is a rare subtype of migraine with aura characterized by fully reversible motor weakness (hemiparesis) during attacks, always accompanied by other aura symptoms, and typically followed by headache with migraine features. 1
Diagnostic Criteria
According to the International Classification of Headache Disorders (ICHD-3), hemiplegic migraine is diagnosed based on the following criteria:
Primary Criteria
- At least 2 attacks fulfilling the criteria for migraine with aura 1
- Aura including motor weakness (hemiparesis) 1
- At least one of the following fully reversible aura symptoms:
Aura Characteristics (at least 3 of the following)
- At least 1 aura symptom spreads gradually over ≥5 minutes 1
- Two or more aura symptoms occur in succession 1
- Each individual aura symptom lasts 5-60 minutes (motor symptoms may last up to 72 hours) 1, 2
- At least 1 aura symptom is unilateral 1
- At least 1 aura symptom is positive (e.g., scintillations, pins and needles) 1
- The aura is accompanied by or followed within 60 minutes by headache 1
Classification Types
- Familial Hemiplegic Migraine (FHM): At least one first- or second-degree relative has aura including motor weakness 3, 4
- Sporadic Hemiplegic Migraine (SHM): No family history of motor weakness aura 3, 4
Clinical Features
Common Symptoms
- Motor weakness (hemiparesis) - defining feature 3, 2
- Sensory symptoms (paresthesia) - very common 3
- Visual aura (scintillations, scotoma) 1, 3
- Speech disturbance (aphasia, dysarthria) 1
- Basilar-type symptoms (occur in up to 70% of patients) 4
- Headache with typical migraine features (unilateral, pulsating, moderate to severe intensity) 1
Severe Attack Features
Associated Conditions
- Permanent cerebellar signs (nystagmus, ataxia, dysarthria) - especially with CACNA1A mutations 4
- Intellectual disability (less frequent) 4, 2
- Epilepsy (in some cases) 3, 4
Genetic Aspects
- Three main genes identified: 3, 4, 2
- CACNA1A (chromosome 19)
- ATP1A2 (chromosome 1)
- SCN1A (chromosome 2)
- All three genes encode ion transporters, supporting the channelopathy theory 3, 4
- Genetic testing can confirm but not rule out the diagnosis (as other unknown genes may be involved) 3
Diagnostic Approach
Required Investigations
- Detailed clinical history focusing on aura symptoms, duration, and family history 1, 2
- Neuroimaging (MRI preferred) to exclude secondary causes 3, 2
- Consider EEG and CSF analysis to rule out other conditions 3, 2
Contraindicated Procedures
- Conventional cerebral angiography (may trigger attacks) 3
Treatment Options
Acute Treatment
- Acetaminophen and NSAIDs are first-line options for headache 3
- Triptans are controversial in hemiplegic migraine due to theoretical vasoconstriction concerns 3, 4
- No specific treatment exists for the aura symptoms 3
Preventive Treatment
Consider when:
First-line Preventive Options
- Flunarizine 3
- Sodium valproate (avoid in women of childbearing potential) 3
- Lamotrigine 3
- Verapamil 3
- Acetazolamide 3
Second-line Preventive Options
Emerging Treatments
- Anti-CGRP monoclonal antibodies (e.g., galcanezumab) show promise in reducing both headache and motor weakness in hemiplegic migraine 6
Important Considerations
- Hemiplegic migraine attacks can mimic stroke or transient ischemic attack, requiring careful differential diagnosis 2
- The differential diagnosis is broad and includes other conditions causing transient neurological deficits 2
- Prognosis is generally good, though some patients may develop permanent neurological symptoms 4
- Treatment is largely empirical due to the rarity of the condition and lack of clinical trials 3, 2