Overview
Definition:
Migraine aura is a transient neurological symptom that precedes or accompanies a migraine headache
It typically involves sensory disturbances
Hemiplegic migraine is a rare subtype of migraine with aura, characterized by neurological deficits, particularly motor weakness (hemiplegia), which can mimic stroke
This form is often genetic and can be familial or sporadic, presenting a significant diagnostic and management challenge in adolescents.
Epidemiology:
Migraine is common in adolescents, with prevalence rates varying from 5-20%
Migraine with aura occurs in approximately 20-30% of migraineurs
Hemiplegic migraine is much rarer, with an estimated incidence of 1 in 10,000 to 1 in 50,000, and accounts for a small percentage of all migraine cases
Genetic forms (FHM) are most common in children and adolescents, often presenting before age 5 but can manifest later.
Clinical Significance:
Differentiating between typical migraine aura and hemiplegic migraine is critical for accurate diagnosis and appropriate management in adolescents
Misdiagnosis of hemiplegic migraine as stroke or other neurological emergencies can lead to delayed treatment and unnecessary interventions
Understanding the genetic basis and management nuances is vital for pediatricians and neurologists preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Migraine aura symptoms are typically visual (scintillating scotoma, photopsia, zigzag lines, visual loss)
Other sensory symptoms include paresthesias (tingling, numbness) usually starting in the hand and spreading up the arm to the face
Motor symptoms are less common but can include transient weakness
Hemiplegic migraine symptoms include unilateral weakness (hemiparesis/hemiplegia), often accompanied by aura symptoms, severe headache, nausea, vomiting, photophobia, and phonophobia
Attacks can last from hours to days and may have residual weakness.
Signs:
During an attack of hemiplegic migraine, focal neurological deficits, including hemiparesis or hemiplegia, may be evident on neurological examination
Deep tendon reflexes may be exaggerated on the affected side, and Babinski sign may be positive
Other findings may include nystagmus, ataxia, or dysarthria
In typical migraine aura, examination findings are usually normal between attacks and may be non-specific during the headache phase.
Diagnostic Criteria:
According to the International Classification of Headache Disorders (ICHD-3), hemiplegic migraine is classified as: 1.1.1 Familial Hemiplegic Migraine (FHM): A migraine attack associated with aura including neurological symptoms typical of hemiplegic migraine, with at least one first-degree or second-degree relative having similar attacks and fulfilling criteria for FHM
Caused by mutations in CACNA1A, ATP1A2, or SCN1A genes
1.1.2 Sporadic Hemiplegic Migraine (SHM): Similar presentation to FHM but without a family history of hemiplegic migraine
May be associated with de novo mutations in genes relevant to FHM or other genes
Migraine with aura criteria (ICHD-3): At least one aura symptom (fully reversible visual, sensory or speech and/or language symptoms, motor symptoms are not included) that gradually develops
and/or at least two of the following characteristics: unilateral location
gradual onset
progression
duration of 5-60 minutes for each symptom
at least one symptom is unilateral
at least one symptom is positive
and the aura is accompanied, or followed within 60 minutes, by headache.
Diagnostic Approach
History Taking:
Detailed history is paramount
Ascertain the exact nature of aura symptoms (visual, sensory, motor), their progression, duration, and unilaterality
Inquire about associated headache characteristics (intensity, location, quality, exacerbating/relieving factors)
Assess for accompanying symptoms like nausea, vomiting, photophobia, phonophobia
Crucially, explore family history for migraines or similar neurological episodes, paying attention to the pattern of inheritance for suspected FHM
Red flags include: sudden onset of severe headache ("thunderclap"), focal neurological deficits lasting longer than typical aura, fever, altered consciousness, seizures not typical for migraine, and absence of typical migraine features.
Physical Examination:
A thorough neurological examination is essential, focusing on cranial nerves, motor strength, sensation, reflexes, coordination, and gait
Examination should be performed during an aura or headache episode if possible, and also during symptom-free intervals to detect subtle deficits
Evaluate for signs of meningeal irritation or increased intracranial pressure
A complete systemic examination should be performed to rule out other potential causes.
Investigations:
Neuroimaging is crucial for suspected hemiplegic migraine to rule out structural lesions like stroke or tumor
MRI brain with contrast is preferred over CT
Diffusion-weighted imaging (DWI) can help identify ischemic stroke
MRI may show transient changes during acute hemiplegic migraine attacks, such as T2/FLAIR hyperintensities in cortical or subcortical areas, particularly in the posterior circulation territory, which usually resolve
EEG may be normal between attacks but can show focal slowing during an episode
Genetic testing for FHM genes (CACNA1A, ATP1A2, SCN1A) is indicated in suspected familial cases
Lumbar puncture may be considered to rule out CNS infections or inflammatory conditions, though often normal in hemiplegic migraine.
Differential Diagnosis:
Differential diagnoses for hemiplegic migraine in adolescents include: Transient Ischemic Attack (TIA) or Stroke (especially in young adults with risk factors), Seizures (particularly complex partial seizures with aura-like features and postictal deficit), Migraine with typical aura (without hemiplegia), Basilar migraine (aura symptoms originate from brainstem), Alternating Hemiplegia of Childhood (AHC - a distinct disorder with similar but more severe and recurrent attacks), Migraine accompaniments (rare, prolonged aura), Intracranial mass (tumor, abscess), CNS infection (meningitis, encephalitis), Metabolic disorders, and Todd's paresis (transient hemiplegia following a seizure).
Management
Initial Management:
For suspected hemiplegic migraine, immediate neurological assessment is required
Rule out mimics of stroke with urgent neuroimaging (MRI brain with DWI)
Stabilize the patient, manage nausea and vomiting with antiemetics (e.g., ondansetron 0.1 mg/kg IV/PO)
Pain management should be cautious due to potential for medication overuse headache and the need to differentiate from typical migraine
abortive agents like triptans (sumatriptan, rizatriptan) can be used if diagnosis is clear and no contraindications exist, but their efficacy in hemiplegic attacks is variable
IV fluids may be necessary for dehydration.
Medical Management:
Acute management for hemiplegic migraine attacks is often supportive and may include hydration, antiemetics, and analgesics
Triptans can be considered for abortive treatment if prescribed by a specialist and no contraindications are present
For FHM, prophylactic medications are often necessary and may include calcium channel blockers (verapamil), beta-blockers (propranolol), or antiepileptic drugs (topiramate, valproate)
Newer treatments targeting specific genetic pathways are under investigation
Avoidance of triggers, if identified, is important.
Surgical Management:
Surgical management is not indicated for hemiplegic migraine itself
However, if investigations reveal an underlying structural lesion mimicking hemiplegic migraine (e.g., tumor, vascular malformation), surgical intervention would be guided by the specific pathology.
Supportive Care:
Supportive care includes ensuring adequate hydration and nutrition, managing sleep disturbances, and providing emotional support
Patients and families should be educated about the condition, potential triggers, and the importance of adherence to prophylactic therapy
Regular follow-up with a pediatric neurologist is crucial to monitor symptom frequency and severity, adjust medications, and assess for any long-term sequelae.
Complications
Early Complications:
Prolonged hemiplegia or hemiparesis lasting beyond the typical migraine attack duration
Recurrent attacks leading to significant functional impairment and disruption of daily life (school attendance, social activities)
Dehydration and electrolyte imbalances due to intractable vomiting
Seizures can occur, especially in genetic forms or during severe attacks
Potential for misdiagnosis leading to delayed or inappropriate treatment for other serious conditions like stroke.
Late Complications:
In some cases of hemiplegic migraine, particularly severe or prolonged attacks, residual neurological deficits may persist
Chronic disability and reduced quality of life due to frequent debilitating attacks
Increased risk of cognitive impairment or learning difficulties in children with early onset and frequent severe hemiplegic migraine attacks
Development of medication overuse headache if abortive medications are used excessively.
Prevention Strategies:
Identifying and avoiding known triggers (stress, certain foods, sleep deprivation, etc.)
Regular prophylactic medication as prescribed by a neurologist
Maintaining a healthy lifestyle including regular sleep, exercise, and stress management
Close monitoring and timely adjustment of prophylactic therapy based on symptom frequency and severity
Genetic counseling for families with known FHM mutations.
Prognosis
Factors Affecting Prognosis:
The prognosis for hemiplegic migraine varies
Favorable prognosis is associated with milder attacks, shorter duration of hemiplegia, successful prophylactic treatment, and absence of significant residual neurological deficits
Prognosis can be poorer in sporadic forms with severe or prolonged attacks, early onset, or associated genetic mutations leading to more complex neurological phenotypes.
Outcomes:
Many individuals with hemiplegic migraine can achieve good symptom control with appropriate prophylactic treatment, leading to a reduction in attack frequency and severity, and improved quality of life
Some may experience complete remission or significant improvement in adulthood
However, a subset may experience chronic disability and persistent neurological deficits.
Follow Up:
Long-term follow-up with a pediatric neurologist is essential
This includes regular clinical assessments to monitor headache frequency, duration, and severity, as well as any changes in neurological status
Imaging may be repeated if there is a change in clinical status
Genetic counseling and testing may be ongoing
Patients and families should be empowered to manage the condition and seek help promptly if attacks worsen or new symptoms emerge.
Key Points
Exam Focus:
Differentiating hemiplegic migraine from stroke in adolescents is a critical exam scenario
Remember the genetic basis of FHM and key genes involved
Understand ICHD-3 diagnostic criteria for hemiplegic migraine
Recognize that MRI may show transient abnormalities during an attack but is primarily used to rule out stroke.
Clinical Pearls:
Always consider hemiplegic migraine in an adolescent presenting with hemiparesis and headache, especially with a positive family history
The history of gradual onset and progression of neurological symptoms, along with typical migraine features, can help distinguish it from stroke
Do not hesitate to initiate prophylactic treatment if attacks are frequent and debilitating.
Common Mistakes:
Mistaking hemiplegic migraine for an ischemic stroke and delaying appropriate migraine-specific management
Inadequate investigation for underlying structural lesions or metabolic causes
Over-reliance on abortive therapies without considering prophylactic management for frequent attacks
Failing to take a thorough family history, which is crucial for diagnosing FHM.