What initial laboratory tests are recommended for a patient presenting with symptoms of hemiplegic migraine?

Laboratory Tests for Hemiplegic Migraine

For patients presenting with symptoms of hemiplegic migraine, initial laboratory tests should include complete blood count, serum electrolytes, glucose, renal and liver function tests, and thyroid-stimulating hormone to rule out other causes of neurological deficits. 1, 2, 3

Initial Diagnostic Approach

Essential Laboratory Tests

• Complete blood count
• Urinalysis
• Serum electrolytes (including calcium and magnesium)
• Blood glucose
• Renal function tests (BUN, creatinine)
• Liver function tests
• Thyroid-stimulating hormone (TSH)

Neuroimaging

• Brain MRI with and without contrast is the preferred initial imaging modality to:
  • Rule out structural lesions
  • Exclude stroke, hemorrhage, or other causes of focal neurological deficits
  • Evaluate for characteristic findings during an attack (though often normal between attacks) 3, 4

Additional Testing Based on Clinical Presentation

• Cerebrospinal fluid (CSF) examination if:
  • First presentation of hemiplegic migraine
  • Atypical features present
  • Need to exclude meningitis, encephalitis, or subarachnoid hemorrhage 1
• Electroencephalogram (EEG) if:
  • Altered consciousness
  • Seizure-like activity
  • Need to differentiate from epilepsy 3

Diagnostic Considerations

Differential Diagnosis Workup

Hemiplegic migraine is a diagnosis of exclusion. Laboratory tests primarily help rule out other conditions that can mimic hemiplegic migraine:

• Stroke: Consider coagulation studies, lipid profile
• Metabolic disorders: Electrolytes, glucose, calcium
• Inflammatory conditions: ESR, CRP
• Vasculitis: Autoimmune panels if clinically indicated
• Mitochondrial disorders: Lactate/pyruvate if suspected

Genetic Testing Considerations

• Genetic testing for CACNA1A, ATP1A2, and SCN1A mutations should be considered, especially in:
  • Familial cases
  • Early onset cases
  • Cases with additional symptoms like ataxia or epilepsy
  • Recurrent episodes 2, 3

Important Clinical Pearls

• Diagnosis of hemiplegic migraine is primarily clinical, based on ICHD-II criteria
• Normal laboratory results do not rule out hemiplegic migraine
• Conventional cerebral angiography is contraindicated as it may trigger an attack 2
• Genetic testing can confirm but not rule out the diagnosis, as some patients have mutations in genes not yet identified 2
• During acute attacks, MRI may show cortical swelling and DWI changes that resolve after the attack 4

Monitoring During Acute Episodes

For severe or prolonged attacks:

• Serial neurological examinations
• Repeat neuroimaging if symptoms persist beyond typical duration
• Monitor electrolytes and hydration status

Hemiplegic migraine can be challenging to diagnose, and a thorough laboratory and imaging workup is essential to exclude other serious neurological conditions before confirming this diagnosis.