Chronic Migraine

Background

• Chronic migraine is a headache disorder in which headaches occur on ≥ 15 days/month for > 3 months, with migraine headaches occurring on ≥ 8 of those days.
• It is reported in 1%-2% of the general population and usually evolves from episodic migraine (with headaches occurring on < 15 days/month), at a rate of 3% per year.
• The risk of transformation from episodic to chronic migraine increases with overuse of acute headache medications.
• Other risk factors include ineffective headache management, female sex, obesity, depression, stressful life events, low educational status, and trigeminal cutaneous allodynia (painful sensation to normally non-noxious stimuli to the face).

Evaluation

• Ask patients about
  • headache characteristics to determine if they are migraine-like, which are usually unilateral, pulsatile, and moderate-to-severe intensity
  • current and recent history of frequency and duration of headaches.
  • medications used to treat headaches, including how effective they are and how often they are taken
  • symptoms that raise suspicion of secondary headache disorders, such as rapid increase in headache frequency, thunderclap headaches, systemic symptoms such as fever or chills, focal neurological symptoms not consistent with aura, and orthostatic worsening
• Chronic migraine can be diagnosed in patients with
  • migraine-like or tension-type-like headache attacks occurring on ≥ 15 days/month, with migraine features on ≥ 8 of those days, for > 3 months
  • no other headache disorder better accounting for headaches

Management

• Ensure patient has realistic expectations - treatment goals are to reduce headache frequency and related disability with preventative measures while avoiding overuse of acute medications (which may lead to medication overuse headache).
• Encourage lifestyle management such as getting regular exercise, getting adequate hydration, and getting enough sleep, which may reduce risk factors and exposure to migraine triggers.
• Evaluate patient for medication overuse headache and treat if suspected.
• Prophylactic medications may reduce headache frequency.
  • When considering prophylactic medications
    • Take into account
      • adverse events (especially in women who are pregnant or breastfeeding), contraindications, and drug interactions
      • effect on comorbidities, and consider using medication that may also treat comorbidity
    • Start at low dose and slowly titrate up to achieve desired effect.
    • Stop chosen medication if intolerable adverse events or severe drug reactions, or if no evidence of efficacy after 2 months of treatment at target dose.
    • If excellent control of headache frequency (such as ≥ 50% frequency reduction from baseline) for 6-12 months, consider tapering or discontinuing medication.
  • First consider topiramate (Strong recommendation); starting dose 15-25 mg at bedtime; increase by 15-25 mg/day per week as tolerated to 100 mg/day at bedtime; may also consider 50 mg at bedtime or up to 200 mg/day in divided doses.
  • Other oral prophylactic medications include
    • propranolol (Strong recommendation); starting dose 20-40 mg twice daily (or 10 mg twice daily in young women); increase by 20 mg twice daily every 1-2 weeks as tolerated to 40-240 mg/day in divided doses (or once daily if long-acting formulation)
    • metoprolol (Strong recommendation); starting dose 25-50 mg twice daily; increase as tolerated to 100-200 mg/day in divided doses or once if sustained release formulation
    • amitriptyline (Strong recommendation); starting dose 10 mg at bedtime or 1 hour before; increase by 10 mg every 1-2 weeks as tolerated to 10-150 mg/day
    • sodium valproate (Weak recommendation); starting dose 250 mg once daily; increase by 250 mg/day in divided doses every week as tolerated to 500-2,000 mg/day in divided doses, with maximum dose per day of 60 mg/kg; use caution in women and girls due to teratogenic effects
  • Botulinum toxin A injections is another option (Strong recommendation).
  • Also consider calcitonin gene-related peptide (CGRP) monoclonal antibodies.
    • CGRP monoclonal antibodies are an emerging therapy and have limited evidence for long-term efficacy and safety outcomes.
    • Erenumab, fremanezumab, and galcanezumab subcutaneous injections are FDA approved for migraine prophylaxis in adults.
• Other therapies to consider include
  • greater occipital nerve block
  • occipital nerve stimulation
  • noninvasive electrical or magnetic stimulation
  • osteopathic manipulative therapy when added to prophylactic medication, but use caution as manipulation may be associated with risk of cervical artery dissection and stroke
• Other therapies may reduce headache frequency and severity in patients with migraine, but evidence for patients with chronic migraine is very limited (see Migraine prophylaxis in adults for additional information).
• At follow-up visits, manage expectations (prophylactic therapies will not completely eliminate headache attacks) and caution against overusing acute medications.