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Migraine

From Mediwikis

Features

  • Prolonged headache (4-72hrs)
  • Nausea/ Vomiting
  • Reduced functional ability
  • Worsens with activity
  • Photophobia
  • Phonophobia
  • Aura
    • positive - eg visual sparkles
    • negative - eg scotoma
    • numbness
    • aphasia/ dysphagia

Risk Factors[1]

  • Family history
  • Childhood motion sickness
  • Caffeine
  • Female
  • Menstruation
  • Change in Barometric Pressure
  • Obesity
  • Snoring
  • Stress
  • Medication Overuse
  • Lack of Sleep

Pathophysiology

Thought to be due to neurogenic inflammation of 1st division trigeminal sensory neurons, which innervate the large vessels and meninges of the brain, causing a change in the way that pain is processed.

Aura result from neuronal dysfunction, that spreads as a wave of neuronal excitation in the cortex. This is followed by a prolonged period of depressed neuronal activity and eventually neuronal recovery.

Cortical depression causes release of excitatory amino acids and other products, causing stimulation of nociceptors in adjacent dura and arterioles, resulting in stimulation of the trigeminal sensory nucleus.

Investigations

Management Options

  • Ensure adequate hydration
  • Trigger avoidance & behavioural modification
  • Menstrual cycle control eg OCP
  • NSAIDs or aspirin 300-600 mg O 4-6 hrly PRN (<4000 mg/d)
  • Antiemetics eg metoclopramide 5-10mg O 8 hrly PRN (<5d)
  • Triptans eg almotriptan 6.25-12.5mg O single dose, may repeat in 2hrs (<25 mg/d)
  • Magnesium Sulphate Ig IV single dose
  • Corticosteroids eg prednisolone 60mg O OD (taper dose over 7-10d)
  • Butalbital containing compounds

Prophylaxis

  • Anticonvulsants eg Sodium valproate 250-500mg O (delayed release) BD
  • TCAs eg amitriptyline 10-150 mg/d O
  • B blockers eg propranolol 80-240 mg/d (immediate release) given in 2-4 divided doses
  • Lamotrigine
  • CCBs eg Verapamil 80mg O (immediate release) TDS
  • Antidepressants eg venlafaxine 37.5-75mg O OD initially (<150 mg/d)
  • Botulinum toxin A (consult specialist advice)

References

  1. http://bestpractice.bmj.com/best-practice/monograph/10/diagnosis/history-and-examination.html