Migraine

Question 1

What is a migraine?

Answer 1

• Severe episodic headache that may have a prodrome of focal neurological symptoms (aura) and associated with systemic disturbance - Can be subclassified as migraine with aura (classical migraine) or without aura (common migraine) and migraine variants (familial hemiplegic, opthalmoplegic and basilar)

Question 2

What is the aetiology of migraine?

Answer 2

• Precise pathophysiological mechanism poorly understood. Early aura of corticol spreading depression associated with intracranial vasoconstriction resulting in localised ischaemia
• Followed by meningeal and extracranial vasodilation mediated by 5-HT, bradykinin and the trimeninovascular systemic
• Familial hemiplegic migraine: Rare, mutation int he P/Q type calcium channel are the cause of this rare form of migraine

Question 3

What are the risk factors for a migraine?

Answer 3

• family history of migraine
• childhood motion sickness
• caffeine intake
• high altitude
• female sex
• menstruation
• divorced, widowed, or separated
• obesity
• habitual snoring
• stressful life events
• overuse of headache medications
• lack of sleep

Question 4

What is the epidemiology of migraine?

Answer 4

• Prevalence is 6% in males and 15-20% in females
• Female: Male= 3:1
• Usual onset in adolescence or early adulthood, but can occur in middle age

Question 5

What are the presenting symptoms of migraine?

Answer 5

• • Headache:
    
    • Pulsating
    • Bilateral.
    • Duration 4-72h.
    • Obtain a detailed history of headache frequency and pattern.
    • Most migraine attacks are episodic and chronic daily headache lasting many weeks suggest either analgesia-overuse headache or secondary headaches
• Associated symptoms:
  
  • Associated with nausea, vomiting, photophobia or phonophobia.
  • May be preceded by aura that may include visual disturbance, flashing lights, spots, blurring, zigzag lines (fortification spectra), blindspots (scotomas) or other sensory symptoms such as tingling or numbness in limbs
• Triggers or risk factors:
  
  • Obtain a detailed history of possible triggers, including stress, exercise, lack of sleep, oral contraceptive pill, certain foods (e.g. caffeine, alcohol, cheese, chocolate and the pattern of analgesia use

Question 6

What are the signs of a migraine on examination?

Answer 6

• Usually no specific physical findings
• Examination of mental state, neurological examination, fundoscopy, sinuses cervical spine, general examination to exclude secondary causes. (e.g. meningocephalitis, idiopathic intracranial hypertension, subarachnoid haemorrhage, space-occupying lesion, temporal arteritis)

Question 7

What are the investigations for migraines?

Answer 7

Diagnosis based on history.

Ix may be needed to exclude other diagnoses:

• Bloods: FBC, ESR
  
  • ​ESR is raised in temporal arteritis, and biopsy of temporal artery shows typical inflammatory infiltrate
  • = normal in migraine
• CT/MRI:
  
  • If suspicion of secondary headache disorders
  • = normal in migraine; may identify space-occupying lesions, ischaemic lesions, or subarachnoid haemorrhage
• Lumbar puncture:
  
  • If suspicion of meningitis
  • LP may be abnormal in patients with headache caused by subarachnoid haemorrhage (SAH), meningitis, and either low or high cerebrospinal fluid pressure.
  • Do not perform until space-occupying lesion excluded
• cerebrospinal fluid (CSF) culture
  
  • ​Culture and microscopy of CSF and samples from other potential sites of infection may identify the infecting micro-organism if headache is caused by systemic or central nervous system infection.
  • = normal in migraine

Question 8

How are migraines managed?

Answer 8

• Medical: beware of analgesia-overuse headaches as pts use OTC preparations - Acute: NSAID (e.g. naproxen), paracetamol, codeine and antiemetics (e.g. metoclopramide). Variety of triptans (5-HT, agonists) are available but commonly used ones are sumatriptan and zolmitriptan (which can be given orally, nasally or subcutaneously). Ergotamine is rarely used due to complex dosing schedules
• Prophylaxis (if more than 2/month, 50% pts benefit: B-blockers, amitriptyline, topiramate and sodium valproate and calcium channel blocker. Menstrual migraine can be controlled by oral contraceptive pill
• Advice: Encourage regular meals and sleep, caffeine restriction, measures to reduce stress, avoid triggers, symptoms diary. Rest in quiet dark room during episode

Question 9

What are the possible complications of a migraine?

Answer 9

• Disruption of daily activity
• Can progress onto analgesia-overuse headache due to chronic use of analgesics
• status migrainosus
  
  • A debilitating migraine attack lasting for more than 72 hours. It is important to look for medication overuse as a possible cause, and to manage this appropriatel
  • Parenteral treatment with corticosteroids is most likely to be effective, and this may require one or more visits to a secondary care centre
• migrainous infarction
  
  • One or more migrainous aura symptoms are associated with an ischaemic brain lesion in appropriate territory, as demonstrated by neuroimaging
  • True migrainous infarction is a rare complication of migraine with aura, and is diagnosed when a typical aura lasts longer than 1 hour and neuroimaging demonstrates an infarction in a relevant area
  • Treatment is as for cerebrovascular infarction. This includes urgent supportive care and consideration of thrombolysis, followed by active rehabilitation.
• migraine-triggered seizures
  
  • ​Migraine headaches related to seizures. Seizures are a known trigger for headaches, which can be migraine-type or tension headaches. Patients with headache just prior to the onset of seizure activity should be investigated for focal non-convulsive seizures (ictal epileptic headache). Focal seizure activity can cause headaches as the only symptom, prior to generalised seizure activity and convulsive seizur
• depression
• chronic migraine
  
  • ​

Migraine headache occurring on 15 or more days per month for more than 3 months in the absence of medication overuse.

Usually starts as migraine without aura that gradually loses its typical presentation.

It is important to look for medication overuse as a possible cause, and to manage this appropriately

• persistent aura without infarction
  
  • ​

Aura symptoms persist for more than 1 week without radiographical evidence of infarction.

Symptoms are often bilateral and may last for months or years.

Reliable treatments are not known, but valproate and acetazolamide may help.

Posterior leukoencephalopathy and migrainous infarction should be excluded by MRI scan

Question 10

What is the prognosis of migraine?

Answer 10

Usually chronic, but majority of cases can be managed well by preventative/early treatment measures