Migraine
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Introduction

Migraine is a common cause of headache affecting about 15% of individuals. Headaches are typically recurrent, and last anywhere up to 72 hours. It is more common in women, and peak incidence is between the ages of 20 and 50.

The word “Migraine” is derived from Greek, meaning “pain that affects half the head”

Migraine is typically associated with nausea and photophobia, and rarely can present with neurological signs and symptoms mimicking a stroke. Some subdivide migraine into several types:

  • Classical migraine – a preceding “aura” (usually visual disturbance) lasting <60 minutes, followed by several unilateral, throbbing headache, possibly with photophobia, nausea and vomiting
  • Common migraine – as for classical, without the aura
  • Hemiplegic migraine – can mimic a stroke or TIA with unilateral neurological signs. Headache may or may not be present. To distinguish from a TIA: – TIA’s have sudden onset, with maximum deficits immediately. Headache is rare. In migraine, the deficits may occur gradually, and almost always accompanied by headache. In both cases aura may be present.
  • Occular migraine – aura without the headache. Also known as ophthalmoplegic migraine
  • Other variations
    • Basilar migraine – includes symptoms such as tongue tingling, vertigo, diplopia, visual disturbance (perhaps even blindness), dysarthria, ataxia
    • Facioplegic Migraine – unilateral face weakness
Migraine can occur in recurrent episodes (similar to tension headache) or in one off, irregular instances.

Epidemiology and Aetiology

  • Incidence – 8-12%.
  • M:F – 1:2
  • Times of relaxation (e.g. often at weekends)
  • Chocolate – due to high phenylethylamine content
  • Cheese – due to high tryamine content
  • Noise / lights
  • Oral contraceptive pill
  • Common around puberty
  • Common around menstruation / pregnancy / menopause
    • In pregnancy, cases often resolve as the pregnancy progresses, and are uncommon in the second and third trimesters. Don’t use aspirin after 30 weeks and when breatfeeding.
  • Sometimes occurs after minor blow to the head
  • Obesity
  • Patent foramen ovale

CHOCOLATE mnemonic for migraine triggers

  • Ch – chocolate
  • O – Oral contraceptive
  • C – caffeine (or withdrawal)
  • Ol – alcohol
  • T – travel
  • E – exercise
In 50% of cases not trigger can be identified. Only in a very few cases will avoiding triggers completely avoid attacks.

Clinical features

  • Visual Aura – a perceived visual disturbace (e.g. zig-zag lines, bright lights, distorted objects, scotomo (dark patches), techopsia (flashes)). These often occur before an attack and last 15-60 minutes. They are caused by reduced blood flow to the occipital cortex before an attack.
    • They also often occur before an epileptic seizure in epileptic patients.
    • Patients may also have a sensory aura – e.g. pins/needles spreading up limbs, or a speech aura – whereby they may suffer temporary dysarthria

      An example of a visual aura in migraine
      An example of a visual aura in migraine
  • Throbbing or pulsing sensation
  • Photophobia
  • Unilateral – the pain often begins locally and then spreads. May become bilateral as the headache progresses
    • Often retro-orbital
    • May radiate to the occiput
  • Vomiting or nausea
  • Irritability
  • Onset is often early int he morning or patient awakes with the headache
  • Heightened sensitivity to pain – all stimuli (e.g. wearing glasses, brushing hair) cause pain
  • Precipitating factors may or may not be apparent (see above)

Diagnostic criteria

According to the International Headache Society (IHS3) criteria to diagnose common migraine:

  • At least two attacks
  • One or more of the following aura symptoms, which fully reverse:
    • Visual disturbance
    • Sensory disturbance
    • Speech disturbance
    • Motor disturbance
  • At least two of:
    • Aura spreads gradually over at least 5 minutes
    • Aura lasts 5-60 minutes
    • At least one symptom is unilateral
    • Headache follows aura within 60 minutes
  • No other attributable cause (especially TIA)
According to the International Headache Society (IHS3) criteria to diagnose classical migraine:
  • At least 5 episodes
  • Headaches last 4-72 hours
  • At least 2 of the following:
    • Unilateral
    • Pulsating
    • Moderate or severe intensity, which inhibits daily activities
    • Worsening by routine physical activity
  • At least two of:
    • Nausea or vomiting
    • Photophobia or phonophobia

A common clinical scenario is trying to attempt to differentiate migraine from tension headache:

MigraineTension
LocationUnilateral – can later become bilateralBilateral
ProdromeYesNo
NatureThrobbingConstant
FrequencyTypically < weeklyDaily
DurationUsually hours – can be daysTypically days
AlcoholMakes it worseMakes it better
Nausea or vomitingYesNo
FHxYesNo
Age of onsetOften < 20 yearsUsually > 20 years

Pathology

Not entirely known. Some genetic pre-disposition. It is possibly related to the dilation/constriction of cerebral blood vessels, and thus the neuropeptide CGRP (calcitonin gene related peptide) is thought to be important.
  • Initial Oligaemia – which causes the aura, is then following by
  • Hyperaemia / blood vessel dilation / oedema – which stimulates nerve endings and causes pain.
  • However in recent years this theory has fallen out of favour.
Some speculation that there is failure of inhibition , particularly in the visual cortex, and this is what actually causes the attacks.

Management

Reassure patients that migraine as not dangerous. Consider a migraine action plan.

Commence treatment at the earliest sign of migraine. 

Non-pharmacological management

  • Lire down
  • Darkened room
  • Sleep
  • Avoid caffeine, orange juice
  • Avoid reading, watch TV or other screens
  • Avoid physical activity
  • Cold packs on the forehead

Pharmacological management

Be aware that patients often have significant nausea and vomiting, and oral agents may not be tolerated. Gastroparesis is also often a features of migraine and thus oral agents may not be well absorbed. 

  • Aspirin 900mg (soluble absorbed more quickly)
    • OR alternative NSAID, such as ibuprofen 400mg, naproxen 750mg, diclofennac 50mg
    • OR paracetamol 1g (second line)
  • Anitemetic e.g.:
    • Metoclopramide 10mg PO, IV or IM
    • Ondansetron 4-8mg PO, SC or IV (second line)
  • Triptans
    • Lots of different triptans are available!
    • They can be repeated after 2 hours if not effective
    • Consider prescribing triptans for patients in whom the above measures have been unsuccessful during a previous migraine
    • Triptans should be given as soon as the patient feels symptoms are beginning
    • They are typically ineffective if used >2 hours after the onset of symptoms
    • Examples include:
      • Sumatriptan 20mg intranasally – repeat at 2 hours if required for maximum of 40mg daily
      • Sumatriptain 50-100mg PO – repeat after 2 hours if required. Maximum dose 300mg daily
      • Rizatriptan 10mg PO – repeat at 2 hours if required. Maximum daily dose 30mg
      • Eletripatn 40-80mg PO – repeat at 2 hours if required. Maximum daily dose 160mg 
      • Zolmitriptan 2.5mg OD – repeat at 2 hours if required. Maximum daily dose 10mg
    • Advise patients to limit triptan use to <10 days per month
    • Risk of serotonin syndrome if patients are also on an SSRI. This is not a contraindication but patients should be warned about the possibly symptoms and to cease both medications immediately if they occur.
  • Migraine in pregnancy
    • Severely limited medication options
    • Aspirin, NSAIDs and triptans are all contraindicated
    • Advise is to try paracetamol 1g QID, and if not successful consider steroids – e.g. prednisolone 50mg OD for 2 days
    • Beware of differentials, including pre-eclampsia

Status migrainosus

This refers to intractable migraine – typically >24 hours despite the above management.

Try:

  • Ketorolac 30mg IM if not had other NSAIDs in last 4-6 hours
  • Sumatriptan 6mg SC if no triptan in last 2 hours
  • Chlorpromazine (largactly(R))
    • 12.5mg in normal saline (e.g. 100mls or 1L) over 1 hour
    • Can repeat twice 30 minutes after previous infusion for a maximum dose of 37.5mg
    • Advised to check electrolytes before administration – particularly for potassium and magnesium
    • Can cause acute dystonic reactions
  • Dexamethasone
    • 12-20mg IV
    • Repeat at 12 hours

Prophylaxis

Lifestyle factors

  • Encourage regular sleep and sleep hygiene
  • Adequate hydration
  • Eat regular meals – avoid skipping meals
  • Limit caffeine to max of 2 cups per day
    • Regular exercise:
    • At least 150 minutes per week e.g. 30 minutes of 5 days per week
  • Regular use of relaxation techniques – e.g. mindfulness, yoga
  • Avoidance of down triggers

Pharmacological management

Many agents are available. Suggest if episodes occur >2 per month despite the above measures.

Recommended to try any particular agents for 8-12 weeks before assessing efficacy
65% of patients will have at least 50% reduced frequency of attacks with treatment.

 

  • Amytriptiline – TCA10mg+ at night. Side effects include drowysness, dry mouth and blurred vision
    • Dose can be titrated upwards every 7 days, to a maximum of 75mg daily
  • Propanol – beta-blocker – give 10mg 3x/day, increasing to 40mg 3x/day if necessary.
    • Avoid in asthma, diabetes and peripheral vascular disease
  • Candesartan – ARB – 4mg daily. Can increase dose by 4mg each week to maximum of 32mg daily. Beware of hypotension
  • Sodium valproate – anti-epileptic – start with 200mg nocte. Can be increased to a maximum of 500mg BD
    • Avoid in pregnancy, obesity and liver disease
  • Topiramate – anti-epileptic – starts ith 25mg note. Can be increased up to a maximum of 100mg BD
    • Avoid in pregnancy and depression
    • Can reduce efficacy of the combined oral contraceptive pill at higher doses
  • Verapamil – calcium channel blocker – start with 90mg OD. Can be increased to maximum of 240mg daily.
    • Avoid in heart failure
    • Be cautious of hypotension
  • Pizotifen – this is an antihistamine and 5-HT antagonist – it causes vasoconstriction of cranial arteries. Give 0.5mg at night (increase to 1mg). Side effects include weight gain, drowsyness, effects of alcohol, glaucoma risk. Rarely can cause arrhythmias and angina.

Gabapentin, pregabalin and venlafaxine are all also sometimes used but there is less evidence as to their efficacy

Other treatments

  • Botox injections to the scalp may be effective for some patients
    • Effects typically only last 3-6 months and repeat procedures are required
  • Acupuncture may benefit some patients
  • Evidence for SSRIs is inconclusive

 

Flashcard

References

  • Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
  • Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy

Read more about our sources

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) currently works as a GP Registrar and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

This Post Has 2 Comments

  1. Paul Booton

    Hi – came across this site whilst trying to find something else. This migraine page is way out of date and helps to perpetuate some migraine myths. im a recently retired GP and headache specialist. i could help you rewrite if interested

    1. Dr Tom Leach

      Thanks Paul, I would love your help in bringing this up to date, have sent you an email. Thanks, Tom.

      *** EDIT – OCTOBER 2020 ***
      For those of you reading this after October 2020, I have now extensively re-written this article. I did not hear back from Paul, but I hope that this goes some way to addressing his concerns.

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