migraine

Question 1

definition of migraine

Answer 1

severe episodic headache

may have prodrome of focal neurological symptoms (aura)

associated with systemic disturbance

subclassified as migraine with aura (classic) or w/o aura (common migraine) and migraine variants (familial hemiplegic, opthalmoplegic and basilar)

Question 2

aetiology of migraine

Answer 2

early aura of cortical spreading depression associated with intracranial vasoconstriction = localised ischemia

followed by meningeal and extracranial vasodilation - mediated by 5HT, bradykinin and the trigeminovascular system

familial hemiplegic migraine - rare, mutations in P/Q-type ca channel cause it

Question 3

epidemiology of migraine

Answer 3

prevalence - 6% in males and 15-20% in females

female more

adolescence or early adulthood, can occur in middle age

Question 4

Sx of migraine

Answer 4

unilateral headache

nausea

vomiting

photophobia

phonophobia

allodynia

prodrome - precedes headaches by hours/days - yawning, cravings, mood/sleep change

aura

• aura followed by headache
• aura and no headache
• episodic severe headaches with no aura, often premenstrual - common migraine

Question 5

migraine aura

Answer 5

visual disturbance,

• flashing lights,
• spots,
• blurring,
• zigzag lines (fortification spectra),
• blindspots (scotomas)
• melting
• hemianopia

sensory symptoms eg tingling/numbness in limbs

motor - dysarthria and ataxia (basilar migraine), opthalmoplegia, hemiparesis

speech - 8% auras, dysphasia, paraphasia

Question 6

headache in migraine

Answer 6

pulsating

bilateral in 30-40%

4-72hr duration

get detailed history of headache frequency and pattern

most are episodic

(chronic daily headache lasting many weeks suggest either analgesia-overuse headache or secondary headaches.)

Question 7

migraine triggers

Answer 7

CHOCOLATE

• chocolate
• hangovers
• orgasms
• cheese/caffeine
• oral contraceptives
• lie-ins
• alcohol
• travel
• exercise

stress

lack of sleep

pattern of analgesia use

associations - obesity, FHx

Question 8

signs of migraine

Answer 8

no specific physical findings

examination of mental state, neurological exam, fundoscopy, cervical spine, general exam to exclude secondary causes - eg meningoencephalitis, idiopathic intracranial HTN, SAH, space occupying lesion, temporal arteritis

Question 9

Ix for migraine

Answer 9

diagnosis based on history

investigations to exclude other diagnoses

blood - FBC, ESR

CT/MRI - if suspicion that secondary

LP - if suspicion meningitis, do not perform until space occupying lesion ruled out

Question 10

medical Mx of migraine

Answer 10

beware of analgesia-overuse headaches - many pts use over the counter

Question 11

acute Mx of migraine

Answer 11

NSAID (naproxen), paracetamol, codeine and antiemetics evne in absence of nausea eg metoclopramide

triptans (5HT1 agonists) - sumatriptan and zolmitriptan used oral

Triptans are CI if IHD, coronary spasm, uncontrolled HTN, recent lithium, SSRIS, or ergot use

Question 12

prophylaxis of migraine

Answer 12

if 2/more per mo, 50% pts benefit

B blockers (propranol 40-120mg/12hr), amitriptyline (10-75mg), topiramate (25-50mg/12h) and sodium valproate, pizotifen (5-HT2 antagonist) CCB - flunarizine

menstrual migraine controlled by OCP

12-weekly botulinum toxin type A injections are a last resort in chronic

Question 13

advice for migraine

Answer 13

encourage regular meals and sleep

caffeine restriction

reduce stress

avoid triggers

symptom diary

rest in dark room in episode

Question 14

complications of migraine

Answer 14

disruption of daily activities

can progress to analgesia over-use headache due to chronic use of analgesics

topiramate -> teratogenic, can interfere with pill efficacy

triptans -> arrhythmias or angina +- MI even if no pre-existing risk

Question 15

prognosis of migraine

Answer 15

chronic

majority well managed with prevention/early treatment

Question 16

diagnostic criteria for migraines

Answer 16

clinical

if no aura - >5 headaches lasting 4-72hr + nausea and vomiting (or photo/phonophobia) + any 2 of:

• pulsating
• unilateral
• impairs, or worsened by routine activity

Question 17

differentials for migraines

Answer 17

cluster or tension headache

cervical spondylosis

high BP

intracranial path

sinusitis/otitis media

dental caries

TIA may mimic aura

Question 18

non-pharmalogical therapies for migraine

Answer 18

warm or cold packs to the head

rebreathing into paper bag (increase PaCO2) may help abort attacks

butterbur extracts or riboflavin supplementation

NICE recommend 10 sessions of acupuncture over 5–8 weeks if both topiramate and propranolol are unsuitable or ineffective.

Transcutaneous nerve stimulation may help

Question 19

migraines in females

Answer 19

incidence of migraine (especially with aura) + ischemic stroke increased by OCP

POP or non-hormonal contraception in migraine +aura

low dose COP can be used if no aura

further increased risk if: smoke, >35yrs, HTN, BMI >30, DM, hyperlipidaemia, FH of arteriopathy <45yrs

warn pts to stop OCP at once if develop aura or worsening headache

Question 20

perimenstrual migraine

Answer 20

if uncontrolled with standard treatment and the onset of headache is predictable then

consider frovatriptan 2.5mg BD or zolmitriptan 2.5mg BD/TDS on the days migraine is expected

Question 21

pathology of migraine

Answer 21

MRI shows episdoic cerebral oedema, dilatation of intracerebral vessels, and reduced water diffusion not respecting vascular territories - so primary event may be neurological

Pet - subcortical disorder effecting modulation of sensory processing

MEG (magneto-encephalographic) studies - resting hyperexcitability at least in the visual cortex, suggesting a failure of inhib circuits

hormones involved

serotonin metabolism involved

triptans also inhibit release of substance P and pro-inflammatory neuropeptides, blocking transmission from the trigeminal nerve and implicating trigeminal nerve dysfuction