Flashcards in Mirgraine Deck (25):
Explain the features of a primary headache, and 3 examples.
Something has gone wrong in the brain circulatory.
Give 3 examples of secondary headaches.
Meningitis - build up of fluid on the brain
Giant cell artheritis
Describe a migraine.
Common and debilitating neurovascular disease.
Attacks of severe headaches and autonomic dysfunction.
What is a common migraine?
Migraine without aura.
What is a classic migraine?
Migraine with aura.
What criteria classify a migraine?
5 or more attacks lasting 4-72 hours.
>2 of the following - unilateral, pulsating, moderate/severe intensity, aggregated by routine physical activity.
1 or more of...nausea/vomiting, photophobia/phonophobia.
Give some epidemiological facts about migraine.
11% of USA and Europe suffer an attack in a year.
More men than women.
Peaks in early-mid adolescence.
Is the brain completely insensitive?
Yes - except for the meninges...
Dura mater, arachnoid mater and pia mater which are densely innervated and receive blood from the middle cerebral and middle meningial arteries.
What 4 areas are involved in migraine?
Blood vessels, trigeminal nerve, dorsal raphe nucleus and locus coeruleus.
Describe the aura experienced before a migraine.
A wave of oligema (poor blood supply), a response to depressed neuronal function, passes over the cortex (2-6mm/minute).
Stays until the migraine starts.
What is CSD?
Cortical spreading depression - increase K+ and NTs...transient increase in cortical blood flow followed by sustained decrease.
Explain the pain associated with a migraine.
Not completely understood.
Migraine involves the dysfunction of the brain stem that normally modulates sensory inputs from the trigeminal ganglion.
3 key factors:
Cranial BVs in dura
Trigeminal sensory nerve innervation of those BVs
Trigeminal links with brainstem, transmits and modulates info to the cortex and via autonomic reflex back to dura!
What roles do the sensory nerves play?
C (unmyelinated) and Adelta (myelinated)
-transmit sensory information to the CNS - initiate reflex
-release neuropeptide...Calcitonin gene related peptide. (CGRP)
What effects does release CGRP have on arterioles?
What effect does substance P have on venules?
Causes plama extravastion - oedema.
BUT NK1 receptor antagonists are not useful in the treatment of migraine.
What role does 5HT play in migraine?
Increase 5HT metabolite excreted in urine in migraine.
Platelet 5HT rapidly drops at migraine onset.
i.v. 5HT can abort migraine.
What non-pharmacological treatments are there for migraine?
Avoid triggers - mutation in VOCC?
Avoid light noise trigger.]
Avoid dietary triggers...
-tyramine in cheese (vasoconstrictor effect...if MAO inhibited)
-Chocolate (phenyltheylamine - amine metabolised by MAO) (theobromine and caffiene - may alter cerebral blood flow and release of NA).
Caffeine - the abrupt withdrawal of caffeine leads to headaches and may exacerbate the migraine.
Name 5 preventative medicines for migraine.
Antidepressants; TCAs, SSRIs, MAOIs
Calcium channel antagonists; verapamil
Seretonin antagonists; methysergide
Beta blockers; propanolol.
How would you treat an acute migraine attack?
As soon as migraine is indicated (by aura)...
-NSAIDs/COX inhibitors...aspirin, ibuprofen etc
- and an anti-emetic for absorption.
Ergot derivative - dihyroergotamine (vasoconstrictor).
Explain the rationale behind triptan use.
'atypical' 5HT receptor - 5HT1B/D...found in cerebral circulation and coronary BVs. AGONST.
Moderate side effects - dont use in CV disease.
Name 3 potential antimigraine mechanisms.
Peripheral neuronal inhibition
Inhibition of nerve transmission in trigeminal cervial complex
Effective, short acting, expensive
Associated with recurrence.
Longer half life than sumatriptan...better oral availability.
effective in advanced clinical trials. NOT USED - liver adverse effects
Act postsynaptically - CGRP effect (vasodilation) is blocked on BV.