Migraine
Definition
Recurrent throbbing headache often preceded by an aura and associated with nausea, vomiting and visual changes
A migraine aura may affect the patients eyesight with visual phenomena such as fortification spectra, shimmering or scotomas, but may also result in pins and needles, dysphasia and rarely weakness of limbs and motor function
Epidemiology
In 90% onset is before 40 years
If onset > 50 then pathology should be sought
More common in FEMALES than males
Usually the severity of migraine decreases with advancing age
Most common cause of EPISODIC HEADACHE (recurrent)
Aetiology
Brain chemical imbalance may be cause
May be caused by changes in the brainstem and its interactions with the trigeminal nerve
No known specific cause but there are partial triggers (CHOCOLATE)
Cheese
Oral contraceptives
Orgasms
Lie-ins
Hangovers
Alcohol
Chocolate
Tumult
Exercise
Risk Factors
Female
Age - can occur at any age but majority have first migraine in adolescence
Strong genetic component thus family history
Pathophysiology
Cortical spreading depression - self-propagating wave of neuronal and glial depolarisation that spreads across the cerebral cortex is thought to cause the aura
Neurogenic inflammation leads to vasodilation and plasma protein extravasation - leading to pain that propagates all over cerebral cortex
Changes in brainstem blood flow lead to an unstable trigeminal nerve nucleus and nuclei in the basal thalamus
Clinical Presentation
Migraine without aura
Migraine with aura
There may be a prodrome that precedes the headache by hours/days - yawning, cravings and mood/sleep changes
General migraine features
Two of - unilateral, pulsing, moderate/severe pain in head, aggravated by routine physical activity
During headache at least one of - nausea and/or vomiting during headache, photophobia and phonophobia
Attacks last 4-72 hours
Not attributable to another disorder
At least 2 attacks
Aura precedes the attack by minutes and may persist during it
Unilateral, pulsatile headache
Visual - chaotic cascading, jumbling, distorting lines, dots or zigzags , scotoma, hemianopia
Somatosensory - paraesthesiae from fingers to face
At least 2 of: unilateral pain, throbbing-type pain, moderate to severe intensity, motion sensitivity
At least 1 of: nausea/vomiting, photophobia/phonophobia, normal examination with no other attributable cause
Differential Diagnosis
The visual and hemisensory symptoms must be distinguished from thromboembolic TIAs
Brain tumour and temporal arteritis
Sudden migraine may resemble meningitis or subarachnoid haemorrhage
Tension headache, cluster headache, medication over-use headache
Treatment
Diagnosis
Always examine - eyes (for papilloedema and other eye issues using fundoscopy), BP, head & neck (scalp, neck muscles and temporal arteries)
Exclude other causes
Mainly clinical diagnosis
Lab tests - CRP & ESR
Indications for neuroimaging (CT/MRI) - worst/severe headache (SAH), change in pattern of migraine, abnormal neurological exam, onset > 50 years, epilepsy, posteriorly located headache
Lumbar puncture indications - SAH (bad headache), severe rapid onset headache, progressive headaches, unresponsive headaches, NEUROIMAGING SHOULD PRECEDE
Acute - Don't offer ergots or opioids, TRIPTANS, NSAIDS, +/- antiemetic
Reduce triggers e.g. avoid dietary factors
Prevention
If more than 2 attacks a month, or acute treatment required more than 2x a week
Beta blockers (not for asthmatics)
Tricyclic anti-depressant
Anti-convulsant