Epidemiology
5% in males, 17% in females
Peaks around 40 YO and gradually declines
Pathophysiology
Abnormal Vasculature
- Vasoconstriction being responsible for aura and rebound vasodilatation the
cause of the pounding headache
Primary Brain Disorder
- Response of brain tissue to some trigger
- Secondarily disordered activity of blood vessels
Aura
- Primary neuronal dysfunction
- Slowly spreading wave of neuronal hypoactivity traveling across brain
tissue
- Corresponding decrease in local blood flow (not follow vasoconstriction
territories)
Headache
- Pain-sensitive Intracranial structures largely supplied by sensory axons
of trigeminal ganglion in the supratentorium, while the upper cervical roots
innervate the posterior fossa
- Related to activation of these sensory axon
- Sterile neurogenic inflammation and promotes local vasodilatation
- Release of peptides and the resulting inflammation and extravasation can
be blocked by ergots, indomethacin, Triptans (+vasoconstriction effect)
No understood neurophysiologic pathways linking between aura and headaches
Enhanced excitability of occipital cortex neurons in migraine patients is a
possible trigger
Clinical Features
85% of migraine sufferers have no aura with the event.
Duration is typically four to seventy-two hours.
Common Migraine
Accurate diagnosis of migraine without aura requires at least two of the
following four characteristics. (not sens or sp)
- Unilateral Position
- Pulsating Quality
- Moderate to Severe Quality
- Aggravated by Activity
In addition, at least one of the following criteria is required:
- Nausea or Vomiting
- Photophobia or Phonophobia
Classical Migraine
In order to fill this criteria, at least three of the following four
characteristics must be present.
- Reversible Aura Symptoms Indicating Brain Dysfunction
- At Least 1 Aura Develops Gradually Over 4 Minutes
- No Single Aura Lasts More Than 60 Minutes
- Headache Follows Aura With a Free Interval Less Than 60 Minutes
Visual aura are the commonest, usu consisting of scintillating scotoma or
flashing lights
Virtually any neurologic symptom or sign can occur
Typical auras : hemiparesthesia, hemiparesis, aphasia, other speech difficulties
Rare type : basilar migraine (brainstem symptoms), lasting longer than 60 min
(prolonged aura), migraine aura without headache
Auras should be distinguished from prodromes : Lethargy, hyperactivity, yawning,
depression, food craving, polyuria, fluid retention
Less Forms of Migraines
Ophthalmoplegic migraine : Paresis of CN III, IV, VI
Retinal migraine : Monocular scotoma or blindness
Childhood Periodic Syndrome
Migraine equivalents
Ill-defined syndromes ass with migraine
Abdominal pain or vomiting without headache
Migrainous Infarction
Complicated migraine
Aura lasting more than 7 days or neuroimaging evidence of cerebral infarction
Migraine with focal deficit
Diagnosis of exclusion
- Hx of previous similar migraines including neuro deficit
- Normal results of prior Ix
Aura and deficits rarely last more than 60 min, expected to resolve prior to
discharge
Treatment
Drugs which block the stimulation of the trigeminovascular system, tachykinin
release, or neurogenic inflammation can all be used to treat migraine.
Agents which stop tachykinin release, (i.e., Sumatriptan, Ergotamine), or
neurogenic inflammation (i.e., NSAID) should be used for acute migraine therapy.
Those agents which inhibit trigeminovascular stimulation (i.e., beta blockers,
calcium blockers, anti-depressants) are useful in preventing migraines.
Wide spectrum of clinical practice
No clear consensus on the best therapy
No migraine treatment has been shown to be superior in all respects
Factors : efficacy, ability to abort migraine, CI, relief of other symptoms,
ADR, cost, ease of administration, time to return to normal activities
DHE (CHS)
5-HT 1D receptor agonist
Highly effective in relieving headaches
Appropriate fist-line therapy
ADR : vomiting (other 5-HT + DA receptor)
Pretreated with metoclopramide or prochlorperazine
Sumatriptan (CHS)
More selective agonist
Effective and less N/V
Frequent but short-lived minor ADR (sc form) : sensations of heat, tingling,
chest discomfort, injection site reaction
More costly, higher 24-hr recurrence rate
Useful for migraines unresponsive to other medications, not given within 24hr of
DHE (vasoconstriction)
Other drugs studied in ED-based RCT
- Metoclopramide
- Chlorpromazine
- Prochlorperazine
- Ketorolac
- Dexamethasone 20 mg IV
- One ED-based RCT reduce rate of 48 to 72 hr recurrent migraine
compared to placebo
- Meperidine and Opioids
- Less effective than other agents but still used, May exacerbate headache
in chronic use
Adjunctive Treatment
Placed in a darkened, quiet area
IV rehydration
Migraine Triggers
Sleep deprivation/excess
Caffeine ingestion or caffeine withdrawal
Wine, especially red, & alcohol in general
Fasting
Sex hormones
Most migraines have no trigger
Strong familial pattern
Migraine in Pregnant
Nonpharmacologic, rest and ice, should be tried first
Medication if intractable or N/V
Acetaminophen and NSAIDs are class B by US FDA
NSAID may inhibit labor and decrease mniotic fluid
Metoclopamide (class B) can be very useful esp if significant N/V
Prophylaxis
- B-blocker without intrinsic sympathomimetic activity
- CCB
- TCA
- NSAID
Titrated for several months before concluding that ineffective
Withdrawn slowly to prevent rebound headaches
Summarized By Thirayost Nimmanon
โดย ธีรยสถ์ นิมมานนท์
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