MIGRAINE
Migraine is recurrent headache associated with visual and gastrointestinal disturbance .The borderline between migraine and tension headache is vague .Over 10% of any sampled population have had these symptoms.
MECHANISMS
Precise mechanism of migraine are unknown .Genetic factors probably play a role ,a rare form of familial migraine is associated with a mutation in the alpha-1 subunit of the P/Q - type voltage - gated calcium channel on chromosome 19.
The headache of migraine ,often throbbing ,is due to vasodilation or oedema o blood vessels , with stimulation of nerve endings near affected extracranial and meningeal ateries.Release of vasoactive substances such as nitric oxide is thought to have a role .Serum 5-hydroxytriptamine rises at the onset of prodromal symptoms and falls during the headache .Magnesium deficiency ,neural exitation by glutamate and asparate ,changes in the hypothalamic -pituatary axis and in endogenous opiods have all been suggested.
Cerebral features ,such as tingling limbs ,asphasia and weakness ,are caused by focal depression of cortical function.
Definite precipitating factors are unusual .Some patients complain of symptoms at times of relaxation ( weekened migraine ).Other find that chocolate ( high in phenylethylamine ) and cheese ( high in tyramine ) precipitate attacks .Migraine is common around puberty , at the menopause and premenstrually ,and sometimes increases in severity or frquency with hormonal contraceptives ,in pregnancy and with the onset of hypertension .There is no reason to support that he development of migraine is suggestive of any major intracranial lesions.However ,since migraine is so common ,an intrcranial mass and migraine sometimes occur together by coincidence .Rarely ,migraine follows a head injury :this can be minor .
CLINICAL PATTERNS
Migraine attacks vary from intermittent headaches indistinguishable from tension headaches to discrete episodes that mimic thromboembolic cerebral ischemia .Distinction between variants is somewhat artificial.
Migraine can be seperated into phases:
Well -being before an attack ( occasional ) .
Prodromal symptoms .
Headaches ,nausea , vomiting .
MIGRAINE WITH AURA ( CLASSICAL MIGRAINE )
Prodromal symptoms are usually visual and related to depression of visual cortical function or retinal function .There are unilateral patchy scotomata ( when the retina is affected ) or cortical hemianopic symptoms.Teichopsia ( flashes ) and fortification spectra ( jagged lines resembling battlements ) are common.Transient aphasia sometimes occurs ,together with tingling , nmbness or vague weakness of one side .The patient feels nauseated.The prodrome lasts from 15 minutes to an hour or more .Headache then follows .This is occasionally hemicranial ( i.e splitting the head ) but often begins locally and becomes generalized .Nausea increases and vomiting follows.The patient is irritable and prefers a darkened room.Superficial temporal arteries are engorged and pulsating.After several hours the attack ceases ,sometimes with a diuresis.Deep sleep often ensues.
MIGRAINE WITHOUT AURA ( COMMON MIGRAINE )
This is the usual variety.Prodromal visual symptoms are vague.There is recurrent headache accompanied by nausea and malaise.
BASILAR MIGRAINE
Prodromal symptoms include circumoral tingling ,tongue numbness ,vertigo ,diplopia ,transient visual disturbance ,blindness ,syncope ,dysarthria and ataxia .These occur either alone or progress to a migrainous headache.
HEMIPARETIC MIGRAINE
This rarity is classical migraine with hemiparetic features .Recovery occurs within 24 hours .Exceptionally ,cerebral infarctio and hemiplegia occurs.
OPTHALMOPLEGIC MIGRAINE
This is a third nerve ,or exceptionally a sixth nerve palsy with a migraine .This is arare and difficult to distinguish from other caues of a third nerve palsy without investigation.
FACIOPLEGIC MIGRAINE
This rarity is unilateral facial weakness during a migraine.
DIFFERENTIAL DIAGNOSIS
The onset of sudden headache may be similar to meningitis or SAH.
Hemiplegic ,visual and hemisensory symptoms must be distinguished from thromboembolic TIAs.In TIAs maximum deficit is present immediately and headache is unusual.
Unilateral tingling or numbness should be distinguished from sensory epilepsy ( partial seizures ) .In epilepsy distinct march ( progression ) of symptoms is usual .
MANAGEMENT
General measures include :
Reassurance and relief of anxiety .
Avoidance of dietry factors - rarely helpful.
Patients taking hormonal contraceptives may benefit from a brand change ,or trying without .Severe hemiplegic symptoms are an indication for stopping hormonal contraceptives.
DURING AN ATTACK
Paracetamol or other simple analgesics should be given ,with an antiemetic such as metoclopramide if necessary .Repeated use of analgesics leads to further headaches.Triptans ( 5-HT ,agonists ) are also helpful .In some 30% of cases where there is recurrent severe migraine ,sumatriptan ,zolmitriptan ,naratriptan and rezatriptan are of value either by prompt self-administered subcutaneous injection ,or orally by wafer or inhaler .Ergotamine tarter ( 1-2 mg orally or rectally ,360 mg by inhaler or 0.25 - 0.5 mg by injection) is also sometimes helpful if given early .Ergotamine and triptans should be avoided when there is vascular disease.
PROPHYLAXIS
It is difficult to discern placebo effects of prophylactic drugs in migraine .When drugs are necessary ,the following are helpful :
Pizotifen ( an antihistamine and a 5-HT antagonist ) 0.5 mg at night for several days ,increasing to 1.5 mg ar night -common side effects are slight weight gain and drowsiness.
Propranolol 10 mg three times daily ,increasing to 40-80 mg three times daily.
Methysergide ( a 5-HT antagonist ) 2-6 mg daily - an occasional side effects is periaortitis which precludes use for longer than 6 months.
Amitriptyline 10-30 mg at night is sometimes helpful .
Sodium valporate ,verapamil ,nifedipine , and naproxen are also used.
Migraine is recurrent headache associated with visual and gastrointestinal disturbance .The borderline between migraine and tension headache is vague .Over 10% of any sampled population have had these symptoms.
MECHANISMS
Precise mechanism of migraine are unknown .Genetic factors probably play a role ,a rare form of familial migraine is associated with a mutation in the alpha-1 subunit of the P/Q - type voltage - gated calcium channel on chromosome 19.
The headache of migraine ,often throbbing ,is due to vasodilation or oedema o blood vessels , with stimulation of nerve endings near affected extracranial and meningeal ateries.Release of vasoactive substances such as nitric oxide is thought to have a role .Serum 5-hydroxytriptamine rises at the onset of prodromal symptoms and falls during the headache .Magnesium deficiency ,neural exitation by glutamate and asparate ,changes in the hypothalamic -pituatary axis and in endogenous opiods have all been suggested.
Cerebral features ,such as tingling limbs ,asphasia and weakness ,are caused by focal depression of cortical function.
Definite precipitating factors are unusual .Some patients complain of symptoms at times of relaxation ( weekened migraine ).Other find that chocolate ( high in phenylethylamine ) and cheese ( high in tyramine ) precipitate attacks .Migraine is common around puberty , at the menopause and premenstrually ,and sometimes increases in severity or frquency with hormonal contraceptives ,in pregnancy and with the onset of hypertension .There is no reason to support that he development of migraine is suggestive of any major intracranial lesions.However ,since migraine is so common ,an intrcranial mass and migraine sometimes occur together by coincidence .Rarely ,migraine follows a head injury :this can be minor .
CLINICAL PATTERNS
Migraine attacks vary from intermittent headaches indistinguishable from tension headaches to discrete episodes that mimic thromboembolic cerebral ischemia .Distinction between variants is somewhat artificial.
Migraine can be seperated into phases:
Well -being before an attack ( occasional ) .
Prodromal symptoms .
Headaches ,nausea , vomiting .
MIGRAINE WITH AURA ( CLASSICAL MIGRAINE )
Prodromal symptoms are usually visual and related to depression of visual cortical function or retinal function .There are unilateral patchy scotomata ( when the retina is affected ) or cortical hemianopic symptoms.Teichopsia ( flashes ) and fortification spectra ( jagged lines resembling battlements ) are common.Transient aphasia sometimes occurs ,together with tingling , nmbness or vague weakness of one side .The patient feels nauseated.The prodrome lasts from 15 minutes to an hour or more .Headache then follows .This is occasionally hemicranial ( i.e splitting the head ) but often begins locally and becomes generalized .Nausea increases and vomiting follows.The patient is irritable and prefers a darkened room.Superficial temporal arteries are engorged and pulsating.After several hours the attack ceases ,sometimes with a diuresis.Deep sleep often ensues.
MIGRAINE WITHOUT AURA ( COMMON MIGRAINE )
This is the usual variety.Prodromal visual symptoms are vague.There is recurrent headache accompanied by nausea and malaise.
BASILAR MIGRAINE
Prodromal symptoms include circumoral tingling ,tongue numbness ,vertigo ,diplopia ,transient visual disturbance ,blindness ,syncope ,dysarthria and ataxia .These occur either alone or progress to a migrainous headache.
HEMIPARETIC MIGRAINE
This rarity is classical migraine with hemiparetic features .Recovery occurs within 24 hours .Exceptionally ,cerebral infarctio and hemiplegia occurs.
OPTHALMOPLEGIC MIGRAINE
This is a third nerve ,or exceptionally a sixth nerve palsy with a migraine .This is arare and difficult to distinguish from other caues of a third nerve palsy without investigation.
FACIOPLEGIC MIGRAINE
This rarity is unilateral facial weakness during a migraine.
DIFFERENTIAL DIAGNOSIS
The onset of sudden headache may be similar to meningitis or SAH.
Hemiplegic ,visual and hemisensory symptoms must be distinguished from thromboembolic TIAs.In TIAs maximum deficit is present immediately and headache is unusual.
Unilateral tingling or numbness should be distinguished from sensory epilepsy ( partial seizures ) .In epilepsy distinct march ( progression ) of symptoms is usual .
MANAGEMENT
General measures include :
Reassurance and relief of anxiety .
Avoidance of dietry factors - rarely helpful.
Patients taking hormonal contraceptives may benefit from a brand change ,or trying without .Severe hemiplegic symptoms are an indication for stopping hormonal contraceptives.
DURING AN ATTACK
Paracetamol or other simple analgesics should be given ,with an antiemetic such as metoclopramide if necessary .Repeated use of analgesics leads to further headaches.Triptans ( 5-HT ,agonists ) are also helpful .In some 30% of cases where there is recurrent severe migraine ,sumatriptan ,zolmitriptan ,naratriptan and rezatriptan are of value either by prompt self-administered subcutaneous injection ,or orally by wafer or inhaler .Ergotamine tarter ( 1-2 mg orally or rectally ,360 mg by inhaler or 0.25 - 0.5 mg by injection) is also sometimes helpful if given early .Ergotamine and triptans should be avoided when there is vascular disease.
PROPHYLAXIS
It is difficult to discern placebo effects of prophylactic drugs in migraine .When drugs are necessary ,the following are helpful :
Pizotifen ( an antihistamine and a 5-HT antagonist ) 0.5 mg at night for several days ,increasing to 1.5 mg ar night -common side effects are slight weight gain and drowsiness.
Propranolol 10 mg three times daily ,increasing to 40-80 mg three times daily.
Methysergide ( a 5-HT antagonist ) 2-6 mg daily - an occasional side effects is periaortitis which precludes use for longer than 6 months.
Amitriptyline 10-30 mg at night is sometimes helpful .
Sodium valporate ,verapamil ,nifedipine , and naproxen are also used.
