C h a p t e r 3 5
Somatosensory Function, Pain, and Headache
873
There are two major types of migraine headache—
migraine without aura and migraine with aura.
Migraine
without aura
, which accounts for approximately 85%
of migraines, is a pulsatile, throbbing, unilateral head-
ache that typically lasts 1 to 2 days and is aggravated by
routine physical activity. The headache is accompanied
by nausea and vomiting, which often is disabling, and
sensitivity to light and sound. Visual disturbances occur
quite commonly and consist of visual hallucinations
such as stars, sparks, and flashes of light.
43
Migraine
with aura
has similar symptoms, but is preceded by a
sensory experience called an
aura
. It typically consists
of visual symptoms, including flickering lights, spots, or
loss of vision; sensory symptoms, including feeling of
pins or needles, or numbness; and speech disturbances
or other neurologic symptoms. These symptoms precede
the headache, developing over a period of 5 to 20 min-
utes, and last from 5 minutes to 1 hour.
43
Although only
a small percentage of persons with migraine experience
an aura before an attack, many persons without aura
have prodromal symptoms, such as fatigue and irritabil-
ity, that precede the attack by hours or even days.
A retinal migraine is a rare form of migraine char-
acterized by recurrent attacks of fully reversible scintil-
lations (visual sensation of sparks or flashes of light),
scotomata (visual blind spots), or blindness affect-
ing one eye, followed within an hour by a headache.
Migraines can also be chronic, occurring on 15 or more
days per month for 3 months or more, in the absence
of medication overuse. Migraine headache also can
present as a mixed headache, including symptoms typi-
cally associated with tension-type or sinus headaches.
These are called
transformed migraine
and are difficult
to classify.
Migraine headaches occur in children as well as
adults.
45,46
Before puberty, migraine headaches are
equally distributed between the sexes. The essential
diagnostic criterion for migraine in children is the pres-
ence of recurrent headaches separated by pain-free peri-
ods. Diagnosis is based on at least three of the following
symptoms or associated findings: abdominal pain, nau-
sea or vomiting, throbbing headache, unilateral loca-
tion, associated aura (visual, sensory, motor), relief
during sleep, and a positive family history.
46
Symptoms
vary widely among children, from those that interrupt
activities and cause the child to seek relief in a dark
environment to those detectable only by direct question-
ing. A common feature of migraine in children is intense
nausea and vomiting. The vomiting may be associated
with abdominal pain and fever; thus, migraine may
be confused with other conditions such as appendici-
tis. More than half of children with migraine undergo
spontaneous prolonged remission after their 10th birth-
day. Because headaches in children can be a symptom
of other, more serious disorders, including intracranial
lesions, it is important that other causes of headache
that require immediate treatment be ruled out.
The pathophysiologic mechanisms of the pain asso-
ciated with migraine headaches remain poorly under-
stood. Although many alternative theories exist, it is well
established that during a migraine the trigeminal cranial
nerve (CN V) becomes activated.
47
This may lead to the
release of neuropeptides, causing painful neurogenic
inflammation within the meningeal vasculature charac-
terized by plasma protein extravasation, vasodilation,
and mast cell degranulation. Another possible mecha-
nism implicates neurogenic vasodilation of meningeal
blood vessels as a key component of the inflammatory
processes that occur during migraine. Supporting the
neurogenic basis for migraine is the frequent presence
of premonitory symptoms before the headache begins;
the presence of focal neurologic disturbances, which
cannot be explained in terms of cerebral blood flow;
and the numerous accompanying symptoms, including
those related to autonomic and somatic nervous system
dysfunction.
Fluctuations in hormone levels, particularly in estro-
gen levels, are thought to play a role in the pattern of
migraine attacks. For many women, migraine headaches
coincide with their menstrual periods. Dietary substances,
such as monosodium glutamate, aged cheese, and choco-
late, also may precipitate migraine headaches. The actual
triggers for migraine are the chemicals in the food, not
allergens.
The treatment of migraine headaches includes pre-
ventive and abortive nonpharmacologic and pharmaco-
logic treatment.
48
Nonpharmacologic treatment includes
the avoidance of migraine triggers, such as foods, that
precipitate an attack. Many persons with migraines ben-
efit from maintaining regular eating and sleeping habits.
Measures to control stress, which also can precipitate an
attack, also are important. During an attack, many per-
sons find it helpful to retire to a quiet, darkened room
until symptoms subside.
Pharmacologic treatment involves both abortive
therapy for acute attacks and preventive therapy. A wide
range of medications is used to treat the acute symptoms
of migraine headache. First-line agents include aspirin
and other NSAIDs (e.g., naproxen sodium, ibuprofen),
combinations of acetaminophen, acetylsalicylic acid,
and caffeine; serotonin (5-HT
1
) receptor agonists (e.g.,
sumatriptan); ergotamine derivatives (e.g., dihydroergot-
amine); and antiemetic medications (e.g., ondansetron,
metoclopramide). Non-oral routes of administration
may be preferred in individuals who develop severe pain
rapidly or on awakening, or in those with severe nau-
sea and vomiting. Both sumatriptan and dihydroergota-
mine have been approved for intranasal administration.
For intractable migraine headache, dihydroergotamine
may be administered parenterally with an antiemetic or
opioid analgesic.
49
Frequent use of abortive headache
medications may cause rebound headache. Because of
the risk of coronary vasospasm, the 5-HT
1
receptor
agonists should not be given to persons with coronary
artery disease. Ergotamine preparations can cause uter-
ine contractions and should not be given to pregnant
women. They also can cause vasospasm and should be
used with caution in persons with peripheral arterial
disease.
Preventive pharmacologic treatment may be neces-
sary if migraine headaches become disabling, if they
occur more than two or three times a month, if abortive
treatment is being used more than two times a week, or
if the individual has hemiplegic migraine, migraine with
