Chapter 38 Migraine Headache and Cluster Flashcards
KEY POINTS 1. The incidence of migraines in females increases into the early forties. 2. Consuming more than about 400 mg of caffeine per day can predispose to chronic migraines. 3. Basilar migraine can present with mental status changes. 4. Vasoconstrictor drugs, such as triptans, are contraindicated in basilar migraine. 5. Analgesic overuse (use of analgesics 10 or more days per month) can lead to chronic daily migraine. 6. The trigeminal autonomic cephalalgias include cluster, hemicr
Migraine headache
represents a very common benign headache syndrome; it is sometimes referred to as a vascular headache
The pain-generating structures of the head include
venous sinuses, meningeal and large cerebral arteries, basal meninges, muscles, skin, and cranial nerves V, IX, and X.
trigeminovascular system
A plexus of largely unmyelinated fibers arises from the
trigeminal ganglion (cranial nerve V) and innervates the
cerebral and pial arteries, the venous sinuses, and the dura
mater
The neurons in the trigeminovascular
system contain
substance P, one of the major nociceptive neurotransmitters of primary sensory neurons; calcitonin gene-related peptide (CGRP), which causes vasodilatation and when infused intravenously into susceptible individuals triggers headache; and neurokinin A, which is similar in structure and function to substance P.
When the trigeminal ganglion is stimulated and causes antidromic activation of the trigeminovascular system,
these peptide neurotransmitters are released near the
blood vessels they innervate; this results in vasodilatation
with consequent extravasation of plasma, or so-called sterile
neurogenic inflammation.
Leakage of plasma proteins
from the dilated blood vessels in turn stimulates
the trigeminal nerve endings and causes nociceptive orthodromic signals to the trigeminal ganglion—the end result of this sterile neurogenic inflammation is the perception of pain in and around the head.
Neurogenic inflammation is
blocked by
substances that act as agonists on a subset of serotonin (5-hydroxytryptamine, or 5-HT) receptors: the 5-HT1D and 5-HT1B receptors.
The major drugs used to
abort acute migraine attacks
agonists at the 5-HT1D/1B receptors. Drugs that act as agonists at these sites are thought to reduce neurogenic inflammation by inhibiting the trigeminal nerve endings and by their actions on blood vessels
Agonists at the 5-HT1D/1B receptors
include
ergot alkaloids (ergotamine, dihydroergotamine) and triptans (sumatriptan and others).
stimulation of the trigeminal ganglion, through antidromic release of neurotransmitters, results in
increased cerebral and extracerebral blood flow.
Stimulation of the
dorsal raphe nucleus
serotonergic nucleus in the midbrain, also increases cerebral blood flow.
stimulation of the nucleus caeruleus
the major source of central noradrenergic input, causes a decrease in cerebral blood flow.
Interneurons in the spinal cord and brainstem that are part of the descending pain modulation system use what as neurotransmitters?
enkephalins and g-aminobutyric acid (GABA) as neurotransmitters
An
ascending serotonergic pathway in the midbrain raphe region
relays painful stimuli to the
ventroposteromedial (VPM) thalamus via the quintothalamic tract.
A descending endogenous
pain modulating system originates in the
periaqueductal gray region of the midbrain, one of whose major relay structures is the nucleus raphe magnus in the medulla. After this relay, the descending pain modulating system connects with the spinal tract of the trigeminal nerve and the dorsal horns of the first through third cervical nerves.
Stimulation of the periaqueductal gray region causes
headache. The major neurotransmitters of this pain-modulating system are norepinephrine, serotonin, and enkephalins
migraine with aura it is thought that the cortex,
particularly the occipital cortex, is hyperexcitable. The cause of this hyperexcitability is
may relate to decreased intracellular magnesium levels, to a dysfunction of brain mitochondria, or to abnormal calcium channels.
The aura phase of migraine begins as
a wave of cortical neural excitation, accompanied by hyperemia, and is followed by an electrical wave of spreading neural depression and oligemia that advances at a rate of 2 to 6 mm/minute (a rate similar to that of the developing aura). During the oligemic phase, blood
flow remains above the ischemic threshold.
Dopamine receptor hypersensitivity
may be responsible for the
nausea, vomiting, hypotension, and dizziness that frequently accompany, and sometimes characterize, attacks of migraine. Antiemetics, most of which are dopamine receptor antagonists (especially at the D2 receptor), are frequently useful, and sometimes
effective in and of themselves in treating migraine
attacks.
The diagnosis of migraine is made by
a suggestive clinical history and a normal neurologic examination
The classic description of migraine
that of a recurrent headache lasting 2 to 72 hr, of moderate to severe intensity, pulsating, aggravated by routine physical activity, and associated with nausea, emesis, photophobia, phonophobia, and/or osmophobia.
The major subtypes of migraine are
migraine with aura and migraine without aura
The most frequent migrainous aura consists of
visual symptoms such as bright spots, dark spots, tunnel vision, or zigzag lines (fortification spectra). Other common auras include numbness or paresthesias in one arm or side of the body
The aura is followed (or sometimes accompanied) by
an intense, crescendo head pain, frequently unilateral or retro-ocular; it may be described as pounding, throbbing, pressure-like, exploding, stabbing, or vise-like
status migrainosus
the headache becomes intractable and lasts a week or longer
basilar migraine
A migraine whose aura seems to originate in the brainstem
or involve both hemispheres
A typical aura in basilar migraine might present
with bilateral visual loss or blindness
basilar migraine patients may complain
of
vertigo, dysarthria, diplopia, tinnitus, ataxia, a decreased
level of consciousness, or bilateral sensory (paresthesias)
or subjective motor symptoms (there should be no objective weakness); sometimes nausea and emesis are
prominent. Some patients present with other types of
auras such as a dysphasia, and as such may resemble a
transient ischemic attack (TIA), a stroke, or an evolving
neurologic catastrophe.
Exertional migraines
Some patients develop severe headache, sometimes described as exploding, related to exertion
ophthalmoplegia
a severe ocular headache that presents with
ophthalmoplegia (usually of the oculomotor nerve and
includes a dilated pupil. The ophthalmoplegia can last
hours to months and is now believed to represent an inflammatory neuritis or the Tolosa–Hunt syndrome.10
Painful ophthalmoplegia usually has a dramatic presentation and always warrants a careful evaluation.
Migraine without Aura
At least five headache attacks: Headaches last 4–72 hr if untreated. Has at least two of the following, but not weakness: Unilateral pain, Pulsating, Intensity is moderate to severe. Aggravated by routine physical activity
Has at least one of the following: Phonophobia, Photophobia, Nausea, Emesis
Migraine with Aura
At least two headache attacks that also fulfill the characteristics of migraine without aura. Headaches usually follow the aura but may begin with it and last 4–72 hr if untreated. Has at least one of the following reversible symptoms (lasting 4 min to 60 min), but no weakness
Positive or negative visual symptoms such as scintillating scotomas, blind spot (scotoma), blurred vision, zigzag lines, homonymous hemianopsia. Positive or negative sensory symptoms such as tingling or numbness
Basilar Migraine
At least two attacks of migraine with an aura whose symptoms are reversible and localize to the brainstem or are bihemispheric, but without weakness
Symptoms can include: Dysarthria, Dizziness or vertigo
Bilateral visual symptoms, including temporary blindness
Diplopia, Nystagmus, Ataxia, Decreased level of consciousness, Bilateral paresthesiae, Tinnitus with or without decreased hearing
Aura without Headache
At least two attacks of symptoms typical of auras, but not weakness, such as visual, sensory or speech disturbances that resolve within 1 hr and are
not followed by a headache
Hemiplegic Migraine
At least two attacks of migraine with a reversible aura of motor weakness that can last 1 hr to days
Also includes one of the following: Positive or negative visual symptoms, Positive or negative sensory symptoms
Dysphasia or dysarthria, Frequently accompanied by symptoms typical of basilar migraine. If at least one first- or second-degree relative has a migrainous aura that includes motor weakness, it is familial hemiplegic migraine and is associated with a mutation in the neuronal calcium channel. If no first- or second-degree relative has a migrainous aura that includes motor weakness, it is sporadic hemiplegic migraine
Migraines can be treated
abortively (after they start) or
prophylactically (with daily medication aimed at reducing
the frequency or intensity of the headaches).
Triptans (Imitrex, Maxalt, Zomig, Frova, Relpax,
Amerge, and others)
5-HT1D/1B receptor agonists
How are Triptans dosed?
A second dose of the same preparation, taken 2 to 24 hr after the first, may again provide significant relief. A
triptan should not be used again for at least 24 hr after
the second dose