When you’re lying awake With a dismal headache And repose is taboo’d by anxiety, I conceive you may use Any language you choose To indulge in without impropriety. “Iolanthe” by W.S. Gilbert
Headache is one of the most common presenting complaints for clinicians and encompasses a diverse spectrum of maladies. The International Headache Society (IHS) has revised their classification of headache diagnoses, and this is summarized in Table 16-1
This chapter addresses the neuro-ophthalmologic aspects of migraines and provides a brief review of other common headaches, facial and ocular pains.
Migraine is a periodic, paroxysmal, protean disorder whose prevalence varies by race and geographic region. In the United States, observed prevalence is lowest among Asian Americans, intermediate in African Americans, and highest among Whites, independent of demographic covariates.2
Similarly, an international meta-analysis found that the prevalence was lowest in Africa and Asia and higher in Europe and Central/South America.3
The highest estimates were found in North America.
In the United States, migraine affects an estimated 18% of women and 6% of men.4
It has been estimated that nearly one in four US households had someone with migraine.6
Higher income and education levels are associated with lower rates of migraine.2
One of the first names for this disorder was the descriptive term hemicrania
; this was later contracted by the French in the 13th century to the word “migraine.” Although descriptions of migraine-like symptoms and conditions were found in Babylonian writings dating back to 3000 BC and in Egyptian papyri from 1550 BC, the first modern description of migraine and its possible causes is attributed to Thomas Willis about 300 years ago. Famous historical migraine sufferers included Julius Caesar, Emmanuel Kant, Alexander Pope, Isaac Newton, and Sigmund Freud. Throughout the 18th and 19th centuries, descriptions of the clinical phenomena and suggestions for therapy appeared in the writings of many prominent men in the medical professions. Edward’s masterful treatise On Megrim, Sick Headache, and Some Allied Disorders
(1873, as detailed by Sacks) is an unequaled description of the disorder.7
Further detailed clinical descriptions are found in the writings of Gowers.8
In contemporary medicine, Dalessio, Goadsby, Raskin, Sacks, Silberstein, Lipton, Stewart, Saper, and Welch have all contributed significantly to the study of migraines. A constant tenet for all is that migraine cannot solely be defined by a unilateral (hemicranial) headache. “It is necessary to state that headache is never the sole symptom of a migraine, nor indeed is it the necessary feature of migraine attacks… Migraine is diagnosed by the entire history, not by physical findings or by the presence of headache alone.”7
Unfortunately, many have limited their concept of migraine to a stereotyped syndrome of visual disturbance followed by unilateral throbbing headache, which can be diagnosed by the response to ergot preparations. In actuality, migraine includes several well-recognized syndromes as well as a variety of “equivalents” less commonly classified as migraine. The symptom-complexes or syndromes of migraine include migraine without aura, migraine with aura, ophthalmoplegic migraine, retinal migraine, as well as the others listed in Table 16-1
. The clinical features of migraine will be discussed according to the formal criteria published by the IHS in 2004.1
Other conditions and syndromes discussed in this chapter include cluster headache, trigeminal neuralgia, atypical facial pain, temporal arteritis, and the headaches produced by intracranial mass lesions, muscle contraction, trauma, vascular anomalies, and ocular lesions.
TABLE 16-1. New IHS Classifications of Headaches
Migraine without aura
Migraine with aura
Childhood periodic syndromes
Complications of migraine
Infrequent episodic TTH
Frequent episodic TTH
Cluster headache and other trigeminal autonomic cephalalgias
Probable trigeminal autonomic cephalalgia
Other primary headaches
Primary stabbing headache
Primary cough headache
Primary exertional headache
Primary headache associated with sexual activity
Primary thunderclap headache
New daily-persistent headache
Headache attributed to head and/or neck trauma
Acute posttraumatic headache
Chronic posttraumatic headache
Acute headache attributed to whiplash injury
Chronic headache attributed to whiplash injury
Headache attributed to traumatic intracranial hematoma
Headache attributed to other head and/or neck trauma
Headache attributed to cranial or cervical vascular disorder
Headache attributed to ischemic stroke or transient ischemic attack
Headache attributed to nontraumatic intracranial hemorrhage
Headache attributed to unruptured vascular malformation
Headache attributed to arteritis
Carotid or vertebral artery pain
Headache attributed to cerebral venous thrombosis
Headache attributed to other intracranial vascular disorder
Headache attributed to nonvascular intracranial disorder
Headache attributed to high CSF pressure
Headache attributed to low CSF pressure
Headache attributed to noninfectious inflammatory disease
Headache attributed to intracranial neoplasm
Headache attributed to intrathecal injection
Headache attributed to epileptic seizure
Headache attributed to Chiari malformation type I
Syndrome of transient headache and neurologic deficits with CSF lymphocytosis
Headache attributed to other nonvascular intracranial disorder
Headache associated with a substance or its withdrawal
Headache induced by acute substance use or exposure
Headache as an adverse event attributed to long-term medication
Headache attributed to substance withdrawal
Headache attributed to infection
Headache attributed to intracranial infection
Headache attributed to systemic infection
Headache attributed to HIV/AIDS
Chronic postinfection headache
Headache attributed to disorder of homeostasis
Headache attributed to hypoxia
Headache attributed to arterial hypertension
Headache attributed to hypothyroidism
Headache attributed to fasting
Headache attributed to other disorder of homeostasis
Headache or facial pain attributed to disorder of cranium, neck, eyes, ears, nose, sinuses, teeth, mouth, or other facial or cranial structures
Headache attributed to disorder of cranial bone
Headache attributed to disorder of neck
Headache attributed to disorder of eyes
Headache attributed to disorder or ears
Headache attributed to rhinosinusitis
Headache attributed to disorder of teeth, jaws, or related structures
Headache or facial pain attributed to a temporomandibular joint disorder
Headache attributed to other disorder of cranium, neck, eyes, ears, nose, sinuses, teeth, mouth, or other facial or cervical structures
Headache attributed to psychiatric disorder
Headache attributed to somatization disorder
Headache attributed to psychotic disorder
Cranial neuralgias and central causes of facial pain
Nervus intermedius neuralgia
Superior laryngeal neuralgia
Other terminal branch neuralgias
External compression headache
Constant pain caused by compression, irritation, or distortion of cranial nerves or upper cervical roots by structural lesions
Ocular diabetic neuropathy
Head or facial pain attributed to herpes zoster
Central causes of facial pain
Other cranial neuralgia or other centrally mediated facial pain
Other headache, cranial neuralgia, central or primary facial pain
The International Classification of Headache Disorders. Published on behalf of the International Headache Society. Cephalalgia. 2004;24(suppl 1):1.
Migraine is a neurovascular process.22
It appears to be a polygenetic “channelopathy” of ion channels in the brain stem nuclei that modulate sensory input.23
An abnormal fluctuation of ions leads to electrophysiologic changes that subsequently cause changes in cerebral blood flow (CBF). Initially, there is a brief decrease in CBF, followed by a rebound vasodilation and increased CBF for several minutes, then finally an extended period of decreased blood flow (several hours).24
The initial electrophysiologic changes, termed CSD, are the likely basis of migraine aura.25
The headache was initially thought to be the solely result of painful vasodilation, but it is now thought to also be caused by activation of the trigeminovascular system (TGVS). The TGVS is superficial cortical and meningeal blood vessels innervated by the trigeminal nerve. It projects to the trigeminal caudal nucleus in the brain stem, which in turn projects to higher order pain centers, causing headache.24
It is unclear if CSD also plays a role in activation of the TGVS.
The role of vascular phenomena in the migraine headache was recognized largely by the work of Wolff and colleagues.27
Research suggests that the migraine attack starts as a neuronal phenomenon with secondary hemodynamic consequences.28
Wolff divided the migraine attack into four phases: preheadache, headache, late headache, and postheadache. The preheadache phase is characterized by the constriction of certain blood vessels that supply the brain. Then, the beginning of the headache phase is characterized by vascular dilatation, particularly involving branches of the external carotid such as the temporal, occipital, and middle meningeal arteries. Local tenderness of the scalp ensues, and the scalp vessels may become rigid. The nature of the headache then changes from a pulsatile type to a more constant dull ache. Alleviation of the early headache phase with vasoconstrictors (e.g., ergotamine) supports vasodilation as a source of pain. However, vasodilatation may occur without pain, and additional factors are involved in the production of the headache. Local tissue changes take place (e.g., vessel edema, scalp swelling, and conjunctival chemosis) that may continue after vasodilatation has ceased.
Various substances have causative roles in the production of large and small vessel dilatation as well as local tissue changes. Among the substances most frequently cited are the kinins (neurokinin and bradykinin), acetylcholine, histamine, serotonin, and reserpine. Migraine, then, may result from dysfunction of brain stem or diencephalic nuclei involved in nociceptive modulation of afferents from the trigeminal vascular system.28
Positron emission tomography has detected activation in the brain stem during attacks of migraine.33
hypothesized that the following sequence occurs: the initial event is a local release of catecholamines (with vasoconstriction and increased urinary excretion of vanillylmandelic acid); during subsequent reactive hyperemia serotonin is released (documented by plasma serotonin decrease36
and increased urinary 5-hydroxy indoleacetic acid37
), presumably from platelets or mast cells, which sensitizes cranial pain receptors perhaps also affected by the kinins.
Additional evidence suggests that there are nervous system connections between the trigeminal ganglia and cerebral blood vessels, the TGVS.38
Trigeminovascular neurons and their peripheral unmyelinated nerve fibers contain the neurotransmitter peptide, substance P. Stimulation of this system by various mechanisms would cause the release of substance P, which is postulated to increase vascular permeability and dilate cerebral blood vessels. The role of this system in the generation of human vascular headache may account for the effects of hormones or other circulating substances that change the receptive field properties of trigeminal ganglion cells.
Individuals prone to chemically induced headaches from ingestion of tyramine, alcohol, phenylethylamine, monosodium glutamate, nitroglycerine, wine, or chocolate also experience spontaneous headaches.39
Extensive studies of the reactivity of blood vessels in migraine40
suggest that abnormal vasomotor responses may be present in patients with migraine between, as well as during, migraine attacks.
There are several lines of indirect evidence that suggest a relationship between serotonin and migraine, making the understanding of the pharmacology of serotonin important for understanding the pharmacology of the new serotonin agonist in migraine therapy11
The serotonin or 5-HT receptors consist of at least three distinct types of molecular structures: guanine nucleotide G proteincoupled receptors, ligand-gated ion channels, and transporters. At least five 5-HT1
receptor subtypes are present in humans. Headaches resembling migraine can be triggered by serotonergic drugs such as reserpine (a 5-HT releaser and depleter) and m-chlorophenylpiperazine (a serotonin agonist).43
Other metabolic and endocrine factors also influence migraine attacks. According to Friedman and Merritt,45
80% of pregnant women previously prone to migraines either lose the headaches or experience improvement. However, Callaghan46
found an increase in the severity of migraine in pregnancy. The use of oral contraceptives appears to increase the incidence and severity of migraine.47
Whitty et al.49
felt that migraine might be precipitated by withdrawal of progesterone, whereas Somerville50
found from a study of three women with regular menstrual migraine that their attacks were related to estradiol withdrawal rather than to decreasing levels of progesterone. Tyramine has also been invoked as a precipitating factor, especially in the so-called allergic migraine;51
however, only approximately 5% of migraine subjects notice headaches precipitated by food. However, some patients are unusually sensitive to chocolate or alcohol, particularly red wines. Recent therapeutic trials with dietary therapy designed to avoid hypoglycemia suggest that glucose and/or insulin metabolism may play a role in the generation of vascular headache.
The role of trauma in the production or exacerbation of a preexisting migrainous tendency is still incompletely defined. Many individuals experience vascular headaches of the common migraine type after even minor head trauma.52
A previously well-controlled migraineur can experience a recrudescence of prior symptomatology after a head trauma. Such exacerbations are usually short-lived with a return to the preinjury status in weeks to months. However, there are some patients who experience post-traumatic migraine headaches for years after a head injury. Other triggering events preceding migraine attacks include bright light, especially sunlight reflected from water, exercise or exertion, and high altitude. Vascular headache of the migraine type may also follow orgasm.53
The role of stress is less clear. It appears more likely that migraine headache follows a period of psychological stress than occurring during the time of stress.
The pathophysiology of the migraine aura itself also has been studied extensively. Wolff showed that the use of a potent vasodilator, amyl nitrate, could abort the migraine scotoma (Fig. 16.1
), supporting the vasoconstrictor hypothesis. Milner54
suggested that the scotomas of migraine and the neurophysiologic phenomenon, Leão spreading depression, may be related. The spreading depression progresses across the cortex at approximately 3 mm per minute, similar to the slow evolution of the visual phenomenon that had been detailed by Lashley,55
and estimated to spread over the occipital cortex at a rate of 3 mm per minute.
It is currently believed that the aura of migraine may be the human counterpart of the animal phenomenon of Leão spreading depression.18
The aura is characterized by a wave of decreased blood flow or oligemia passing across the cortex30
at a slow rate (2 to 6 mm per minute) consistent with the spread of the visual phenomenon through the visual cortex, as mentioned above.19
There is a short phase of hyperemia preceding the oligemia that may be a correlate of the scintillating scatoma, also a characteristic of migraine with aura.59
However, persistent oligemia is probably a response to depressed neuronal function and is present when the headache starts, as noted by Goadsby.58
Such findings coupled with the direct evidence of adequate local oxygen supply62
vitiate the theory that migraine is just a vascular headache.61
FIG. 16.1 A: Effect of inhalation of small amount of amyl nitrite on preheadache scotomas in migraine subject. The amount was insufficient to cause a drop in blood pressure or “light-headedness.” B: With inhalation of a large amount of amyl nitrite, a drop in pressure occurred with amblyopia and faintness. (From Wolff HG. Headache and Other Head Pain. 2nd ed. New York, NY: Oxford University Press; 1963, with permission.)
Three cardinal factors are important in the pathogenesis of migraine, according to Goadsby.61
These include the cranial blood vessels, the trigeminal innervation of these vessels, and the reflex connection of the trigeminal system with a cranial parasympathetic outflow. The pain sensitive structures within the cranium, such as large blood vessels or the dura mater, are innervated by branches of the ophthalmic division of the trigeminal nerve,63
and the posterior fossa structures are innervated by branches of C2 nerve roots.64
Involvement of the ophthalmic division of the trigeminal nerve and the overlap with structures innervated by C2 explain the common distribution of the pain of migraine in the frontal and temporal regions, as well as involvement of parietal occipital and high cervical regions, by referred pain.61
Peripherally, the trigeminal afferents are activated in migraine by the release of calcitonin gene-related peptide (CGRP) a vasodilator,65
and while the mechanism of pain generation is not entirely clear, animal studies suggest that pain is caused by a sterile neurogenic inflammation in the dura mater.66
This may, in part, explain the prevention of migraine pain by substances such as botulinum toxin type A, which inhibit the release of CGRP.67
The pain may be a combination of an altered perception—as a result of peripheral or central sensitization—of craniovascular input that is not usually painful61
and the activation of feed-forward neurovascular dilator mechanism that is functioning specific to the first ophthalmic division of the trigeminal nerve.69
Again, the effect of botulinum toxin type A in reducing migraine pain may interfere with this peripheral activation and, therefore, functions to provide peripheral desensitization.67
Eighty percent of migraineurs experience photophobia, or exacerbation of the headache by what is normally a tolerated level of light, during migraine attacks.70
This photophobia is not a product of the traditional image forming pathway of the visual system, for example, the photoreceptors, retinal ganglion cells (RGCs), lateral geniculate nucleus, and visual cortex.71
Instead, it is a nonimage forming system of vision that originates in intrinsically photosensitive RGCs (ipRGCs) that appears to be the origin of photophobia. These ipRGCs contain the photoreceptor melanopsin and function without any synaptic input from the rods and cones.71
Their peak spectral sensitivity lies in the blue range at approximately 480 nm.72
The axons of these ipRGCs project via the optic nerve to the suprachiasmatic nucleus, intergeniculate leaflet, and the olivary pretectal nucleus.72
It is through these projections that the melanopsin system mediates such nonimage forming visual functions like the pupillary light response and circadian rhythms. Both of circadian rhythm and pupillary light response are preserved in some blind patients. That is because the melanopsin-containing ipRGCs are spared in some blinding eye conditions, for example, mitochondrial optic neuropathies (Leber and dominant optic atrophy) and peripheral retinal degenerations (retinitis pigmentosa); however, they tend to be preferentially targeted in glaucoma.72
TABLE 16-2. Migraine Without Aura
Migraine without aura
Previously used terms: common migraine, hemicrania simplex
Recurrent headache disorder manifesting in attacks lasting 4-72 h. Typical characteristics of the headache are unilateral location, pulsating quality, moderate or severe intensity, aggravation by routine physical activity and association with nausea and/or photophobia and phonophobia
At least five attacks fulfilling criteria B-D
Headache attack lasting 4-72 h (untreated or unsuccessfully treated)
Headache has at least two of the following characteristics:
Moderate or severe pain intensity
Aggravated by causing avoidance of routine physical activity (e.g., walking or climbing stairs)
During headache at least one of the following:
Nausea and/or vomiting
Photophobia and phonophobia
Not attributed to another disorder
Likewise, migrainous photophobia is preserved in some blind patients. Noseda et al.71
not only found that light modulated the activity of a subset of trigeminovascular thalamic neurons but also that most retinal projections to the thalamus consisted of axons of ipRGCs. They therefore posit that the melanopsin system carries the photic signal from the retina to the nociceptive thalamic TGVS, and thereby exacerbates migraine headache pain.
MIGRAINE WITHOUT AURA
The IHS classification has improved the diagnosis of headaches. It has also facilitated clinical research on migraine. In order to establish a diagnosis of migraine without aura, five attacks are needed (Table 16-2
). Each attack must last 4 to 72 hours and have two of the following four pain characteristics: unilateral location, pulsating quality, moderate to severe intensity, and aggravation by routine physical activity. In addition, the attacks must be associated with at least one of the following: nausea, vomiting, or photophobia and phonophobia. With these criteria, no single characteristic is mandatory for a diagnosis of migraine. A patient who has severe pain aggravated by routine activity, photophobia and phonophobia, meets these criteria as does the more typical patient with unilateral throbbing pain and nausea.
Migraine usually lasts several hours or the entire day. When the migraine persists for longer than 3 days, the term “status migrainosus” is used. Frequency of attacks varies widely from a few per lifetime to several per week.11
The average migraineur experiences from one to three headaches per month.5
A precise location ascribed to migraine, such as unilateral or temporal, is misleading, for as Wolff40
The sites of migraine are notably temporal, supraorbital, frontal, retrobulbar, parietal, postauricular, and occipital… They may as well occur in the malar region, in the upper and lower teeth, at the base of the nose, in the median wall of the orbit, in the neck, and in the region of the common carotid arteries and down as far as the tip of the shoulder.
The prodromes of common migraine are vague, preceding the attack by hours or days, and include psychic disturbances (such as depression or hypomania), gastrointestinal manifestations and changes in fluid balance. Usually the onset of the common migraine headache is unilateral, but the pain often becomes holocephalic. In an individual patient, the headache is commonly more prominent on a single side, with occasional or rare alternation. Some individuals always experience a unilateral headache, while in approximately one-third the headache is diffuse from onset. Traditionally, the character of the headache is described as throbbing, but this may be a feature only at onset, with the discomfort soon changing to a steady ache. The victim can often relieve unilateral headache by carotid artery or temporal artery compression, only to experience resurgence of the pain after release.
Nausea in some degree almost always accompanies common migraine. Vomiting can occur at the height of an attack, sometimes with relief of the headache, but more often heralds an intensifying phase of the episode, which continues for many minutes or hours. Usually the migraine sufferer becomes pallid and seeks seclusion, darkness, quiet, and a cold towel or ice bag for the head. Frequently at the time of nausea with vomiting, a diuretic phase with polyuria ensues, the consequence of fluid retention that occurred in the hours or days preceding the acute headache.
Ocular signs and symptoms may occur in common migraine, such as conjunctival injection, periorbital swelling, excessive tearing, foreign body sensation, and photophobia; however, these phenomena are more prominent in cluster headache.
MIGRAINE WITH AURA (CLASSIC)
The new term for classic migraine, that is migraine with aura, requires at least two attacks with any three of the following four features (Table 16-3
): one or more fully reversible aura symptoms, aura developing over a course of more than 4 minutes, aura lasting less than 60 minutes, and headache after aura within 60 minutes. Migraine with aura refers to a more well-defined clinical constellation than does migraine without aura. The episodes are characterized by definite prodrome or aura, which is usually a visual sensation; however, sometimes motor or other sensory phenomena precede the headache. The headaches of classic migraine tend to be more compact and intense, rarely lasting more than 12 hours; most often 2 to 3 hours.
Many general characteristics are shared by common and classic migraine. Both varieties affect men and women and can occur at any age, often seemingly triggered by a significant event such as puberty, school graduation, or marriage. A family history is usually present both in classic and common migraine, and there may be an earlier history of colic as a baby or car illness as a small child. The full history of a complete migraineur would include migraine with aura in the teens, migraine without aura with nausea and vomiting in the second and third decades, followed by simple periodic headache or isolated migrainous auras in later life.
Migraine with aura is subclassified into migraine with typical aura (homonymous visual disturbance, unilateral numbness or weakness, or aphasia), migraine with prolonged aura (or lasting longer than 60 minutes), FHM, basilar migraine, migraine without headache, and migraine with acute-onset aura.
The primary feature of migraine with aura is the visual aura. Extensive reviews of this phenomenon are found throughout the literature.7
Although many variations occur, the following description by Richards50
summarizes the most common type of visual phenomena (Figs. 16.2
The visual disturbance usually precedes the headache … [it] begins near the center of the visual field as a small gray area with indefinite boundaries. If this area first appears during reading, as it often does, then the migraine is first noticed when words are lost in a region of “shaded darkness.” During the next few minutes the gray area slowly expands into a horseshoe with bright zigzag lines appearing at the expanding outer edge. These lines are small at first and grow as the blind area expands and moves outward toward the periphery of the visual field.
One important aspect of the visual disturbance just described is that it expands slowly over 10 to 20 minutes. The initial region of visual abnormality is most often near fixation and then, as described by Lashley,55
with increase in size the disturbed area moves or “drifts” across the visual field so that its central margin withdraws from the macular region as its peripheral margin invades the temporal; the area may be totally blind (negative scotoma), amblyopic, or outlined by scintillations.
TABLE 16-3. Migraine with Aura
1.2 Migraine with aura
Previously used terms: classic or classical migraine; ophthalmic, hemiparesthetic, hemiplegic, or aphasic migraine, migraine acompania, complicated migraine
Recurrent disorder manifesting in attacks of reversible focal neurologic symptoms that usually develop gradually over 5-20 min and last for <60 min. Headache with features of migraine without aura usually follows the aura symptoms. Less commonly, headache lacks migrainous features or is completely absent
At least two attacks fulfilling B
Migraine aura fulfilling criteria B and C for one of the subforms 1.2.1-1.2.6
Not attributed to another disorder*
1.2.1 Typical aura with migraine headache
Typical aura consisting of visual and/or sensory and/or speech symptoms. Gradual development, duration no longer than 1 h, a mix of positive and negative features and complete reversibility characterize the aura which is associated with a headache fulfilling criteria 1.1 Migraine without aura
At least two attacks fulfilling criteria B-D
Aura consisting of at least one of the following, but no motor weakness:
Fully reversible visual symptoms including positive features (e.g., flickering lights, spots or lines) and/or negative features (i.e., loss of vision)
Fully reversible sensory symptoms including positive features (i.e., pins and needles) and/or negative features (i.e., numbness)
Fully reversible dysphasic speech disturbance
At least two of the following:
Homonymous visual symptoms† and/or unilateral sensory symptoms
At least one aura symptom develops gradually over ≥5 min and/or different aura symptoms occur in succession over ≥5 min
Each symptom last ≥5 and ≥60 min
Headache fulfilling criteria B-D for 1.1 Migraine without aura within 60 min
Not attributed to another disorder‡
* History and physical and neurologic examinations do not suggest any of the disorders listed in groups 5-12, or history and/or physical and/or neurologic examinations do suggest such disorder but it is ruled out by appropriate investigations, or such disorder is present but attacks do not occur for the first time in close temporal relation to the disorder.
† Additional loss or blurring of central vision may occur.
‡ History and physical and neurologic examinations do not suggest any of the disorders listed in groups 5-12, or history and/or physical and/or neurologic examinations do suggest such disorder, but it is ruled out by appropriate investigations, or such disorder is present but attacks do not occur for the first time in close temporal relation to the disorder.
The scintillations surrounding the negative scotoma make “fortification” figures or spectrums, so called by the appearance of a “map of the bastions of a fortified town.”55
The scintillations are brilliant, with the intensity of a bright fluorescent bulb flickering at a rate of 5 to 10 cycles per second (Figs. 16.4
was particularly impressed with the intensity of the visual sensation. Many migraine sufferers can precisely recall their own vivid visual experiences well enough to describe them precisely or even on occasion to paint them (Figs. 16.6
). Not all migraine visual disturbances begin near the fixation point; some patients consistently experience scotomas starting eccentrically in the visual field, and these sensations can appear alternately or simultaneously in both hemifields (Fig. 16.8
). Other less dramatic visual auras also occur: just the sensation of peripheral brightness or awareness of a rhythmicity or pulsating character in the intensity of the ambient light. The duration of these visual symptoms is measured in minutes rather than the brief few seconds of flashing, bright moving spots, or transient flickering phenomena characteristic of occipital epileptic discharges.9
Additional visual disturbances are categorized by Klee and Willanger,74
consisting of metamorphopsia, diplopia, polyopia, and apparent movement of stationary objects. Variations in the scotomas of migraine, including their occurrence in patients with acquired blindness, are well described.74
The auras of migraine, although most commonly only visual, have many other associated manifestations, such as hemihypesthesias, perioral anesthesia, vertigo, and transient aphasia. The aura or prodromes of classic migraine may be precipitated by intense stimuli: bright lights, loud noises, head trauma, or the intake of certain foods in susceptible individuals.
FIG. 16.2 Successive arcs expand across half of visual field, as shown in two diagrams based on airy. The spectra may take 20 to 25 minutes to expand from a fuzzy gray area near the fixation point (dot) to the outer limit of the visual field. (From Richards W. The fortification illusions of migraines. Sci Am. 1971;224:88, with permission.)
FIG. 16.3 Emerging honeycomb pattern from plotting data derived from visual phenomena in migraine subjects. Honeycomb and tendency for inner angle between lines to approximately 60° suggest a hexagonal organization of occipital cortical cells. (From Richards W. The fortification illusions of migraine. Sci Am. 1971;224:88, with permission.)
FIG. 16.4 Successive maps of a scintillating scotoma to show characteristic distribution of the fortification figures. (Modified from Lashley KS. Patterns of cerebral integration indicated by scotomas of migraine. Arch Neurol Psychiatry. 1941;46:333. Copyright © 1941, American Medical Association.)
FIG. 16.5 Variations in fortification figures. Coarser and more complicated figures are generally in lower part of field. (From Lashley KS. Patterns of cerebral integration indicated by scotomas of migraine. Arch Neurol Psychiatry. 1941;46:333. Copyright © 1941, American Medical Association.)
In the usual sequence of migraine with aura the sensory prodrome precedes the onset of the headache (in accord with the traditional concept of vasoconstriction followed by vasodilatation). The visual disturbance rarely may have a simultaneous onset with headache or, once having disappeared, may recur following the onset of headache. Such unusual patterns, or strict unilaterality for all attacks, should increase suspicion of a mass lesion or vascular malformation. As opposed to definite periodicity with symptom-free intervals and predictable circumstances, as in migraine without aura, migraine with aura may occur “out of the blue” and in multiple attacks over a few days.
Migraine-with-aura attacks tend to diminish in the third and fourth decades. Although most migraine patients experience a stereotyped clinical pattern, there is a well-recognized group in which both classic and common migraine attacks are admixed.78
Some patients with classic migraine may lose the headache component eventually and suffer only isolated auras thereafter. This monosymptomatic pattern stresses the importance of accurate history-taking when confronted by a patient with isolated visual phenomena (migraine dissociée). Haas79
emphasized the occurrence of “migraine aura status.” The differential diagnosis should include consideration of vertebro-basilar transient ischemic attacks. Symptomatology that favors migraine has been reviewed by Fisher80
and includes luminous visual images, build-up of images, progression from one aura to another, and benign outcome.
FIG. 16.6 Left-sided fortification spectrum of migraine. Illustration by Dr. Hubert Airy of his own scotomas. A bright stellate object (A) appeared suddenly below and to the left side of fixation (o). It rapidly enlarged, first as a circular zigzag, but on the inner side the zigzag was faint (B); as arc increased in size, it was broken centrally (C). In (D), original circular outline had become oval. Rectangular lines that made up the fortification spectrum became longer as the process extended peripherally. When spectrum had extended through greater portion of the field (E), upper portion also began to expand (F). At this time, the lower part of spectrum disappeared. The phenomenon ended in a whirling focus of light (G) 20 minutes after it began. At this time, a headache appeared on the right side. (From Gowers WR. Visual sensations in migraine. In: Subjective Sensations of Sight and Sound: Abiotrophy and Other Lectures. London, UK: Churchill; 1907, with permission.)
FIG. 16.7 Inhibitory character within angled oval of an expanding fortification spectrum. Outside the limiting line, vision is preserved; within it, vision is lost. This occurs at first over the whole area; afterwards, when the sphere is broken and has become oval, loss is most intense close to the limiting line and becomes less toward the middle. (From Gowers WR. Visual sensations in migraine. In: Subjective Sensations of Sight and Sound: Abiotrophy and Other Lectures. London, UK: Churchill; 1907, with permission.)