++
Migraine headaches are common. In a review by Stewart and colleagues
of four prevalence studies that used the IHS criteria, overall migraine
prevalence was 6% among men and 16% among women.13 The
initial onset of migraine headaches most commonly occurs during
between the ages of 10 and 25 years. Migraine headaches occur for
the first time after age 40 uncommonly. In one incidence study,
for example, 77% of patients with migraine first sought
medical attention for migraine before age 40.14 The
new appearance of a migraine-like headache in a person over age
40 should prompt consideration of other possible diagnoses. Hamelsky
and colleagues characterize migraine prevalence in more detail in
Chapter 17.
++
In practice, clinicians most commonly entertain the diagnoses
of migraine and tension-type headache for patients with long-standing
recurring headaches. Although less common than tension-type headache,
migraine is more likely to cause sufferers to be disabled by their
headaches and to seek medical attention for their symptoms.15
++
Tables 18-1 and 18-2 list the IHS criteria for the diagnosis
of migraine without aura and migraine with aura, respectively. The
principal historical features are headaches that are unilateral,
throbbing, moderate to severe in intensity, and worse with ordinary
physical activity; last from 4 to 72 hours; and are associated with
nausea, photophobia, and phonophobia. All of these features are, however,
not equally useful to clinicians in establishing a diagnosis of
migraine. Table 18-3 summarizes reported clinical series that detailed
the frequency of particular clinical features in patients with migraine
and tension-type headache. These data were pooled from multiple
series published over the past four decades. All studies were classified
as to their use of the IHS diagnostic criteria or other criteria.
Sensitivity, specificity, and likelihood ratios were calculated
for the diagnosis of migraine as compared with tension-type headache.
A positive likelihood ratio indicates the increase in the odds of
the diagnosis of migraine if the particular feature is present.
A negative likelihood ratio indicates the decrease in the odds of
the diagnosis of migraine if the feature is absent.
++
++
++
++
Nausea, exacerbation by physical activity, photophobia, and throbbing
headache are the most sensitive features for the diagnosis of migraine.
Sensitivities are 81%, 81%, 79%, and
73%, respectively. Despite the origin of the word migraine
from “hemicrania,” only 65% of migraines
are unilateral, and this is the least sensitive of the major clinical
criteria. When compared with tension-type headache, the most specific
features for migraine are nausea, phonophobia, photophobia, and
unilateral headache, with specificities of 96%, 87%,
86%, and 82%, respectively.
++
The features with the best overall predictive value are nausea,
photophobia, phonophobia, and exacerbation by physical activity.
The particularly high positive predictive value of nausea results in
part from the inclusion of large numbers of patients who were classified
according the IHS criteria. The IHS criteria for the diagnosis of
tension-type headache require the absence of nausea. However, questionnaire
studies that have used less restrictive criteria for the diagnosis
of tension-type headache have also found nausea to be highly specific.34,35 Headache
duration is less useful to distinguish between the two diagnoses,
with the exception that headaches lasting less than 4 hours are
less likely to be migraine.
++
Authors used many different diagnostic criteria for migraine
and tension-type headache in the pre-IHS era. Despite these varied
definitions, the likelihood ratios for all pooled studies are not substantially
different than those restricted to studies using the IHS criteria.
The data suggest that the pre-IHS studies also included fairly uniform
populations of patients.
+++
Features of
Migraine Aura
++
Among patients with migraine, one third experience migraine with
aura. In a study of 4,000 randomly selected 40-year-olds in a Danish
population, the lifetime prevalence of migraine without aura was
11.8%; that of migraine with aura was 5.5%.36 The
migraine aura is sufficiently characteristic that a carefully obtained
history of an aura substantially increases confidence in the diagnosis
of migraine. Both the subjective aura elements and the duration
of the aura are important features. Table 18-4 summarizes the sensitivity
of various aura features among pooled series of patients having
migraine with aura.
++
++
Visual auras are most common; 84% of patients having
migraine with aura experience a visual aura. Positive visual phenomena
occur slightly more frequently than negative visual phenomena. Positive
phenomena include zigzags (fortification spectra), stars, or flashes.
Many eloquent descriptions of visual auras exist in the medical
literature. In an early review of migrainous visual aura, Alvarez
described his personal experience of fortification spectra.42 “Another
time I saw a fine zigzag line running up and down and a coarse one
running below it, horizontally. Later, the two ran together, end
to end, and bowed out to the right. The line resembles a snake fence,
or an old-style fortification with projecting angles. In some spells,
the line is so brilliant one can see it easily with the eyes open.”*
++
[* Reprinted from the American Journal of Ophthalmology,
vol. 49, Alvarez WC. The migrainous scotoma as studied in 618 persons,
pp. 489–504. Copyright 1960, with permission from Elsevier Science.]
++
Negative visual phenomena include scotoma and hemianopsia. The
presence of hemianopsia is one of the features that establishes
a diagnosis of migraine with typical aura (previously referred to
as complicated migraine). Disturbances of visual perception are
least common. In the study of Queiroz and colleagues,39 these
included, in descending order of frequency, foggy vision, looking
through heat waves or water, tunnel vision, mosaic vision, micropsia
or macropsia, corona phenomena, and complex hallucinations. Lewis
Carroll, the author of Alice in Wonderland, was known to suffer
from migraine with aura; some authors have speculated that Alice’s
visual distortions in his novel may have paralleled complex visual
hallucinations that he experienced during migrainous auras.43
++
The duration of the aura is also characteristic. IHS criteria
require that each aura feature last from 4 to 60 minutes. In practice,
the most common aura duration is 20 minutes, and 70% of
visual auras last less than 30 minutes (see Table 18-4). Auras that
last a few seconds or minutes are distinctly uncommon in migraine
and should raise the possibility of seizure phenomena.
++
Nonvisual auras nearly always occur in conjunction with visual
auras rather than as isolated events. In one study, only 4% of
auras were complex nonvisual auras that occurred in isolation without
accompanying visual auras.37 Among nonvisual auras,
sensory auras are most common, followed by aphasia and motor auras.
The sensitivities are 20%, 11%, and 4%,
respectively. Sensory auras are unilateral, usually begin in the
hand, and then progress to the arm, face, and tongue.38 Aphasic
aura symptoms include paraphasia, impaired production of language,
and impaired comprehension of language. Motor auras usually occur
in conjunction with sensory auras rather than in isolation.
+++
Historical Features
of Migraineurs
++
Individuals with migraine are more likely to have a family history
of migraine, and a childhood history of vomiting attacks or motion
sickness. Although these factors, by themselves, are insufficient
to establish a diagnosis of migraine, they can be useful in the
evaluation of an individual patient if the type of primary headache
remains uncertain after taking a careful history.
++
Of these features, the familial tendency is the least controversial.
In a recent review of over 2,500 patients with data on family history,
58% of migraineurs had a family history of migraine as
compared with 12% of unselected individuals without headache.44 In
a case-control study, Stewart and colleagues reported a relative
risk of 1.50 among family members of probands with migraine.45 A
positive family history was more often present among patients with
severe migraine and disability. Russell and coworkers noted different
family histories among patients having migraine without aura and
those having migraine with aura.46 In their study
of 183 patients, migraine without aura was associated with a 2.9
relative risk of family history of migraine without aura, but no
increase in risk of migraine with aura. Patients having migraine
with aura were twice as likely to have family histories of both
migraine with and without aura than expected.
++
Neither childhood vomiting attacks nor motion sickness are criteria
for the diagnosis of migraine in the IHS classification. However,
each of these features is more common in patients destined to develop
migraine that in those without migraine. Thirty-two percent of patients
with migraine report a history of childhood vomiting attacks as
compared with only 14% of individuals without headaches.44 Data
for a history of motion sickness are similar. Children who develop
disabling headaches by the age of 5 years are 2.8 times more likely
to report motion sickness than those without disabling headaches.47 In
addition, children with migraines score significantly higher on a
motion sickness susceptibility questionnaire than children without
migraines.48