Clinical Practice Guideline
for
MIGRAINE HEADACHES
Developed for the
Aerospace Medical Association
by their constituent
organization
American Society of Aerospace Medicine Specialists
Overview: The epidemiology of migraine and other
primary headache syndromes has become clearer due to a number of large-scale
population-based studies using standardized case definitions. The estimated prevalence of this disorder in
the general adult population is approximately 6% for men and 18% for
women. Prevalence is highest between
25-55 years of age. The condition most frequently begins in adolescence.
Migraine is not a homogeneous disorder as attacks may vary in intensity,
duration, frequency of occurrence, and in associated features. This variability
may occur from one migraine sufferer to another, or even in one migraine
sufferer from one headache to the next.
Migraine sufferers may also describe headache patterns consistent with
more than one headache type (e.g. tension-type headaches and migraine
headaches). Some experts view migraine
and tension-type headaches as distinct diseases while others now view them
merely as ends of a continuum of severity. In the end, the diagnosis in both
clinical practice and epidemiological research is almost entirely dependent on
the patient’s description and constellation of symptoms of prior attacks. The International Headache Society (IHS)
subclassifies migraine as either migraine without aura (common) or migraine
with aura (classical). The difference is
simply to presence or absence of aura (usually visual). Recent studies have described a possible
association between migraine with aura and patent foramen ovale (PFO). However, the aeromedical
significance of this remains to be determined. Features characteristic of both types of
migraine include unilateral location (although generalized headache occurs in
up to 30-40% of patients, and both acephalgic and ophthalmic migraines also
occur), severe pulsating quality (although there may be a range starting from
dull, deep and steady pain), an onset that tends to be gradual over minutes to
hours, and a duration which may last from hours to days. Onset is common upon awakening in the morning
and in the late afternoon, but may occur at any time during the day or night.
Associated features include nausea (87%), vomiting (56%), photophobia (82%),
phonophobia, visual disturbances (36%), lightheadedness (72%), vertigo (33%),
and alterations in consciousness (18%).
Precipitating factors include stress (often during post-stress "let
down"), fatigue, physical exertion, glare, hunger, certain foods and/or
medications, atmospheric changes (e.g. weather, altitude, and ambient
temperature), fluorescent lighting and chronobiologic challenges (e.g.
alterations in sleep/wake cycles, jet lag, changing seasons, etc.). Migraine may also be precipitated by
menstruation (presumably due to hormonal changes).
Standard
migraine therapy can be divided into abortive and prophylactic. Abortive pharmacotherapy includes the early
use of a triptan (sumatriptan, rizotriptan,
and others), a NSAID, or dihydroergotamine
(DHE). An established migraine may
require the use of IV promethazine, DHE, or oral steroids and sedation. Narcotics are often used, but have little
place in migraine therapy. Prophylactic
pharmacotherapy is indicated when the sufferer experiences three or more
migraine headaches per month. This
includes the use of beta-blockers, calcium channel blockers, SSRI’s (selective
serotonin reuptake inhibitors) and other antidepressant medications, certain
anti-seizure drugs (e.g., topiramate and gabapentin), and ergotamine preparations (rarely used
now). The first-line of prevention (if
identified), however, is the avoidance of known or suspected triggers,
especially foods which may precipitate migraines in individual patients. In the military services none of the
aforementioned pharmacologic therapies are, themselves, waiverable for
flying. Fortunately for the aviation
community and despite the high prevalence of migraine in the general
population, many experience less severe and less frequent attacks which are
effectively treated with simple abortives such as NSAIDs
or acetaminophen/aspirin.
Aeromedical Concerns: The pain of a migraine (or
preferably for aeromedical classification, “severe”) headache may disrupt
concentration at best and be totally incapacitating at worst. Headaches in any form are detrimental to safe
flight as it may distract an aircrewman from his/her duties. Migraine headaches are worrisome because of
the associated visual phenomenon (aura or photosensitivity) which could
interfere with collision avoidance, instrument interpretation, or depth
perception. Associated features such as
visual disturbance, vomiting, or vertigo could themselves be incapacitating
during flight. The visual and other
aura, nausea and vomiting, and transient neurologic deficits (that may include
aphasia, hemisensory and hemimotor impairment, vertigo, syncope, confusion and
disorientation) which may accompany migraine are of obvious concern. Fortunately, migraine with aura and migraine
associated with neurological symptoms are relatively rare. Concern would be greatest for those flying
single seat aircraft, or in aircraft where complete
crew participation and coordination is essential for mission completion. Additional concern exists because of the
potential duration of the headaches and the consequent fact that the aircrewman
would need to be grounded until complete resolution occurs (potentially
days). The
other issues being the varying medications that are used in treatment are in
many cases disqualifying.
Treatment and Aeromedical Disposition: For any headache, the initial question should always be whether the
described headache is that of a primary headache syndrome, e.g., migraine,
tension headache, etc. or that of a secondary headache syndrome, e.g., headache
associated with an underlying disease such as brain tumor, vasculitis, benign
intracranial hypertension, Chiari malformation,
etc. A complete evaluation with neurological
consultation is indicated if a secondary headache syndrome is suspected. Ophthalmological consultation may also be
indicated in the event of associated visual disturbance. New onset migraine-type headaches, a change
in previous migraine character, or occurrence of complicated migraine are all
likely to necessitate brain imaging (typically a CT scan or MRI).
In civil airmen that are granted waivers there is a requirement for
yearly current status evaluations from the treating physician. In general with civil aviation the FAA would
like the airman to be in remission from the headaches for six-months, however
they have allowed airmen to have up to three headaches per month. This, of course, depends on the characteristics
of the headache. All civil airmen that
are given medical certification are reminded of the necessity to ground
themselves and report to the FAA any changes in the frequency of headaches or
medications (FAR 61.53).
Experience: A documented history of migraine (or
severe) headache or of any recurrent or incapacitating headache would be
disqualifying for duty involving flying in military aviation. Any history of disabling migraine headache
must be considered disqualifying for flying duties. Waiver for migraine is now
being given by all three services depending upon severity, frequency, and the
absence or presence of aura. Generally,
those who suffer less than three severe headaches per year, can successfully
treat them with over-the-counter analgesics such as ibuprofen or acetaminophen,
and do no have associated aura or neurological accompaniments, are given
waiver. Those who suffer aura may
require specialty consultation and consideration. Prior to issuance of a waiver, a thorough
neurologic evaluation by a qualified Neurologist should be obtained. Individuals with persistent neurological
sequelae with or without headache would require an extensive neurologic work-up
and probably not be considered for a waiver.
Civilian airmen may be granted medical certification when there
have been no documented headaches for a six month period. A civil airman might be granted an
Authorization for Special Issuance in the case where a migraine manifests
itself consistently by an aura, which gives the pilot sufficient warning and
does not involve any neurologic deficits.
Frequent migraines, headaches that are associated with neurologic
deficits and ophthalmic migraines are all disqualifying for civil aviation.
Cases of complicated migraine, such as those having a loss of
consciousness or significant associated neurological deficit other than a
partial visual field loss, result in automatic disqualification with little
chance for waiver at any time in the future.
Any aircrew with a history of transient visual disturbance with or
without headache should be initially disqualified.
The FAA will allow civil airmen to pilot aircraft if they
are taking prophylactic medications. If
they take one of the triptan derivatives they must then ground themselves for a
24 hour period. As of early August 2006
there were 880 first-class, 928 second-class and 2,709 third-class airmen
currently issued with a diagnosis of migraine headache.
This allowance is variable in the
military services. Use of prophylactic
medication is not allowed in the USAF.
References.
Raskin,
Neil Hugh. Headache, 2nd Edition. Churchill
Livingstone, NY 1988.
Rappaport,
Alan. Headache Disorders. WS Sanders
Co. Phil 1996.
Dalessia,
Donald. Wolffs Headaches and other Head Pain, 6th
Edition.
Saper, Joel R. Diagnosis and Symptomatic
Treatment of Migraine. Headache 1997; 37(1): S1-S13.
Solomon,
Seymour. Migraine Diagnosis and Clinical Symptomatology.
Headache Sep 1994; 34(Supplement): S8-S12.
August 7,
2006