Clinical Practice Guideline
Developed for the
Aerospace Medical Association
by their constituent organization
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.
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August 7, 2006