Clinical Practice Guideline

for

SEIZURE DISORDERS

Developed for the

Aerospace Medical Association

by their constituent organization

American Society of Aerospace Medicine Specialists

 

Overview: Epilepsy is defined as recurrent (two or more) unprovoked seizures.  Epilepsy is unequivocally disqualifying for all flying duties.  A single unprovoked convulsion may be sufficient to constitute a diagnosis of a seizure disorder for military purposes.  No military waivers have been granted for epilepsy or seizure disorders to date regardless of treatment, of the passage of time, or of the normalcy of the EEG. 

 

An initial, isolated convulsive and/or altered consciousness event may be due to a number of causes – some of these causes may lend themselves to a recurrence (especially if unprovoked), while others may not (especially if provoked).   Those causes that do not create recurrent events may be eligible for waiver.  Common examples of isolated events of transient loss of consciousness that may not be epilepsy include those associated with fever as a child, vasovagal syncope (convulsive syncope), and acceleration induced (G-LOC).

 

Many abnormal EEG’s on their own merit, independent of another medical condition (including epilepsy) are disqualifying for all types of flying duties.

 

The risk of developing new onset epilepsy ranges from about 0.04% at age 20, to 0.02% at age 50 before rising sharply to 0.08% by age 70.  The late rise is because of the increase in precipitating factors such as neuronal degeneration and cerebrovascular disease.  After a single, unprovoked seizure in adults assuming all studies (neurological exam, MRI, EEG) are normal, the risk of recurrence is about 35% for 5 years.  Of the 35%, about 50% occur in the first 6 months and about 60% within the first year.  The risk of a second seizure increases with risk factors such as previous neurological insult or a sibling with epilepsy.  Relapse even after a symptom-free interval of several years without therapy is possible.  The major etiologies of epilepsy are cerebrovascular disease (13%), developmental (6%), head trauma (4%), brain tumor (4%), infection (3%), degenerative disease (2%), and idiopathic (68%).  The EEG does not prove or disprove the diagnosis of epilepsy although an unequivocally abnormal EEG with a good history of seizure does support the diagnosis.  However, the EEG can be completely normal in someone with frank epilepsy.

 

Diagnosis is based on a neurologist’s evaluation, complete with detailed history, exam, diagnosis, treatment, and prognosis.  A MRI with coronal cuts to evaluate for mesial temporal sclerosism and an EEG (awake and sleep-deprived with anterior temporal electrodes and photic stimulation and hyperventilation) should be part of the neurologist’s work up.

 

Medication therapy is not waiverable.

 

Aeromedical Concerns: The risk of seizure in flight is obvious.  Incapacitation is in most cases sudden, unpredictable, unavoidable, prolonged, complete, and potentially more frequent in the stressful flying environment, and constitutes a direct threat to the health and safety of self, others, and the success of the mission.

 

Medical Work-up: Every effort must be made to try and reconstruct what happened before and after a suspected seizure event.  Special attention should be paid to the clinical notes made by anyone that had contact with the patient, for example; medical technicians, paramedics, nurses and providers.  The medical history should address the relevant period preceding and during the suspected event and include a review of travel, sleep, diet, work and all medications, whether prescription or over-the-counter.

 

Accounts from witnesses must be included in the medical record, either as a written statement from the eyewitness, or as an account documented by a provider.  If written accounts were not accomplished initially, than every effort should be made to identify possible witnesses and include their accounts.  A witness’s account should not be excluded because there are concerns about the reliability of that witness.  Instead, include the account with a statement addressing why there are concerns about the reliability of the witness. 

 

Neurological consultation is essential.  Investigation is necessary to improve the certainty of diagnosis, to find a precipitating cause in case treatment is necessary, and to identify the seizure type so that appropriate maintenance therapy can be given.  The investigation of a first seizure will usually include EEG and MRI scan.  A thorough aeromedical evaluation may also be requested.

 

Aeromedical Disposition (military): A history of febrile convulsions before the age of 5 is waiverable for military entry into flight training, but requires normal neurology consult, EEG studies, and MRI scan at a minimum.  Convulsive movements during G-LOC while centrifuge training will not require waiver application or put the aviator at risk to be disqualified.  Truly epileptiform abnormalities such as spikes, sharp waves, and spike-wave complexes are disqualifying.  However, other EEG findings considered normal variants, (small sharp spikes [SSS], benign epileptiform transients of sleep [BETS], wicket spikes, 6 Hz [phantom] spike and wave, rhythmic temporal theta waves of drowsiness [psychomotor variant] and 14 or 6 Hz positive spikes) are not necessarily disqualifying.  Almost 50% of those with abnormal EEGs have returned to flight status.  All other cases of convulsive episodes or altered consciousness events compatible with possible epilepsy, whether treated or untreated, are disqualifying and resulting in immediate grounding action pending further evaluation. 

 

Aeromedical Disposition (civilian): Everything that has been mentioned in the aeromedical disposition equally applies to the civilian sector.  The history as obtained from a witness is most important!  Epilepsy or seizures are one of the Fifteen Specifically Disqualifying medical conditions.  For a single idiopathic seizure, the FAA policy is that the airman is denied their medical certificate for any class for four years and must be off medications for the most recent two years.  For two or more seizures the airman is denied medical certification for ten years and must be off medications for the most current of three years.  Should a seizure be a manifestation of a treatable medical problem and that problem is adequately treated the airman may be granted medical certification earlier than mentioned in the previous sentences.  An example would be a treatable brain tumor.  Even if the airman is adequately treated the antiepilepsy medications are not acceptable. The side effects of these medications are incompatible with aviation duties.   

 

Aeromedical Disposition (NASA):  A history of seizures (including absence) is disqualifying for spaceflight duties. Febrile seizures prior to the age of 5 or seizures clearly due to a toxic etiology are not disqualifying. Benign childhood epilepsy syndrome may be considered after obtaining neurologic opinion.

 

Waiver Experience (military): No patients with the diagnosis of epilepsy have received waivers to date.  In aviators with provoked seizures and a history of childhood seizures, consideration for a waiver to return to flying duties is entertained.  In the US Air Force database, a total of 65 cases were noted that carried a diagnosis of seizure disorder of some sort requesting a flying waiver.  Of that total, 25 were granted a waiver for an approval rate of 38.5%.  Ten waiver applicants were for initial pilot training, six were for a trained pilot or navigator and the remaining nine were for non-pilot aircrew.  In each of the 25 cases, the history was for childhood febrile or infantile seizures or for provoked seizures.  There were no listed approved waivers for the diagnosis of epilepsy.

 

Waiver Experience (civilian):  There are no airmen granted issuance unless they have fulfilled the criteria mentioned in the civilian disposition paragraph above, which means that they had a seizure problem but are now sufficiently beyond the observable time period so they could be considered. 

 

Waiver Experience (NASA): Seizure disorder is not waiverable.

 

References:

 

1. Merritt’s Neurology, 11th Edition, 2005.

 

2. Murro, A, Management of Seizures – Current Concepts, Medical Education Course Syllabus, Medical College of Georgia, Augusta GA, obtained on 29 August 2006 from http://www.neuro.mcg.edu/amurro/epilepsy/szsyl.htm  

 

3. Engel, Jerome, Jr.  Seizures and Epilepsy, Philadelphia: F. A. Davis 1989:pp 30-4.

 

4. Annergers, J.  The Epidemiology of Epilepsy in the Treatment of Epilepsy, Principles and Practice.  Edited by Elaine Wiley.  Philadelphia:  Lea and Febiger, 1993:pp 158-63.

 

 

January 19, 2008