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,
4.
Annergers, J. The Epidemiology of Epilepsy in the Treatment of Epilepsy, Principles
and Practice. Edited by Elaine Wiley.
January
19, 2008