Clinical Practice Guideline
Developed for the
Aerospace Medical Association
by their constituent organization
Overview: Multiple sclerosis is a chronic demyelinating disease of the central nervous system. The cause remains unknown but probably involves a combination of genetic and environmental factors. It is a disorder of young adults in temperate climates. The average age of onset is between 20 and 40 years of age, with a 2:3 male to female ratio. The diagnosis of multiple sclerosis depends on dissemination of CNS lesions in time and space. Accepted modalities for determining the diagnosis include clinical signs, MRI findings, evoked potentials (positive in 50-90% of cases), and CSF studies (positive in 60-90% of cases). Upon presentation with only one symptom (e.g. optic neuritis), the diagnosis of multiple sclerosis cannot be made if the patient lacks dissemination of lesions in time and space. However, the risk of recurrence can be determined by results of studies such as serum anti-myelin antibodies, which are slowly becoming available for clinical use. In cases presenting with a single symptom, a diagnosis of monophasic syndrome is often made and a neurologist determines whether or not immunomodulating treatment is indicated.
Aeromedical Concerns: The unpredictable nature and potentially rapid onset of CNS symptoms is generally considered incompatible with a safe flying environment. Multiple sclerosis may present with visual disturbances, bladder dysfunction, ataxia, vertigo, weakness, spasticity, paresthesias, or fatigue. Symptoms can present over a period as short as a few hours. Full neuropsychological testing may be needed to confirm normal higher cerebral function in aircrew. One study has demonstrated mild cognitive deficits (e.g. verbal impairment and decreased attention span) in 53% of patients with a diagnosis of possible MS. The treatment of monophasic syndrome now often involves immunomodulating agents. Beta-interferon is incompatible with flight due to a 50-75% chance of flu-like symptoms and a 2-4% chance of psychosis. Glatiramer is also used for immunomodulation and is nearly as efficacious as interferon and may prove to be compatible for flying with monophasic syndrome. However, this is still in the consideration phase.
Medical Work-up: The following consults and tests are required for proper medical evaluation leading to an aeromedical disposition:
A. Neurology consultation
B. Ophthalmology consultation
C. Evoked potentials
D. CSF IgG synthesis index
E. Oligoclonal bands
F. MRI scan of the head
G. Serum anti-myelin antibodies (anti-MOG and anti-MBP) may be ordered by the consulting ACS neurologist in cases of monophasic syndrome.
Aeromedical Disposition (military): Multiple sclerosis is disqualifying from military flying. No military waivers have been granted. Nonetheless, aviators with a single, monophasic episode of neurologic dysfunction (e.g. optic neuritis) with a full and complete recovery who remain asymptomatic for a period of 1 year and in which extensive studies fail to reveal other evidence of demyelination may be considered for a waiver after a thorough aeromedical evaluation.
Aeromedical Disposition (civilian): Airmen with multiple sclerosis that is in remission and in whose presenting signs and symptoms are not debilitating can be considered for an authorization for special issuance for all classes. Airmen who experience cognitive disorder as a manifestation of their illness are not waived. Interferon beta 1-alpha and Copaxone (glatiramer acetate) are a acceptable medications but the new medication, trade name Tysabri or Natalizumab is not acceptable. Tysabri increases the risk of progressive multifocal leukoencephalopathy (PML) and opportunistic viral infection of the brain that usually leads to death or severe disability. Each case is reviewed on its own merits.
Aeromedical Disposition (NASA): Multiple sclerosis is disqualifying for spaceflight duty.
Waiver Experience (military): A large military database was queried and revealed six waiver submissions since September 2001 for a diagnosis that included multiple sclerosis. Of those, only one was granted a waiver. This case was felt to be more consistent with a single demyelinating episode and did not meet the criteria to be considered multiple sclerosis.
Waiver Experience (civilian): As of 2007 there were currently issued 87 first-class, 63 second-class, and 173 third-class airmen with this medical condition.
Waiver Experience (NASA): Waiver would not be considered for confirmed multiple sclerosis.
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January 19, 2008