Fit for Duty: Autonomic Nervous System Dysfunction in US Service Members (P05.201)

Objective: To characterize autonomic nervous system (ANS) abnormalities unique to active duty US service members and compare those findings to civilian counterparts. Background Autonomic dysfunction is increasingly recognized as a contributor to morbidity in patients with traumatic brain injury (TBI). The signature injury of Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) is TBI so the military offers a special population to study ANS dysfunction. The purpose of this study is to analyze the difference in autonomic complaints and autonomic testing results of active duty compared to civilian patients. Design/Methods: We reviewed retrospectively the records of all patients who were evaluated at a Military Medical Treatment Facility (MTF) autonomic laboratory over a 12 month period. These patients included 56 active duty military and 49 civilians. The percentage of patients who presented with orthostatic intolerance (OI) and syncope was calculated and the distribution of diagnoses was evaluated. Tests considered included the heart rate response to deep breathing, valsalva, and tilt table testing. Results: Active duty service members were most commonly referred to the autonomic laboratory for OI (N=13, 23%) and syncope (N=23, 41%). 37 (66%) had normal studies, 13 (23%) were found to have OI and four were diagnosed with postural orthostatic tachycardia syndrome (POTS). Civilians were commonly referred to the autonomic laboratory for OI (N=10, 20%) and syncope (N=20, 40%). 27 (55%) of the studies were normal, six had orthostatic intolerance, four had POTS, and four had adrenergic failure. Conclusions: Autonomic disorders are underrecognized in the military. Active duty service members with autonomic dysfunction may be classified as unfit for duty due to the rigorous nature of work in the military. ANS disorders in service members should be recognized early so they may be properly addressed and increase the service members likelihood of returning to full duty. Disclosure: Dr. Crimmins has nothing to disclose. Dr. Etienne has nothing to disclose.