Hypopituitarism caused by blast-related mTBI may result in PTSD-like symptoms

Abstract

Recent studies in civilian populations have found the prevalence of hypopituitarism as a result of head injuries from all causes to be between 25 and 50%. However, the neuroendocrine effects of concussion, or mild traumatic brain injury (mTBI) due to explosive blasts have received relatively little attention. Blast-related mTBI is the most common injury sustained by U.S. troops deployed to Iraq or Afghanistan. Approximately 20% of returning service members have experienced one or more blast-related concussions. Posttraumatic hypopituitarism (PTHP) has been shown to result in several symptoms that overlap considerably with those of PTSD. These include fatigue, depression, sexual dysfunction, anxiety, social isolation, and detrimental effects on sleep, learning and memory, body composition, and quality of life. We are investigating the prevalence of PTHP in two groups of Veterans of deployment to Iraq or Afghanistan. Members of the TBI group sustained at least one blast-related mTBI; members of the deployment control (DC) group experienced similar extreme conditions but did not experience a blast concussion. We conducted screening for growth hormone deficiency (GHD), hypogonadism, thyroid deficiency, and secondary adrenal insufficiency (sAI) by measuring basal blood samples and by testing for GHD and sAI with the glucagon stimulation test. Eighteen of 44 (36.4%) TBI group participants and seven of 32 (15.6%) DC group participants screened positive for pituitary hormone deficits. GHD and sAI were observed most frequently. We used behavioral self-reports and cognitive testing to examine symptom prevalence. Veterans with TBI and pituitary dysfunction endorsed more severe and/or frequent symptoms than those in the TBI group without hypopituitarism or the DC group. These findings and observations suggest that screening for pituitary dysfunction after head injuries holds promise for not only recognizing appropriate treatment options that might not otherwise be considered, but also facilitating recovery and rehabilitation of these service members.