Endocrine Abstracts

Introduction: Studies of traumatic brain injury from all causes have found evidence of chronic hypopituitarism, defined by deficient production of one or more pituitary hormones at least 1 year after injury, in 25–50% of cases. Most studies found the occurrence of posttraumatic hypopituitarism (PTHP) to be unrelated to injury severity. Growth hormone deficiency (GHD) and hypogonadism were reported most frequently. Hypopituitarism, and in particular adult GHD, is associated with symptoms that resemble those of PTSD, including fatigue, anxiety, depression, irritability, insomnia, sexual dysfunction, cognitive deficiencies, and decreased quality of life. However, the prevalence of chronic PTHP after blast-related concussion, or mild TBI (mTBI), an extremely common injury in modern military operations, has not been characterized.

Design: We measured concentrations of 12 pituitary and target-organ hormones in two groups of male US Veterans of combat in Iraq or Afghanistan. One group consisted of participants with blast-related mTBI whose last blast exposure was at least 1 year prior to the study. The other consisted of Veterans with similar military deployment histories but without blast exposure.

Results: In total, 11 of 26, or 42% of participants with blast concussions were found to have abnormal hormone levels in one or more pituitary axes, a prevalence similar to that after other types of TBI. Five members of the mTBI group were found with markedly low age-adjusted IGFI levels indicative of probable GHD, and three had testosterone and gonadotropin concentrations consistent with hypogonadism. Five of the blast concussion group exhibited abnormal vasopressin and/or oxytocin levels suggestive of posterior pituitary dysfunction. Indications of dysfunction in multiple hormonal axes were observed in five Veterans with mTBI. None of the deployment control subjects exhibited any hormonal abnormalities.

Conclusion: Blast mTBI is associated with a high frequency of PTHP. If symptoms characteristic of both PTHP and PTSD can be linked to pituitary dysfunction, they may be amenable to treatment with hormone replacement. Routine screening for chronic hypopituitarism after blast concussion shows promise for appropriately directing diagnostic and therapeutic decisions that otherwise may remain unconsidered and for markedly facilitating recovery and rehabilitation.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.