High Prevalence of Chronic Pituitary and Target-Organ Hormone Abnormalities after Blast-Related Mild Traumatic Brain Injury

Abstract

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 PTHP after blast-related mild TBI (mTBI), an extremely common injury in modern military operations, has not been characterized. 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. Eleven 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 found in other forms of TBI. Five members of the mTBI group were found with markedly low age-adjusted insulin-like growth factor-I (IGF-I) levels indicative of probable GHD, and three had testosterone and gonadotropin concentrations consistent with hypogonadism. 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.

Chronic Hormonal Imbalance and Adipose Redistribution Is Associated with Hypothalamic Neuropathology following Blast Exposure

“…[1][2][3][4][5] Recently, pituitary dysfunction has been shown to be a consequence of bTBI in soldiers returning from war, [5][6][7] with evidence suggesting that bTBI can cause impairment of hypothalamicpituitary pathways. 8 Further, it has been hypothesized that altered pituitary function may lead to cognitive and neuropsychiatric dysfunction.…”

“…11,12 GH deficiency and ACTH dysfunction have been related to cognitive deficiencies following TBI and can lead to symptoms such as fatigue, anxiety, irritability, insomnia, sexual dysfunction, and decreased quality of life. 3 Tümer and colleagues 14 reported on increased hypothalamic expression of oxidative stress and activation of the sympathoadrenal medulla at an acute time-point of 6 h following blastinduced neurotrauma (BINT) in rats. 13 This study demonstrated that exposure to blast was associated with increased biosynthesis of catecholamine in the brain and elevated levels of stress-related biomarkers in serum.…”

On Treating Athletes with Banned Substances: The Relationship Between Mild Traumatic Brain Injury, Hypopituitarism, and Hormone Replacement Therapy

“…This pattern of deficiency following TBI makes sense, because the cells that produce GH and gonadotropins (the somatotrophs and gonadotrophs, respectively) are arguably more vulnerable to damage because of their location in the lateral wings of the pituitary, which only have one blood supply [31]. GH and gonadotropin are hormones that are of great interest in the discussion of performance enhancing drugs, because of the role of GH in building body mass, and the role of the gonadotropins in producing testosterone.…”

“…The two hormones deficiencies that are most frequently related to TBI are GH deficiency and gonadotropin deficiency [31]. This pattern of deficiency following TBI makes sense, because the cells that produce GH and gonadotropins (the somatotrophs and gonadotrophs, respectively) are arguably more vulnerable to damage because of their location in the lateral wings of the pituitary, which only have one blood supply [31].…”

Evaluation of pituitary functions during acute phase of head trauma

“…Ancak, kafa travması sonucu oluşan hasardan sadece primer hasar sorumlu değil-dir. Primer doku hasarını takiben ortaya çıkan birçok karmaşık fi zyopatolojik olaya bağlı olarak sekonder hasar da oluşmaktadır [3][4][5] . Beyin hasarında rol oynayan Travmatik beyin hasarına (TBH) bağlı hipofi z hormon bozuklukları genellikle nonspesifi k belirtiler ile seyretmektedir ve bu nedenle tanı gecikebilir.…”