Growth hormone deficiency following traumatic brain injury in adults: Still much of a clinical enigma.

Traumatic brain injury (TBI) is a significant public health concern globally, contributing to substantial morbidity and mortality across all age groups. Clinical manifestations range from no symptoms to mild alterations of consciousness to a comatose state and death. Endocrine abnormalities should no longer be considered rare after TBI, with growth hormone deficiency (GHD) being the most common pituitary hormone abnormality followed by hypogonadism, hypocortisolism, and hypothyroidism. Yet the clinical entity of GHD is often under-recognized, as the presenting symptoms can be mistaken as part of the TBI itself. In addition, the severity of other post-TBI comorbidities, lack of guidelines of when to perform hormonal testing and the practical difficulties of conducting GH stimulation testing are important factors that contribute to the delay or missing the diagnosis altogether. Furthermore, there are no validated GH cut-points of currently available GH stimulation tests in TBI patients per se. Following the confirmation of diagnosis of GHD, previous studies have shown that the poor outcomes of post-TBI GHD could be improved and possibly even reversed by GH replacement; however, to date, data on the beneficial effects of such long-term therapy in TBI patients remains scarce. The present review reports evidence on post-TBI GHD, including clinical consequences if untreated, challenges in screening and diagnostic work-up, and principles of therapeutic management. It is essential for healthcare providers to be aware and to screen for this enigmatic clinical entity. There remains an unmet need for developing stronger evidence, and for guidelines establishing recommendations for screening and diagnosis so that they can be incorporated as optimal standard of care in the management of TBI patients.