Growth hormone deficiency after moderate traumatic brain injury with normal (or high) IGF-1; a case report demonstrating benefit of replacement therapy and clinical pearls for diagnosis

<b>Objective:</b> Traumatic brain injury (TBI) is a common cause of acquired pituitary dysfunction in adults. The prevalence of anterior pituitary dysfunction after TBI varies widely, but growth hormone deficiency (GHD) is reported as the most common, ranging from 5-20% after mild to severe TBI. GHD can be difficult to diagnose: 1) its neuropsychological symptoms are nonspecific and overlap with many chronic TBI symptoms; 2) GHD frequently remits if present in the first year after TBI; 3) screening laboratories are not reliable; and 4) validated, easy to administer, confirmatory stimulation tests are not widely available. A diagnosis of GHD is often delayed until 5 years or more after injury. Nonetheless, replacement therapy is associated with improvement in GHD related symptoms, including cognition. This study aims to present a case of GHD after moderate TBI. <b>Methods:</b> We present a case of GHD after a moderate TBI and discuss the chronic effects of GH replacement therapy on his neuropsychological testing and symptoms, as well as clinical pearls for the diagnosis of GHD in persistently symptomatic patients with remote TBI. <b>Results:</b> This case demonstrates that clinical suspicion should supersede inconclusive screening results and prompt referral for definitive provocative testing. Even when diagnosed late, targeted GH replacement therapy can yield significant improvements in debilitating fatigue, metabolic health, and specific domains of neurocognition. <b>Conclusions:</b> Enhanced clinical awareness and a more proactive approach to endocrine surveillance by providers can prevent years of morbidity, reduce diagnostic delays, and offer patients a greater potential for functional recovery.