Traumatic Brain Injury Blog


Neuroendocrine issues, often overlooked following TBI, leave patients with unnecessary chronic symptoms

By on March 27, 2020 In Rehabilitation, Research

In prior posts I have discussed the growing evidence that traumatic brain injuries, even so-called “mild” traumatic brain injuries (mTBI), can lead to neuroendocrine dysfunction (NED) – most commonly growth hormone (GH) deficiency due to pituitary dysfunction. Although growth hormone deficiency often results in physical symptoms such as loss of lean muscle mass and strength, increased body fat around the waist, and dyslipidemia, other common GH deficiency symptoms overlap with the symptoms of “persistent post-concussion”- such as fatigue, poor memory, anxiety, depression, emotional lability, poor attention and poor concentration.

My earliest post on this issue discussed the August 2012 Department of Defense (DOD) clinical recommendations for screening for neuroendocrine dysfunction in “mild” traumatic brain injury (“mTBI”) cases – where indicative symptoms persist for more than three month or appear within three years. The guidelines contemplated a simple blood test, but subsequent studies, also discussed in this blog, showed that the only reliable means of detecting GH deficiency is provocative testing, which is expensive and takes several hours (the guidelines do suggest further assessment by an endocrinologist, even where the screening test is negative, if symptoms of NED persist.)

Recent literature is somewhat inconsistent concerning the practicality of engaging in this expensive testing in mTBI cases. An article published in the International Journal of Molecular Science in July, 2019  recommends provocative testing in the chronic phase (symptoms persisting more than 6 months) but concludes that for mTBI cases, screening is “not routinely advised…as it is not cost effective and the evidence for significant pituitary dysfunction following a single MTBI is rather weak.”

A review and meta-analysis of research on the prevalence of NED, recently published in January, 2020 in the Journal of Neurotrauma reaches a different conclusion. Acknowledging that incidence does seem to vary between mTBI and other TBIs, it concludes that overall “approximately one-third of TBI sufferers have persistent anterior pituitary dysfunction 12 months or more following trauma.”  The article cites literature supporting what the DOD reports in its material – that between 15 and 30% of mTBI patients with persistent symptoms test positive for NED.

Needless to say, this is an issue insurers would like to avoid, since the cost of supplement injections to treat NED, such as GH deficiency, can cost $15-$20,000 a year or more. Although high, this expense is clearly justified in light of evidence supporting the effectiveness of this treatment in reducing the persistent physical, emotional and cognitive symptoms.

The Journal of Neurotrauma article notes that “although several groups have provided guidelines for screening [of NED] there is little evidence that surveillance is widespread.”

In most places, screening for NED is not occurring, especially for persistent post-concussion symptoms. This needs to change. The importance of this issue was brought home to me with a client who suffered a single mTBI several years ago, but continued to have symptoms of fatigue as well as emotional and cognitive complaints. He was followed at a respected teaching hospital, but never referred for NED screening. To get a second opinion I referred him to the Spaulding Rehabilitation program in Boston, which apparently does routine NED screening. The client was determined to be growth hormone deficient, was prescribed treatment, and has experienced significant improvement. Spread the word!

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