One of the most common symptoms following any form of traumatic brain injury – including concussion and mild TBI – is fatigue. Fatigue can be the result of the injury, including the secondary metabolic and chemical changes that cascade following the injury. Many health care providers overlook the potential that other aspects of the injury may be wholly or partially responsible for fatigue.
One explanation for symptoms of fatigue is an injury to the pituitary gland. The pituitary gland is a small organ suspended from the underside of the brain. It is particularly vulnerable in an acceleration/deceleration mechanism of injury including rear-end crashes and falls. Pituitary injury can result in growth hormone deficiency and deficiency in thyroid stimulating hormone (TSH). The risks of pituitary injury include increase in morbidity and mortality, weight gain, and hair loss. Testing to document pituitary injury can include TSH levels, testosterone level, IGF-1 (Insulin-like Growth Factor-1), and T4. These tests should be performed by 8 a.m. to derive the most accurate laboratory results. Practice Guidelines for the treatment of endocrine consequences of traumatic brain injury can be found at: Evaluation and Treatment of Adult Growth Hormone Deficiency: An Endocrine Society Clinical Practice Guideline | The Journal of Clinical Endocrinology & Metabolism | Oxford Academic (oup.com)
Another condition that can account for post TBI fatigue is autonomic dysfunction. Autonomic dysfunction can best be understood as potentially involving functions that we consider to be automatic – that is – not requiring special effort or intentionality. Examples of autonomic functions include blood pressure, breathing, heart rate, digestion including bowel and bladder function. Diagnosis of autonomic dysfunction is a clinical diagnosis and may be supported by some structural abnormalities in the brain. Esterov D, Greenwald BD. Autonomic Dysfunction after Mild Traumatic Brain Injury. Brain Sci. 2017 Aug 11;7(8):100.