Growth Hormone Deficiency
Adult growth hormone deficiency (AGHD) is an under-recognized condition that contributes to abnormal body composition, reduced quality of life, dyslipidemia, and reduced bone density. It is most commonly caused by pituitary tumors or their treatment. GH replacement in confirmed deficiency improves body composition, bone density, lipids, and subjective wellbeing.
Symptoms
Increased body fat (particularly visceral), decreased lean muscle mass, fatigue, reduced exercise capacity, poor quality of life, low mood, impaired memory and concentration, reduced bone density, and an adverse lipid profile.
Causes and risk
Pituitary adenoma or its treatment (surgery, radiation) is the most common cause in adults. Traumatic brain injury, cranial radiation for other tumors, and childhood GH deficiency that persists into adulthood are other causes. Severe AGHD is defined biochemically by a GH stimulation test.
How it is evaluated
IGF-1 is a screening test -- a low value in the appropriate clinical context is strongly suggestive. Dynamic stimulation testing (insulin tolerance test or glucagon stimulation test) is the gold standard for diagnosis. Full pituitary hormone panel, bone density (DEXA), and fasting lipid panel complete the evaluation.
Treatment
Recombinant human growth hormone administered by daily subcutaneous injection. Doses are titrated to maintain IGF-1 in the mid-normal range. We monitor for side effects including fluid retention, arthralgia, and glucose intolerance. Response is assessed by body composition, bone density, and quality-of-life measures.