Growth hormone replacement in hypopituitarism
For information about short stature and growth hormone deficiency in children, see here.
The diagnosis of growth hormone deficiency may require testing in a specialist endocrinology unit. For a patient with fewer than three pituitary hormone deficiencies, but with risk factors for growth hormone deficiency (eg pituitary lesion, head injury, subarachnoid haemorrhage) and symptoms suggestive of growth hormone deficiency, testing is required for diagnosis. The gold-standard test is the insulin tolerance test; the glucagon stimulation test and arginine stimulation test are suitable alternatives. For a patient with three or more pituitary hormone deficiencies (eg thyroid, adrenal and gonadal deficiencies) and a low plasma insulin-like growth factor 1 (IGF-1) concentration, testing is not necessary (although is required to access treatment on the Pharmaceutical Benefits Scheme [PBS]).
In an adult with growth hormone deficiency, somatropin (recombinant human growth hormone) can improve body composition, bone density and sense of wellbeing, and can possibly reduce long-term cardiovascular disease risk. Somatropin is accessible through the PBS for symptomatic adult growth hormone deficiency via the Australian growth hormone program1. Its use is limited by strict eligibility criteria, and it can only be started by a specialist.
For growth hormone replacement therapy in an adult, use:
somatropin 0.2 to 0.4 mg subcutaneously, daily. Adjust dose every 2 to 3 months according to plasma insulin-like growth factor 1 concentration. hypopituitarism (adult) somatropin
Titrate the somatropin dose to achieve a plasma insulin-like growth factor 1 concentration in the middle of the age-adjusted reference range.
Women typically need a higher somatropin dose than men to achieve a normal plasma insulin-like growth factor 1 concentration. Concomitant use of oral estrogen therapy (eg for coexisting hypogonadism) decreases sensitivity to growth hormone, increasing the dose requirement further. Encourage women taking oral estrogen to switch to a transdermal estrogen preparation, which does not affect growth hormone sensitivity.
No data are available to indicate that growth hormone therapy is beneficial or safe in the management of normal ageing without proven growth hormone deficiency. Use of growth hormone therapy in this setting is not recommended.