Adults
GH treatment can confer a number of measurable benefits to severely GH-deficient adults, such as enhanced energy and strength, and improved bone density. Muscle mass may increase at the expense of adipose tissue. Although adults with hypopituitarism have been shown to have a reduced life expectancy, and a cardiovascular mortality rate of more than double controls, treatment has not been shown to improve mortality, although blood lipid levels do improve. Similarly, although measurements of bone density improve with treatment, rates of fractures have not been shown to improve.Effects on quality of life are unproven, with a number of studies finding that adults with GHD had near-normal indicators of QoL at baseline (giving little scope for improvement), and many using outdated dosing strategies. However, it may be that those adults with poor QoL at the start of treatment do benefit. Epidemiology
The incidence of idiopathic GHD in infants is about 1 in every 3800 live births, and rates in older children are rising as more children survive childhood cancers which are treated with radiotherapy, although exact rates are hard to obtain. The incidence of genuine adult-onset GHD, normally due to pituitary tumours, is estimated at 10 per million.
Severe GH deficiency in childhood additionally has the following measurable characteristics:
Proportional stature well below that expected for family heights, although this characteristic may not be present in the case of familial-linked GH deficiency
Below-normal velocity of growth
Delayed physical maturation
Delayed bone age
Low levels of IGF1, IGF2, IGF binding protein 3
Increased growth velocity after a few months of GH treatmentIn childhood and adulthood, the diagnosing doctor will look for these features accompanied by corroboratory evidence of hypopituitarism such as deficiency of other pituitary hormones, a structurally abnormal pituitary, or a history of damage to the pituitary. This would confirm the diagnosis; in the absence of pituitary pathology, further testing would be required. Classification
Growth hormone deficiency can be congenital or acquired in childhood or adult life. It can be partial or complete. It is usually permanent, but sometimes transient. It may be an isolated deficiency or occur in association with deficiencies of other pituitary hormones.The term hypopituitarism is often used interchangeably with GH deficiency but more often denotes GH deficiency plus deficiency of at least one other anterior pituitary hormone. When GH deficiency (usually with other anterior pituitary deficiencies) is associated with posterior pituitary hormone deficiency (usually diabetes insipidus), the condition is termed panhypopituitarism. Treatment
GH deficiency is treated by replacing GH with daily injections under the skin or into muscle. Until 1985, growth hormone for treatment was obtained by extraction from human pituitary glands collected at autopsy.