The two types of AGHD and what you can do about them

Generally, adults with growth hormone deficiency can be divided into two groups: those who were GH-deficient as children and continue to be so as adults (childhood-onset patients), and adults with pituitary disease who became GH-deficient as adults (adult-onset patients).

Signs and symptoms of both childhood-onset and adult-onset AGHD may include:

Increased body fat, especially around the abdomen
Decreased muscle mass
Lower bone mineral density
Predisposition to atherosclerosis (hardening of the arteries)

adult-onset AGHD

Some people with adult growth hormone deficiency were not GH-deficient as children. These people are said to have adult-onset AGHD.

The usual cause of adult-onset AGHD is damage to the pituitary gland, which is responsible for secreting GH. This damage is most commonly caused by one or more tumors in and around the pituitary. Such a tumor may compress the gland, or the damage may occur when the tumor is removed through neurosurgery. The pituitary gland may also be damaged by infection, blood vessel disease, severe head injury, or radiation treatment for tumors of the head or neck. Injury to the pituitary gland may affect the production of one or more pituitary hormones, including GH.

Signs and symptoms of adult growth hormone deficiency associated with pituitary disease may include:

Increased body fat, especially around the abdomen
Decreased muscle mass
Lower bone mineral density
Increases in LDL ("bad") cholesterol and decreases in HDL ("good") cholesterol
Decreased insulin sensitivity
Increased hardening of the arteries (atherosclerosis)

childhood-onset AGHD

In many people, adult growth hormone deficiency is the continuation of a disorder that began in infancy or childhood. This type of AGHD is referred to as childhood onset AGHD.

In some cases, the causes of GH deficiency in childhood cannot be determined; this type of disorder is referred to as idiopathic. Known causes may include:

Developmental defects in or near the pituitary gland
Genetic problems with the production of GH
Damage to the pituitary gland or the surrounding area due to tumors, infection, radiation treatment, or severe head injury
Some children with GH deficiency may gain the ability to secrete GH with time and may not require GH therapy as adults. However, scientific evidence suggests that many adults who were GH-deficient as children and continue to be GH-deficient as adults may need to continue therapy into adulthood in order to have enough GH to meet metabolic demands as adults (although many factors can contribute to such conditions).

Signs and symptoms of childhood-onset AGHD may include:

Increased body fat, especially around the abdomen
Decreased muscle mass
Lower bone mineral density
Predisposition to atherosclerosis (hardening of the arteries)

References
Lifshitz F, ed. Pediatric Endocrinology. 4th ed. New York, NY: Marcel Dekker Inc; 2003.