Growth Hormone Deficiency

Question 1

Where is growth hormone produced?

Function?

Answer 1

Growth hormone is produced by the anterior pituitary gland. It is responsible for stimulating cell reproduction and the growth of organs, muscles, bones and height. It stimulates the release of insulin-like growth factor 1 (IGF-1) by the liver, which is also important in promoting growth in children and adolescents.

Question 2

Congenital vs acquired growth hormone deficiency cause?

Associated with?

Answer 2

Congenital growth hormone deficiency results from a disruption to the growth hormone axis at the hypothalamus or pituitary gland. It can be due to a known genetic mutation such as the GH1 (growth hormone 1) or GHRHR (growth hormone releasing hormone receptor) genes, or due to another condition such as empty sella syndrome where the pituitary gland is under-developed or damaged.

Acquired growth hormone deficiency can be secondary to infection, trauma or interventions such as surgery.

Growth hormone deficiency can occur in isolation or in combination with other pituitary hormone deficiencies like hypothyroidism, adrenal insufficiency and deficiencies of the gonadotrophins (LH and FSH). When the pituitary does not produce a number of pituitary hormones this is called hypopituitarism or multiple pituitary hormone deficiency.

Question 3

Presentation of growth hormone deficiency?

Answer 3

Growth hormone deficiency may present at birth or in neonates with:

Micropenis (in males)
Hypoglycaemia
Severe jaundice

Older infants and children can present with:

Poor growth, usually stopping or severely slowing from age 2-3
Short stature
Slow development of movement and strength
Delayed puberty

Question 4

Investigations for growth hormone deficiency?

Answer 4

Growth hormone stimulation test:

Growth hormone stimulation tests involve measuring the response to medications that normally stimulate the release of growth hormone. Examples of these medications include glucagon, insulin, arginine and clonidine. Growth hormone levels are monitored regularly for 2-4 hours after administering the medication to assess the hormonal response. In growth hormone deficiency there will be a poor response to stimulation.

Other investigations:

Test for other associated hormone deficiencies, for example thyroid and adrenal deficiency
MRI brain for structural pituitary or hypothalamus abnormalities
Genetic testing for associated genetic conditions such as Turner syndrome and Prader–Willi syndrome
Xray (usually of the wrist) or a DEXA scan can determine bone age and help predict final height

Question 5

Treatment for growth hormone deficiency?

Answer 5

Daily subcutaneous injections of growth hormone (somatropin)
Treatment of other associated hormone deficiencies
Close monitoring of height and development