Growth hormone is produced by the anterior pituitary gland. It plays a central role in the growth of muscles, bones and tissues. It also has metabolic effects and stimulates cell regeneration and proliferation. It stimulates the release of insulin-like growth factor 1 (IGF-1), mainly from the liver, which also plays an important role in growth.
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 affecting the GH1 (growth hormone 1) or GHRHR (growth hormone releasing hormone receptor) genes or to another condition, such as empty sella syndrome, where the pituitary gland is underdeveloped or damaged.
Acquired growth hormone deficiency is often idiopathic (without a clear cause) but can be secondary to infection, trauma or surgery.
Growth hormone deficiency can occur in isolation or with other pituitary hormone deficiencies. When the pituitary gland does not produce several pituitary hormones, this is called hypopituitarism or multiple pituitary hormone deficiency. Hypopituitarism can cause:
- Hypothyroidism (inadequate TSH resulting in low thyroid hormones)
- Adrenal insufficiency (inadequate ACTH resulting in low cortisol)
- Hypogonadism (inadequate LH and FSH leading to low sex hormones)
Presentation
Growth hormone deficiency in children may present with:
- Poor growth (severe slowing from 2 – 3 years onwards)
- Short stature
- Delayed development of movement and strength
- Delayed puberty
Investigations
Testing growth hormone in a blood sample does not provide helpful information. Growth hormone levels can fluctuate massively in someone without growth hormone pathology, making a single sample meaningless.
Insulin-like growth factor-1 (IGF-1) can be tested on a blood sample. IGF-1 levels are more stable than growth hormone levels. IGF-1 may be used as an initial test for growth hormone deficiency.
Growth hormone stimulation tests are used to diagnose growth hormone deficiency. These involve measuring the response to a stimulus that should increase growth hormone release. Growth hormone levels are monitored before and after the stimulus. Failure of the growth hormone level to rise indicates growth hormone deficiency. The insulin tolerance test is one option, which involves giving short-acting insulin to induce hypoglycaemia (low blood sugar), which should stimulate growth hormone release. Other options include giving glucagon or arginine.
Other investigations include:
- Testing for other hormone deficiencies (e.g., hypothyroidism and adrenal insufficiency)
- MRI brain for structural pituitary or hypothalamus abnormalities
- X-ray of the left hand and wrist can be used to estimate the bone age
Treatment
A paediatric endocrinologist will manage children with growth hormone deficiency. Treatment involves:
- Growth hormone therapy (somatropin) involving daily subcutaneous injections
- Close monitoring of height and development
TOM TIP: Growth hormone therapy may also be used to improve height in patients with Prader-Willi syndrome, Turner syndrome and chronic renal insufficiency.
Last updated February 2025
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