Somatotrophin (Growth Hormone) Deficiency

What are the causes of Growth Hormone Deficiency?

The most common causes of growth hormone deficiency are listed below:

  • Craniopharyngioma - a tumour arising from the remnants of Rathke's pouch
  • Pituitary adenoma
  • Parasellar tumours.

What are the symptoms of Growth Hormone Deficiency?

The most obvious signs of growth hormone deficiency are found in children. These children usually present with progressive growth failure below their expected percentiles (on standard growth charts).

In the adult, growth hormone deficiency can present in a wide variety of non-specific symptoms, such as:

  • Psychological changes
  • Malaise
  • Osteoporosis
  • Poor muscular tone
  • Impaired hair growth.

How is Growth Hormone Deficiency diagnosed?

The most important part in the diagnosis of growth hormone deficiency is to distinguish pituitary dwarfism from other causes of short stature (for example genetics, nutritional factors and emotional factors).

There is also a clinically similar syndrome known as Laron dwarfism. This type of dwarfism is due to a hepatic growth hormone receptor defect, which will then result in a somatomedin deficiency.

CT or MRI scans are used to exclude the presence of hypothalamic or pituitary tumours.

Thyroid function tests are often used to rule out the possibility of hypothyroidism. The growth hormone levels are then measured both before and after a stimulation test. Growth hormone release is usually stimulated by a vigorous exercise test and the response measured. There are a number of different stimulation techniques for inducing growth hormone release including a clonidine test, an arginine test and an insulin test.

How is Growth Hormone Deficiency treated?

In children, before epiphysial fusion, the treatment of choice for growth hormone deficiency is recombinant growth hormone. The growth hormone is given subcutaneously until growth is complete.

Somatomedin therapy is being studied at the moment and may soon be used for the treatment of conditions such as Laron dwarfism.