GROWTH HORMONE DEFICIENCY
The pituitary gland is a pea-sized gland
located at the base of the brain. It is the body's master
hormone gland. It produces many hormones. Hormones are chemical
substances that are carried by the bloodstream to every part of
the body where they control and coordinate numerous body
Without hormones, our body's functions will
be thrown into a state of disorder and dysregulation.
Growth hormone (or somatotrophin) has
important regulatory actions on all body tissues. In
childhood, it is responsible
for linear growth. A child who does not produce sufficient
growth hormone fails to grow like his peers. He is shorter and
smaller. His puberty may be delayed. Without treatment, he would
become a short adult.
growth hormone has other functions. Such an adult would not
become shorter, but often has the following problems:
• Decreased energy levels
• Social isolation
• Lack of positive well being
• Depressed mood
• Increased anxiety
• Increased body fat, particularly central adiposity.
• Decreased muscle mass
• Decreased bone density, with increased risk of fracture.
• Increased LDL cholesterol ('bad' cholesterol) and decreased
HDL cholesterol ("good" cholesterol)
• Decreased cardiac muscle mass
• Impaired cardiac function
• Decreased total and extracellular fluid volume.
• Decreased insulin sensitivity and increased prevalence of
impaired glucose tolerance and diabetes.
• Accelerated atherogenesis
How does growth
hormone deficiency develop?
GH deficiency is a virtually invariable
component of hypopituitarism. Hypopituitarism (meaning low
pituitary function) is discussed in the section on
Hypopituitarism. In childhood GH deficiency, GH lack may be
a isolated or solitary defect. Older adults often have low, or
lower GH levels because of aging.
The diagnosis of GH deficiency is made by
measuring serum GH concentrations in response to dynamic tests.
The gold standard is the insulin tolerance test (ITT). This
involves creating low blood glucose readings in a person, and
then measuring his GH response. A normal response is a clear
rise. An international consensus has now been reached which
states that a level of GH < 10 mU/l in response to hypoglycaemia
is diagnostic of severe GH deficiency in patients with
structural pituitary disease and/or other pituitary deficiencies
and/or a history of childhood GHD. The IGF1 test is not
sensitive or reliable for diagnosing GH deficiency.
Treatment consists of replacing growth
hormone. This is done using daily injections of growth hormone.
A very small amount of GH is injected under the skin over the
abdomen or thigh. The injection is virtually painless. Patients
(or parents) will be taught to do this themselves. It is not
difficult to learn to do this.
The internet advertises and touts many
alternative forms (pills, sprays, potions) of GH replacement.
None of these are scientific or effective. None is approved by
the Food and Drug Adminstration of the United States. They are a
waste of time and money. Some may even be harmful. Only GH injections have been shown to be safe and to work.
What can you
Overall, at least 80% of patients with
growth hormone deficiency given growth hormone replacement
demonstrate a significant improvement, especially in fat
distribution, body composition and parameters reflecting well
being and quality of life. Children with childhood
GH deficiency experience an increase in growth velocity, and
often catch up with their peers.