A B C D E F G H I J K L M N O P R S T U V W

GROWTH HORMONE DEFICIENCY

What is Growth Hormone Deficiency ?

Growth hormone is one of the six main substances made in the pituitary gland. This gland, the size of a small pea, sits above the roof of the mouth at the bottom of the brain. Growth hormone is released from the pituitary directly into the bloodstream. This happens as pulses or bursts, particularly during deep sleep, stress and when fasting. Growth hormone works by making the gristle (cartilage) in young bones grow. It also stimulates the liver to make a another chemical which also has growth effects on bone and other organs. If it is made in very large amounts, growth hormone causes an overgrowth of bones and also other tissues. This rare condition is called acromegaly. However, in some people, both young and old, growth hormone production can also fall for a number of reasons. In children, growth then slows down. This can occur at all ages, but is most obvious in adolescence when children appear to miss out on the usual growth spurt. It was once thought that growth hormone was no longer needed in adults. However, research has shown that tiredness, poor muscle strength, thin bones (osteoporosis) and some psychological changes may be due to growth hormone deficiency.

How does it occur ?

Sometimes the cells which make growth hormone simply seem to wither. In other cases a benign (non-cancerous) tumour of the pituitary gland stops its neighbouring cells from making growth hormone. There are various other conditions which give rise to pituitary damage – see HYPOPITUITARISM . In addition, it seems that the production of growth hormone declines in old age. In some elderly people this occurs even faster than in others.

Why does Growth Hormone Deficiency occur ?

We do not understand why some people develop growth hormone deficiency in the absence of a tumour. It does not appear to be hereditary.

Treatment Involved for Growth Hormone Deficiency

In children , it is important for your doctor to make sure that your child does not have any other cause of poor growth. Blood tests and special x-rays will be done to check for this. X-rays of the bones help decide how mature they are, and therefore how much room there is for further growth. Measuring a child's height every 2 to 3 months with accurate equipment is a must. This rate of growth is checked against standard charts to see how your child compares. Measurement of growth hormone itself is now quite easy. A child may first be exercised very vigorously to check the blood growth hormone response. Various drugs can be given to test the body's ability to make blood growth hormone. One of the most reliable methods is to give an injection of insulin into a vein. Lowering the blood sugar level in this way raises the blood growth hormone in normal people, but not in those who are growth hormone deficient. This test is occasionally dangerous and is only done by specialists under the highest level of supervision. Once growth hormone deficiency is confirmed, then growth hormone can be given by injection from three times a week to daily, usually by the child itself, using specially pre-loaded pens for simplicity. There was a scare about the development of a brain condition called Creutzfelt Jakob disease (CJD), but this only occurred as a rare side-effect of the use of growth hormone from human pituitaries taken at autopsy. This type of growth hormone is no longer used. The injections are not painful but have to be continued for many years, until the bones have stopped growing. Quite often growth rate doubles: from 3 or 4 cm per annum up to 8 cm per annum or more. Other substances can be given to stimulate growth too. Some of these work by triggering the release of your child's own growth hormone from the pituitary gland. Other substances used are similar to a hormone which the liver makes. This substance (IGF-1) is normally made by the liver as a direct result of growth hormone. It is useful for particular types of poor growth where growth hormone itself may not be effective. In adults , the diagnosis is more difficult, partly because of the normal decline of growth hormone with age. It is not easy to be certain in any one person how many of their symptoms can be put down to growth hormone deficiency, even if the tests confirm the condition. Secondly, treatment is expensive. It is not easy to balance such costs against the benefit which may result from treatment in an individual person. Nevertheless some adults are made dramatically better, whether the deficiency was due to a pituitary tumour or whether the shortage of growth hormone was just related to ageing.

During Treatment for Growth Hormone Deficiency

Children need careful height measurement to check that they are responding: bigger doses may be needed as they get older. X-rays will be repeated to check bone maturity too. Some adults develop diabetes, thought to be due to the growth hormone causing insulin not to work so well. Surprisingly, it is well tolerated treatment at all ages, although new methods other than injections are being researched.

After Treatment for Growth Hormone Deficiency

Once treatment stops, a child's growth slows down or stops. However, the growth hormone deficiency persists. This can make both children and adults run low blood sugar levels, since growth hormone is one of the chemicals which keeps the blood sugar normal in all people. Shakiness and sweating are symptoms which may result from this.

If Growth Hormone Deficiency is Left Untreated

In children , a failure to grow. If left too long, the bones may "fuse" under the normal maturing effect of sex hormones: once the growing ends of the bones have fused, no amount of growth hormone will help. In adults , the patient would continue to have the same symptoms: there is increasing evidence that mortality is somewhat higher for reasons that are not entirely clear. Adults are particularly prone to get low blood sugar symptoms.