Monday, September 29, 2008

Growth Hormone Deficiency and Short Stature in Children

Children with growth hormone deficiency are short, but not all short children have growth hormone deficiency and not all short adults have had growth hormone deficiency.

Children can be short for a variety of reasons. Some people will be short as adults because they lacked growth hormone production, others will be short as adults because they were unable to respond to growth hormone. Some people can be short as adults because they grew too fast as children.

Growth in length is fastest in the womb, then continues to be rapid in the first year of life. It then slows down in childhood and there is a period of rapid growth again in puberty before we stop growing at the end of the pubertal years. The height gained during each phase of growth is important. If growth during any of these phases is poor or the duration of any of these phases of growth is somehow shortened, the growth in the other phases may not be able to make up the difference and we can end up with a short adult.

Children who were born premature or too small for their gestational age , children who had serious illness and growth failure during infancy or childhood, and children whose puberty comes too early or too late are therefore at risk of being short adults. For example, if a girl has periods too early, then she may start the puberty growth spurt before the childhood growth phase has ended and this may limit her total time for growth – leading to a short adult height. Some boys have delayed puberty and they may also have a poor potential for being tall because both parents are short.

Growth hormone therapy can help some of the children who are short to grow taller, if the problem is a lack of growth hormone production. It is less able to help if there is a problem with the ability of the body to respond to the growth hormone. In children who are no longer able to make enough growth hormone, such as those who have had certain brain tumours and had the pituitary gland removed as a result, growth hormone will restore growth in the majority of cases, unless they had also radiotherapy to the neck and spine, in which case growth hormone can still help but results may not be as good.

For children whose puberty has come too early, we may have to hold back puberty with medications and we may also need to give growth hormone if the estimated final height as an adult is too short.

If a child is short and wants to seek help, we will need to do some xrays and blood tests before deciding on the best course of action. In summary, we may need to treat an underlying illness which is preventing proper growth, or we may need to give growth hormone to promote better height growth. Sometimes we may need to also treat the other hormone disease that are associated with being short. For example we need to be aware that some chromosome disorders ( eg Turner’s Syndrome ) and some metabolic conditions ( eg hypothyroidism) may be the cause of the poor growth.

Growth hormone has to be given by injections but this does not appear to be a big problem. Modern needles for growth hormone are very fine and almost painless. Special needle-less injector devices are also available to administer growth hormone. However, one should be wary of taking products which claim to be able to stimulate growth when inhaled or taken by mouth as they not work as claimed. Growth treatment may take months to years to complete but the results are often worth it. Other medications may sometimes need to be given and potential side effects need to be looked for and managed.

Not all short children need to be given growth hormone therapy and some may need more than growth hormone . Sometimes the problem is the timing of the growth spurt. In other cases, the underlying illness, such as poorly controlled asthma , may need to also be addressed

The first thing to do is to realize that there is something wrong with your child’s growth and have him or her be assessed by a doctor experienced in assessing and treating growth problems. Secondly, the doctor can assess and find out what is wrong and what needs to be investigated or treated. Thirdly, while growth hormone will make many short children taller, not everyone is suitable for treatment with growth hormone and potential side effects need to be looked out for, treated, and ideally prevented in order to optimize the risk benefits and cost benefits of treatment. Finally, children with short stature may also need some emotional support and sufficient exercise to keep them healthy.

Dr Warren Lee,
MBBS, M Med Paeds, FAMS, FRCP ( London ) , FRCPCH ( UK)
Senior Consultant Paediatrician and Paediatric Endocrinologist
Dr Warren Lee’s Paediatrics, Growth and Diabetes Centre Pte Ltd