18 January 2012 | Dr Rakesh Amin | Consultant Endocrinologist | The Portland Hospital
Children come in all shapes and sizes, and in the majority of cases, children are the height they are, or start puberty at the age they do, for all the right reasons and this should raise no concern for parents as long as the child is healthy.
However, in a minority of cases some children can be of ‘excessively’ short or tall stature, or might start showing signs of starting puberty at an unexpected age. This is usually linked to the behaviour of the child’s hormones. If you are concerned about your child’s developments, you should seek the advice of your GP who if necessary will refer you to an endocrinologist, who specialises in hormones.
To help decide whether a problem exists, as a start point, it is often best to consider puberty and growth separately;
On average the physical change from childhood into adulthood occurs due to a rise in natural chemicals in the blood called ‘hormones’ (oestrogen in girls and testosterone in boys). With ‘normal’ puberty this rise in hormones usually occurs between the ages of 8-12 years in girls and a bit later in boys, between ages 9-14 years.
In girls the physical change of puberty begins with the appearance of breast buds, followed by pubic hair and then periods usually by the age of 13 years. In boys puberty begins with the testicles getting bigger; then the penis enlarges and finally pubic hair starts appearing. During puberty there is also a growth spurt, which is at its greatest at around age 13 in girls and 14 in boys. However, problems can develop if puberty occurs too early (precocious) or too late (delayed).
Early or ‘precocious’ puberty is when the physical changes of puberty start before aged 8 in a girl and 9 in a boy. This may be problematic as, in both girls and boys, early puberty will also be accompanied by a growth spurt. Whilst this growth spurt will result in your child initially being taller than their friends, which might seem like a good thing at the time, eventually they will stop growing sooner than their peers and may actually end up short or shorter than average as an adult.
Special and quite complicated hormone tests are often needed to confirm that puberty has genuinely commenced. If it has, then treatment may be required to switch-off or delay the hormones in the blood that have triggered puberty.
This treatment, requiring injections to be given regularly, will stop or slow the rate of physical change. After stopping the treatment, puberty tends to restart and progress at a normal rate.
For teenagers, delayed puberty can be upsetting due to their physical immaturity compared to their friends. If there are no signs of puberty by around the age of 12 in girls or 14 in boys, an assessment by a specialist paediatrician may be required, as the problem can sometimes be due to the brain, ovaries or testes not functioning properly.
The majority of cases are simply due to extreme delay and often no treatment is required. This is called ‘constitutional delay’ in growth and puberty which can often run in families. On occasions some children do benefit from treatment for constitutional delay which usually consists of giving testosterone to boys and oestrogen to girls in order to ‘kick start’ puberty and the response tends to be good.
Growth is an important indicator of a child’s general health and well-being. There are three main phases of growth during childhood and adolescence. Initially there is a period of rapid growth in the first one to two years after birth. This is followed by a slower period of growth during the childhood years of around 4-6 cm per year. During adolescence, the puberty hormones (testosterone in a boy and oestrogen in a girl), in addition to causing the physical change of puberty, combine with growth hormone to cause a growth spurt to occur. This should result in a growth rate of over 8 cm per year. During the later puberty years the puberty hormones also start the process of causing growth plates to close. This process will eventually result in complete closure of the growth plates and a final height being achieved, which is irreversible. The age at which this occurs is variable and dependent on when puberty starts, but is usually around age 15 in a girl and 16 in a boy.
A child who may have a growth condition should be under the care of a growth specialist with training in interpreting information on growth to understand whether growth is excessively slow or excessively fast.
If your child is short but their height is within normal limits for your family and they are growing at a normal rate, this is referred to as genetic or familial short stature which has no effective treatment.
However, there is good treatment for a number of other causes of poor growth. Growth Hormone Deficiency occurs when the body is unable to produce sufficient growth hormone to promote growth and usually becomes apparent from the second year of life, when the growth rate slows to below 4-5 cm per year and the child crosses down centile lines on the growth chart in their Personal Child Health Record (often referred to as little red book).
Once the diagnosis of Growth Hormone Deficiency has been made, treatment involves replacing growth hormone into the body by a daily injection under the skin for the whole of childhood. Depending on the exact reason for the Growth Hormone Deficiency, a good final height can be achieved and the child often ends up with an adult height that is normal for their family.
The cause of tall stature in most children is most often simply due to having tall parents. This is referred to as ‘constitutional’ or familial tall stature. Tall stature can cause problems, particularly at school as a child’s size can seem inappropriate for their classroom peers.
Treatment to limit tall stature is generally unsuccessful, however by the late teenager years, most tall adolescents have learnt to accept their height and are otherwise happy and well adjusted. Occasionally tall stature may also be associated with various conditions that require specialist assessment; these include chromosomal abnormalities and syndromes such as Marfan syndrome and Sotos syndrome.
An appointment at The Portland Hospital with Dr Rakesh Amin, Consultant Paediatric Endocrinologist, can be arranged by telephone on +44 (0)20 7390 8020 or fax +44 (0)20 7112 8074.