Short Stature, Growth Hormone Deficiency, and Primary IGF-1 Deficiency

Abstract

Regular monitoring of a child’s growth, using height and weight measurements, is an essential part of the nursing role, as outlined in a previous chapter.

Sequential measurements provide information regarding a child’s general health and are invaluable in assessing whether there is a concern regarding their growth pattern. Body proportions, general health, and parental heights will give an indication as to whether the child fits their family pattern or has a growth problem. Review of sequential measurements can help establish whether they have familial or idiopathic short stature, or if they may have a growth and/or other hormone deficiencies.

Growth hormone deficiency (GHD) affects approximately 1:4000 children (Davies, Assessment of growth failure in children: MIMS for Nurses Pocket Guide, 2004).

It can be classified into congenital or genetically associated conditions, or may be acquired due to insult or injury. It may be an isolated deficiency or part of a more complex condition of multiple pituitary hormone deficiencies. Isolated growth hormone deficiency (GHD) is primarily a clinical diagnosis, based upon auxological features, and confirmed by biochemical testing. Once a cause for short stature or GHD is established, treatment can be initiated, which requires daily injections of growth hormone. Growth hormone insensitivity syndrome (GHIS) is rare and requires twice daily injections of insulin-like growth factor 1 (IGF-1).

A long-term commitment to treatment is required by both the patient and their family for best results. A good understanding of the condition and ongoing education is essential to ensure the maximum benefits of treatment are attained.

Growth is a slow process, and often it is easy for families to become complacent or discouraged with treatment regimes. By examining patient behaviour and any concerns they may have regarding their stature, we are in a position to encourage compliance with treatment by recognising that short-term pain (of injections) leads to long-term gain, once final height is reached.

This chapter explores the pathophysiology, clinical characteristics, investigations, and management of children with growth hormone deficiency and growth hormone insensitivity, the treatment required, and nursing considerations needed to manage these children through the ages. The role of the multidisciplinary team will be discussed with emphasis on the role of the Paediatric Endocrine Nurse Specialist in supporting these children and families through many years of treatment.

Appendix: GH Stimulation Test Information Sheet

GLUCAGON/ARGININE STIMULATION TEST

INFORMATION SHEET

What is this test?

This test is carried out to assess hormones that the pituitary gland produces. Glucagon causes a number of temporary hormonal signals resulting in the release of growth hormone from the pituitary gland and stimulation of cortisol production. These levels are then measured in a series of blood tests. Arginine is an amino acid which also stimulates growth hormone secretion in the hypothalamus and pituitary gland. Some older children may need to take low doses of priming hormones before the test if they have delayed puberty so that the testing is accurate; your doctor will have advised if this is needed.

When is this test ?

Your child is booked to attend for a glucagon/arginine stimulation test on.

How should I prepare my child?

• Your child will need to be admitted to the hospital for the day (approximately 5 h).

• Your child should have nothing to eat or drink, except water, from 12 midnight the night before the test. Babies less than 12 months or children under 10 kg need to fast for 4 h, so should have an early morning feed.

• Please call to confirm with the endocrine testing nurse, the day before the test.

• If your child is unwell, please contact us as the test may need to be rescheduled.

• Bring a favourite toy, activity, DVD, or book on the day to keep your child occupied.

• You will be admitted by the clerk and directed to the endocrine testing area.

What happens next?

• The nurse will record your child’s height, weight, temperature, pulse and blood pressure, and oxygen saturations.

• Before we insert a cannula (a small needle with a plastic tube attached) into the vein, and so that we cause as little discomfort as possible, anaesthetic cream or an ice stick can be used to anesthetise the area. We will need to take multiple blood samples during the test, and the cannula allows all the samples to be taken from the same site.

• At the beginning of the test, a blood sample is taken and then an injection of glucagon is given into the thigh muscle.

• Another blood sample is collected one hour later, and further samples are then taken at ½ hourly intervals for another 2 h.

• The arginine solution is then given via an intravenous drip into the cannula over 30 min.

• Four more blood samples are then taken every 15 min once the infusion is completed.

• Some children may feel nauseated or complain of abdominal pain during the test, but this is usually temporary. Occasionally, a child may vomit. We can give medication to ease this.

• Your child’s blood glucose level is checked during the test because low values sometimes occur and may need to be treated.

And finally…. after the test?

At the end of the test your child may eat, the cannula is removed and you will be discharged home.

Results are usually available after 2 weeks, so before leaving make sure that you have details of the follow-up appointment. If you have any questions following the test, contact your child’s doctor or endocrine clinic.