Short stature or delayed growth
The first step in the investigation of a child with short stature is to confirm that the child really is short; since there are frequently serious errors of measurement due to poor technique, poor equipment as well as incorrect entries on the growth charts. Another key area is determining whether the child is shorter than expected for the family as a number of conditions can be ruled out when the genetic target height is low.
When a child is noted to be inappropriately short, assessment of body proportion can rule out the small percentage of children with abnormalities of their skeletal architecture following which one can continue with a staged investigation plan. It should be born in mind that endocrine causes of poor growth are relatively rare. In the first instance, systemic or multisystem disease and non-organic conditions such as psycho-social deprivation should be considered. Subsequently, prior to considering full endocrine investigations, it is appropriate to document an abnormally slow growth rate as pituitary function tests are rarely indicated in the presence of normal growth and indeed their interpretation in children with normal growth is very difficult. Normal growth may be defined as more than 5 cm per year in mid-childhood and a significantly abnormal height velocity would be less than 4 cm per year.
The planning and the interpretation of tests of pituitary function and growth hormone secretion requires some fore thought. As there is a physiological diminution of growth hormone secretion in the latter part of pre-puberty, the stimulated peak of growth hormone may fall below the recommended cut off (which should be determined locally based on the specific growth hormone assay). In children with a bone age over 10 years, it is appropriate to pre-treat (prime) with sex steroid therapy. In a boy this can be done with intramuscular Sustanon (testosterone) 100 mg five days before the investigation or in a girl, ethinyloestradiol 10 micrograms each day five days prior to the investigation. This upregulates the pituitary gland into increasing the growth hormone output into pubertal activity.