Evaluation of thyroid function in children with undiagnosed short stature in north India.

Fifty-five children with short stature were investigated for the aetiology of short stature with special reference to hypothyroidism. Clinical and laboratory parameters including anthropometry were determined to exclude any chronic systemic disorders. Thyroid function tests such as thyroxine (T4) and thyroid stimulating hormone (TSH) estimation by radioimmunoassay, radioactive iodine uptake and thyroid scan, using 131I and perchlorate discharge test, were performed. In addition, growth hormone was estimated under basal conditions and after insulin-induced hypoglycaemia. Thirty-five were boys and 20 were girls. The age at presentation in the boys was 3-12 years whereas in the girls it was 8-13 years. Forty-three of the 55 children had delayed bone age. Abnormal thyroid function was present in 25 children (45.45%). Of these, 11 (20%) had primary hypothyroidism with low or normal uptake, whereas 14 (25.45%) had glands with high uptake of 131I and elevated TSH. Three children with primary hypothyroidism had reduced growth hormone reserve. On follow-up with thyroxine, there was an increase in growth velocity in all. This study indicates that thyroid function tests should be performed routinely in children with undiagnosed short stature.