[Primary or tertiary hypothyroidism as a cause of growth disturbances in 13-month old boy?]

Due to the screening examination it is possible to diagnose primary hypothyreosis at the very beginning. On the other hand, hypothyreosis may be also caused by insufficient secretion of TSH or TRH. We present a 13-month old boy (A.I.) admitted to our Department because of short stature. The child was from normal pregnancy, birth spontaneous at full term with weight 4400 g, length 56 cm, 10 points in Apgar scale, TSH - 1,87 micro IU/ml in the screening examination. The psychomotor development was normal. At the admission the height was 72 cm (below 3 c), weight - 10,1 kg, body proportions normal, atresic fontanels, 7 teeth. Additional examinations revealed: skeletal age - 3 months, blood cell count normal, biochemical examinations normal except for level of cholesterol (209 mg/dl). We found lack of the GH secretion after clonidine. TSH value was slightly above normal range. The levels of free thyroid hormones, anti-TPO antibodies and thyroid ultrasonography were normal. The TSH level was increased in the stimulation test with TRH. Result of the MR examination of the brain was normal. On the basis of the whole picture tertiary hypothyreosis can not be excluded. The normalisation of thyroid hormone levels and GH in stimulation test with glucagone was obtained after therapy with L-thyroxine.

In cases of unclear growing disorders the full diagnostics of the hypothalamic-hypophyseal-thyroid axis should be done because of the possibility of regulatory centres insufficiency.