Thyroid function tests and hypothalamic-pituitary-adrenal axis in infantil autism: Some basic endocrine topics of debate

Abstract

Purpose: The present study aimed to determine dysfunction in thyroid hormone tests and hypothalamic-pituitary-adrenal axis in 5 autistic children. Methods: Basal serum TSH, $T_{3}$, $T_{4}$, prolactin and cortisol levels were measured and their responses to TRH, ACTH stimulation tests and the overnight dexamethasone suppression test (DST) were evaluated. Results: Baseline and post TRH stimulation, serum levels of TSH, $T_{3}$, $T_{4}$, and prolactin were within the normal range in all patients. Basal cortisol levels were within the normal range in three patients while two had increased morning plasma levels. Basal cortisol mean levels increased significantly after ACTH administration. Four patients had suppressed cortisol levels after overnight DST but in one patient this was not suppressed after low dose DST. Conclusion: These results suggest that some autistic children may have a hypothalamic- pituitary-adrenal-axis abnormality.