Study of the thyroid functions in patients with chronic kidney disease at Alexandria University Children’s Hospital

Abstract

Introduction The relationship between kidney and thyroid has been found since many years. Thyroid hormones directly affect the kidney through influencing the renal growth and development, glomerular filtration rate (GFR), renal transport systems, sodium and water homeostasis, and any impairment in thyroid functions can lead to or aggravate kidney disorders. On the contrary, the kidney plays an important role in thyroid hormone metabolism, degradation, and excretion so any disturbance in the hypothalamic–pituitary–thyroid axis has been correlated with reduced kidney functions. The earliest and the most common thyroid function abnormality in patients with chronic kidney disease (CKD) is a low triiodothyronine (T3) level (especially total T3 than free T3). This is called ‘low T3 syndrome.’ Moreover, CKD has an increased incidence of primary hypothyroidism and subclinical hypothyroidism. Detailed knowledge of all these interactions is extremely important for both the nephrologists and endocrinologists to plan the optimal management of the patient. Aim The purpose of the work was to study the thyroid functions in children with CKD (including patients on dialysis) attending Alexandria University Children’s Hospital. Patients and methods The study was a cross-sectional prospective study. The age of the studied cases ranged from 2 to 15 years. Overall, 52 male and 33 female patients were subjected to detailed history taking and full clinical examination. All patients were evaluated for serum creatinine, blood urea, serum thyroid-stimulating hormone, free triiodothyronine (FT3), and free thyroxine (FT4). Results A total of 55 (64.7%) cases had normal thyroid functions, 18 (21.2%) cases had low T3 syndrome, 10 (11.8%) cases had subclinical hypothyroidism, and two (2.4%) had hypothyroidism. No significant correlation between eGFR and thyroid-stimulating hormone levels was found, but there was a significant positive correlation between levels of free T3 and eGFR. Conclusion The low T3 syndrome is a relatively common thyroid disorder among children with CKD followed by subclinical hypothyroidism (11.8%). We recommend regular monitoring of thyroid functions in children with CKD for early detection of any disturbance to reduce the morbidity and mortality of CKD.