All issues > Volume 31(8); 1988

Original Article

J Korean Pediatr Soc. 1988;31(8):1037-1047. Published online August 31, 1988.

Thyriod Function Studies in Children with Nephrotic Syndrome.

In Hoon Lee¹, Chan Yung Kim¹

¹Department of Pediatrics, College of Medicine, Pusan National University, Pusan, Korea

Received: January 4, 1988;  Accepted: February 22, 1988.

Abstract

To evaluate the influence of nephrotic syndrome on the thyroid function test in children, serum T3, T4, free T4, TSH, TBG and rT3 were measured using radioimmunoassay in 14 clinically euthyroid children with nephrotic syndrome who were admitted to Department of Pediatrics, Pusan National University Hospital from July, 1986 to August, 1987. Control group was 15 children who visit our outpatient department for minor complaints in absence of thyroid diseases and systemic illnesses. The results of the study were as follows: 1) Mean T3 was significantly lower in the patients group (78.5±29.6 ng/dl) than in the control group (139.5±27.5ng/dl) (P<0.001). 2) Mean T4 was significantly lower in the patient group (6.19 ±1.72 ug/dl) than in the control group (8.48±1.91 ug/dl) (P< 0.005), but it was less statistically significant in comparision with decrease of serum T3. 3) Mean TBG was significantly lower in the patients group (19.06±8.61 ug/ml) than the control group (30.03 ± 7.51 ug/dl) (P < 0.005). 4) Mean rT3 was significantly higher in the patients group (517.3±92.1 pg/ml) than the control group (256 ±91.1 pg/ml) (P< 0.001). The reciprocal change in nephrotic syndrome was noted between serum T3 and rT3, and their corrlation coefficiency showed significance of —0.85. 5) Mean TSH and free T4 were 3.61 ±2.07 ug/dl, 1.43 ±0.70 ng/dl in the patient group, whereas 2. 54 ±1.39 //g/ml, 1.61 ±0.52 ng/dl in the control group. They did not reach statically significant differences. 6) Serum T3 and T4 decreased in nephrotic syndrome in paralel with decrease of TBG and their correlation coefficiency were 0.60 and 0.74. In the case of lower T4，free thyroxine index was decreased in significant correlation (r=0.70), but the ratio of rT3 to T3 was increased significantly (r=-0.54). 7) There was sightly correlation between TBG and 24 hours urine protien but poor correlation was noted between thyroid function tests and other renal variables such as serum albumin, cholesterol, BUN, creatinine and C3. These hormonal changes make nephrotic syndrome to be one of “euthyroid sick syndrome”. The causes of the changes were urinary excretion of thyroid hormones, decreased activity of pituitary-thyroidal axis and abnormality of T4 peripheral metabolism. These result from the compensatory mechanism of excessive metabolism in nephrotic syndrome.

Keywords :Nephrotic syndrome, Thyroid hormone, T3, T4, TBG, rT3，TSH, Free T4, Free thyroxine index