Studies on growth and the nutritional, metabolic, and hormonal status of children with chronic renal failure on regular haemodialysis
El Beshty, Mohamed Mahmud
The purpose of this study was to assess the nutritional, metabolic and hormonal status of children with chronic renal failure, and to study the pathogenesis of the growth retardation which is an important clinical problem affecting these children. Sixteen children on regular haemodialysis were observed over a period of one year. Growth was subnormal in most patients with delay in skeletal maturation, and growth potential fell with advancing bone age. Body weight was less affected than height presumably because all children received energy supp1ementsin their diet. Puberty was delayed but a pubertal children grew better and had/more normal body cell mass than prepubertal children. Significant increases were found in the fasting levels of blood glucose, plasma insulin, growth hormone, glucagon, Cortisol, luteinizing hormone, prolactin, triglycerides, cholesterol, glycine and alanine, and significant decreases were observed in plasma thyroxine, triiodothyronine, testosterone, branched-chain amino acids, free fatty acids and glycerol. Growth velocity correlated positively with plasma valine, leucine and gonadotrophin levels. In boys, growth velocity correlated positively with plasma testosterone and inversely with prolactin levels. Plasma triglyceride concentration was related to both carbohydrate intake and plasma insulin level. There were also positive correlations between growth hormone and fatty acids, growth hormone and the branched-chain amino acids, serum somatomedin and plasma transferrin, and between transferrin and the % deficit in weight for height and for age. Extracellular water was increased and intracellular water (cell mass) was decreased, but body fat was normal or increased in most patients. Glucose intolerance with hyperinsulinaemia, non-suppressable hyperg1ucagonaemia and paradoxical a rises in plasma growth hormone levels after/glucose load were observed. Fasting plasma alanine concentration correlated inversely with glucose disappearance rate (Kg). The fall in plasma free fatty acids was more marked than normal and was related to plasma insulin response. Basal oxygen consumption was increased particularly in the more wasted children. Manipulation of the diet for a further period of one year by increasing the ratio of polyunsaturated to saturated fats lowered plasma cholesterol level but not plasma triglycerides. On the basis of the findings, it is suggested that the primary defect is a peripheral resistance to insulin with respect to glucose utilization accompanied by a decrease in the mobilization of endogenous fat for energy production and a diversion of amino acids for energy purposes with an increase in hepatic g1uconeogenesis and body protein depletion. It was also suggested that energy and protein requirements of uraemic children may be increased, and that energy supplements as carbohydrate would increase body fat without affecting cell mass. It is hoped that the information obtained from the study will be helpful in further understanding the pathogenesis of growth retardation in children with chronic renal failure and their nutritional needs, and will provide guidelines for future research.