Urinary retinol excretion in children with acute watery diarrhoea.

Children with diarrhoea due to rotavirus infection excrete retinol in urine. This study aimed at demonstrating the extent and mechanism of urinary retinol excretion in children with acute watery diarrhoea caused by pathogens other than rotavirus. Thirty-two children, aged five months to five years, hospitalized with watery diarrhoea predominantly due to enterotoxigenic Escherichia coli in Bangladesh, were studied. Their serum retinol and retinol-binding protein (RBP) were low at admission and increased significantly after recovery from illness. The mean hospital stay of these patients was four days. Forty-seven percent of the children excreted retinol in urine on day 1, and about 38% continued excreting retinol on day 3. The estimated urinary retinol loss of 3.44 micromol for the illness episode represented more than 40% of liver retinol reserve (8.25 micromol) in malnourished children. A conservative estimate of the loss would represent at least 20% of the liver reserve in relatively better-nourished children. Kidney tubular dysfunctions of increased RBP excretion significantly predicted urinary retinol excretion in children with watery diarrhoea.