Lactulose-mannitol intestinal permeability test in children with diarrhea caused by rotavirus and Cryptosporidium

Background: The relationship between intestinal permeability and acute secr etory diarrheal syndromes caused by rotavirus and Cryptosporidium parvum in infants less than 36 months of age was studied using the lactulose-mannito l excretion assay. Methods: An oral solution containing 0.4 g/kg lactulose and 0.1 g/kg mannit ol was administered to 15 infants with rotavirus. 7 with Cryptosporidium in fection and a control group of 7 with secretory diarrhea admitted to the Or al Rehydration Unit of the National Children's Hospital in Lima, Peru. Urin ary sugar excretion was measured using an enzymatic spectrophotometric meth od. The ratio of urinary excretion of lactulose to mannitol was used to mea sure intestinal mucosal permeability, with higher ratios indicative of incr eased intestinal permeability. Infants in all three groups were retested 20 days after the initial test. Results: The (mean +/- SE) lactulose:mannitol (L:M) excretion ratios during the acute phase (day 1) of diarrhea in infants with rotavirus or Cryptospo ridium and control infants were 0.67 +/- 0.1. 0.76 +/- 0.16. and 0.26 +/- 0 .04, respectively. In the convalescent phase (day 20) the ratios were 0.19 +/- 0.02, 0.28 +/- 0.05, and 0.29 +/- 0.07, respectively. Significant reduc tions in L:hl ratios were noted in rotavirus patients between days 1 and 20 (paired t-test; P < 0.01), Cryptosporidium patients between days 1 and 20 (paired t-test; P < 0.05), and between control subjects on day 1 and rotavi rus patients on day 1 and Cryptosporidium patients on day 1 (unpaired t-tes ts; P < 0.05 for both). There were no significant differences in control su bjects between days 1 and 20, control subjects and rotavirus patients on da y 20, or control subjects and Cryptosporidium patients on day 20. Conclusions: The results indicate that increased intestinal permeability ca used by rotavirus or cryptosporidium infections in Peruvian infants less th an 36 months of age is a significant but reversible phenomenon. The tempora l relationship observed in the current study and the contribution of such a lterations in intestinal mucosal integrity to the burden of diarrheal disea se and the development of malnutrition in developing countries is discussed .