Disaccharidase activity in infants and comparison based on symptoms and histological changes.

Objectives: There is uncertainty regarding disaccharidase activity (DA) in infants. In this study, values for DA in infants were established and compared with symptoms and intestinal mucosal histological appearance.

Patients And Methods: Disaccharidase activity and histological appearance of endoscopically obtained intestinal mucosal biopsy specimens from 131 infants (75 males; mean age 180 days; range 20-364 days) obtained during an 8-year period were reviewed. Patients were divided into 2 groups on the basis of absence (group 1; n = 56) or presence (group 2; n = 75) of failure to thrive (FTT) and/or diarrhea. These groups were subdivided into 3 subgroups on the basis of histological findings: normal histological appearance (A), mild histological abnormalities (B), and moderate to severe histological abnormalities (C).

Results: The DA from patients in group 1A represent values in infants who were free of diarrhea/FTT and who had normal intestinal mucosal histological appearance. The geometric means (95% CI) in units of DA were as follows: lactase 33.7 (normal range 29.0-39.1), sucrase 48.9 (normal range 44.2-54.1), maltase 160.5 (normal range 144.4-178.3), and palatinase 11.2 (normal range 9.7-12.9). Differences in DA were not related to symptoms, in the absence of histological abnormalities (1A vs 2A), but rather on the presence of histological abnormalities even in the absence of symptoms (1A vs 1B). Differences were also found when patients with FTT and/or diarrhea with abnormal histological appearance (2B and 2C) were compared with patients with no FTT and/or diarrhea with a normal brush border (1A).

Conclusions: We outline DA values in a large cohort of infants. DA in infants, as in children, relates to intestinal mucosal histological appearance rather than to symptoms.