A correlative study of etiology, clinical features and rectal mucosal pathology in adults with acute infectious diarrhea in southern India.

For detailed etiological studies we isolated invasive enteric bacterial pathogens in 16, non-invasive pathogens in 13 and no pathogens in 11 of 40 adults with untreated acute diarrhea of less than 5 days duration at a tertiary care hospital in southern India. It was possible to establish a system for the objective assessment of the clinical severity of illness. Hemorrhage in the rectal mucosal lamina propria. especially pericryptal, was a striking feature in rectal biopsies. This was associated with a vascular lesion with endothelial damage. The prevalence of the vascular lesion did not correlate with the etiological agents or the severity of the histological abnormality in the rectal mucosa. However, there was a good correlation between the presence of vascular abnormalities and clinical severity. While the vascular changes could be the result of non-specific trauma to the rectal mucosa due to diarrhea, it is suggested that they may have an as yet unknown role in determining clinical severity.