Local Shwartzman reaction in the rectal mucosa in acute diarrhoea.

A microvascular lesion characterized by endothelial and platelet damage leading to intravascular coagulation, thrombosis and vascular dehiscence with haemorrhage was found in capillaries and venules in the rectal mucosal lamina propria of adults with acute diarrhoea. The lesion morphologically resembled the local Shwartzman reaction. There was no correlation between the prevalence of the vascular lesion and the presence of recognized enteric pathogens, but there was a significant correlation with the clinical severity of the illness. It is suggested that this vascular lesion could be the result of the failure of the epithelioluminal barrier in the colon and it may also be one of the determinants of the clinical severity of illness in adults with acute diarrhoea.