ABSTRACT
There are many etiologies responsible for severe intractable diarrhea in infancy, for instance, autoimmune enteropathy, microvillus inclusion disease, tufting enteropathy, food allergy, post-enteritis syndrome, chronic intestinal pseudo-obstruction, Hirschsprung's disease, intestinal lymphangiectasia, congenital sodium or chloride diarrhea, and congenital enzymatic deficiency. This article reports a case of microvillus inclusion disease in a Thai patient. He presented with severe intractable watery diarrhea with persistent metabolic acidosis. After extensive investigation, the diagnosis of microvillus inclusion disease was made, based on the ultrastructural findings of microvillus inclusions in the cytoplasm of the enterocyte on electron microscopic study. Various treatments were introduced to the patient without clinical improvement, including cholestyramine, metronidazole, probiotics, and octreotide. He was dependent on total parenteral nutrition and subsequently died from TPN-related complications. Even though it is a rare disease, it should be considered if an infant has chronic secretory diarrhea.