Chronic Diarrhea After Infectious Enteritis: Not the Diagnosis You Are Thinking of

Abstract

Microscopic colitis is described as an inflammatory bowel disease characterized by chronic, non-bloody diarrhea with normal or close to normal endoscopic findings. Histopathological examination reveals two subtypes: collagenous colitis and lymphocytic colitis, which are indistinguishable clinically. Microscopic colitis has a female preponderance, with a mean age at diagnosis of 65 years. The pathogenesis of microscopic colitis is unclear, but it is likely to be multifactorial, involving mucosal immune responses to luminal factors in a genetically predisposed individual. We present two cases of young patients presenting with chronic diarrhea, which began after episodes of infection enteritis, both ultimately diagnosed with lymphocytic colitis. A 30-year-old male presented to the office with diarrhea for 5 months. The change in bowel habits occurred after an episode of apparent food poisoning due to eating oysters. While acute vomiting subsided, he continued to have painless, watery, non-bloody bowel movements 5-6 times per day particularly after meals with nocturnal symptoms. Physical examination, labs and chemistry were unremarkable. Colonoscopy was macroscopically normal. Random colon biopsies revealed increase in lymphoid cells in the lamina propria and intraepithelial regions. A 23-year-old female presented with diarrhea and 10lb weight loss over the preceding six months. Diarrhea was painless, non-bloody, watery, multiple times a day, particularly after meals and waking her from sleep. Medical interview identified a trip to Mexico which preceded her diarrheal illness and during which she suffered from a seemingly self-limited episode of infectious enteritis. Physical exam, CBC, chemistry, serology for celiac disease and stool studies were unremarkable. Colonoscopy was remarkable for mild patchy erythema throughout the colon, biopsies revealed changes consistent with lymphocytic colitis. Loperamide did not improve diarrhea in either case. Both patients were started on budesonide 9mg and tapered over several weeks, which led to full remission of diarrhea and return to normal bowel habits. Simple infectious enteritis can be a predisposing factor for microscopic colitis and should be considered along with post-infectious irritable bowel syndrome when patients do not improve with time and supportive care alone. This diagnosis should be considered in very young patients even though they are not the typical demographic for the disease.2090 Figure 1. Colon Biopsy