A Case of Collagenous Gastroenteritis with Pseudomembranes

A 51-year-old woman was admitted to hospital with a two-month history of watery diarrhea and 9 kg weight loss. Stool frequency was eight to 10 per day but without blood, steatorrhea or abdominal pain. There was no history of recent antibiotic use or infectious contacts. Her history was significant for type I diabetes mellitus treated with insulin. She was a lifelong nonsmoker who consumed no alcohol. The family history was unremarkable. Physical examination was normal. Laboratory data showed an elevated white blood cell count of 13.3×109/L (normal range 4.8×109/L to 10.8×109/L), a C-reactive protein level of 15.4 mg/L (normal range 0 mg/L to 8 mg/L) and an albumin level of 19 g/L (normal range 33 g/L to 45 g/L). Her tissue transglutaminase level was 0 U/mL (normal range 0 U/mL to 10 U/mL) with a normal immunoglobulin A level. Stool testing was negative for bacterial and parasitic pathogens, while Clostridium difficile testing was negative on three separate occasions.