[Diagnosis of factitious diarrhea (Munchausen syndrome) by colon biopsy]

The differential diagnosis of chronic diarrhea is broad. Most of the illnesses causing diarrhea can be diagnosed through a carefully taken medical history, stool examination, few complementary laboratory tests as well as an endoscopy and, if needed, a radiological examination. However, a few causes could still remain undiagnosed and special diagnostic techniques must then be implemented. The diagnosis of self-induced diarrhea by concealed laxative abuse is a special challenge and should be considered in every case of diarrhea where the cause remains unclear. This paper reports such a case where the diagnosis of the habitual laxative abuse with Bisacodyl was made with the help of the pathologist on the basis of stepwise taken colonic biopsies. The most important histological criteria are a champagne glass-like ectasia of the deep curved crypts, combined with increased goblet cell content and increased mucus production in the presence of an intact surface-epithelium.