Diarrhea in a transplant recipient may be caused by infection, metabolic problems, or adverse drug effects. The immunosuppressive drug most frequently associated with diarrhea in transplant recipients is mycophenolate mofetil (MMF). We present the case of a patient with 2 potential explanations for diarrhea lasting several weeks, which occurred years after liver transplantation. Whereas stool samples were positive for cryptosporidia, the histopathological findings were compatible with MMF colitis. However, diarrhea resolved after treatment of cryptosporidial infection, despite continued MMF medication. This case shows that histopathological findings of MMF colitis may be misleading and do not prove that diarrhea is drug induced.
© 2011 John Wiley & Sons A/S.