
A 67-year-old man complainsof abdominal distention and bouts ofdiarrhea with intermittent constipation.These symptoms have beenpresent for weeks but recently havebecome more severe. The patienthas not seen blood in his stool. Hedenies fever, travel to a foreign country,and recent trauma. He has hypertension,which is well controlledwith calcium channel blockers.
























































































































































































































































































