On examination, the patient was in sinus rhythm, was moderately dehydrated, had right-sided abdominal tenderness, and had no organomegaly or palpable masses. Digital rectal examination results were negative for blood. Laboratory tests showed moderate leukocytosis (white blood cell count, 15 600/μL [to convert to ×109per liter, multiply by 0.001]; with an elevated neutrophil count of 13 600/μL), an elevated C-reactive protein level (157 mg/L [to convert to nanomoles per liter, multiply by 9.524]), and an erythrocyte sedimentation rate of 32 mm/h. Arterial blood gas showed no lactic acidosis. Stool culture results were negative for pathogenic growth as well as for Clostridium difficiletoxin. The patient was admitted for resuscitation and investigation.