Can You Diagnose the Cause of This Patient's Diarrhea?

This article will review the case of a 53-year-old female with a diagnosis of metastatic esophageal cancer receiving treatment on a clinical trial protocol combining chemotherapy/immunotherapy with FOLFOX and nivolumab, who presents to the clinic with 2 weeks of progressively worsening diarrhea. She experienced up to 12 loosely formed to watery bowel movements that were brown in color, not malodorous, and did not float. She also experienced associated abdominal pain and cramping, but denied fever, malaise, nausea, or vomiting. Vital signs were stable. Labs and CT chest, abdomen, and pelvis did not reveal a definitive cause. Dietary modification with a bland diet and loperamide did not significantly improved her symptoms.