USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 2-year-old boy comes to the emergency room because of a mass protruding from his rectum. The mass is dark red and minimal bleeding is present. His parents say that the mass was noticed when the child was being toilet trained that morning and was straining to have a bowel movement. He immigrated from China two weeks prior. The parents also say that the child had diarrhea for the past week with some blood and mucus present. Which of the following is the most likely causative agent for rectal prolapse in this child?