Paediatricsmiddle twist
A previously well 2-year-old boy has passed two large, dark red stools today. He has had no abdominal pain, has not drawn up his legs, has not vomited and has had no diarrhoea; he was breastfed until twelve months and has grown steadily along the 50th centile. He is pale, with a heart rate of 165 and a capillary refill of three seconds. His abdomen is soft and non-tender with no palpable mass, and the perianal skin is intact. Which one of the following is the most likely cause of the bleeding?