A 6-week-old infant has an umbilical discharge containing intestinal fluid. Where is the fistula most likely connected?

The presence of an umbilical discharge containing intestinal fluid in a 6-week-old infant is suggestive of a patent omphalomesenteric duct or Meckel's diverticulum. When the omphalomesenteric duct fails to close properly, it can lead to a connection between the intestine and the umbilicus.

In this scenario, when the discharge contains intestinal fluid, it indicates that the fistula is most likely connected to a portion of the intestine. The distinction is important, as the omphalomesenteric duct typically connects to the distal ileum, which is the terminal segment of the small intestine before it empties into the large intestine.

A specific connection to the ileum (the last part of the small intestine) explains the presence of intestinal fluid in the discharge. Such a connection would allow digestive contents to pass through the fistula, resulting in the observed symptoms. Other segments of the gastrointestinal tract, such as the cecum, duodenum, and jejunum, are either less commonly associated with omphalomesenteric fistulas or would not typically present with intestinal fluid in the umbilical discharge. Therefore, the most likely connection for the fistula in this scenario is to the ileum.