Surgical aspects of an outbreak of Yersinia enterocolitis.

Eleven patients with Yersinia enterocolitica infections were identified in the Upper Valley of New Hampshire and Vermont during October and November of 1995. Three children presented with an appendicitis-like picture. Two underwent appendectomy, one of whom was the outbreak's index case. Both appendectomy patients presented with lower abdominal pain, fever, vomiting, and a right lower quadrant mass associated with leukocytosis. Both had terminal ileitis, and in both, cultures of peritoneal fluid and a mesenteric lymph node grew Y. enterocolitica. Even during an outbreak there is no consistently reliable nonoperative way to separate a sporadic case of appendicitis from one whose appendicitis-like symptoms are due to Yersinia. In addition, a small percentage of Yersinia patients will present with true appendicitis as a complication of their disease.