Dientamoeba fragilis infection presenting to the emergency department as acute appendicitis.

Dientamoeba fragilis is a non-enteroinvasive, protozoan parasite of the human large intestine with a worldwide prevalence. Considered for years to be a non-pathogenic organism, more recent studies suggest that up to 25% of adult hosts and up to 90% of infested children may manifest clinical disease. D. fragilis infestation has been implicated in chronic gastrointestinal syndromes characterized by protean complaints such as post-prandial abdominal pain, chronic diarrhea, flatulence, fatigue, anorexia, and weight loss. Rarely, D. fragilis infestation is the etiology of acute abdominal pain, mimicking a surgical abdomen. A case report is presented that details a patient with a 1-month history of vague abdominal complaints who presented to the Emergency Department with an apparent episode of acute appendicitis.