An Unlikely Guest With an Overstayed Welcome: Cyclospora-Induced Postinfectious Irritable Bowel Syndrome.

Introduction: Postinfectious irritable bowel syndrome is a phenomenon that can occur following bouts of acute gastroenteritis. While bacterial pathogens are typically implicated in the development of postinfectious irritable bowel syndrome, viral and parasitic infections should also be considered as inciting pathogens.

Case presentation: An immunocompetent, 65-year-old woman presented with several weeks of watery diarrhea, which polymerase chain reaction testing confirmed to be a Cyclospora infection. Resolution of diarrhea was achieved with antibiotic treatment, however, months later she presented to the gastroenterology service with persistence of loose stools and abdominal cramping consistent with a diagnosis of postinfectious irritable bowel syndrome.

Discussion: Postinfectious irritable bowel syndrome has a similar presentation to sporadic irritable bowel syndrome, with diagnosis aided by the identification of an inciting pathogen. To our knowledge, this is the first documented case of Cyclospora-induced postinfectious irritable bowel syndrome. While parasitic infections typically aren't implicated in cases of postinfectious irritable bowel syndrome, this case highlights the value of considering this condition as a cause of protracted diarrhea in patients previously diagnosed with Cyclospora.