What is considered a definite contraindication for colonoscopy?

A definite contraindication for colonoscopy is peritonitis. This condition represents a serious and often life-threatening infection of the abdominal cavity. When peritonitis is present, performing a colonoscopy would not only be ineffective but could also exacerbate the patient's condition by potentially leading to perforation of the bowel or further contamination of the peritoneal cavity. Medical management is crucial in these cases, and surgical intervention may be necessary to address the underlying cause of the peritonitis before considering any endoscopic procedures.

Other conditions may complicate colonoscopy, such as anticoagulation therapy, which requires careful management rather than outright contraindication; a history of diverticulitis, which necessitates consideration of individual patient factors; and severe hypertension, which can usually be managed. In contrast, peritonitis unequivocally prohibits the procedure due to the extreme risks involved.