Standard colonoscopy involves the visual inspection of the rectum and large intestine by insertion of a flexible video camera through the anus. Approximately 5 to 10 percent of people report abdominal pain or discomfort after a colonoscopy, according to an October 2011 "Gastrointestinal Endoscopy" article authored by the American Society for Gastrointestinal Endoscopy. This discomfort is usually mild and harmless. In rare cases, however, abdominal pain might indicate a serious complication that may be life-threatening. If you experience persistent pain after a colonoscopy -- particularly pain that grows worse rather than better -- consult your doctor or go to the nearest emergency room.
Trapped gas is the most common cause of abdominal pain after a colonoscopy. To view the lining of the colon, your doctor must inject air through the colonoscope to inflate the bowel. The air is suctioned out as much as possible at the completion of the exam, but substantial amounts may remain. As the colon contracts to expel the gas, you may experience mild to moderate gas pains. Follow your doctor's instructions regarding pain after colonoscopy.
Tearing of the Colon
As the colonoscope is bent and pushed through the intestine, it is possible to generate stress on the colon and tear it. These tears do not occur at the leading end of the instrument but at some point behind the lens. They may not be seen by the camera, therefore, and the pain may not be felt immediately. As bowel contents continue to leak through the tear, pain becomes progressively worse and requires immediate medical treatment, usually with surgery.
Perforation of the Colon
The colon may be accidentally perforated by pushing the leading end of the scope through the intestinal wall. A hole may also be created while removing a polyp with miniaturized instruments passed through the scope. Perforations are often recognized and treated immediately. But some perforations may not be apparent to the doctor during the exam. Leakage of bowel contents through the perforation and the resulting pain may be slow or delayed and not occur until you return home. As with a tear, the pain typically worsens with time and surgical repair is usually necessary.
Pain After Polyp Removal
The colonoscope enables your doctor not only to find disease but also to remove small growths known as polyps. Some people develop pain after polyp removal that is very similar to that of tearing or perforation of the colon. With this situation, however, leakage of bowel contents does not occur, and you may be treated successfully without surgery. However, emergency evaluation is necessary to make the diagnosis and nonsurgical treatment requires close monitoring.
Injuries Outside the Colon
The colon has attachments to other organs, such as the liver and spleen. Rarely, pushing the scope through the bowel may pull on those attachments and cause tearing of those organs. Bleeding is the most common outcome and may result in worsening abdominal pain accompanied by a fast heartbeat, dizziness and fainting. This complication requires emergency medical evaluation and treatment, which may include surgery.