Colonoscopy Complications
Colonoscopy is a widely used medical procedure in which a flexible scope equipped with a tiny video camera is inserted through the rectum into the colon to examine the full length of the large intestine for any irregularities. It is prescribed most often as a periodic follow-up for patients who have suffered from colorectal cancer or for those believed to be at high risk to develop cancer. Although it is a relatively safe procedure, it is not without its risks.
California Study
An investigative team at the Northern California Kaiser Permanente health system reviewed the electronic records of more than 16,000 colonoscopies performed from 1994 to 2002. The team's goal was to gather evidence that would shed light on the nature and severity of colonoscopy complications. All of the 16,318 colonoscopies reviewed were performed on asymptomatic patients who were at least 40 years old. The study found an overall incidence of serious complications of 5 in every 1,000.
Bleeding
The scope used to examine the colon provides a conduit for the insertion of other instruments that are used to take tissue samples or remove polyps on the mucosal lining of the large intestine. Patients are generally advised to stop taking all blood-thinning medications, including aspirin, for a few days before the procedure to reduce the risk of excessive bleeding. Despite these precautions, the taking of a tissue sample or removal of a polyp occasionally causes bleeding that does not stop quickly, and further intervention is needed. The California study found the incidence of bleeding complications in colonoscopies that included biopsies was 4.8 per 1,000.
Perforation
Perforation of the intestinal wall is probably the most serious complication to occur as the result of a colonoscopy. The Kaiser Permanente study found a perforation rate of 1.1 per 1,000 in colonoscopies in which biopsies were taken and only 0.6 per 1,000 in those with no biopsy. The study also found that the level of perforation was noticeably higher in patients who were over 60 years old.
Sedation-Related Complications
Most colonoscopies are performed while the patient is sedated, most often with medications in the benzodiazepine family. This is so-called conscious sedation; the patient may be awake but usually has little memory of the procedure after it's over. Complications related to sedation include allergic reaction to the sedative or excessive dosage, which can result in respiratory depression. Such complications, although rare, can occur.
Other Risks
Another complication of colonoscopy can be infection, which is very rare but has occurred in a small number of cases where the equipment used was not sterilized properly. Also very rare, but documented in an article in the Journal of Medical Case Reports, is an obstruction of the small bowel that was caused by a colonoscopy a patient underwent in Britain. Although it's not a serious complication, many patients report feelings of fullness in their colon for a short time after the procedure. This is usually caused by the introduction of air into the colon to allow for easier passage of the scope through the large intestine.
Tags: large intestine, study found, colonoscopies performed, Colonoscopy Complications, complications colonoscopies
