POSSIBLE COLONOSCOPY COMPLICATIONS

Most people go through a colonoscopy without much discomfort or any problem. But some people worry about the procedure and want to know every bad thing that can happen even if the chances are low. So here you are. 

• Dehydration. Fluids or tablets are almost always used to cleanse the intestine the night before, so the doctor can see the surface.  These medicines can cause vomiting. Fortunately, that vomiting can usually be stopped by slowing the rate that the liquid or pills are taken. Using a different medicine can help too, though that is rarely needed.
• Vomiting can also come at the end of the procedure for patients who are sensitive to the medicine that's used to relax the patient. Usually, any nausea or vomiting be taken care of with medication and IV (intravenous) fluids can be used to correct any dehydration.
• Oxygen levels can decrease for a few seconds during a colonoscopy. This is usually managed promptly. This happens approximately once for every 100,000 procedures done. Similarly, low blood pressure is rarely a problem, occurring in fewer than 5 times for every 1,000 procedures done. This can vary with the different sedation medicines and can be increased for older patients and for those with other conditions, particularly obesity, heart or lung diseases. 
• Bleeding usually results when taking small biopsies, removing polyps or sometimes when the scope touches the intestinal wall. The amount may be less than a teaspoonful. It is seen after a procedure in 2 to 6 patients for every 1000 procedures done, with only 4 or fewer patients per 10,000 having any significant amount of blood loss. These percentages can increase when polyps are removed, for older patients, for those under 10 years of age or for those who are on aspirin and similar medications to prevent heart or clotting problems (it is usually recommended that those medicines be stopped well in advance and held before restarting them). 
• Infections are so rare that the American Heart Association does not recommend using any antibiotics for patients with heart disease. There was a scare several years ago about scopes that were not well cleaned, but this was for a different kind of scope, where the angled tip  of the scope could not be well cleaned (and that problem has not been corrected by using a different cleaning method). 
• Perforations are the greatest concern, because even a very small tear or hole in the intestine requires immediate surgery and it can be associated with significant and severe complications. Fortunately, a perforation is also rare, occurring 1-2 times in a 1000 in those with only mild problems that are not related to IBD. Removing a polyp can increase the risk to 2-4 per 1000, but simply being over 60 doubles the risk. 

But all of that needs to be put in perspective.

• You should discuss any concerns you have with your doctor, especially if you are in one of the groups with increased risk.