About 1 in 200 people who undergo a<unk>  experience a serious complication. Perforation of the colon occurs in about 1 in 2000 procedures, bleeding in 2.6 per 1000, and death in 3 per 100,000, with an overall risk of serious complications of 0.35%. In some low-risk populations screening by<unk>  in the absence of symptoms does not outweigh the risks of the procedure. For example, the odds of developing colorectal cancer between the ages of 20 and 40 in the absence of specific risk factors are about 1 in 1,250 (0.08%). The rate of complications varies with the practitioner and institution performing the procedure, and other variables. Perforation The most serious complication generally is gastrointestinal perforation, which is life-threatening and in most cases requires immediate major surgery for repair. Fewer than 20% of cases may be successfully managed with a conservative (non-surgical) approach. A 2003 analysis of the relative risks of sigmoidoscopy and<unk>  brought into attention that the risk of perforation after<unk>  is approximately double that after sigmoidoscopy (consistent with the fact that<unk>  examines a longer section of the colon), a difference that appeared to be decreasing. Bleeding Bleeding complications may be treated immediately during the procedure by cauterization using the instrument. Delayed bleeding may also occur at the site of polyp removal up to a week after the procedure, and a repeat procedure can then be performed to treat the bleeding site. Even more rarely, splenic rupture can occur after<unk>  because of adhesions between the colon and the spleen. Anaesthesia As with any procedure involving anaesthesia, other complications would include cardiopulmonary complications such as a temporary drop in blood pressure and oxygen saturation usually the result of overmedication, and are easily reversed. Anesthesia can also increase the risk of developing blood clots and lead to pulmonary embolism or deep venous thrombosis. (DVT) In rare cases, more serious cardiopulmonary events such as a heart attack, stroke, or even death may occur; these are extremely rare except in critically ill patients with multiple risk factors. In rare cases, coma associated with anesthesia may occur. Bowel preparation Dehydration caused by the laxatives that are usually administered during the bowel preparation for<unk>  also may occur. Therefore, patients must drink large amounts of fluids during the day of<unk>  preparation to prevent dehydration. Loss of electrolytes or dehydration is a potential risk that can even prove deadly. In rare cases, severe dehydration can lead to kidney damage or renal dysfunction under the form of phosphate nephropathy. Other Virtual<unk> es carry risks that are associated with radiation exposure.<unk>  preparation and<unk>  procedure can cause inflammation of the bowels and diarrhea or bowel obstruction. During<unk> es where a polyp is removed (a polypectomy), the risk of complications has been higher, although still low at about 2.3 percent. One of the most serious complications that may arise after<unk>  is the postpolypectomy syndrome. This syndrome occurs due to potential burns to the bowel wall when the polyp is removed, and may cause fever and abdominal pain. It is a rare complication, treated with intravenous fluids and antibiotics. Bowel infections are a potential<unk>  risk, although rare. The colon is not a sterile environment; many bacteria that normally live in the colon ensure the well-functioning of the bowel, and the risk of infections is minimal. Infections can occur during biopsies when too much tissue is removed and bacteria protrude in areas they do not belong to, or in cases when the lining of the colon is perforated and the bacteria get into the abdominal cavity. Infection may also be transmitted between patients if the<unk>  is not cleaned and sterilized properly between tests. Minor<unk>  risks may include nausea, vomiting or allergies to the sedatives that are used. If medication is given intravenously, the vein may become irritated. Most localized irritations to the vein leave a tender lump lasting a number of days but going away eventually. The incidence of these complications is less than 1%. On rare occasions, intracolonic explosion may occur. A meticulous bowel preparation is the key to prevent this complication. Signs of complications include severe abdominal pain, fevers and chills, or rectal bleeding (more than half a cup or 100ml).
Colonoscopy
Proctoscopy
Sigmoidoscopy
GI cocktail
Defecography
Capsule endoscopy
Chromoendoscopy
Colonic polypectomy