Risks of a colonoscopy

Colonoscopy is also known as colonoscopy in the technical language. This is an examination of the intestine using a long endoscope to which a camera is attached to examine the tissue. It is one of the most important examinations for the early detection of colon cancer and can be performed by specialists in doctor’s offices or as an outpatient in hospital.

Procedure of the colonoscopy

The colonoscopy is performed by a gastroenterologist. In order to have a good view of the inside of the intestine, the patient must perform a thorough intestinal cleansing with laxative the day before the procedure. The intestine should be free of stool and food residues.

For the procedure, the patient can be put under mild anaesthesia with painkillers and will be monitored. The examination can also be carried out without anaesthetic, but many patients find the advancement of the endoscope unpleasant. The doctor carefully inserts the endoscope into the intestine under visual control.

While rinsing with water and unfolding the intestinal wall by introducing air, the physician pushes the endoscope forward until it reaches the transition between the large and small intestine. Now the actual procedure begins. The doctor pulls the endoscope back slowly and under close observation of the intestinal mucosa.

The camera attached to the endoscope is movable and by turning it the doctor can finally capture all areas. Meanwhile, the doctor has the possibility to take biopsies (tissue samples), remove polyps or small tumours or even stop gastrointestinal bleeding with staples. Especially polyps are easy to remove and are an important prophylactic measure.

They are often the benign precursors of a tumour, which can develop into a malignant one over time. Depending on the indication, the examination takes between twenty minutes and half an hour. Patients with pre-administered anaesthetics should not drive a car afterwards, be picked up from the hospital and take it easy. Patients at risk are admitted to hospital for a further day for observation, depending on their previous illnesses.

Risks

The risks of a colonoscopy are many and varied, but they rarely occur with a trained doctor. Nevertheless, they cannot be ruled out one hundred percent, which is why patients are informed in detail in advance and must consent to the examination. In principle, colonoscopy is considered to be well tolerated and usually free of complications, but slight abdominal pain may occur after a colonoscopy.

Patients can also have the examination performed while conscious. Often the insertion and advancement of the endoscope causes unpleasant pain or an unpleasant feeling. This can be counteracted with medication, but this can then spontaneously lead to intolerance reactions.

Patients who wish to undergo a colonoscopy under anaesthesia may develop a hypersensitivity reaction to the drugs used. This can occur immediately or even later, so careful monitoring is advisable. In this way, a possible allergic reaction can be detected and countermeasures can be taken immediately.

Bleeding can occur when the endoscope is advanced or when cysts or polyps are removed. These can be stopped directly by means of appropriate instruments. The intestinal wall can then be very thin and easily injured in places.

In the worst case, the injury can lead to a complete rupture of the intestinal wall, a so-called perforation in the free abdominal cavity is then present. This complication can have far more serious consequences. Even if the intestine has been thoroughly cleaned before the endoscopy, there may still be residual stool inside.

In the event of a perforation, these can then enter the abdominal cavity and cause inflammation. This is known as peritonitis, which can have serious consequences under certain circumstances and depending on the patient’s general condition. Other organs can be affected and eventually lead to blood poisoning (sepsis), which is a life-threatening situation and requires intensive medical care and treatment with antibiotics.

In order not to challenge this risk, the intervention should be well considered with regard to its necessity in the case of acute inflammation of the intestinal mucosa. Not only germs and bacteria can be carried into the abdominal cavity through an injury in the intestinal mucosa, but tumour cells can also be flushed out. As a result of the ablation of tumorous tissue, individual tumor cells can be detached if the wall is damaged or perforated.

There is then a risk that they will adhere to other organs or other tissue and trigger the growth of a new tumour (metastasis) there. If a perforation has taken place, it is urgently necessary to carefully rinse the abdomen with a lot of fluid in order to minimize the risk of the complications mentioned above. Patients with a known disease of the cardiovascular system generally have higher risks during surgery than healthy people. Any operation, especially under anaesthesia, is a strain on the circulation and can lead to serious complications. The risks increase with age.