Rectosigmoidoscopy: what is it and what is it for?

Rectosigmoidoscopy: what is it and what is it for?

Rectosigmoidoscopy is a minimally invasive and uncomplicated procedure that allows early detection of malignant pathologies such as familial polyposis and colon and rectal cancer. Learn more about this endoscopic study.

Rectosigmoidoscopy: what is it and what is it for?

Last update: January 11, 2022

Rectosigmoidoscopy is a minimally invasive medical procedure that involves viewing the end of the large intestine through an endoscope. In this way, It is possible to study pathologies of the anus, rectum and the final portion of the colon.

The initial diagnosis of colon pathologies is based on the medical history, physical examination, and complementary laboratory tests. This test is quite useful, since it makes it possible to take a biopsy for tissue study and treatment under specific conditions.

In particular, it is considered of utmost importance for its role in the timely diagnosis of chronic diseases such as colorectal cancer and familial polyposis. Are you interested in knowing more about it? We tell you in detail about its advantages and uses.

Advantages of rectosigmoidoscopy over colonoscopy

Colonoscopy is a similar study in which – in the same way – an endoscopic probe is used that is inserted through the anal canal. However, this is intended to study the total length of the colon.

And although rectosigmoidoscopy allows to visualize only the final part of the large intestine, It does not require a previous complete intestinal lavage, or a special diet, or sedation.

What is rectosigmoidoscopy used for?

This procedure allows the anus, rectum, and sigmoid colon to be visualized, which represent roughly the last 30 cm of the large intestine. It is useful for the following:

  • Determine the presence of any rectal mass (polyps or tumors).
  • Define the origin of lower gastrointestinal bleeding, especially when anal pathology is suspected (such as internal hemorrhoids).
  • Observe the presence of diverticula.
  • Suspicion of ulcerative rectocolitis (type of inflammatory bowel disease).
  • Look for causes of chronic diarrhea with occult blood in the stool and other intestinal habit irregularities.
  • Study the cause of non-obvious chronic anemia.
Rectosigmoidoscopy involves the introduction of an endoscopic probe to view the anus, rectum, and sigmoid colon.


Rectosigmoidoscopy procedure

Rectosigmoidoscopy is performed on an outpatient basis. It begins with the person lying on the table on their left side, with their legs bent. The inspection of the perianal region is carried out; then, the digital rectal examination is continued. Finally, the endoscopic probe is inserted.

No sedation is required, but it can be a bit uncomfortable when inserted through the anus. The endoscopic probe is approximately 1 cm in diameter, can be flexible or rigid, and has a camera and light source at its tip.

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During the process, the endoscope allows evidence of erosive lesions, polyps, tumors, sources of bleeding, among others. In addition, it works as a treatment by allowing resection of lesions, taking biopsies or cauterizing sources of bleeding. After this, the person can continue with their daily activities without any restriction.



Pre-procedure preparation

Although a complete intestinal lavage is not required, before a rectosigmoidoscopy it is recommended to perform at least the emptying of the final part of the large intestine to facilitate visualization.

This can be done with the use of an enema or glycerin suppositories. It is recommended to place one 4 hours before the procedure and another 2 hours before. Wait at least 10 minutes before evacuating.

Solids or liquids should not be consumed during the previous 6 hours. In case of taking medications for high blood pressure, thyroid or glucose, it is recommended up to 2 hours before.

Contraindications of the procedure

The Rectosigmoidoscopy Procedure it is minimally invasive, safe, with rare and mild complications. Its only contraindications are the following:

  • Presence of acute diverticulitis.
  • Acute myocardial infarction.
  • First trimester of pregnancy (especially if contrast is used).

Special cares

Before the procedure, a blood clotting test must have been performed to reduce the risk of bleeding. In the same way, the gastroenterologist must know if the patient consumes any medication that can alter blood clotting, such as aspirin or anticoagulants.

In case of presenting prostheses or alterations in the heart valves, congenital heart malformations or a history of infections, preventive antibiotic treatment is used for bacterial endocarditis.

Before the rectosigmoidoscopy, the doctor conducts a review and interviews the patient to determine if there are possible risks during the procedure.

Side effects of rectosigmoidoscopy

This procedure may cause a little pain, bloating, abdominal cramps and a sensation of gas that usually disappear within hours.

More serious complications, such as accidental bleeding or perforation of the intestine with the endoscope, are very rare. Bleeding is more common in cases where a polyp was removed or a biopsy was obtained.

Preventive importance

In cases of a history of familial polyposis, a discard must be made after 10 years to establish if the person is a carrier of the disease.

To do this, it starts with genetic testing. If these are negative, should be done at 18, 25 and 35 years to avoid false negatives. When the genetic test is positive, it is necessary to do preventive rectosigmoidoscopy from puberty until the development of polyps.

However, in the case of adenomas and rectal cancer, an evaluation should be performed every 5 years in people older than 50 years.

In short, rectosigmoidoscopy is a minimally invasive procedure that plays an important role in the diagnosis and treatment of diseases in the colon. Even so, it is limited because it does not evaluate the entire intestine, which leaves out 30% of the cancers.

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