What is a Colonoscopy?

Colonoscopy can sequentially and clearly observe the mucosal status of the anal canal, rectum, sigmoid colon, colon, and ileocecal, and can perform pathological and cytological examination of the living body.

Basic Information

Chinese name: Colonoscopy
Specialty classification: Gastroenterology

Indication: Unexplained stool blood or persistent fecal occult blood, etc.
Contraindications: Cardiopulmonary insufficiency, shock, abdominal aortic aneurysm
complication: Gastrointestinal bleeding, intestinal perforation, intestinal infection

Colonoscopy indications

1. People with unexplained stool blood or persistent fecal occult blood positive;

2. Have lower and lower gastrointestinal symptoms, such as chronic diarrhea, long-term progressive constipation, changes in bowel habits, abdominal pain, bloating and other unclear diagnoses;

3. X-ray barium enema examination is suspected of terminal ileum and colonic lesions, or the nature of the lesions can not be determined;

4. X-ray barium enema examination is negative, but there are obvious intestinal symptoms or suspected malignant changes;

5. Low bowel obstruction and abdominal mass, can not rule out colon disease;

6. Unexplained weight loss and anemia;

7. Those who need colonoscopy, such as colon polypectomy, hemostasis, sigmoid torsion or intussusception reduction;

8. Those who need to check the anastomosis after colectomy;

9. Patients who need regular colonoscopy after colon cancer, polypectomy and inflammatory bowel disease treatment;

10. Those who need colonoscopy to assist in the exploration and treatment of bowel diseases;

11. People who need a general survey of large intestinal diseases.

Colonoscopy contraindications

Absolute contraindication

Severe cardiopulmonary insufficiency, shock, abdominal aortic aneurysm, acute peritonitis, bowel perforation, etc.

2. Relative contraindications

(1) Pregnancy, extensive adhesions in the abdominal cavity, and various causes of intestinal stenosis, chronic pelvic inflammatory disease, cirrhosis, ascites, mesenteric inflammation, abnormal bowel flexion, and advanced cancer with extensive intra-abdominal metastasis, etc., if necessary, check At the time, be carried out carefully by experienced surgeons;

(2) Severe ulcerative colitis. Patients with multiple colon diverticula should see the enteroscopy clearly, and do not use the slide-in method to advance the colonoscopy;

(3) Those who have had abdominal surgery, especially pelvic surgery, have suffered from peritonitis, and have a history of abdominal radiotherapy should enter slowly slowly. Gentle, severe pain should be terminated to prevent intestinal wall tears and perforations;

(4) Patients who are frail and elderly, and who have severe cardiovascular and cerebrovascular diseases and who cannot tolerate the examination, must be cautious during the examination;

(5) Those with severe purulent inflammation or painful lesions in the anus and rectum, who cannot tolerate the examination, must be cautious during the examination;

(6) Pediatrics and people with mental illness or those who cannot cooperate should not be inspected, if necessary, they can be administered under general anesthesia;

(7) Women's menstrual periods are generally not suitable for examination.

Colonoscopy complications

Gastrointestinal bleeding

2. Intestinal perforation

3. Inadequate disinfection leads to intestinal infection.

Preparation before colonoscopy

1. Fully understand the condition before surgery, including detailed medical history, physical examination, biochemical examination and other imaging data such as barium enema, understand whether there is coagulopathy and whether to use anticoagulants, and whether there are drug allergies and acute and chronic infections Related diseases, if such diseases are suspected, relevant laboratory tests should be performed to determine whether there are indications and contraindications for colonoscopy. If colon deformity or stenosis is suspected, barium enema is usually performed first to understand the shape of the bowel cavity.

2. Informed consent. Due to a series of complications of colonoscopy and treatment, explain the purpose of the examination and possible problems to the patient, ask for their consent and sign an informed consent form, explain the precautions and coordinate with the position of the examination. Do a good job of explaining to the patient to relieve his thoughts and tensions in order to obtain his cooperation and ensure the success of the examination.

3. Take a low-fat, fine, soft, low-slag semi-liquid diet 1 to 2 hours before the test. Patients with severe constipation should be given laxatives or prokinetic drugs 3 hours before the test to expel stools retained in the colon. Breakfast is fasted on the day of the test. People with diabetes, the elderly or those who are not hungry can drink sugary water and beverages appropriately.

4. Intestinal preparation. Intestinal cleanliness is a prerequisite for successful inspection. The success of colonoscopy and the cleanliness of the intestine are one of the keys. If there is fecal accumulation in the colon, it will affect entering the microscope and observing the lesions. At present, there are many methods for cleaning the intestine, each with its own characteristics. The commonly used method is the polyethylene glycol (PEG) method: PEG has a high molecular mass, and is neither hydrolyzed nor absorbed in the intestine, so it is in the intestinal fluid. Produces high osmotic pressure and forms osmotic diarrhea. Dissolve 20-30g of PEG in 2000-3000ml of water and take it orally 4 hours before surgery until the discharged liquid is clear. PEG can also be added to the electrolyte solution to increase the osmotic pressure. For example, the compound polyethylene glycol electrolyte powder consists of PEG and electrolyte. 2-3 bags of PEG are dissolved in the electrolyte solution each time, which can reduce the amount of drinking water to 2000ml. . This method takes a short time to clean the intestines, consumes less water, and has less irritation to the intestines. Generally, it does not cause water and electrolyte imbalances. However, there is more yellow liquid in the intestine, and part of it forms a yellow foam, which affects the visual effect.

5. Preoperative medication. Preoperative medications for colonoscopy ensure smooth insertion. Careful observation and search for lesions, accurate biopsy and fine endoscopic treatment are important. Pre-medication for some nervous patients can also help reduce pain and better cooperate with the examination.

(1) Antispasmodics can inhibit intestinal peristalsis and relieve spasm, which is conducive to inserting and looking for lesions, biopsy and endoscopic treatment. 10 to 15 minutes before the test, intramuscular injection of 20mg anisodamine or scopolamine 10mg, the action time of 20 to 30 minutes. If you need to stabilize the bowel during the operation, you can intramuscularly or intravenously. For glaucoma, enlarged prostate or recent urinary retention, use vitamin K38 ~ 16mg intramuscularly or nifedipine 10mg sublingually instead.

(2) Sedation and analgesics With the improvement of the technique of insertion, the pain of insertion has been significantly reduced, and analgesics have rarely been used in China. For only a few people who are nervous, poorly tolerant, or in need of disease, intramuscular injection of diazepam 10mg or intravenous bolus 5-10mg. Individual patients can use intramuscular injection of diazepam 5 to 10 mg plus pethidine 25 to 50 mg as appropriate. When using analgesics, the surgeon should always be vigilant due to the increased pain threshold, and the patient feels insensitive to the severe pain before perforation. If the surgeon continues to enter the mirror, there is a risk of perforation or serous membrane tear, especially intestinal adhesions Or cases of ulcers. Therefore, for patients with sigmoid colon, transverse colon adhesion, or deep ulcers in the bowel segment

(3) Anesthetics In recent years, some hospitals at home and abroad have promoted painless examination, that is, colonoscopy under general anesthesia. Intravenous injection of drugs that have sedative or anesthetic effects makes patients comfortable and quiet, in a state of shallow anesthesia, forgetting the microscopic examination process, and achieving the goal of painless examination; this method increases patient compliance and facilitates the examination of doctors The operation and diagnosis have improved the inspection success rate. The commonly used drug is propofol plus fentanyl. However, colonoscopy under general anesthesia is inserted in a non-responding state, and even if forced to be inserted when the bowel is overstretched, perforation, serosal tears, and major bleeding are prone to occur. Therefore, the indications should be strictly grasped and the action of insertion Be gentle.

Precautions after colonoscopy

1. During the colonoscopy, gas will be continuously injected to facilitate the observation of the intestinal mucosa. Due to the accumulation of air in the large intestine after surgery, patients may feel discomfort with abdominal distension, which usually disappears after a few hours.

2. For patients undergoing colonoscopy biopsy or polyp resection, they need to enter a liquid diet, pay attention to changes in stool color, and observe the symptoms of abdominal pain and blood in the stool.

3. After colonoscopy or microscopy treatment, if there is persistent abdominal pain, or there is a large amount of bleeding in the stool, the doctor should be informed in time, and further treatment if necessary.