Original popular science article: Colonoscopy for patients with constipation, are you doing the right bowel preparation?

Editor: Kang Yan Reviewer: Yang Pengbin

(Gao Ruiping) With the acceleration of people's pace of life, the increase of work pressure and the change of dietary structure, more and more people are suffering from constipation. If there are alarm symptoms, it is very necessary to undergo colonoscopy. However, colonoscopy for constipated patients has its own particularities. Have you done the right intestinal preparation? Here, we have detailed the popular science knowledge in this regard. We also talk about the precautions for colonoscopy and the key points that need to be observed, hoping to benefit the general public.

With the accelerated pace of life, increased work pressure and changes in dietary structure, more and more people are suffering from constipation. According to the statistics of "Chinese Expert Consensus on Chronic Constipation (2019, Guangzhou)", the prevalence of chronic constipation in adults in the Chinese community is 4.0%-10%, which increases with age, and the prevalence of women is significantly higher than that of men. Constipation is manifested in life as persistent difficulty in defecation, a sense of incomplete defecation and a decrease in the number of bowel movements. Patients are very painful and often defecate once every 3-4 days, or even 7-10 days. The stool is dry, hard and spherical, and sometimes manual assistance is required to defecate, which is miserable. If the above symptoms persist for more than 6 months, you may have chronic constipation.

What causes chronic constipation and what should I do? Of course, the most common cause is our bad living habits, such as eating too refined food, eating less vegetables and fruits, sitting or lying in bed for a long time, weakening the motility of the intestines, or interpersonal tension and long-term depression, which can cause autonomic nervous system dysfunction and inhibit intestinal motility. Of course, there is also a type of disease that may cause organic lesions in our colon.

If there are alarm symptoms, such as recent significant weight loss, blood in the stool, and obvious palpable masses in the abdomen, your doctor may advise you to have a colonoscopy. Because, according to the 2019 Journal of Cancer, the mortality rate of colorectal cancer in my country has jumped to second place, becoming the second largest tumor after lung cancer. The number of patients has increased year by year, seriously threatening people's lives and health, and colonoscopic pathological biopsy is currently the gold standard for diagnosing colorectal cancer. How to improve the quality of intestinal preparation is crucial to the effectiveness of colonoscopy. A foreign statistical result shows that if the intestine is not prepared adequately, the detection rates of early and late polyps will decrease by 44% and 23%, respectively.

The most commonly used intestinal cleanser at home and abroad is compound polyethylene glycol electrolyte powder, which does not affect the absorption and secretion of the intestine, and therefore does not cause water and electrolyte imbalance. It is the first choice for intestinal preparation. For patients with constipation, due to various reasons, such as diabetes, advanced age, history of abdominal surgery, and other diseases with limited activity, the difficulty of intestinal cleansing is aggravated. In order to solve this problem, we might as well try the following methods:

1. Oral administration in divided doses every other day: Our practice is to take one box of compound polyethylene glycol electrolyte powder (add 1000ml of water) orally at 7-8 pm the night before the colonoscopy, and take two boxes of compound polyethylene glycol electrolyte powder orally 4-6 hours before the next day, and ask the patient to move more during this period. If constipation is severe, sometimes the patient is asked to drink one box of compound polyethylene glycol electrolyte powder at 3 pm and 8 pm the day before the colonoscopy, and take two boxes of compound polyethylene glycol electrolyte powder orally 4-6 hours before the next day. Ask the patient to move more until clear water-like stool is discharged.

2. Compound polyethylene glycol electrolyte powder combined with enema solution: One day before the colonoscopy, give the patient 2-3 enema solutions and ask the patient to use them anally to clean up the dry and hard stool near the rectum. Then take compound polyethylene glycol electrolyte powder according to normal procedures.

3. Compound polyethylene glycol electrolyte powder combined with lactulose: Our practice is to take 40 ml/day of lactulose orally 2 days before intestinal preparation to achieve the purpose of cleaning the intestines in advance, and then take compound polyethylene glycol electrolyte powder according to normal procedures.

4. Compound polyethylene glycol electrolyte powder combined with Simotang: Simotang oral liquid is a Chinese patent medicine preparation. Its main ingredients are Linderae umbellatae, Areca catechu, Aquilaria wood, and Citrus aurantium. It has the functions of promoting qi and relieving pain, and treating constipation caused by insufficient gastrointestinal motility. Using Simotang oral liquid to clean the intestines in advance 2 days before intestinal preparation will also have a good effect.

For patients with constipation, we also need to grasp the following key points during the intestinal cleansing process. Instruct patients to take easily digestible porridge, noodles and other foods orally. Do not eat foods with shells or seeds 2-3 days before colonoscopy. During medication, try to move as much as possible to increase the peristaltic function of the gastrointestinal tract and accelerate defecation. During the intestinal cleansing process, it is necessary to observe possible complications of the patient, such as nausea and vomiting, abdominal distension and pain, decreased blood pressure and palpitations. If these occur, give the patient correct guidance to eliminate the patient's nervousness. During the intestinal cleansing process, patients also need to be informed to observe the stool discharged. The following picture can be used to understand the situation of our intestinal cleansing.

In short, the quality of intestinal cleaning is crucial for colonoscopy and for our discovery of early lesions. Discovering an early cancer can save a life and a family. Let us work together to fight for the health of our people.