Colonic diverticulosis

Introduction to colonic diverticulosis The colonic diverticulum is a colonic wall that protrudes outward to form a pocket, which can be a single, but more often a series of saclike projections that are outward from the lumen of the intestine. The colonic diverticulum can be divided into two categories: true and acquired. The true diverticulum is the congenital full-thickness of the colon wall, and the diverticulum contains layers of the intestinal wall. The acquired diverticulum is the mucosa that is excreted through the weak points of the muscular layer of the intestinal wall, so it is secondary to the increase in pressure in the intestinal lumen, forcing the mucosa to protrude outward through the weak area of the muscle of the intestinal wall. basic knowledge The proportion of sickness: 0.0031% Susceptible people: common in the elderly Mode of infection: non-infectious Complications: peritonitis intestinal obstruction

Cause of colonic diverticulosis

Congenital factors (30%):

Evans suggested that congenital right colon diverticulosis may be due to abnormal embryonic development of the intestinal wall. Waugh believes that the cecal diverticulum is caused by overgrowth of the cecum at 7-10 weeks of embryonic development. Normally, the development of this part should be atrophy. Patients with colonic diverticulosis have a family history. Most of the diverticulosis is caused by acquired diseases. The histological study did not find congenital abnormalities in the muscular wall of the colon wall. The increase in the incidence of diverticulosis with age also provides strong evidence for this. The congenital colonic diverticulum is rare.

Anatomical factors (30%):

(1) Factors affecting the formation of diverticulum: one is the tension of the colon wall, and the other is the pressure difference between the colon cavity and the abdominal cavity. The intracavity pressure of any part can be measured by Laplace's pressure law, Laplace's pressure law (P=kT/R, P is the pressure in the colon cavity, T is the tension of the intestinal wall, R is the radius of the colon, and k is a constant.): The pressure in the intestinal lumen is proportional to the tension of the intestinal wall and inversely proportional to the radius of the intestinal wall. Recently, it has been proved by a pressure gauge. During continuous segmental movement, the colon, especially the sigmoid colon, can produce high intraluminal pressure. The largest intraluminal pressure in the colon is located in the descending colon and sigmoid colon. This pressure is sufficient to cause the mucosa to protrude into the diverticulum of the colon muscle.

(2) Structural features of the colon wall: It may also be a factor in the incidence of diverticulum. The collagen fibers in the colonic ring muscle are cross-distributed, which maintains the tension of the colon wall. As the age increases, the collagen fibers in the colon cavity become Fine, elastin fiber weakens, the colon wall elasticity and tension are reduced, therefore, the narrowest, most hypertrophic sigmoid colon is the predilection site of the diverticulum, the muscle of the colonic band is in a contracted state, so it is not easy to have a diverticulum, it has been confirmed that the diverticulum patient The sigmoid smooth muscle bundle is thicker than normal. Even if there is no thick muscle bundle, the abnormal smooth muscle bundle is a manifestation of the early diverticulum. The abnormal smooth muscle bundle is not only confined to the sigmoid but also to the colon. Other sites, such as the upper rectum, are more pronounced after sigmoid resection. These weaknesses in the colon wall have been manifested in the early stages of the disease. In addition, connective tissue disorders caused by structural protein changes are also in the early stages of diverticulosis. Certainly works.

(3) Colonic movement: divided into two types: rhythmic contraction and propelled contraction. The former mainly mixes the contents of the right colon to the back and forth, and promotes the absorption of water and salt. The latter transports the feces to the distal end, and the group creeps (mass Peristalsis can cause feces to be pushed directly from the right colon to the sigmoid colon and the upper rectum. The colon is prone to occur on the weak intestinal wall between the colonic bands (Fig. 3). When the segmental motion increases, the intraluminal pressure increases. The weak part of the vein is likely to form a diverticulum where the blood vessels enter the colon wall (Figure 4).

Other factors (25%):

(1) Obesity: Obesity was previously thought to be related to diverticulosis, but studies have confirmed that this is not the case. Hugh et al found that subcutaneous fat thickness was not associated with diverticulum incidence.

(2) Cardiovascular disease: There is no correlation between hypertension and diverticulosis, but the incidence of diverticulum in patients with atherosclerosis is increased, which is presumed to be related to the ischemia of the inferior mesenteric artery. The incidence of diverticulosis in male patients who have had previous episodes of myocardial infarction 57%, significantly higher than male patients in the same age group (25%), aged over 65 years, the incidence of diverticulum in patients with cerebrovascular accident was significantly higher than the control group.

(3) Affective factors and irritable bowel syndrome: no psychological and emotional factors were found to be associated with diverticulosis. This is different from irritable bowel syndrome. There are many similarities between irritable bowel syndrome and diverticulosis (such as stool weight). , the content of fecal bile acid and fecal electrolyte, etc.), the former intestinal base pressure is also increased, and the two often exist simultaneously, EMG examination both have fast waves, both food and neostitis Excessive stress response, and high-fiber diet can correct the abnormal delivery time, increase stool weight, reduce intestinal pressure, it is generally believed that inhibition of exhaust and defecation will increase intestinal pressure and promote diverticulum formation, but This is not the case, because the young people's sphincter function is very strong, the incidence of diverticulum is not high, and the elderly with rectal sphincter relaxation is more frequent, and in patients with megacolon and constipation, the diverticulum is rare.

Colonic diverticulosis prevention

Eat less slag of fruit or crude fiber vegetables and irritating foods to avoid increasing bowel movements and worsening symptoms. During the attack period, you should eat a liquid diet to make the stool soft and slippery, reduce the stagnation, and make it easy to be discharged from the diverticulum. You can take 5ml liquid paraffin or senna leaf tea every night before going to sleep. It is not suitable for colon enema to avoid perforation. .

Complications of colonic diverticulosis Complications peritonitis intestinal obstruction

1. Block

After the inflammation is limited, an inflammatory mass is formed, which adheres to the surrounding tissue. If the inflammation of the diverticulum begins at the edge of the mesentery, it is easy to form an inflammatory mass. If there is an inflammatory attack in the past, the omentum usually adheres tightly to the intestinal tract, even if the inflammation eventually With regression, the sigmoid colon disease can not return to normal.

2. Abscess

In the past, if there is no inflammation around the diverticulum, abscess is easily formed during the onset of diverticulitis. Abscess is the most common complication of diverticulosis. There are 10% to 57% of patients with diverticulum complicated with abscess. The source of the disease includes:

1 Form an abscess around the colon at the edge of the mesentery.

2 Mesenteric abscess is formed in the mesenteric diverticulum.

3 Abscess caused by suppurative lymph nodes, abscess easily surrounded by surrounding tissues, such as the small intestine, omentum, parietal peritoneum or uterus, abscess along the mesentery, colon after the peritoneum or rectum, causing hip symptoms.

3. Suppurative peritonitis

Suppurative peritonitis can be diffuse or localized. Diffuse suppurative peritonitis is characterized by turbid peritoneal effusion, thickening of the serosal edema of the intestinal wall, and obvious peritoneal edema. If the perforation is limited, the sigmoid colon may be covered by the omentum. Small intestine, bladder, pelvic peritoneum, rectum and uterus, gangrenous sigmoiditis can also cause suppurative peritonitis, but less common, and the mortality rate is higher.

4. Fecal peritonitis

Diverticulum perforation causes fecal peritonitis, fecal fluid accumulation in the abdominal cavity, cavity and colon communication, although relatively rare, but the mortality rate can be as high as 75%, fecal peritonitis can cause severe circulatory failure, endotoxemia and Gram negative Septic shock.

Symptoms of colonic diverticulosis Common symptoms Urinary frequency abscess Abdominal pain Mucus will lose weight Pelvic mass Peritonitis Urgent diarrhea and blood in the stool

(a) colonic diverticulosis

Asymptomatic diverticulum 80% to 85% of diverticulosis without any symptoms, about 55% of patients with right colonic diverticulum are asymptomatic, even if there are mild symptoms, rarely see a doctor, the common abdominal symptoms are intermittent pain in the left axilla or lower abdomen, Abdominal distension, irregular bowel movements, mucus, heavy weight, weight loss and loss of appetite, etc., anemia is not common, these symptoms may also be caused by the simultaneous intestinal irritation syndrome, progressive bowel habit change, blood in the stool, abdominal pain There are diarrhea, loss of appetite, weight loss and anemia are the manifestations of colorectal cancer. It is not easy to distinguish from diverticulosis from the medical history. Suspicious cases should be treated with barium enema and colonoscopy. Some patients may have hiatal hernia and gallstones. Positive findings, normal rectal examination, electronic colonoscopy can clearly find a simple colon diverticulum.

(two) acute diverticulitis

There are varying degrees of localized abdominal pain in acute attacks, which may be stinging, dull and cramping. Most of the pain is in the left lower abdomen, occasionally on the pubis, right lower abdomen, or the entire lower abdomen. Patients often have constipation or frequent bowel movements. , or both of the same patient, can relieve pain after venting, inflammation adjacent to the bladder can produce frequent urination, urgency, depending on the location and severity of inflammation can also be accompanied by nausea and vomiting, low fever during physical examination, mild bloating, left The lower abdomen is tender, and the left lower abdomen or pelvic mass, there is occult blood in the feces, and a small amount of feces have blood in the naked eye, but there is a rare occurrence of major bleeding in the presence of inflammation around the diverticulum. In addition, there is mild to moderate white blood cell increase.

Examination of colonic diverticulosis

X-ray inspection

(1) Abdominal plain film examination: Abdominal plain film examination of simple diverticulosis is usually normal, so it is of little value. The imaging features of diverticulitis are: intestinal wall displacement or stenosis, mucosal changes, proximal or distal to the lesion. Multiple diverticulum can still be seen in the intestine segment, abdominal abdomen can be found in the abdominal plain abscess, small intestine, colonic obstruction caused by multiple gas-liquid plane and flatulent intestine.

(2) Enema: the use of tincture or water-soluble contrast agent for contrast enema is of great value in the diagnosis of asymptomatic diverticulosis, more reliable than colonoscopy, and the diverticulum filled with diverticulum appears as a bulge protruding the colon wall. After the agent is discharged, you can still see diverticulum imaging, no inflammation, colonic sputum or sputum filling, may cover the diverticulum, sometimes squat indoors or accumulate stool and easily confused with polyps, so you should observe in multiple directions, film, Post-empty filming improves diagnostic accuracy.

(3) cystography: when the barium enema is difficult to display the fistula, cystography can clearly show the colonic bladder spasm, the most diagnostic test of colonic bladder spasm is cystoscopy or cystography, can be found in the bladder wall blister edema, vein It is difficult to find the sigmoid colon and the fistula at the top of the bladder.

2. CT scan

CT scans in foreign countries have gradually increased the incidence of diverticulitis. In the case of inflammation, the barium enema image is not specific, while CT scan can reveal thickening of the colon wall, inflammation around the colon, fistula, sinus, abscess and stenosis (Fig. 17). CT diagnosis It can be found that 98% of patients with diverticulitis have inflammation around the colon, and the sensitivity is high. Although the enema can be found in the cavity, it is not easy to find inflammation around the colon lesion. CT examination is used for the following cases:

1 suspected fistula or abscess formation.

2 There was no improvement in the situation after conservative treatment.

3 The diagnosis of special cases is not clear.

4 patients with right hepatic diverticulitis or giant colonic diverticulum at the same time, CT scan is helpful for preoperative percutaneous puncture drainage abscess, and the value of the diagnosis of colonic bladder spasm is also greater.

3. Sigmoidoscopy

It is also often used in the onset of diverticulitis. Especially in the case of colonic obstruction, in order to distinguish it from polyps and tumors, a small amount of air should be filled in the microscopic examination, but it is not suitable for colonoscopy in the active period of acute diverticulum. After the subsidence.

Diagnosis and diagnosis of colonic diverticulosis

Can be diagnosed based on clinical performance and laboratory tests.

Differential diagnosis

Colonic diverticulosis should be differentiated from abnormalities of intestinal wall movement, such as irritable bowel syndrome, tumor, appendicitis, and colitis of the colon.

Colon cancer

Colon cancer and diverticulosis have more similarities: the incidence increases with age, can occur in any colon, sigmoid colon, clinical symptoms are similar, such as changes in bowel habits, lower abdominal pain, can cause obstruction or perforation, Clinical course is more insidious, can cause bleeding, but diverticulitis is more severe abdominal pain, accompanied by fever, leukocytosis, colon cancer hemorrhage is occult blood positive or a small amount of bleeding, and diverticulosis bleeding can be small, moderate or massive bleeding, about 20% of diverticulum patients have polyps or tumors. Boulos et al reported that 23% of diverticulum patients have colonic polyps, 8% of diverticulum patients have malignant colon tumors, and barium enema has a higher false positive rate for both. Forde Reported that 12 cases were suspected to be tumors in 12 patients, after sigmoidoscopy to exclude malignant tumors, the false positive rate of diagnosis of barium enema was 10% to 20%, and the false positive rate of diagnosis of polyps was 22% to 35%. For left colon lesions, sigmoidoscopy is the preferred method of examination.

2. Appendicitis

When cecal diverticulitis or sigmoid diverticulitis is located in the right lower abdomen, there may be symptoms similar to appendicitis, but appendicitis is more common than diverticulitis. It is characterized by metastatic abdominal pain. Early pain of cecal diverticulitis is fixed in the right armpit, not in the umbilicus. Weekly or upper abdomen, the pain does not start from the umbilical or upper abdomen, from the onset of symptoms to the long admission time (3 to 4 days), vomiting is rare, nausea and diarrhea are more common, if appendicitis is not ruled out, surgical exploration is required. If diverticulitis is found, it is usually removed together. Therefore, when the right lower quadrant pain is encountered and the cause is not clear, a CT scan may be performed to rule out diverticulitis.

3. Inflammatory bowel disease

Colonic inflammatory disease and diverticulitis can have abdominal pain, changes in bowel habits, blood in the stool and fever, ulcerative colitis is easy to distinguish from diverticulitis, ulcerative colitis almost all affect the rectum, so rectal microscopy can easily and accurately exclude ulcers Colitis, diverticulitis and Crohn's disease can form sinus, obstruction and abscess. When multiple intraluminal lesions and longitudinal submucosal fistulas are found by angiography, Crohn's disease is more likely, elderly patients When diverticulosis and Crohn's disease are more difficult to identify, a proper enema or endoscopy is available for proper diagnosis.

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