Diverticulum bleeding

Introduction Diverticulum hemorrhage is a common clinical symptom of diverticulosis. The diverticulum is an outward saclike protrusion of any part of the gastrointestinal tract (digestive tract). The most common part of the diverticulum is the large intestine. Several diverticulums exist simultaneously, called diverticulosis. Diverticulosis is an outward saclike protrusion of any part of the gastrointestinal tract (digestive tract). The most common part of the diverticulum is the large intestine. Several diverticulums exist simultaneously, called diverticulosis, which is a pathological condition that often occurs after middle age. If inflammation occurs in the diverticulum, it is called diverticulitis. Diverticulosis is the simultaneous presence of several diverticulum, usually in the large intestine. The opening of the diverticulum can bleed, sometimes it can bleed, the blood enters the intestine, and then exits through the anus. This bleeding can occur when feces are trapped in the diverticulum and damage the blood vessels (usually the blood vessels beside the diverticulum). The ascending colon is more common than the diverticulum of the descending colon. Colonoscopy can determine the cause of the bleeding. Most of the diverticulosis occurs in bleeding. The condition can be divided into two stages: 1) Stage of diverticulum formation: The colon wall is bulged to form an abnormal sac, called a diverticulum. 2) Diverticulitis stage: The body's metabolites and bacteria are retained in the diverticulum, causing inflammation and even causing perforation. Most patients will only stay in the first stage.

Cause

(1) Causes of the disease

1. Congenital factors Evans suggested that congenital right colonic 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 atrophic. Some 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.

2. Acquired factors Some scholars believe that the low-fiber diet in western developed countries is the main cause of diverticulosis. The following clinical findings can confirm:

1 The incidence rate has obvious geographical distribution characteristics.

The incidence increased gradually after the 1 250s.

3 The incidence of diverticulosis changed after the diet of the mobile population changed.

4 Incidence increases with age.

5 high-fiber diet can prevent diverticulosis.

(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 at any location can be determined by Laplace's pressure law. Laplace's law of pressure (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, k is a constant) Description: The pressure in the intestinal lumen is proportional to the tension of the intestinal wall, and the radius of the intestinal wall In inverse proportion. Recently, pressure gauge studies have shown that the colon, especially the sigmoid colon, can produce high intraluminal pressure during continuous segmental motion. The largest intraluminal pressure in the colon is located in the descending colon and the sigmoid colon. This pressure is sufficient to cause the mucosa to protrude from the colon muscle to form a diverticulum.

(2) Structural features of the colon wall: 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 inside the colon cavity become thinner, the action of elastin fibers decreases, and the elasticity and tension of the colon wall decrease. Therefore, the narrowest and most hypertrophic sigmoid colon is a predilection site for the diverticulum. The muscles of the colonic band are in a contracted state, so the diverticulum is less likely to occur. It has been confirmed that the sigmoid smooth muscle muscle bundle of the diverticulum patient is thicker than normal. Even without the formation of a hypertrophic smooth muscle bundle, the abnormal smooth muscle bundle is a manifestation of the early diverticulum. Abnormal smooth muscle bundles are not limited to the sigmoid colon, but can also be found in other parts of the colon, such as the upper rectum. This is more pronounced after sigmoid resection. In the early stages of the disease, these weak points in the colon wall have been shown. In addition, connective tissue disorders caused by structural protein changes play a role in the early stages of diverticulosis.

(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 to promote the absorption of water and salt. The latter transports the feces distally. Mass peristalsis can cause feces to be pushed directly from the right colon to the sigmoid colon and the upper rectum. The colonic diverticulum is prone to occur on the weak intestinal wall between the colonic bands (Figure 3). When the intraluminal pressure increases during segmental motion, these potentially weak sites tend to form diverticulum where the blood vessels enter the colon wall.

(4) Compliance of the intestinal wall: Abnormality of the intestinal wall may also be the cause of the diverticulum. The study of the dynamics of the colon in resting and stimulating states supports this view. Eastwood et al. found that symptomatic colonic diverticulum patients showed excessive abnormal colonic stress responses to certain drugs, food, and dilated balloons. Normally, the pressure and volume in the lumen are linear. However, the pressure in the diverticulum patient quickly reached a stable period, and the pressure remained stable even as the volume increased. The threshold of stress response in diverticulum patients is significantly lower than that in normal people. The cause of decreased colon wall compliance may be related to hypertrophic smooth muscle and structurally disordered collagen fibers.

(5) Pressure in the colon cavity: The baseline pressure of the diverticulum patient was found to be significantly higher than that of the normal person. When the pressure in the sigmoid colon is abnormally increased, the patient may experience pain and discomfort in the left armpit and delayed bowel movement. The myoelectric frequency of diverticulum patients is 12 to 18 Hz, which is higher than that of normal people (6 to 10 Hz). The colonic EMG of the diverticulum patient is different from the irritable bowel syndrome, and the relationship between the two is still not obvious. Patients with diverticulum with pain often have intestinal irritation syndrome, and the underlying pressure of such patients tends to increase. After the diverticulum patient was fed, given neostigmine or morphine, the colonic motor index was significantly higher than normal. Dingding does not increase the internal pressure of the sigmoid colon, and prufenin and bran can reduce the intracolonic pressure. Abnormal pressure in resting and stimulating conditions does not improve after resection of the sigmoid colon, suggesting a complete colonic dysfunction.

In short, the cause of diverticulum remains to be elucidated, which may be the result of colonic smooth muscle abnormalities, increased intracavitary pressure during segmental contraction, decreased compliance of the intestinal wall, and low-fiber diet.

3. Relevant factors

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

(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 ischemia of the inferior mesenteric artery. In male patients with previous myocardial infarction, the incidence of diverticulum was 57%, which was significantly higher than that of male patients in the same age group (25%). The incidence of diverticulum was significantly higher in patients aged 65 years and older with cerebrovascular accidents than in the control group.

(3) Emotional factors and irritable bowel syndrome: No psychological and emotional factors were found to be associated with diverticulosis, which is different from irritable bowel syndrome. There are many similarities between irritable bowel syndrome and diverticulosis (such as stool weight, fecal bile acid and fecal electrolyte content). The former's intestinal base pressure is also increased, and both often exist simultaneously. EMG examination has both rapid wave appearance, excessive stress response to food and neostigmine stimulation, and high fiber diet can correct the abnormal delivery time, increase stool weight, and reduce intestinal pressure. . It is generally believed that inhibition of venting and defecation increases intra-intestinal pressure and promotes 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. The elderly with rectal sphincter relaxation are more frequent. In addition, patients with megacolon and constipation were found to have diverticulum.

(4) Intestinal inflammatory diseases: The relationship between intestinal inflammatory diseases and diverticulosis is complicated. Patients with diverticulum have an increased intracolonic pressure with ulcerative colitis. About 2/3 of patients with diverticulosis and Crohn's disease developed perianal symptoms such as ulcers and lower fistulas. The incidence of Crohn's disease complicated with diverticulum is five times higher than that of normal people. The main clinical features are pain, incomplete intestinal obstruction, abdominal mass, rectal bleeding, fever and leukocytosis. Berridge and Dick used radiology to study the relationship between Crohn's disease and colonic diverticulosis, and found that when Crohn's disease gradually developed, diverticulosis gradually "disappeared"; conversely, when Crohn's disease gradually eased, diverticulosis reappeared. This peculiar phenomenon is prone to inflammatory masses, abscesses and fistulas and other complications, especially in the elderly are more likely to form granuloma. Radiological examination showed that the mucosa of the diverticulum was intact except for abscesses and stenosis, and mucosal ulcers and edema of Crohn's disease (Fig. 7). Fabriaus et al found that Crohn's disease on the left side often coincided with diverticular disease.

(5) Others: Diverticulosis is associated with biliary tract disease, hiatal hernia, duodenal ulcer, appendicitis and diabetes, often accompanied by hemorrhoids, varicose veins, abdominal wall hernia, gallstones and hiatus hernia. Small sample studies found no significant relationship between diverticulosis and duodenal ulcer and arterial disease. Case-control studies have found that ingestion of non-steroidal anti-inflammatory drugs is prone to severe diverticulum complications.

(6) Nodules and rectal malignant tumors: The relationship between diverticulosis and knots, rectal polyps and tumors remains unclear. Edwards found that patients with diverticulum had a lower incidence of malignant tumors and benign adenomas than the general population, and rarely had polyps and colorectal cancer.

(two) pathogenesis

1. Good hair: The diverticulum can be single, but most of them are multiple. The diverticulum can appear anywhere in the colon, but the distribution is also uneven. The diverticulum of the right colon was almost exclusively in the cecum. Lauridson and Ross found that 79% of the right colonic diverticulum occurred 5 cm above the ileocecal valve and 2 cm below the cecal area, and mostly occurred in the anterior wall, the posterior wall occult diverticulum Often it brings difficulties to the diagnosis. The rectal diverticulum is rare, and it may be that the muscular layer of the rectum is sufficient to prevent the mucosal layer from protruding outward. During the operation, the diverticulum was found in the rectum. After careful dissection, the sigmoid colon was often caused by adhesion between the pelvic cavity and the rectum. The most common site of the left colon is the sigmoid colon, and some reports can be as high as 96%. The incidence of colon cancer is also very common.

Parks divides the colonic diverticulum into four types: about 65% in the sigmoid colon; 24% in the sigmoid colon and other colons; 7% in the entire colon; and 4% in the proximal end of the sigmoid colon. Hughes found that 16% of the diverticulum distributed throughout the colon was found by autopsy. Parks reported 19% of colonic diverticulum in the sigmoid and descending colons, compared with 30% reported by Hughes.

The colon contains two layers of muscles, the inner layer is the ring muscle, and the outer layer is the longitudinal muscle, which is gathered into three longitudinal colon bands with a distance of 120°. In patients with colonic diverticulum, the toroidal muscles are thickened, the colonic band is shortened, and the lumen is narrowed. The colonic diverticulum is prone to weakness in the colon wall, not on the colonic band, but on the intestinal wall between the colonic bands, and the position of the external process is very close to the mesenteric vessel branch penetrating the ring muscle into the submucosal layer, thus Four locations close to the mesenteric membrane tend to form a diverticulum.

2. Pathological changes

Diverticulum structure: Histology shows that the colonic diverticulum contains mucous membranes and serosal membranes, no muscle layer, and the muscle wall protrudes through the colon wall, which should be a pseudo-diverticulum. It is easy to cover the fat around the colon and the middle of the intestine. Sometimes the diverticulum is not the main cause of the disease. Extensive smooth muscle thickening can cause severe local symptoms. In surgically resected sigmoid specimens, thickened lines can often be seen. Membrane and colon wall. The size of the diverticulum varies widely, from 1 mm for the small to a few centimeters for the larger, and 27 cm for the largest diverticulum. The small diverticulum is spherical, the wide opening is in the shape of a flask, the neck is narrow, and the fecal stone or the accumulated gas forms a flap to enlarge the diverticulum, which is easy to form diverticulitis, causing lymphoid follicle hyperplasia, when inflammation affects surrounding tissues. It can destroy the mucosa and form an abscess. The diverticulum is easy to identify when it is located on the edge of the mesentery. If the colon is rich in fat and the surface of the diverticulum is covered with enteric fat, it is not easy to find. The diverticulum is easily found through the endoscope, and usually there is a fecal stone in the cavity that protrudes into the intestine.

3. Muscle abnormalities: Muscle abnormalities are the most common and most diagnostic features of diverticulosis. The colonic band and the ring muscle are obviously thickened. In severe cases, the mucosa of the colonic zone is columnar. These characteristics are most obvious in the sigmoid colon. Hughes found that only 40% of patients with cecal diverticulum had a muscle thickening of more than 1.8 mm, while 72% of patients with sigmoid diverticulum had a muscle thickening of more than 1.8 mm. Muscle hypertrophy was more pronounced when the lesion spread throughout the colon. Histological studies have found that the ring muscle breaks and is filled by fibrous connective tissue, while muscle cells have no hyperplasia and hypertrophy.

Elastin plays an important role in the pathogenesis of diverticulosis. The colon of the diverticulum patient has a large amount of elastin. Normally, the elastin is located only in the ring muscle, the tension of the colon decreases with age, and the collagen fiber becomes denser with age. From the specimens excised from the sigmoid diverticulum, the thick muscles and fine elastic fibers of the colonic zone were more common than those of normal people, but not in the ring muscles. Electron microscopic observation showed that there was no difference in muscle cell length and organelle composition between diverticulum patients and normal subjects. The only lesions observed in surgically resected specimens were abnormalities in muscle abnormalities and elastin distribution.

an examination

Related inspection

Urinary system CT examination of urinary total nitrogen intravenous urography

1. Urinary angiography: manifested as a bulge shadow outside the bladder, with a neck connected to the bladder.

2. B-ultrasound performance: showing a pocket-like or spherical spheroidal dark area connected to the side or back wall of the bladder, and the echo of the posterior wall is enhanced.

3. CT findings: An enhanced scan reveals a sac sac that highlights the contrast agent outside the bladder. If the sputum is combined with stones or tumors, there is a filling defect.

Differential diagnosis

Differential diagnosis

1. 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; Cause obstruction or perforation; clinical course is more concealed; can cause bleeding. However, diverticulitis is more severe with abdominal pain, accompanied by fever and leukocytosis; colon cancer hemorrhage is occult blood positive or a small amount of bleeding, while diverticulum hemorrhage 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 had colonic polyps, 8% of diverticulum patients had malignant colon tumors, and barium enema had a higher false positive rate for both. Forde reported that 11 of 12 patients were suspected of having tumors. Malignant tumors were excluded by sigmoidoscopy. The false positive rate of diagnosis of barium enema is 10% to 20%. The false positive rate of diagnosis of polyps is 22% to 35%. Therefore, for left colon lesions, sigmoidoscopy is the preferred method of examination.

2. Appendicitis: When the cecal diverticulitis or the sigmoid diverticulitis is located in the right lower abdomen, there may be symptoms similar to appendicitis, but appendicitis is more common than diverticulitis, and it is characterized by metastatic abdominal pain. The early pain of cecal diverticulitis is fixed in the right axillary fossa, not in the umbilical or upper abdomen. The pain does not start from the umbilical or upper abdomen. It is longer from the onset of symptoms to the admission (3 to 4 days), vomiting is rare, nausea and Diarrhea is more common. If appendicitis is not ruled out, surgical exploration is required. If diverticulitis is found, it is usually removed. Therefore, when the right lower quadrant pain is encountered and the cause is not clear, a CT scan can 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 rule out ulcerative colitis. Both sinusitis, obstruction, and abscess can be formed in both diverticulitis and Crohn's disease. When multiple intraluminal lesions and longitudinal submucosal fistulas are found by angiography, Crohn's disease is more likely. In elderly patients with diverticulosis and Crohn's disease, it is difficult to identify, enema or endoscopy for correct diagnosis.

4. Gastrointestinal bleeding: When the diverticulum is bleeding, the symptoms are similar to duodenal ulcer bleeding. For example, a large amount of bright red blood is discharged through the rectum, often accompanied by hypovolemic shock, which should be carefully identified. Asking for medical history, physical examination, indwelling gastric tube, and gastroscopy can rule out upper gastrointestinal bleeding. Congenital vascular dysplasia, arteriovenous malformation, telangiectasia, vascular disease, etc. are the causes of lower gastrointestinal bleeding. Diverticulosis with massive hemorrhage, radionuclide scanning and colonoscopy are helpful for diagnosis, but selective mesenteric angiography is the most reliable and most diagnostic test for acute bleeding, depending on the angiography, distribution, contrast agent spillage and Intestinal tube visualization determines the location of the lesion and distinguishes between diverticulum, tumor and vascular malformations.

diagnosis

Most patients with diverticulosis have no symptoms. However, some scholars believe that when patients have unexplained abdominal pain, diarrhea and other abnormal bowel movements, the exact cause may be diverticulosis. The opening of the diverticulum can bleed, sometimes it can bleed, the blood enters the intestine, and then exits through the anus. This bleeding can occur when feces are trapped in the diverticulum and damage the blood vessels (usually the blood vessels beside the diverticulum). The ascending colon is more common than the diverticulum of the descending colon. Colonoscopy can determine the cause of the bleeding.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.