Jejuno-ileal diverticula

　　Intestinal diverticula are often acquired and associated with increased intra-abdominal pressure. They are usually accompanied by changes in small intestinal motility, such as progressive systemic sclerosis, visceral disease, and neuropathy, which can lead to atrophy and fibrosis of the smooth muscle of the small intestine, causing the intestinal wall to dilate cystically and herniate into the submucosal layer through a weak muscle layer. Visceral neuropathy causes dysfunction of small intestinal motility, leading to intra-luminal hypertension, and diverticula may herniate into the muscular layer at weak points due to the entry of large blood vessels, sometimes causing paralytic ileus. Krishnamurthy (1983) conducted a histological study and found that the number of muscle cells in the muscular layer of the jejunum and ileum decreased and showed degenerative or fibrotic changes, and some of the ganglia in the intermuscular plexus also showed degenerative changes, hence proposing that the disease may be the manifestation of systemic sclerosis in the small intestine.

　　Common complications of jejunal diverticula include the following types:

　　I. Intestinal obstruction

　　It is the most common complication, and the causes of intestinal obstruction are various. Small diverticular invagination may become the starting point for intussusception, large diverticula may undergo diverticular volvulus, chronic diverticulitis may cause thickening and twisting of the adjacent jejunal wall, etc., all of which can cause acute intestinal obstruction. Long-term retention of contents within the diverticulum can form intestinal stones, and the fall of large stones into the intestinal lumen can block the intestines. Clinically, it is difficult to differentiate from intestinal obstruction caused by other reasons, and often diagnosis is obtained only after laparotomy.

　　II. Gastrointestinal bleeding

　　Intestinal diverticular bleeding is one of the important causes of gastrointestinal bleeding, accounting for about 5% to 29% of complications of jejunal diverticula. The mode of bleeding from diverticula is very inconsistent, ranging from acute onset with massive hematemesis or fresh stool to chronic intermittent blackish stools or vomiting coffee-like substances. There may be a period of gastrointestinal symptoms before bleeding. The causes of diverticular bleeding include:

　　1. Diverticulitis or diverticular ulcer formation leads to rupture of blood vessels in the diverticular wall, causing bleeding.

　　2. Overgrowth of bacteria in the diverticulum leads to intestinal dysfunction and hyperperistalsis, which damages the mucosa within the diverticulum.

　　3. The movement of intestinal stones within the diverticulum can cause mucosal injury, and diverticular bleeding is often misdiagnosed as bleeding from peptic ulcer, intestinal hemangioma or leiomyoma, and colitis, etc. Therefore, for elderly patients over 60 years old with gastrointestinal bleeding, the possibility of this condition should be considered.

　　III. Diverticular perforation

　　Thin-walled diverticula without muscular layer are prone to secondary perforation after diverticulitis or diverticular ulceration. Foreign bodies in the intestinal tract may slide into the diverticulum and puncture the thin wall, causing perforation. Abdominal closed compression injuries can also lead to diverticular perforation due to a sudden increase in intraluminal pressure. After perforation, it may lead to localized or diffuse peritonitis, which is often confused with perforation of peptic ulcer or appendicitis. Attention should be paid to differentiation in diagnosis.

　　IV. Pneumoperitoneum and extraintestinal gas cysts of the intestinal wall

　　In a few cases, diverticula perforation may occur without forming peritonitis and present as spontaneous pneumoperitoneum. Due to the dysmotility of the intestinal tract in multiple diverticula, there is the production of purposeless and irregular strong peristalsis, leading to small perforations in thin-walled diverticula. The intestinal gas is easily leaked into the peritoneal cavity through the perforation, causing the intraluminal pressure to drop. The wall of the diverticulum at the perforation site collapses or closes, thus preventing the entry of intestinal contents or feces into the abdominal cavity. The patient may have symptoms such as bloating, abdominal pain, discomfort, and nausea or vomiting. Abdominal X-ray films may show free gas under the diaphragm. If the perforation is concealed between the two leaves of the mesentery, the leaked intestinal gas is confined between the intestinal wall and mesentery, forming an extraintestinal gas cyst. Occasionally, a perforation may only involve the mucosa and submucosa, forming an intramural serosal gas cyst.

　　Intestinal diverticula are often asymptomatic due to their large opening, good drainage, and are commonly discovered during upper gastrointestinal imaging, with about 60% of jejunal diverticula being asymptomatic. Sometimes, they may present with symptoms of mild dyspepsia, such as nausea, discomfort in the upper abdomen after meals, bloating, intestinal rumbling, or flatulence. However, these are not specific symptoms, and diverticula are often diagnosed only after complications occur. The complications of diverticula include diverticulitis, bleeding, perforation, or obstruction; particularly jejunal diverticula, can lead to blind loop syndrome, causing malabsorption and megaloblastic anemia.

　　Diverticulitis is often caused by foreign bodies or stones, and can have acute attacks, but it is rarely diagnosed. Perforation is less common, and perforation of the terminal ileal diverticula can be misdiagnosed as appendiceal perforation. After perforation, it can form localized abscesses, intestinal fistulas, or diffuse peritonitis. Bleeding is a relatively common complication, usually in small amounts and chronic, with rare massive bleeding episodes. Emergency surgery is often required, but it is often misdiagnosed as bleeding from peptic ulcer disease. During surgery, it is important to carefully search for the presence of small intestinal diverticula and to accurately determine the source of bleeding. When complicated with intestinal obstruction, symptoms such as intermittent abdominal colic may occur. Intestinal obstruction can be caused by torsion or intussusception of the intestinal loop where the diverticula are located, with the diverticula becoming the starting point of the intussusception. It can also be caused by inflammatory adhesions formed after diverticulitis or perforation. In addition, there are reports of diverticula being complicated with pneumatosis cysts and malignant transformation.}

　　Diverticulosis of the small intestine can also cause blind loop syndrome, with malabsorption, leading to chronic diarrhea, fatty diarrhea, anemia, malnutrition, weight loss, and other symptoms. There are reports that malabsorption syndrome occurs in up to 50% of cases with diverticulosis. Normally, the jejunum is sterile when fasting, but in cases of jejunal diverticulosis, various bacteria can be cultured. When the normal peristalsis of the small intestine is disturbed, food stagnation occurs, and it cannot move quickly and continuously towards the distal part. Bacteria in the intestines will then proliferate; the poor fluidity of the contents of the diverticula, accumulation of chyme, and putrefaction provide a favorable condition for bacterial proliferation. Overgrowth of bacteria in the small intestine can lead to chronic diarrhea, steatorrhea, malabsorption, malnutrition, anemia, and other conditions. The occurrence of steatorrhea is mainly related to bile salts. The proliferating bacteria can almost decompose all the conjugated bile salts in the intestines into unconjugated bile salts. Without conjugated bile salts, lipids cannot form into tiny micelles, and fats can only dissolve in water and be easily absorbed by the villi of the small intestine and absorbed into the epithelial cells. Non-conjugated bile salts do not have this effect on fats, causing fats to be unabsorbed and leading to steatorrhea. At the same time, the products of the bacteria's action on fatty acids can also cause watery diarrhea in patients, leading to disorders in water and electrolyte metabolism. Some chronic diarrhea patients may show peripheral nerve symptoms or myopathy. Overgrowth of bacteria in the small intestine can also interfere with the normal metabolism of carbohydrates and affect protein absorption. It is possible that bacteria utilize proteins from food, resulting in hypoproteinemia in patients. Overgrowth of bacteria also affects the absorption of vitamins, especially vitamin B12. Impaired absorption of vitamin B12 may not be due to the inhibition of intestinal mucosal absorption function by bacterial toxins, but rather because vitamin B12 is utilized by bacteria. Some experimental studies have shown that even when vitamin B12 binds with intrinsic factor, bacteria can compete and seize vitamin B12. Therefore, diverticulosis of the small intestine can be complicated by megaloblastic anemia.

　　The main prevention of jejunoileal diverticula is to prevent the increase in intraluminal pressure, such as: intestinal obstruction, gastrointestinal decompression treatment: the accumulated gas and liquid at the upper end of the obstruction are extracted by gastrointestinal decompression, which reduces the intraluminal tension, is conducive to improving the blood circulation of the intestinal wall, alleviating systemic toxic symptoms, and improving respiratory and circulatory function.

　　The clinical diagnosis of jejunoileal diverticula can be made using the following methods:

　　1. Routine examination:In the absence of bleeding and inflammation, the hematocrit, hemoglobin level, and white blood cell count are within the normal range, and the fecal occult blood test is negative.

　　2. Bacterial culture:If there is a disorder in the metabolism of fat and vitamin B12, it is necessary to perform bacterial culture of the small intestinal contents.

　　3. Small intestine air-barium double-contrast examination

　　Intestinal contrast imaging has a high diagnostic rate. The examination catheter is inserted into the duodenojejunal flexure, and 300 to 400 ml of 50% (W/V) suspension is injected through the catheter. After the barium reaches the ileocecal region, an appropriate amount of air is injected and antispasmodic drugs are injected intramuscularly. Gentle pressure is applied to each group of small intestines in sections, and multiple body positions need to be used for the operation to ensure that the barium can fill various differentially directed diverticula. The shadow of the imaged diverticula on the mesenteric side of the small intestine is circular or oval in shape, with smooth and even edges, and opens into the intestinal cavity with openings of different widths. In the cavity of larger diverticula, three planes of gas, liquid, and barium can be displayed. In the case of diverticula with wide openings, the contrast agent can freely enter and exit between the diverticula and the intestinal cavity, which is a characteristic X-ray contrast manifestation of this disease.

　　4. Radionuclide imaging diagnosis

　　Concurrent gastrointestinal bleeding cases can be diagnosed by 99mTc red blood cell imaging. After intravenous injection of 99mTc-labeled red blood cells at a dose of 550 to 740 MBq, the imaging is immediately collected using a gamma camera or SPECT system at a rate of 1 frame per 5 minutes until 30 minutes, followed by abdominal anterior and lateral images at 1 hour and 2 hours later. If necessary, delayed imaging is performed 6 hours later. When the bleeding amount in the intestinal wall activity is 0 or 1 ml/min, the labeled red blood cells enter the intestinal cavity with the blood flow, forming an abnormal radioactive accumulation phenomenon. This method can perform bleeding localization and continuous dynamic observation. The positive diagnostic rate can reach 75% to 97% within 24 to 36 hours of multiple imaging. The bleeding site determined by this method to be located in the upper part of the jejunum can suggest the diagnosis of this disease.

　　5, Selective superior mesenteric artery angiography

　　Technically excellent angiography is very valuable for cases with massive bleeding, with bleeding speed > 0.5 ml/min, the contrast agent in the intestinal lumen clearly showing the bleeding site, and even directly showing the nature of the lesion.

　　6, Fiberoptic enteroscopy

　　Some authors recommend performing fiberoptic enteroscopy to directly observe diseases in the small intestine, which has a high diagnostic rate. However, the mastery of this technology requires strong professionalism and needs further promotion and use.

　　Patients with small and large intestinal diverticula should eat foods rich in protein and other nutrients, such as lean meat, beef, mushrooms, jujube, sesame seeds. In addition, foods for the prevention and treatment of deficiency syndromes include black fungus, yam, coriander, chive, eggplant, coix seed, water chestnut, lotus root, fennel, lychee, chicken, lamb, fig, etc.

　　If the small intestinal diverticula are small and asymptomatic, no treatment is needed. If there are symptoms such as steatorrhea or anemia, vitamin B12 and oral antibiotics can be used first. If the drugs are ineffective or there are complications such as diverticulitis perforation, hemorrhage, obstruction, etc., surgical treatment is required, and the diverticula are removed. If only the inverted diverticulum is treated, it can lead to intussusception in the future, and this method is now rarely used. For a single small diverticulum, only diverticulectomy may be performed, but during the operation, it is often necessary to remove the diverticulum along with the local small intestine. The diverticula seen during the operation are often more than those found by X-ray contrast, and if it is not possible to widely resect the multiple diverticula scattered throughout the small intestine, only the intestinal segment containing the large diverticula can be resected, and the small diverticula are not treated. If 50% of the small intestine is resected, and the distal ileum and ileocecal valve are preserved, malnutrition will not occur.