1: Definition:
currently includes bleeding caused by lesions in the middle gastrointestinal tract (duodenal papilla to ileocecal valve ) and lower gastrointestinal tract (ileocecal valve to rectum), more than 90% of which come from the large intestine , and are rare in the small intestine but Diagnosis is difficult.
2: Cause: (Cause classification: ① Organ primary disease: Cause and nature classification: Infection/tumor/immune allergy/endocrine metabolism/genetic inheritance/physical chemistry///// Organ structural abnormality (organ wall/ Blood vessels); ② Systemic diseases or other organ diseases involve the onset . )
1: Primary intestinal diseases:
① Inflammatory lesions: non-specific enteritis ( ulcerative colitis, Crohn's disease , non-specific isolated colon Collapse, etc.) ; Infectious enteritis (intestinal tuberculosis, enteric typhoid, bacillary dysentery and other bacterial enteritis, etc. Parasitic infections include Amoeba , Schistosoma , Giardia lamblia Enteritis, bleeding caused by a large number of hookworms or whipworm infection have also been reported); Neurofibrosarcoma, etc.); benign tumors (leiomyoma, lipoma, hemangioma, neurofibroma, cystic lymphangioma, myxoma, etc.); Intestinal stromal tumors can also bleed. Polyps are more common in the large intestine (mainly adenomatous polyps, but also juvenile polyposis and Peutz-Jeghers syndrome).
③Chemical and physical damage: Radiation enteritis, NSAIDs-related intestinal mucosal damage, etc.
④ Structural lesions of the intestinal wall: diverticula (bleeding from Meckel's diverticulum of the small intestine is not uncommon), intussusception, intestinal duplication malformation, intestinal pneumocystis (more common among plateau residents), hemorrhoids and anal fissures.
⑤ Intestinal wall vascular lesions : ischemic intestinal necrosis (arteriosclerosis and oral contraceptives); telangiectasia ; varicose veins ( portal hypertension rare site of variceal bleeding can be located in the terminal rectum, colon, ileum ); vascular malformation (colonic vasodilation is common in the elderly and is acquired, often located in the cecum and right colon).
2: systemic diseases involving the intestines
leukemias and hemorrhagic diseases ; rheumatic diseases such as systemic lupus erythematosus , polyarteritis nodosa , Behcet's disease, etc.; malignant histiocytic diseases ; Uremic enteritis; malignant tumor infiltration of adjacent organs in the abdominal cavity or abscess rupture that invades the intestinal cavity can cause bleeding.
According to statistics: the most common causes are colorectal cancer and large intestinal polyps, followed by intestinal inflammatory diseases, including enteric typhoid fever, intestinal tuberculosis, ulcerative colitis, Crohn's disease and necrotizing enteritis Sometimes it can cause massive bleeding.
Three: Diagnosis:
1: Basic diagnosis:
without vomiting blood only bloody stool or dark red stool can be established . ( Upper gastrointestinal bleeding may also appear as dark red stool if the amount is large; bleeding in the high small intestine and right colon may appear tarry due to long residence time in the intestinal cavity. At this time, upper gastroscopy should be used to eliminate bleeding).
2: Determine the location and cause of the disease Diagnosis: According to characteristic symptoms/signs/auxiliary examinations gradually narrow the scope of the lesion location and cause of the disease:
① Medical history and symptoms: a: Age: Elderly patients are often diagnosed with colorectal cancer, colonic vasodilation, and ischemia. Enteritis is common. Meckel's diverticulum, juvenile polyps, infectious enteritis, and hematological diseases are more common in children. b: Medical history: Tuberculosis, Schistosomiasis , and a history of abdominal radiotherapy can cause intestinal diseases.Arteriosclerosis and oral contraceptives can cause ischemic enteritis. c: Stool color and characteristics: Blood attached to the surface of the stool is mostly anorectosigmoid disease, and blood dripping or spurting after defecation is often hemorrhoids or anal fissure. Dark red blood is more common in colon bleeding/tarry stool that stays for a long time. Tarry stools are more common in small intestinal bleeding and right colon bleeding. Mucus, pus and bloody stools are more common in bacillary dysentery, ulcerative colitis, and colorectal sigmoid cancer. d: Accompanying symptoms: Accompanying fever is seen in inflammatory lesions. Systemic diseases such as leukemia, lymphoma, malignant histiocytosis and connective tissue disease are also often accompanied by fever. Crohn's disease, intestinal nuclei, intussusception, and colorectal cancer are common in incomplete intestinal obstruction .
② Physical examination Special attention should be paid to: (1) Skin and mucosa examination for rash, purpura , telangiectasia; whether superficial lymph nodes are swollen. (2) During abdominal examination, pay attention to tenderness and abdominal mass. (3) Routinely inspect the anus and rectum, pay attention to hemorrhoids, anal fissures, and fistulas; digital rectal examination for masses.
③Laboratory examination: Those suspected of typhoid fever should undergo blood culture and Feida test. Those suspected of tuberculosis should undergo a tuberculin test. Those with suspected systemic diseases should undergo corresponding examinations
④ Imaging examination: Most bleeding locations and causes need to be confirmed by imaging examinations, except for some acute infectious enteritis such as dysentery , typhoid fever, necrotizing enteritis, etc. a: Colonoscopy : The preferred method for diagnosing lesions in the large intestine and terminal ileum. b: Enteroscopy: balloon (single balloon and double balloon)-assisted enteroscopy can theoretically examine the entire small intestine and stop bleeding under the microscope, and is the most effective method for diagnosing small intestinal bleeding. c: Capsule endoscopy: is a non-invasive examination that can locate active mucosal bleeding, but its shortcoming is that tissue biopsy and treatment cannot be performed. d: CT small bowel imaging or MR small bowel imaging (CTE or MRE) (also known as CT enterography and MRI enterography:)
Small bowel imaging CTE
The preferred examination method for those who are not suitable for enteroscopy or capsule endoscopy (suspected small bowel stenosis). It can indicate the location of small intestinal lesions, especially multi-site lesions or extraintestinal lesions. It is of great value. Compared with intestinal barium meal angiography, CTE is highly sensitive to small intestinal inflammation. Compared with capsule endoscopy, it can detect extraluminal complications and has replaced small intestinal barium meal angiography. First line small bowel disease imaging means. The role of CTE (CT small bowel imaging) in the diagnosis and treatment of inflammatory bowel disease: The diagnosis of inflammatory bowel disease often requires a combination of colonoscopy and/or enteroscopy. CTE steps Orally take a large amount (at least 1400ml) of neutral contrast contrast agent to dilate the small intestine (or inject contrast agent through the small intestinal catheter) to contrast the intestinal wall with the intestinal lumen. Inject iodine contrast agent intravenously, and undergo multi-slice spiral CT enhanced scanning. , a technology that obtains thin-section scanning images of the abdomen and pelvis, and then post-processes the images to display the intestinal cavity, intestinal wall, mesentery , intra-abdominal blood vessels, retroperitoneum and intra-abdominal parenchymal organs in multiple directions. The main manifestations of CTE in Crohn's disease are: Increased or asymmetric thickness of the intestinal wall, obvious intestinal wall enhancement, intestinal wall stratification, fibrofatty hyperplasia, increased mesenteric fat density, and comb-like sign. The sensitivity to active inflammation is significantly higher than that of small intestinal barium meal because Crohn's disease is a transmural lesion rather than just limited to the intestinal mucosa, and barium meal cannot fully reflect the situation. CTE imaging findings are highly consistent with Crohn's disease activity and other endoscopic findings, as well as serum CRP concentration. Studies have shown that CTE is more sensitive than ileoscopy and small bowel barium meal angiography, and has higher specificity than capsule endoscopy. CTE Disadvantages: 1, insufficient intestinal tone or inability to tolerate intravenous contrast agents (renal dysfunction, severe contrast agent allergies) limit its application, and other examinations must be used instead. 2. CTE causes more radiation exposure that is 3 to 4 times that of small intestinal barium meal, but this is being solved with the advancement of CT technology; and with the improvement of magnetic resonance resolution, MRE (magnetic resonance enterography) is being used clinically. Advantages : It can simultaneously observe the intestinal lumen, intestinal wall, extraintestinal lymph nodes, mesentery, mesenteric blood vessel relationships and adjacent structures, accurately determine the number of small intestinal tumors monitor early small intestinal tumors, and accurately display mucosal lesions, intestinal wall thickening and For extraintestinal complications, the depth of infiltration of small intestinal tumors can be determined, and metastasis can be detected in time through whole-abdominal scan. e: X-ray barium angiography: X-ray barium enema is used to diagnose lesions of the large intestine, ileocecal region and appendix. Double air barium angiography is generally recommended. Because this examination can easily miss the diagnosis of flatter lesions and sometimes cannot determine the nature of the lesions, colonoscopy is still required for patients with negative lower gastrointestinal bleeding. The sensitivity is low and the missed diagnosis rate is high. Double small intestinal air barium angiography can improve the diagnostic rate, but small intestinal intubation is required. Traditional X-ray barium enterography has become a supplementary examination method for small intestinal lesions. f: Selective angiography and radionuclide scan: Angiography : needs to be performed when is actively bleeding, and is suitable for those who cannot undergo endoscopy or those with severe acute massive bleeding. For patients with persistent massive bleeding, selective abdominal arterial angiography should be performed promptly. When the bleeding volume is 0.5ml/min, the bleeding overflow site of the contrast medium can be found and located, and embolization can be treated at the same time. Radionuclide scan : Technetium-labeled autologous red blood cells are injected intravenously for abdominal scanning. When the bleeding rate is 0.1ml/min, the labeled red blood cells overflow at the bleeding site to form a densely stained area, which can be located, and the bleeding can be monitored for up to 24 hours. The examination is less invasive and can be used as preliminary positioning, but there are false positives of and positioning errors, so the clinical value is limited.
⑤Surgical exploration: Various examinations cannot identify the bleeding focus, and if persistent heavy bleeding threatens the patient's life, surgical exploration is required. Some small lesions, especially vascular lesions, are difficult to detect during surgical exploration. Intraoperative endoscopy can be used to help find bleeding lesions.
Four: Treatment:
Lower gastrointestinal bleeding treatment flow chart
Lower gastrointestinal bleeding mainly involves treatment of the cause, and its treatment flow is shown in the figure above.
1: Symptomatic treatment:
① General treatment : Supplementing blood volume is detailed in the previous section "Upper gastrointestinal bleeding".
② Drug hemostatic treatment: ① Thrombin retention enema is sometimes effective for bleeding below the left colon. ② Application of vasoactive drugs Intravenous infusion of vasopressin and somatostatin may have a certain role . If arteriography is performed, 0.1~0.4U/min of vasopressin can be infused through the arteries after the completion of the angiography. The hemostatic effect on bleeding in the right colon and small intestine is better than intravenous administration.
③ Endoscopic hemostasis If bleeding lesions can be found during emergency colonoscopy, endoscopic hemostasis can be tried.
④ Arterial embolization treatment In cases where arterial infusion of vasopressin after arteriography is ineffective, super-selective intubation can be performed and embolic agents can be injected into the bleeding focus. The main disadvantage of this method is that it may cause intestinal infarction. In cases where surgical resection of intestinal segments is planned, it can be used as a temporary hemostasis.
⑤ Emergency surgical treatment If bleeding persists despite conservative medical treatment and is life-threatening, emergency surgery is indicated regardless of whether the bleeding lesion is confirmed or not.
2: Treatment of the cause
Choose drug treatment, endoscopic treatment, and elective surgical treatment according to different causes.
Fengtai District Xiluoyuan Community Health Service Center (Li Xuefeng) July 3, 2022
