What Is Hematochezia?

Blood is excreted from the anus, and the color of stool is bright red, dark red, or tar-like (black stool), which are all called stool blood. Blood in the stool is just a symptom, not a disease. Blood in the stool is more common in lower gastrointestinal bleeding, especially in colon and rectal lesions, but it can also be seen in upper gastrointestinal bleeding. The color of blood in the stool depends on where the gastrointestinal bleeding occurs, the amount of bleeding, and how long the blood stays in the gastrointestinal tract. Blood in the stool with bleeding from the skin, mucous membranes, or other organs is more common in hematological diseases and other systemic diseases such as leukemia and disseminated intravascular coagulation.

Basic Information

English name: hematochezia
Visiting department: Gastroenterology
Common locations

Common causes: Caused by gastrointestinal inflammation, ulcers, tumors, hemorrhoids, etc.
Common symptoms: Often manifested in bright red, dark red, or tar-like stools (black stools)
Contagious: no

Causes of blood in the stool

1. Diseases of the digestive tract itself, such as esophageal / fundamental varices bleeding, stomach, intestinal ulcers and inflammation, parasitic infections, tumors (including polyps and cancer), hemorrhoids, intussusception, anal fissure, dry stool Hurt etc.

2. Diseases of systems other than the digestive tract, such as hematological diseases, acute infectious diseases, vitamin deficiency, poisoning or toxic effects of drugs.

3. Children with blood in the stool, mostly caused by intestinal polyps, bright red, painless, blood and stool are not mixed; can also be seen in bacterial dysentery, intussusception, blood system diseases. Blood in the stool of adults is mostly caused by hemorrhoids, anal fistula, anal fissure, intestinal polyps, bowel cancer, and inflammatory bowel disease.

Clinical manifestations of blood in the stool

Bloody stool

Most of them are acute (immediate) bleeding, and the blood flows out of the blood vessel and excreted in the feces in a short time, or directly out of the stool. The bleeding blood looks similar to trauma and bleeding, bright red or purplish red, dark red, and can be coagulated into a blood clot after a long time. Common in the following diseases:

(1) Hemorrhoids External hemorrhoids and mixed hemorrhoids can cause fecal bleeding in various periods, usually with blood in the stool or dripping after the stool. External hemorrhoids generally have no stool bleeding.

(2) Intestinal polyps are painless stool bleeding. Bleeding during defecation, stop after defecation, the amount varies, generally blood is not mixed with feces, or the position and number of polyps are high, and it can also be mixed with feces.

(3) rectal prolapse bleeding may occur during defecation after prolonged illness.

(4) Anal fissure Blood in the stool. The bleeding method is blood on the side of the stool, which is not mixed with the stool. Some patients drip blood after stool.

2. pus / mucus bloody stool

That is, the discharged feces contains both pus (mucus) and blood. Pus (mucus) fluid and blood are often found in tumors and inflammation in the rectum or colon. The following diseases are common:

(1) Rectal cancer The blood color is fresh or dark red, and there may be mucus in the stool, often the blood, mucus and stool are mixed.

(2) Colon cancer With the course of the disease, stool bleeding gradually occurs, mostly bloody stools containing pus or mucus, and the blood color is darker.

(3) Ulcerative colitis Mucus or purulent stool, accompanied by left lower abdominal pain or lower abdominal pain.

(4) Intestinal infectious diseases such as bacterial dysentery, amoebiasis, etc.

3. Black stool

Also called tar stool, the stool is black or brownish black. One of the most common symptoms of upper gastrointestinal bleeding. If there is less bleeding and the bleeding rate is slow and the blood stays in the intestine for a long time, the excreted stool is black; if there is more bleeding and the stay in the intestine is shorter, the discharged blood is dark red; The amount of bleeding is particularly large, and it can appear bright red when discharged quickly.

4. Occult blood in the stool

Small (micro) gastrointestinal bleeding does not cause changes in stool color. It is positive only in the stool occult blood test, which is called occult blood stool. All diseases that cause gastrointestinal bleeding can develop occult bloody stools, and common ulcers, inflammation, and tumors. The fecal occult blood test detects small (micro) amounts of blood in the stool. Intestinal polyps (cancer) can be positive in early fecal occult blood, and regular fecal occult blood testing is an important way for colorectal tumor screening (primary screening).

5. Accompanying symptoms

(1) Anal and perianal lesions Blood in the stool is bright red, anal pain is intolerable, or swelling has hemorrhoids, or accompanied by anal fissure.

(2) Upper gastrointestinal diseases Hematemesis is usually accompanied by black stools, which can occur when the amount of bleeding is high and the speed is fast.

(3) Lower gastrointestinal diseases Depending on the primary onset of bleeding, the accompanying symptoms vary.

Blood test in stool

Laboratory inspection

Including blood, urine, and stool routine; fecal occult blood test can be checked without blood in the naked eye but excluding occult blood. Depending on the primary disease, fecal bacterial culture and parasite detection can be performed; biochemical tests, including liver and kidney function, electrolytes, blood glucose, blood lipids, coagulation function, and tumor markers.

2. Etiological examination

(1) Examination of abdominal ultrasound, CT, MRI, PET-CT, gastroenteroscope, enteroscopy, capsule endoscopy, duodenoscopy, etc. to determine the location and nature of gastrointestinal lesions.

(2) Examination of bone marrow aspiration, except for blood system diseases.

(3) Digital anal diagnosis can help find rectal tumors.

Blood in the stool

1. Pay attention to the characteristics of blood in the stool

(1) Understand the occurrence and development of blood in the stool. Internal hemorrhoids and anal fissures often bleed after stool; chronic non-specific colitis, colon polyps, etc., often show repetitive, intermittent small amounts of blood in the stool; mid-to-late (colorectal) rectal malignancy can be persistent small amounts of blood in the stool.

(2) Distinguish bloody stool characteristics, bleeding pattern, color, and bleeding volume. Such as internal hemorrhoid bleeding is drip-like or spray-like; anal fissure is blood attached to the surface of feces or toilet paper stained with less bleeding; if there is more bleeding, blood is stored in the intestinal cavity, and it can be black when discharged. Gastrointestinal lesions; if it is purplish red, dark red, or blood clots; or the blood is bright red, it is mostly from the lower digestive tract; mixed with mucus and odor, you should think of the possibility of rectal malignancy.

2. Pay attention to the accompanying symptoms of blood in the stool

Such as proctitis, rectal polyps (cancer) and other blood in the stool are often accompanied by anal slump, anxiety and heavy; internal hemorrhoids, polyp blood in the stool without anal pain; anal fissure with anal pain and constipation; chronic colitis often with diarrhea, left lower abdominal pain; hemorrhagic Necrotic colitis, intussusception accompanied by severe abdominal pain and even shock.

Differential diagnosis of blood in stool

It is mainly the identification of the primary disease of blood in the stool, which can be comprehensively judged based on the characteristics of the blood in the stool and the accompanying symptoms, laboratory tests, and imaging studies. In addition, animal blood, drugs, etc. may cause changes in the color of feces. Pay attention to asking and identifying them. ^[1]