Definition: Blood is discharged from the anus, and the color of stool is bright red, dark red or tarry (black stool), which is called blood in the stool. Blood in the stool is just a symptom, not a disease. Blood in the stool is more common in lower gastrointestinal bleeding, especially bleeding from colon and rectal lesions, but it can also be seen in upper gastrointestinal bleeding. The color of blood in the stool depends on the location of the gastrointestinal bleeding, the amount of bleeding and the time the blood stays in the gastrointestinal tract. Hematochezia with bleeding from the skin, mucous membranes or other organs is more common in blood system diseases and other systemic diseases, such as leukemia and diffuse intravascular coagulation.
1. Diseases of the digestive tract itself, such as rupture and bleeding of esophagus/gastric varices, gastric and intestinal ulcers and inflammations, parasitic infections, tumors (including polyps and cancers), hemorrhoids, intussusception, anal fissures, dry stools Hurt etc.
2. Diseases of other systems outside the digestive tract, such as blood diseases, acute infectious diseases, vitamin deficiencies, poisoning or drug toxicity.
3. Children have blood in the stool, mostly caused by intestinal polyps, the blood is bright red, painless, and the blood does not mix with stool; it can also be seen in bacillary dysentery, intussusception, blood system diseases, etc. Adult blood in the stool is mostly caused by hemorrhoids, anal fistulas, anal fissures, intestinal polyps, intestinal cancer, and inflammatory bowel disease.
1. Bloody stool
Most of them are acute bleeding. The blood flows out of the blood vessels in a short time and is discharged in the stool through the anus, or it flows out directly after the stool. The blood flowing out looks similar to traumatic bleeding, bright red or purplish red, dark red in color, and can coagulate into blood clots after a while. Often in the following diseases:
(1) Hemorrhoids External hemorrhoids and mixed hemorrhoids can cause fecal bleeding in each period, usually with fresh blood attached to the stool or blood dripping after the stool. External hemorrhoids generally have no stool bleeding.
(2) Intestinal polyps are painless stool bleeding. Bleeding during defecation, and stop after defecation, the amount varies. Generally, blood does not mix with feces, or polyps are high in position and large in number, and can also mix with feces.
(3) Rectal prolapse After a long period of illness, there may be bleeding during defecation.
(4) Anal fissure Blood in the stool, the bleeding method is that there is blood on the side of the stool surface, which does not mix with the stool, and some patients drip blood after the stool.
2. Pus blood/mucus blood in stool
That is, the excreted stool contains both pus (mucus) fluid and blood. Pus (mucus) and bloody stools are often found in tumors and inflammations in the rectum or colon. The following diseases are common:
(1) Rectal cancer The blood color is fresher or dark red, there may be mucus in the stool, and the blood, mucus, and stool are often mixed.
(2) Colon cancer. Stool bleeding gradually occurs with the prolonged course of the disease, mostly bloody stools containing pus or mucus, with darker blood.
(3) Ulcerative colitis Mucus stools or pus and blood stools, accompanied by pain in the left lower abdomen or lower abdomen.
(4) Intestinal infectious diseases such as bacillary dysentery, amoebic enteropathy, etc.
3. Black stool
Also known as tarry stool, stool is black or brownish-black. It is one of the most common symptoms of upper gastrointestinal bleeding. If the amount of bleeding is small and the bleeding rate is slow, the blood stays in the intestine for a long time, and the excreted stool is black; if the amount of bleeding is large and the residence time in the intestine is short, the discharged blood is dark red; The amount of bleeding is particularly large, and it can be bright red when it is discharged quickly.
4. Occult blood in stool
A small amount (minor amount) of gastrointestinal bleeding will not cause a change in the color of the stool. It is only positive in the stool occult blood test, which is called occult blood stool. All diseases that cause gastrointestinal bleeding can cause occult blood in the stool, common ulcers, inflammations and tumors. The fecal occult blood test can detect small (trace) blood components in the stool. The early fecal occult blood of intestinal polyps (cancer) can be positive, 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, pain in the anus is unbearable, or swollen with hemorrhoids, or accompanied by anal fissure.
(2) Upper gastrointestinal diseases Hematemesis is usually accompanied by melena, and bloody stools can occur when the bleeding is large and fast.
(3) Lower gastrointestinal diseases. According to the original disease of bleeding, the accompanying symptoms are different.