你的大便看到血液可以理解的设定担心你的头脑赛车。您可能会注意到在卫生纸或红色或栗色条纹的少量血液in your stool。

新鲜血液大量通常会导致勃艮第的颜色便或将染上一点儿颜色花露水粉红色或红色。新鲜便血通常表示从下胃肠（GI）道的出血，包括结肠，直肠和肛门。

很少，新鲜的血液的信号重来自上GI道的出血通道 - 食管，胃和上部小肠。更常见的是，上GI出血导致黑色粪便由于血液的击穿，因为它通过消化系统。

有在大便的新鲜血液许多可能的原因（医学上称为hematochezia或直肠出血)由lower GI bleeding, ranging in severity from hemorrhoids to inflammatory bowel disease to cancer. If you notice blood in your stool, contact your doctor right away to determine the next steps.

1. Diverticulosis

Diverticuli are small pouches that project outward from the walls of the intestines. They most commonly develop toward the end of the large intestine, or colon.

The presence of multiple diverticuli in the colon,known as diverticulosis, most frequently affects older adults. Diverticulosis usually causes no symptoms. Painless bleeding, however, occurs in approximately 10 to 15 percent of people with the condition, according to the默克诊疗手册16。

Diverticulosis is the leading cause of lower GI bleeding requiring hospitalization, as noted in a July 2013Current Gastroenterology Reportsreview article27。Mild abdominal cramps often precede the bleeding, followed by an urgent need to empty the bowels.

Most bleeding from diverticulosis stops spontaneously, but careful monitoring in the hospital is typically necessary.People with severe or persistent bleedingoften require intravenous fluids, a blood transfusion and/or other treatments.

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2. Hemorrhoids

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Hemorrhoidsare enlarged blood vessels in the lower rectum or anus. A March 2016 review article in the journalClinics in Colon and Rectal Surgeryreports that this common condition most frequently affects people ages 45 to 65, but can develop in adults of all ages3。

Hemorrhoids are categorized by their severity and whether they occur internally, externally or both. Hemorrhoids can cause lower GI bleeding and usually arises from internal rather than external hemorrhoids. The amount of bleeding due to hemorrhoids varies from a streak on the toilet tissue to blood dripping into the commode after passing stool.

Minimal hemorrhoidal bleeding is typically treated with lifestyle changes, includingincreased dietary fiber and fluid intake。Significant or recurring bleeding due to internal hemorrhoids is usually treated with an ablation procedure, which destroys the hemorrhoidal tissue responsible for the bleeding.

3. Colonic Ischemia

Colonic ischemia（CI）是指通过血流量减少触发结肠组织损伤和相关联的缺氧。这种情况通常是暂时的，并且损害通常被限制到结肠衬的一隔离段。CI通常会导致便血，主要的通道affects people age 50 or older。

A number of medical conditions increase the risk for CI, including diabetes, atherosclerosis, heart failure and chronic obstructive pulmonary disease.

Symptoms of CI vary, but many people experience sudden lower abdominal cramps accompanied by a strong urge to move the bowels. Bloody diarrhea or maroon or bright-red blood in stool typically follows within 24 hours of the initial symptoms.

Although colonic ischemia ranges in severity, most people do well with early diagnosis and medical treatment in the hospital. Immediate surgery is necessary if a segment of the bowel dies, a medical emergency known as gangrenous colitis.

4. Colonic Angiodysplasia

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Angiodysplasia is a 10-dollar word that generically refers to a blood vessel abnormality.结肠血管发育不良describes a degenerative process in which the walls of previously healthy blood vessels in the colon weaken and thin over time. People with this condition usually have several abnormal blood vessels in their colon.

大多数人结肠血管发育不良体验无出血或其他症状。然而，这些薄壁的容器有时渗出并导致新鲜便血。结肠血管发育不良是下胃肠道出血的第二最常见的原因and fresh blood in the stool among seniors (behind diverticulosis)5。

Bleeding from colonic angiodysplasia usually causes no pain or other symptoms, but it ranges from mild to severe and tends to recur. Treatment for bleeding from colonic angiodysplasia that doesn’t stop on its own usually involvesdestruction of the bleeding vessels。Medication and surgery may be recommended for some people.

5.炎症性肠病

Inflammatory bowel disease(IBD) refers toCrohn diseaseandulcerative colitis, conditions characterized by chronic GI tract inflammation. With Crohn disease, inflammation can develop anywhere along the GI tract. Inflammation is limited to the colon and rectum in people with ulcerative colitis.

血便，通常在腹泻的形式，发生更常见溃疡性结肠炎，而且还与涉及结肠或直肠克罗恩病发生。Pus and mucus might also be present in the stool.

IBD的其他可能的症状包括腹痛，发热，体重减轻和执着，迫切需要移动的肠子。Most people with IBD experience cyclical flare-ups interspersed with periods of low disease activity.

IBD可发生于任何年龄，但它是最常见诊断的人比30的药物，以减轻炎症和疾病相关的症状依旧治疗克罗恩病和溃疡性结肠炎的中流砥柱年轻。

Specific treatment recommendations depend on disease severity. Blood transfusions may be needed during periods of heavy bleeding. Surgery is sometimes recommended for people with severe disease or complications that cannot be managed with medical therapy.

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6.Colorectal Polyps and Cancer

Colorectal polypsare growths that arise from the lining of the colon or rectum. Most aren’t cancerous, but these growths are important because some can become cancerous over time.

In fact, most cases ofcolorectal cancer arise from a polyp6。大肠息肉和癌症大小不一，大部分原因没有明显的体征或症状，直到他们成为大。这就是为什么大肠癌筛查是非常重要的。

大息肉和大肠癌可以流血，并导致新的便血。Small amounts of blood are often detectable only with laboratory testing. Visible blood, however, is also possible. Bleeding from colorectal polyps or cancer typically causes no pain. Other symptoms are uncommon, although large growths sometimes cause diarrhea or constipation.

Colorectal polyps are typically removed during a colonoscopy procedure. Depending on the size and microscopic appearance of the removed polyps, doctors recommend repeat colonoscopy screening at varied time intervals. If colorectal cancer is detected, treatment may involve surgery, chemotherapy, radiotherapy or a combination of these treatments.

Other Causes of Blood in Stool

Many other conditions can lead to fresh blood in the stool, although they are less likely than the causes already discussed above.

1. Anal Fissures

肛裂是small tears of the anus, the opening through which stool passes from the body. They cause pain and a small amount of bleeding when passing stool. Most heal on their own, but longstanding or deep fissures can lead to anal ulcers, which also commonly bleed with bowel movements.

2.感染性直肠炎

Infectious proctitis refers to aninfection of the rectum, which can cause fresh blood in the stool. The condition is usually a sexually transmitted infection, most commonly caused by the bacteria responsible for gonorrhea and/or chlamydia. Other symptoms include rectal pain and anal discharge.

3. Infectious Colitis

Infectious colitis is a食物中毒的形式这导致炎症结肠。典型的症状包括水样腹泻，这可能是血淋淋的，有腹部绞痛，甚至发烧一起。Common causes includecertain strains of S_almonella_,Shigella,Campylobacterand大肠杆菌bacteria.

4. Meckel憩室

Meckel憩室is a pouchnear the junction of the small and large intestines. It’s a remnant of the umbilical cord that is present from the time of birth in approximately 2 to 3 percent of people.

大多数人有这种情况从来没有遇到的症状，但出血发生在那些受影响的一小部分血便。由于麦克尔憩室症状的儿童比成人更共同发展。

5.直肠静脉曲张

直肠静脉曲张扩大，脆弱blood vessels in the rectum。They most often occur in people with cirrhosis due to a backup of blood caused by impaired blood flow through the liver. These fragile blood vessels can rupture and cause massive, life-threatening bleeding. Emergency treatment is needed to control bleeding from rectal varices.

6.沉重的上消化道出血

重从食道，胃或小肠出血有时会引起便血。Brisk upper GI bleeding使血液通过消化系统tem quickly, often appearing as bloody or maroon-color diarrhea. Possible causes include peptic ulcer disease, severe inflammation of the stomach and ruptured veins in the esophagus.

When to Call Your Doctor

• Dizziness, lightheadedness or fainting
  
• Rapid heart rate or breathing
  
• Paleness
  
• 冷，皮肤湿冷
  
• Low blood pressure
  
• Agitation, confusion or drowsiness
  :

What Do YOU Think?

Have you ever seen blood in your stool? What did you do? Did you consult your doctor? Did you discover the cause of the blood in your stool? What treatment did your doctor prescribe? Share your thoughts and questions in the comments below.