Blood in the Stool – Blood, Stool, and Possible Causes

A visit to the “colon doctor” is still generally considered rather uncomfortable. However, thanks to modern, gentle endoscopy techniques, fear of colon examinations is unfounded.

Endoscopic colonoscopy guarantees a gentle “walk through the colon” without any incisions. A thin tube is inserted into the colon through the anus. Using a small camera and a light source, the doctor can examine the inside of the colon in detail.

In addition, tiny instruments can be advanced through the tube. This allows the doctor to take tissue samples if necessary or to remove any intestinal polyps directly, eliminating the need for a separate surgery.

Colonic polyps can become malignant over the years and eventually lead to colon cancer. If these growths are detected and removed early enough, the risk of colon cancer is eliminated. Thanks to constantly improving technology, there are ever-better ways to remove tumors from the inside.

The procedure itself is a breeze: You drift off into a dreamlike state thanks to a gentle anesthetic, wake up again after about half an hour—and haven’t noticed a thing.

A colonoscopy allows the colon to be carefully examined from the inside © phonlamaiphoto | AdobeStock

Blood in the stool can indicate the following diseases.

Anal fissure

Wounds in the anal canal that occur spontaneously. It’s not yet clear exactly why the mucous membrane tears, but anal fissures are benign and easy to treat with laser therapy. Nitro ointments can also help.

Angio dysplasia

Congenital vascular malformations that can bleed. An experienced physician can easily stop the bleeding.

However, these malformations—which sometimes cause more severe bleeding—can be eliminated with laser treatment.

Colonic polyps

Thickening of the mucous membrane that may be precursors to colorectal cancer and therefore must not be underestimated under any circumstances. Gastroenterologists must detect and remove these at an early stage.

This is why there is a constant call for men and women to undergo a colonoscopy by age 40 at the latest.

Colonic polyps are a precancerous condition and can be completely removed via colonoscopy © Alex | AdobeStock

Hemorrhoids

Very common blood-filled sacs that can “burst,” causing blood in the stool. They only need to be treated if they lead to persistent bleeding or if the symptoms interfere with the patient’s quality of life (itching or increased moisture). As a rule, it is sufficient to ensure that stools are soft and well-formed.

Only if the hemorrhoids prolapse with every bowel movement or repeatedly cause bleeding are they treated by ligation.

It is important for those affected to maintain extreme hygiene by showering and drying with a soft terry cloth towel. Hemorrhoids, including the large intestine, should be examined by a specialist.

Gastritis

Gastritis is an inflammation of the stomach lining, which is divided into three major groups:

• Autoimmune gastritis (A-gastritis): Autoimmune diseases are disorders of the immune system. They are associated with an increased risk of stomach cancer and gastric lymphomas. Autoimmune gastritis is caused by inflammation of the stomach lining. The condition prevents the body from absorbing the essential vitamin B12. In the past, before B12 could be administered via injection, people often died from this condition.
• Bacterial gastritis (B-gastritis): Most often, or almost always, caused by Helicobacter pylori bacteria. These bacteria can be effectively treated, so this form of gastritis has a good prognosis. B-gastritis is associated with duodenal and gastric ulcers and can also lead to stomach cancer.
• Chemical-toxic gastritis (C-gastritis): This can be caused by smoking, gastroesophageal reflux disease (GERD), or certain medications, among other factors.

There are also other, though rarer, forms of gastritis.

Gastric Bleeding

Fortunately, gastric bleeding is becoming increasingly rare because medications are constantly improving and people are receiving them at an earlier stage. The causes are mostly gastric ulcers, gastric tumors, vascular malformations, and other, rarer causes.

Mallory-Weiss syndrome

Tears in the mucous membrane caused by frequent belching, which in turn is triggered by fatty foods and alcohol. Generally harmless, but definitely requires medical evaluation!

Gastroenteritis

Gastroenteritis generally refers to viral infections that cause short-term symptoms and discomfort. It usually resolves on its own.

Mesenteric infarction

A mesenteric infarction occurs when a section of the small or large intestine is no longer supplied with blood. This can be caused by a blockage in a blood vessel due to atherosclerosis or an embolism.

In such cases, a rapid and comprehensive diagnosis is of the utmost importance. Only then can life-saving treatment be initiated. Otherwise, the patient could die from the accumulation of toxins.

Pseudomembranous colitis

An inflammation caused by the toxin produced by the bacterium *Clostridium difficile*. This inflammation almost always develops following antibiotic therapy. During endoscopy, the condition is recognizable by its appearance as small caps on the mucous membrane.

Ulcerative colitis

A chronic inflammation of the large intestine whose exact causes are not yet fully understood. Ulcerative colitis can be alleviated or slowed down with medication.

Crohn’s disease

Chronic inflammation that can occur in any part of the gastrointestinal tract. However, Crohn’s disease most commonly affects the lower sections of the small intestine and the large intestine. The disease is incurable but can be managed with medication.

Ulcerative colitis and Crohn’s disease are two distinct forms of chronic inflammatory bowel disease © bilderzwerg | AdobeStock

Diverticulitis

An inflammation affecting the section of the intestine where diverticula are located. In Germany, more than 50 percent of people have diverticula. Diverticulitis can range from harmless to life-threatening. It is usually treated with conservative therapy (flushing the intestines to clear diverticula and antibiotics).

Vasculitis

An inflammation of the blood vessels that frequently occurs in immune-mediated diseases. The gastrointestinal tract may also be affected. Vasculitis can be severe, but it is quite rare.

Is blood in the stool always dangerous?

Blood in the stool is always a warning sign, even if it is often caused by harmless conditions such as hemorrhoids. However, blood in the stool can indicate a serious condition such as colorectal cancer or other bowel diseases. Therefore, any bleeding should be evaluated by a doctor.

What are the possible causes of blood in the stool?

Possible causes of blood in the stool include enlarged hemorrhoids, anal fissures, intestinal polyps, or inflammation of the intestine such as ulcerative colitis. Bleeding in the upper digestive tract, such as from a stomach ulcer, can also cause black stools or tarry stools. In rare cases, it may be due to more severe bleeding in the large intestine or a malignant condition.

What does bright red or black blood in the stool mean?

Bright red blood in the stool or fresh blood on toilet paper usually indicates a source of bleeding in the lower part of the gastrointestinal tract, such as the rectum. Black blood or black-colored stool is more likely to indicate bleeding in the upper digestive tract. Dark red blood may indicate significant bleeding in the large intestine. The color and consistency of the stool provide important clues.

How is the cause of blood in the stool diagnosed?

If blood in the stool is suspected, the first step is a physical examination and a detailed medical history. Depending on the findings, a colonoscopy may be performed to identify the source of bleeding in the small or large intestine. Hidden blood in the stool, or occult blood, can also be detected through special tests.

When should you see a doctor if you have blood in your stool?

You should always consult a doctor if you have blood in your stool, especially if you also experience symptoms such as abdominal pain, weight loss, vomiting, or persistent bleeding. Blood in the stool can have many different causes and should never be ignored. Early evaluation helps to detect and treat potential conditions in a timely manner.