What is blood in the stool?

Blood found in your feces (stool), on toilet paper or in the toilet after a bowel movement is often times is harmless, but can signal a serious health condition. Blood in your stool is also sometimes discovered in routine diagnostic tests.

Causes of blood in stool

Less serious causes of blood in the stool include:

  • Food poisoning — harmful bacteria in food can cause bloody stool
  • Hemorrhoids — swollen blood vessels in the rectum or anus
  • Anal fissure — a tear in the lining of the anus

More serious causes of bloody stool include:

  • Chronic inflammatory bowel diseases such as Crohn’s disease or Ulcerative Colitis
  • Colon polyps — These usually harmless, benign growths form on the lining of the colon and can sometimes grow or become cancerous
  • Colon or anal cancer

Risk factors for blood in stool

The risk of finding blood in your stool could increase if you have:

  • A history of stomach bleeding or hemorrhoids
  • Had previous peptic ulcers (open sores in the upper digestive tract)
  • Undiagnosed or diagnosed inflammatory bowel disease
  • A genetic, pre-disposed risk for colorectal or upper GI cancers

Symptoms of blood in stool

Blood present in the feces can appear bright red or black and tarry.

Symptoms that are often present in conjunction with blood in your stool are:

  • Abdominal pain
  • Fatigue
  • Weakness
  • Shortness of breath
  • Pale skin

Diagnosis of blood in stool

A primary care doctor should evaluate you if you find blood in your stool. During a physical exam, your physician will ask a series of questions to try and determine the location of the bleeding. If the blood is bright red or maroon-colored, it could indicate a digestive tract issue such as hemorrhoids. If the blood is black or tarry, it could indicate an ulcer or other upper GI condition.

To confirm the diagnosis, your doctor may order a series of diagnostics including:

  • Hemoccult test — this simple test may detect hidden blood in your stool, but cannot determine where the cause of bleeding.
  • Esophagogastroduodenoscopy (EGD) — during this procedure, your doctor inserts an endoscope into the stomach to determine the source of the bleeding.
  • Nasogastric lavage — helps your doctor see where the bleeding is occurring; during the procedure, the contents of the stomach are removed to determine if the stomach is bleeding, if there is not evidence of bleeding in the stomach, the cause of the bleeding is likely in the lower digestive tract.
  • Colonoscopy — your doctor will insert a scope into the rectum to view the colon and collect tissue samples for biopsy.
  • Enteroscopy — checks the small intestine for any abnormalities; your doctor will insert a tube with a camera attached into your mouth or rectum and threaded to the upper or lower digestive tract, as the camera passes through the digestive track, it takes images to help diagnose the location of the bleeding.
  • Barium x-ray — barium is swallowed or inserted into the rectum, helping display the digestive system on an x-ray.
  • Angiography — can determine the location of the bleeding in the digestive tract; during the procedure, a dye is injected into a vein so the vessels will show up on an x-ray or CT scan.

Treatment for blood in stool

Initial treatment for blood in the stool is to stop the bleeding. Once the bleeding has stopped, your doctor will develop a plan to treat the cause of the bleeding.

Depending on the cause, your doctor may recommend:

  • Medication — antibiotics, anti-inflammatories or medications to suppress stomach acid are commonly prescribed to stop rectal bleeding
  • Surgery — could be required to repair or remove digestive tract abnormalities

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