What Causes GI Bleeding?

Causes of GI bleeding can be divided into two categories: upper or lower, depending on the location in the GI tract.

Common causes of upper GI bleeding include:

• Peptic ulcers
• Gastritis (bleeding in the stomach)
• Esophageal varices (abnormal, enlarged veins in the esophagus) secondary to portal hypertension
• Cancer
• Inflammation of the GI lining from ingested corrosive materials (suicide attempt)
• Mallory-Weiss tears (tears in the lining of the esophagus) due to a severe vomiting episode

Common causes of lower GI bleeding include:

• Diverticulitis
• GI cancer
• Inflammatory bowel disease (Crohn’s disease, ulcerative colitis)
• Infectious diarrhea
• Angiodysplasia (swollen, fragile blood vessels in the colon)
• Colon polyps (small clumps of cells that form on the lining of the colon leading to GI bleeding)
• Hemorrhoids
• Anal fissures (small tears in the lining of the anus)
• Proctitis (inflammation of the lining of the rectum)
• Tumors (Benign or cancerous tumors of the esophagus, stomach, colon or rectum can weaken the lining of the digestive tract and cause bleeding.)

Causes of minor GI bleeding include:

• Hemorrhoids
• Anal fissures or tears

Causes of more severe GI bleeding include:

• Ulcers
• Cancer (anywhere along the GI tract)
• Polyps
• Inflammation in the GI tract such as esophagitis, gastritis or colitis
• Variceal bleeding, typically caused by liver damage
• Inflammatory bowel disease (Crohn’s disease, ulcerative colitis)
• Angiodysplasia
• Diverticulosis
• Meckel’s diverticulum (a bulge in the lower part of the small intestine)
• Mallory-Weiss tears
• Trauma

Other factors that can trigger conditions causing a gastrointestinal (GI) bleed include:

• Use of nonsteroidal anti-inflammatory drugs (NSAIDs) and other medicines that cause gastritis
• Infections such as travelers’ diarrhea, amebiasis, or tuberculosis
• Severe injuries to the GI tract or chest or abdominal trauma
• Constipation and straining during bowel movements
• Alcohol-induced liver failure or gastritis
• Burns
• Liver cirrhosis
• Forceful coughing or laughing
• Lifting or straining
• Childbirth
• Cigarette smoking
• Helicobacter pylori infection
• Chronic vomiting
• GI surgery

• In upper GI bleeding, stomach acid or bacterial/viral toxin can irritate the esophageal lining to the point of bleeding.
• Severe retching may cause tears in the lining of the upper GI tract causing blood in vomitus.
• Portal hypertension due to liver failure or splenic vein thrombosis may cause bleeding in the esophageal vascular system or rectal blood vessels.
• In lower GI bleeding, straining and passing hard or wide stools can injure the rectal lining and cause bleeding.
• Polyps are finger-like overgrowths of the lining of the intestine that may bleed when the stools rub against them.
• Diverticulosis is a condition where pouches develop in the lining of the intestine and bleed due to trauma.
• Any type of cancerous mass anywhere in the GI system may rupture, causing bleeding.