Lower Gastrointestinal (GI) Bleeding

Lower GI bleeding happens when there is bleeding in the large intestine (colon). You may see bright red blood, dark maroon blood, black sticky stools, or even blood clots. Sometimes, the bleeding is hidden and only shows up on a blood test with a low blood count or anemia. A stool test can also detect blood. Bleeding can be mild, but in some cases, can be very severe or life-threatening.

Here are some common reasons why lower GI bleeding can happen:

1. Diverticular disease: This is one of the most common causes of lower GI bleeding. Small pouches develop in the large intestine. A blood vessel in the pouch bursts open and bleeds.
2. Angiodysplasias: Abnormal blood vessels in the intestine leak blood. This is the second most common cause of lower GI bleeding.
3. Colon polyps: Growths in the colon can bleed.
4. Tumors: Cancerous or non-cancerous growths in the large intestine cause bleeding.
5. Inflammatory bowel disease (IBD): Crohn’s disease or ulcerative colitis cause inflammation and ulcers or sores in the intestines.
6. Hemorrhoids: Swollen blood vessels near the anus, develop due to constipation, straining, or sitting for a long time on the toilet. You may see red blood on the toilet paper with wiping.
7. Anal fissures: Small tears in the anus that may cause rectal pain and bleeding. You may notice bright red blood in the toilet bowl or with wiping.

Lower GI bleeding may be visible or hidden. When blood is visible, patients notice bright red blood, black sticky stools, or dark blood when using the bathroom. Patients with hidden blood may have anemia or low blood count. You may feel tired. When bleeding is heavy, you may notice dizziness or faint. Other symptoms can include belly pain, difficulty breathing, chest pain, or lightheadedness.

When symptoms are very serious, due to heavy rapid bleeding, you can go into shock. Signs of shock can include low blood pressure, fast heart rate, fainting, or less urine output.

Risk factors for lower GI bleeding can include:

1. Taking NSAID medicines like ibuprofen
2. Not getting regular screenings for colon cancer
3. Use of alcohol and smoking
4. Health problems that increase the risk of angioectasias: heart valve disease, heart disease, cirrhosis, and kidney disease.

Different tests can be done to check for GI bleeding or anemia.

1. Blood testing: check for low blood count (anemia or low hemoglobin).
2. Stool testing: find hidden blood in poop.
3. Colonoscopy: use a long flexible tube with a light and camera to check the colon and to treat or stop bleeding.
4. Imaging tests: A scan to find bleeding in the intestines.
5. Capsule endoscopy: A pill-sized camera that takes pictures in the body. The camera transmits images to a recorder on your belt. After the test, the capsule will pass out into a bowel movement.

Treatment involves several steps:

Give oxygen, fluids, or blood transfusions if needed

Your doctor might recommend stopping blood-thinning medications.

Your doctor will do an upper endoscopy, colonoscopy, or both tests. If you have severe bleeding, you may need angiography, a procedure done under a CT scan done by a doctor called a radiologist.

If severe, surgery may be done to remove a part of the intestine. Surgery can be lifesaving.

Lower GI bleeding can be mild or very dangerous.

Symptoms can be obvious (blood in stool) or hidden (feeling tired from anemia).

Tests like colonoscopy and stool testing can help to find the problem.

Treatment may include simple testing, colonoscopy, angiography, embolization, and rarely surgery.

To prevent bleeding, avoid NSAID medications and get screened for colon cancer.