Rectal BLEEDING (III)

 

The rectum is the last portion of the large bowel that ends just before the anus. Bleeding from this area can be a mild or life-threatening matter. Thus, the presence of bleeding must be carefully checked to avoid unpleasant consequences.

Colour of blood stool

Blood in the stool can be bright red, maroon or black. Causes of blood in stool range from harmless, annoying conditions of the gastrointestinal tract such as hemorrhoids and polyps to serious conditions such as cancer.

The color of the blood during rectal bleeding often depends on the location of the bleeding in the gastrointestinal tract.

+ Generally, the closer the bleeding site is to the anus, the blood tends to be a brighter red. Thus, bleeding from the anus, rectum and the sigmoid colon are usually bright red;

+ Bleeding from the transverse colon and the right colon (transverse and right colon are several feet away from the anus) tend to be dark red or maroon colored;

+ Worst is bleeding that is black, sticky and foul smelling known as melena. It usually signifies bleeding is from the upper gastrointestinal tract (like bleeding from ulcers in the stomach or the duodenum or from the small intestine) as blood usually remains up there longer, allowing more time for bacteria to break it down into chemicals, blackish in color.

In rare instances, massive bleeding from the right colon, small intestine, or ulcers of the stomach or duodenal can cause rapid transit of the blood through the gastrointestinal tract, resulting in bright red rectal bleeding. Possibility is someone who has swallowed a foreign body that causes injury to the stomach lining, bleeding stomach ulcers, or cuts/ruptures of vessels in the lining of the esophagus which induces continual or forceful vomiting.

For anemic patients with lost of much iron, bleeding from the gastrointestinal tract can be so slow as to cause either rectal bleeding or melena. In these patients bleeding is occult not visible to the naked eyes and can only be verified by testing the stool for blood in the laboratory. The causes and symptoms are quite similiar as rectal bleeding.

Causes of Rectal Bleeding

+ Rectal Fissure

Mild rectal bleeding of bright red blood occurs due to a tear in the lining of the rectum caused by the passage of hard stools. The exposed nerves and vessels cause moderate-to-severe pain especially during bowel movements.

+ Colon polyps/tumor/cancer

For polyps and tumors, rectal bleeding is less frequent. If it does occur, usually slow, chronic and minimal.

• Polyps: Lumps of tissue or polyps bulge out from the lining of the colon. Bleeding occurs when large polyps develop. Usually harmless, some types can be pre-cancerous.

• Tumors: Both benign and malignant forms are frequently found in the colon and rectum. Most sufferers are above 50 years but can also affect younger people too.
• Colorectal cancer: A growth left untreated on the lining can grow into the muscle layers underneath, and then through the bowel wall.

+ Hemorrhoids

Hemorrhoids are swollen rectal veins in the anal (external) and rectal (internal) area that can cause burning, painful discomfort and bleeding as a result of hard stools and straining with bowel movements. Treatment focuses on relieving these symptoms with the use of stool bulking agents and softeners.

+ Diverticulitis (Diverticulosis)

Diverticula are protusions in the weak points of the intestinal wall of a constipated patient where high pressure is constantly applied to force small portions of hard, dry stool through the intestine due to weak bowel muscles, insufficient fibre and water intake. There is no arising problem unless tiny cuts in the pouches become infected or inflamed, causing fever, chills, nausea and pain, which may require surgical removal.

+ Bacterial infection

Bacterial dysentery is commonly the source of infectious, bloody diarrhea caused by bacteria like Salmonella, Shigella, Escherichia coli, and Clostridium difficile. The symptoms include abdominal pain, fever and bloody diarrhea, commonly treated with antibiotics.

+ Angiodysplasia

This is a vascular problem that involves enlarged veins and capillaries in the wall of the right colon found mainly in elderly people. These areas become fragile and the bleeding is usually painless, slow, chronic and not obvious until massive bleeding occurs. Sufferers complain of weakness, fatigue and shortness of breath.

+ Peptic & Gastric Ulcer

A peptic ulcer usually arises in the duodenum or first part of the small intestine, just after the stomach. This area is rather acidic and thus gives extreme pain. As many as 70-90% of ulcers are associated with Helicobacter pylori, a spiral-shaped bacterium that lives in the acidic environment of the stomach. Ulcers can also be caused or worsened by drugs such as aspirin, Plavix, ibuprofen and other NSAIDs (non-steroid anti-inflammatory drugs).

Though only 4% of duodenal ulcers are malignant, medical attention is needed if there is vomiting of blood due to bleeding directly from a gastric ulcer, or from damage to the esophagus.

 

Critical conditions

Immediate medical attention is required when rectal bleeding is present with one or more of the following symptoms:

• Fever

• Stomach pain or swelling

• Nausea or vomiting

• Bleeding continues or worsens

• Recent weight loss

• Altered bowel habits

• Severe or prolonged diarrhea

• Pencil-sized stools, involuntary seepage of stools, or difficulty in passing motion

Emergency conditions

If any of these signs and symptoms are present -

• Black or maroon stools

• Large volume blood loss

• Rectal pain

• Dizziness, weakness, or fainting spells

• Rapid or irregular heartbeat

• Difficulty breathing

Other comments

The majority of people with significant rectal bleeding are elderly who have many other medical problems as well. As a result, they tend to suffer increased rates of illness and death.


Fortunately, In recent years, death from rectal bleeding has significantly decreased largely due to more efficient emergency departments, recent advances in procedures and evolving surgical management.

Though about 80% of acute rectal bleeding episodes will resolve without treatment, the chance of recurrence is 25%. This underscores the need for making a definitive diagnosis and in discovering the source of the bleeding so that the corrective actions can be taken at an early stage.

FULL REFERENCE: Fauci, Anthony S., et al. Harrison’s Principles of Internal Medicine. 17th ed. United States: McGraw-Hill Professional, 2008.