Common Causes of Hematochezia

Hematochezia is a medical term that refers to the passage of blood from the rectum. The blood of hematochezia is usually maroon or dark red. This blood has not been altered by enzymes and acids of the stomach. This type of gastrointestinal (GI) bleeding most commonly originates in the ileum, ascending colon, transverse colon, descending colon, and/or sigmoid colon.

Bleeding from the upper GI tract (stomach, esophagus and small intestine) is the cause of hematochezia in only a minority of cases. These infrequent cases, in which upper gastrointestinal bleeding presents as hematochezia, usually involve large amounts of brisk bleeding.

Blood originating in the upper gastrointestinal tract more often presents as hematemesis (vomiting of blood) and/or melena (dark blood from the rectum). Patients with melena often describe dark, tarry stools with a very distinct smell. Melena occurs when blood from the upper GI tract has been broken down by enzymes and mixed with the feces.

Bright red blood per rectum is a commonly used phrase in medicine, often abbvreviated BRBPR. This term implies a condition similar to that which hematochezia describes. However, the bright red color of BRBPR implies very fresh blood, often originating close to or within the rectum itself.

There are many causes of hematochezia. Internal hemorrhoids is the most frequent cause of lower gastrointestinal bleeding. Hemorrhoidal bleeding is generally minor, only coating stool with blood or spotting toilet paper and is frequently fits more of a bright red blood per rectum picture, rather than the maroon stools of hematochezia.

Colorectal cancer is responsible for approximately 10 percent of cases of rectal bleeding in patients over age 50. The most common presentation of colorectal cancer is hematochezia or melena, change in bowel habits, and/or abdominal pain.

Hematochezia is more often a sign of rectal cancer rather than colon cancer, while a change in bowel habits is a more common presenting symptom for left-sided colon cancers (which tend to be encircling, constricting lesions).

Ulcerative and inflammatory diseases of the colon are common causes of hematochezia. The inflammatory bowel disorders Ulcerative colitis and Crohn's disease are associated with many other symptoms such as diarrhea, abdominal pain and extraintestinal skin, joint and eye symptoms.

Diverticular bleeding is the most common cause of brisk hematochezia, accounting for over 30 percent of cases of massive rectal bleeding. Many patients with diverticular bleeding, which occurs in 15 percent of patients with diverticulosis, are elderly. Constipation requiring straining during bowel movements can contribute to blood vessels breaking within the diverticula and thus leads to hematochezia.

Angiodysplasia, a small malformation of blood vessels in the gut, is another possible cause of hematochezia. This condition has a very similar presentation to diverticular bleeding. Angiodysplasia often presents as painless hematochezia that is episodic and self-limiting in nature. It is also the most common source of hematochezia in patients over age 65.

Hematochezia can represent a minor problem such as hemorrhoids or a more serious underlying disease of the digestive tract. Any individual who experiences blood mixed in their stools, maroon stools, or dark, tarry stools should see a physician right away.