Blood in the stool can come from many sources. The causes range from not harmful to very serious conditions. A common way to divide causes of bleeding is based on the source of bleeding. The GI tract can be divided into upper and lower, with some causes of bleeding affecting the entire tract (upper and lower). Blood in the stool often appears different depending on its source. These differences can help when diagnosing these conditions. The rate of bleeding can also make blood in the stool look different from typical cases.
The development of blood in a person's stool results from a variety of conditions, which can be divided into major categories of disease. These broad categories include cancerous processes or abnormal structure of bowel wall, inflammatory disease, colitis caused by infection or medications and vascular compromise.
The gut wall is important for the movement of waste products through the GI tract. Repetitive attempts to have a bowel movement can lead to tearing around the exit of the rectum (anal fissure)
This list of diagnoses include diseases in which the wall of the bowel is compromised by disease.
Diseases causing inflammation in the GI tract can lead to blood in the stool. Inflammation can occur anywhere along the GI tract in Crohn's disease, or in the colon if a person has ulcerative colitis.
The tests that are considered to evaluate of the passage of blood in the stool are based on the characteristics of bleeding (color, quantity) and whether or not the person passing blood has a low blood pressure with elevated heart rate, as opposed to normal vital signs. The following tests are combined to determine the causes of the source of bleeding.
Melena is defined as dark, tarry stools, often black in color due to partial digestion of the red blood cells.
Hematochezia is defined as bright red blood seen in the toilet either inside of, or surrounding the stool.
Hematochezia is typically presumed to come from the lower portion of the GI tract, and the initial steps of diagnosis include a digital rectal exam with fecal occult blood test, which if positive, will lead to a colonoscopy. If the person has a large amount of blood in their stool, an Esophagogastroduodenoscopy test may be necessary. If no source of bleeding is found on these examinations, a capsule endoscopy may be performed, in order to more closely examine the small bowel, which cannot be seen with the other types of studies. With melena, a digital rectal exam with fecal occult blood test is often also performed, however the suspicion for a source from the upper GI tract is higher, leading first to the use of esophagogastroduodenoscopy with the other tests being required if no source is identified. The anoscopy is another type of examination, which can be used along with a colonoscopy, which exams the rectum and distal portion of the descending colon.
A texture described as tarry stool is generally associated with dark black stool seen in partially digested blood. This is generally associated with melena.
A person's age is an important consideration when assessing the cause of the bleeding.
Treatment of bloody stool depends largely on the cause of the bleeding. Bleeding is commonly associated with symptoms of fatigue, dizziness, headaches, or even shortness of breath, and these associated symptoms also require treatment. These symptoms are the result of blood loss, and occur due to a lack of red blood cells circulating in the vascular system, resulting in less oxygen reaching the tissues and organs. Blood in stool can be associated with serious complications as a result of blood volume loss (hemorrhage) or a slow leak of the blood leading to low levels of hemoglobin in the circulating blood (anemia).
Diagnostic measures can be used as interventions to help stop bleeding in some cases. Bleeding that occurs due to a neoplasm (cancer growth) can be treated using colonoscopy and clipping, surgical intervention, or other measures, depending on the form and stage of cancer. Similarly, stomach cancer is treated depending on the staging, although typically requires surgical and medical therapy.
Structural compromise leading to blood in stool is caused by a variety of conditions, and therefore requires different treatment for each condition. Peptic ulcer disease alone can be divided into multiple causes, but is generally initially controlled primarily with a proton pump inhibitor, with the addition of an H2 blocker, or in serious cases, requiring surgical intervention. Diverticulitis and diverticulosis require antibiotic treatment, and may require surgical intervention.
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