Blood in stool

The upper GI tract is defined as the organs involved in digestion above the ligament of Treitz and comprises the esophagus, stomach, and duodenum.[9] Upper gastrointestinal bleeding is typically characterized by melena (black stool). Bright red blood may be seen with active, rapid bleeding.[11]

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.[5]

• Colorectal cancer[12][13][14][15][16]
• Gastric cancer[17]

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)

• Constipation[18][19][20]

This list of diagnoses include diseases in which the wall of the bowel is compromised by disease.[5]

• Peptic ulcer disease[21][11][22][23]—divided into either duodenal or gastric ulcers, most common causes include:
  • Non steroidal anti-inflammatory drug (NSAID)—the use of these medications results in a structural change in the wall of the gut, namely ulcers, and potential blood in the stool.[24]
  • H. pylori infection—this bacterial infection can erode the wall of the stomach or duodenum, leading to a structural change in the stomach wall and bleeding in the stool.[23][25]
  • Chronic disease[23]
• Diverticulitis[26] and diverticulosis[27] result from an out pouching of the colonic mucosa, or gut wall, leading to a break down of weak gut wall and an increased susceptibility to infection due to the bacteria in the GI tract, thus the potential for vascular compromise, the collection of bacteria in the area of perforation (abscess), the abnormal formation of communication between another part of the hollow GI tract (fistula), or blockage of the bowel (obstruction).[26]
• Meckel's diverticulum is a congenital remnant of the omphalo-mesenteric duct that connected the fetal yolk sac to the intestines which is normal closed off and destroyed during the process of development.[28] If a portion, or all of this duct remains a diverticulum or fistula can result, leading to the potential for a source of bleeding.[28]

Diseases causing inflammation in the GI tract can lead to blood in the stool.[29] Inflammation can occur anywhere along the GI tract in Crohn's disease,[30] or in the colon if a person has ulcerative colitis.[31]

• Crohn's disease[32]
• Ulcerative colitis[33][34][35]

• Enteritis—inflammation of the small intestine, which has many causes including autoimmune conditions (e.g. Crohn's disease), certain drugs (e.g. ibuprofen), radiation therapy, and Coeliac disease.[36]

• Food poisoning—the bacteria that is associated with bloody diarrhea is typically E. coli
• Campylobacter enteritis[37]
• Shigellosis[38]
• Salmonellosis (Salmonella enteritis/Salmonella enterocolitis)[39][40]
• Bacterial gastroenteritis[41]
  • Campylobacter jejuni
  • Clostridium difficile
  • Escherichia coli enteritis—most common cause of travelers' diarrhea[42]
  • Salmonella enterica
  • Shigella dysenteriae[38] see also dysentery
• Staphylococcus aureus[36]

• Radiation enteritis[43]

• Angiodysplasia of the GI tract
• Arteriovenous malformation
• Anal fissure
• Esophageal varices[44]
• Hemorrhoids[45][46]
  • Internal hemorrhoids are covered by a layer of mucosa and epithelium, making them more likely to bleed, but typically do not cause pain.[5]
  • External hemorrhoids are less likely to bleed, they are covered by a different type of epithelium (squamous) but can cause significant pain as a result of thrombosis of the blood vessels within them.[5]
• Polypectomy during a colonoscopy can lead to a small amount of bleeding seen in the stool after the procedure

• Blood in the diet, for example, the traditional diet of the Masai includes much blood drawn from cattle.

Mucus may also be found in stool.[4]

A texture described as tarry stool is generally associated with dark black stool seen in partially digested blood.[6] This is generally associated with melena.

A person's age is an important consideration when assessing the cause of the bleeding.[4]

Anemia is a common complication of blood in the stool, especially when there is a large amount of blood or bleeding occurs over a long period of time.[51] Anemia is also commonly associated with an iron deficiency, due to the importance of iron in the formation of red blood cells (RBCs).[50] When anemia is diagnosed as a result of blood in the stool, vitamins that are important for RBC formation (folate, vitamin B12, and vitamin C) are frequently prescribed in order to ensure that all the materials are available for those cells that are made.[50]

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.[52] Similarly, gastric cancer is treated depending on the staging, although typically requires surgical and medical therapy.[53]

The treatment for motility issues, namely constipation, is typically to improve the movement of waste through the GI tract. This is done by using stool softeners (which work by pulling water into the stool while in the colon), addition of fiber to the diet, and use of osmotic laxatives (which help fluid movement through the colon, improving overall motility). Improving a persons gut motility can reduce the straining during defection and decrease the risk of developing of anal fissures.[54] Anal fissures are associated with pain and blood on the toilet paper, and require time for healing.[55] Treatment includes topical nitrates or calcium channel blockers and surgical interventions for chronic or complex cases.[55] Similar to anal fissures, internal hemorrhoids can cause blood on the tissue when wiping, and be felt at the opening of the anus. Treatment options for hemorrhoids can be dependent on whether an underlying cause exists. An anorectal varices related hemorrhoids caused by cirrhosis, however symptomatic treatment often involves removal.[45]

Colitis can be divided into infectious and drug induced, as can the treatment for these conditions. With infectious colitis, treatment is pathogen dependent, and generally requires the use of antibiotics. With drug-induced colitis, treatment typically involves removal of the offending agent, as is the case in NSAID induced PUD,[24] however, removing radiation from a cancer patient is not always practical within a treatment regimen, so medical treatment is the primary mode of treatment.[56]

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.[11] Diverticulitis and diverticulosis require antibiotic treatment, and may require surgical intervention.[26]

Inflammatory bowel disease is also divided into separate conditions, namely ulcerative colitis and Crohn's disease, which have different medical treatment regimens, and may require surgical intervention in more serious conditions.[30]