Blood in stool

In medicine, when referring to human feces, blood in stool looks different depending on (1) how early it enters the intestines (and thus how much digestive action it has been exposed to) and on (2) how much there is (a little bit, more than a little, or a lot). This is why bright red blood in the stool has different clinical significance (and a different name) than brown or black blood in the stool. Thus the term can refer either to melena, with more blackish appearance, originating from upper gastrointestinal bleeding, or to hematochezia, with more red color, originating from lower gastrointestinal bleeding. The term "blood in stool" is usually not used to describe fecal occult blood, which refers to blood that is not visible and thus is found only after chemical testing is performed.

In infants, the Apt test can be used to distinguish fetal hemoglobin from maternal blood.

List of causes

Common causes of blood in the stool include:

• Anal fissure
• Colorectal cancer^{[1][2][3][4][5]}
• Crohns disease^[6]
• Ulcerative colitis^[7]
• Internal hemorrhoids^[8][9]
• Inflammatory enteritis - inflammation of the small intestine, which may be caused by various forms of food poisoning as well as by other conditions:^[10]
  • E. coli enteritis, the most common cause of travelers' diarrhea^[11]
  • Campylobacter enteritis^[12]
  • Shigellosis^[13]
  • Salmonellosis (salmonella enteritis/samonella enterocolitis)^[14][15]
  • Bacterial gastroenteritis^[16]
  • Staphylococcus aureus^[10]
  • Radiation enteritis^[17]
• Diverticulosis^[18]
• Upper gastrointestinal bleeding^[19]
• Peptic ulcer disease^[20]
• Esophageal varices^[21]
• Gastric cancer^[22]

See also

• Fecal occult blood

References