In medicine, when referring to human feces, blood in stool looks different depending on how early it enters the digestive tract â€" and thus how much digestive action it has been exposed to â€" and how much there is. The term can refer either to melena, with a black appearance, originating from upper gastrointestinal bleeding; or to hematochezia, with a red color, originating from lower gastrointestinal bleeding. The term "blood in stool" is usually only used to describe visible blood and not fecal occult blood, which is found only after chemical testing.
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
- Crohns disease
- Ulcerative colitis
- Internal hemorrhoids
- Inflammatory enteritis - inflammation of the small intestine, which may be caused by various forms of food poisoning as well as by other conditions:
- E. coli enteritis, the most common cause of travelers' diarrhea
- Campylobacter enteritis
- Shigellosis
- Salmonellosis (salmonella enteritis/samonella enterocolitis)
- Bacterial gastroenteritis
- Dysentery
- Staphylococcus aureus
- Radiation enteritis
- Diverticulosis
- Upper gastrointestinal bleeding
- Peptic ulcer disease
- Esophageal varices
- Gastric cancer
- constipation
See also
- Fecal occult blood