- Clinical science
Gastrointestinal (GI) bleeding is a symptom of conditions that damage the wall GI tract. GI bleeding is categorized into upper GI bleeding (UGIB) and lower GI bleeding (LGIB) depending on the source of the bleeding relative to the ligament of Treitz. In the majority of cases, bleeding is localized in the esophagus, stomach, or duodenum (UGIB). LGIB may occur in the rectum, colon, jejunum, and, in rare cases, the ileum. Gastric and duodenal ulcers are the most common causes; angiodysplasia, inflammatory diseases, and carcinomas can also cause GI bleeding. Depending on the source of the bleeding and how long the blood remains in the digestive tract, clinical symptoms may include vomiting blood (hematemesis), tarry black stool (melena), and fresh blood in the stool (hematochezia). Diagnosis includes evaluation of blood loss (e.g., hematocrit) and localization of the source of bleeding (e.g., endoscopy). Hospitalization is essential to monitor for signs of hemodynamic instability and shock caused by anemia and severe blood loss. The source of bleeding can often be located and treated simultaneously during endoscopy with injection therapy (e.g., epinephrine) or ligation.
Upper gastrointestinal bleeding (UGIB)
- ∼ 70–80% of GI hemorrhages 
- The source of the bleeding is proximal to the .
- Lower gastrointestinal bleeding (LGIB)
|Most common etiologies of GI bleeding |
|(UGIB) ||(LGIB) |
|Erosive or inflammatory|| || |
|Tumors|| || |
|Traumatic or iatrogenic|| |
|Other causes|| |
Bleeding from the upper respiratory tract (e.g., nocturnal nosebleeds) can be mistaken for GI bleeding because the blood can be swallowed and vomited or appear in the stool as melena. Careful examination and history taking is the key to differentiating respiratory sources of bleeding from GI ones.
- Anemia due to chronic blood loss
- Acute hemorrhage: signs of circulatory insufficiency or hypovolemic shock
|Melena|| || |
In case of hemodynamic instability, hemodynamic resuscitation should be initiated before further diagnostic workup (see “Treatment” below).
Localization of bleeding
Fecal occult blood test
- May detect small quantities of blood
- Cannot differentiate between UGIB and LGIB 
- A positive result should be followed up with endoscopy/colonoscopy.
- Colonoscopy: a procedure during which a flexible fiber-optic instrument is passed through the anus to visualize the mucosa of the colon
- Upper endoscopy: a procedure during which a flexible fiber-optic instrument is passed through the mouth to visualize the inner layer of the upper GI tract up to the duodenal papilla
- Should be performed within 24 hours of admission 
- Used to identify the source of intestinal bleeding (e.g., bleeding vessel, mucosal inflammation)
- Biopsies can be taken for further diagnosis (e.g., colorectal/gastric carcinoma).
- Therapy can be initiated immediately (e.g., epinephrine injection therapy, clipping of a bleeding vessel).
- Nasogastric tube lavage: a procedure in which a nasogastric tube is passed into the stomach and releases small amounts of liquid, which are removed with other contents of the stomach (e.g., blood in the case of GI bleeding)
Other: If the above diagnostics fail to locate the source of the bleeding, evaluate for small bowel bleeding.
- Radionuclide scan (RBCs labeled with technetium-99)
- Video capsule endoscopy
- Push enteroscopy
- Diagnosis of vascular etiologies (e.g., angiodysplasia)
- Localization of the source of bleeding before surgical resection
- Surgery/exploratory laparotomy should be considered after other therapeutic options have failed. 
Approach according to the patient's hemodynamic status
|Hemodynamically stable patient||Hemodynamically unstable patient|
|Suspected UGIB|| || |
|Suspected LGIB|| || |
The Forrest classification describes the type of lesion seen during endoscopy and helps to evaluate the risk of renewed hemorrhage (without the need for repeated intervention).
|Description||Risk of recurring hemorrhage|
|Ia||Spurting arterial hemorrhage||85–100% of cases|
|Ib||Oozing hemorrhage||25–55% of cases|
|IIa||Lesion with a visible vessel||20–50% of cases|
|IIb||Lesion with an adherent clot||20–40% of cases|
|IIc||Flat lesion covered with hematin||5–10% of cases|
|III||Lesion without active hemorrhage (flat ulcer base)||5% of cases|
Laboratory tests 
- Erosive or inflammatory
- Portal hypertensive gastropathy
- Traumatic or iatrogenic
- Hemosuccus pancreaticus
Lower GI bleed
- Erosive or inflammatory
- Trauma or iatrogenic
- Anorectal trauma
- Lower abdominal trauma
- During surgery or coloscopy
- Anastomotic bleeding
- Aortoenteric fistula
- Anal fissures
- Brisk UGIB
- Infectious colitis/enteritis
- Radiation-induced colitis
- Fecal impaction
- Meckel diverticulum
The differential diagnoses listed here are not exhaustive.
Initial management 
- Consider elective intubation in patients with altered mental or respiratory state and severe ongoing hematemesis.
- Hemodynamic resuscitation
- IV (e.g., esomeprazole)
- Management of anticoagulants
If there is any suspicion of GI bleeding, two large-caliber peripheral venous catheters should be inserted and preparations should be made for a possible blood transfusion.
Interventions to stop bleeding 
- Used to locate the site of the (suspected) bleeding and to initiate therapy
- Angiography: vasoconstriction of a bleeding vessel via e.g., intraarterial vasopressin infusion or embolization
- Surgery (laparotomy): if bleeding cannot be contained through endoscopic intervention (rarely the case)
Treatment of underlying disease
See “Treatment” sections in ““, “ “, “ “, “ “, “ “, “ “, “ “, and “ .“
- liver cirrhosis) (in patients with
We list the most important complications. The selection is not exhaustive.