• Clinical science

Gastrointestinal bleeding


Gastrointestinal bleeding is categorized as either upper or lower bleeding, with the ligament of Treitz serving as an anatomical landmark to differentiate between the two. In approx. 70–80% of cases, the source of bleeding is localized in the esophagus, stomach, or duodenum (upper gastrointestinal bleeding, or UGIB). Lower gastrointestinal bleeding (LGIB) may occur in the colon, jejunum, and, in rare cases, the ileum. Although gastric and duodenal ulcers are frequently the cause, angiodysplasia, inflammatory diseases, and carcinomas may also contribute to gastrointestinal 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), black, tarry stool (melena), and fresh blood in stools (hematochezia).

Hospitalization is essential to monitor for signs of hemodynamic instability and shock caused by anemia and blood loss, which require swift intervention. The source of bleeding can often be located and treated simultaneously during endoscopy with injection therapy (e.g., epinephrine, sclerosants, fibrin glue) or ligation.


Etiology of upper and lower gastrointestinal bleeding

Upper gastrointestinal bleeding Lower gastrointestinal bleeding
Erosive or inflammatory
Traumatic or iatrogenic
  • Following interventions such as polypectomy or biopsy
  • Post-surgery anastomotic bleeding
  • Portal hypertensive gastropathy



Classification based on clinical manifestation

  • Occult bleeding: These cases show no clinical signs of bleeding. The presence of iron deficiency anemia caused by chronic blood loss may, however, indicate that bleeding has occurred.
  • Overt bleeding: Evident gastrointestinal bleeding with accompanying clinical symptoms.

Forrest classification of gastrointestinal hemorrhages

  • The Forrest classification describes the clinical findings during endoscopy and helps to evaluate the risk of renewed hemorrhage (without the need for repeated intervention).


Description Risk of recurring hemorrhage
I Active hemorrhage
Ia Spurting arterial hemorrhage 85–100% of cases
Ib Oozing hemorrhage 25–55% of cases
II Inactive hemorrhage
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

Clinical features

Clinical features of gastrointestinal bleeding
  • Anemia due to chronic blood loss
  • Acute hemorrhage: signs of circulatory insufficiency or hypovolemic shock
    • Tachycardia
    • Hypotension (dizziness, collapse, shock)
    • Reduced vigilance
  • Melena (black, tarry stool)
  • Hematemesis
  • Hematochezia: indicates brisk bleeding; may cause severe blood loss with hemodynamic instability
  • Hematochezia
  • Melena
  • Colonic bleeding (maroon, jelly-like traces of blood in stools)
  • Rectal bleeding (streaks of fresh blood on stools)

Melena may be caused by upper as well as lower gastrointestinal blood loss! Bleeding of the mouth and throat (nocturnal nosebleeds, tumors) should also be considered as a possible cause!


Lower gastrointestinal bleeding

  • Occult bleeding or hemodynamically stable hematocheziacolonoscopy→ if negative, perform esophagogastroduodenoscopy (EGD)
  • Melena (more common with a UGI source of bleeding) → EGD → if negative, perform colonoscopy
  • Hemodynamically unstable hematochezia
  • If EGD and colonoscopy fail to locate the bleeding → evaluate small bowel bleeding or consider angiography for vascular etiologies (e.g., angiodysplasia)

Upper gastrointestinal bleeding

  • Hematemesis or melenaEGD → if negative, perform colonoscopy
  • Nasogastric tube aspiration
    • Can be considered if suspicion of UGIB is only low to moderate
    • Bright red blood or coffee-ground material is indicative of UGI source
  • If EGD and colonoscopy fail to locate the bleeding → evaluate small bowel bleeding

Small bowel bleeding

There is no one test that can be recommended, as it depends entirely on the circumstances.

  • Push enteroscopy
  • Video capsule endoscopy
  • Radionuclide scan (RBCs labeled with technetium 99)



Conservative treatment

  • General support: nasal cannula oxygen supplementation, IV substitution of fluids (no oral intake of food or fluids)
  • Consider elective intubation in patients with altered mental or respiratory state and severe, ongoing hematemesis
  • IV proton pump inhibitors
  • Prepare for blood transfusion (typing and cross-matching)

Interventional treatment

  • Emergency EGD; : in the event of significant bleeding
    • Injection therapy (epinephrine), sclerotherapy, ligation, or thermal coagulation may be used to treat an identified source of bleeding.
    • Bleeding polyp (e.g., in the colon) → polypectomy
    • If present, see treatment of esophageal variceal hemorrhage.
  • Angiography: vasoconstriction via vasopressin
  • Surgery (laparotomy): if bleeding cannot be contained through endoscopic intervention (rarely the case)

If there is any suspicion of gastrointestinal bleeding, two large caliber peripheral venous catheters should be inserted and preparations made for a possible blood transfusion!


We list the most important complications. The selection is not exhaustive.