Melena (Blood in Stool) in Dogs

Melena (Blood in Stool) in Dogs

By: Dr. Bari Spielman

Section: Overview

Melena is the presence of digested blood in the feces and makes the stools appear black and tarry. Melena is different from fresh blood in the stool (hematochezia). Melena may represent a severe, life-threatening illness, and should not be ignored. It must especially be addressed if it persists or worsens.

Melena develops when bleeding occurs into the stomach or small intestines. The bleeding must be high in the intestinal tract in order for the blood to be digested and become discolored. Bleeding into the colon or rectum (hematochezia) appears as fresh blood in the stool.

General Causes

  • Infectious agents
  • Certain drugs
  • Cancer
  • Foreign bodies in the stomach or intestines
  • Infiltrative and inflammatory gastrointestinal diseases
  • Ingestion of blood
  • Coagulopathies (bleeding disorders)
  • Metabolic and other diseases that cause gast
    rointestinal ulceration
  • Hemorrhagic gastroenteritis (HGE)
  • Perioperative hemorrhage (bleeding associated with surgery on the intestinal tract)
  • Gastrointestinal ischemia (lack of blood supply)
  • Ingestion of heavy metals (uncommon causes)

    What to Watch For

  • Dark, almost black stools
  • Diarrhea
  • Vomiting
  • Pale gums
  • Other areas of bleeding or bruising on the body
  • Weight loss
  • Poor appetite
  • Excessive drinking or urinating
  • Excessive urinating

    Diagnosis

    A thorough history and physical examination are often helpful in determining if melena is present and in suggesting an underlying cause. To determine the exact cause, additional tests are usually necessary and include the following:

  • Complete blood count (CBC)
  • Biochemical profile
  • Urinalysis
  • Fecal examination
  • Abdominal and chest radiographs (X-rays)
  • Serology for certain infectious diseases
  • Coagulation profile
  • Abdominal ultrasonography
  • Upper gastrointestinal barium series
  • Endoscopy

     
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