What is the Difference Between Hematochezia and Melena?

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The main difference between hematochezia and melena lies in their appearance and the location of the bleeding in the gastrointestinal tract.

Hematochezia is the passage of fresh blood per anus, usually in or with stools. It is often more liquid and less viscous in the stool. Common causes of hematochezia include:

  • Internal hemorrhoids
  • Diverticular disease, such as diverticulitis
  • Anal fissures
  • Colon cancer
  • Ischemic colitis
  • Inflammatory bowel disease (IBD)
  • Neoplastic polyps
  • Benign tumors

Melena is the passage of black, tarry, and foul-smelling stools. The blood is mixed with stool, making it tar-like and sticky. Melena usually originates from higher up in the gastrointestinal tract, such as the stomach or the upper small intestine. Common causes of melena include:

  • Gastrointestinal vascular malformations
  • Bleeding disorders, such as hemophilia or von Willebrand disease
  • Peptic ulcers
  • Gastrointestinal infections
  • Medications, particularly nonsteroidal anti-inflammatory drugs (NSAIDs)

Distinguishing between hematochezia and melena is critical for identifying the source of bleeding and determining the appropriate course of treatment. For example, treatment for hematochezia may include surgery for colon cancer or following a high-fiber diet for diverticular disease, while treating melena may involve medications to decrease acidity in the stomach for peptic ulcers.

Comparative Table: Hematochezia vs Melena

Here is a table comparing the differences between hematochezia and melena:

Feature Hematochezia Melena
Definition Passage of fresh blood per anus, usually in or with stools Passage of black, tarry stools
Color Bright red Black, tarry, jet-black, ink-like
Origin Lower gastrointestinal tract Upper gastrointestinal tract
Causes Internal hemorrhoids, diverticular disease, anal fissures, colon cancer, ischemic colitis, inflammatory bowel disease, neoplastic polyps, benign tumors Peptic ulcers, gastritis, esophageal varices, upper GI bleeding due to certain medications
Treatment Treatment usually focuses on addressing the underlying cause, e.g., surgery for colon cancer or following a high-fiber diet for diverticular disease Treatment may involve medications to decrease acidity in the stomach for peptic ulcers, addressing the underlying cause

Both hematochezia and melena are symptoms of gastrointestinal bleeding but have distinct differences in color, origin, causes, and treatment.