Stool Blood: Understanding Melena and Hematochezia

What is melena? Hematochezia? What causes each?

a) Melena is black, tarry stool; Hematochezia is bright red blood in stool

b) Melena is bright red blood in stool; Hematochezia is dark, tarry stool

c) Both refer to the same condition

d) Neither term is related to stool

Final answer:Melena is black, tarry stool, typically indicating upper gastrointestinal bleeding, while hematochezia is bright red blood in stool, usually pointing to lower gastrointestinal bleeding. Their presence can indicate disorders like gastric ulcers, colorectal cancer, or hemorrhoids.

Answer:

Melena is black, tarry stool, typically indicating upper gastrointestinal bleeding, while hematochezia is bright red blood in stool, usually pointing to lower gastrointestinal bleeding. Their presence can indicate disorders like gastric ulcers, colorectal cancer, or hemorrhoids.

Explanation:

Melena is characterized as black, tarry stool and hematochezia is defined as bright red blood in stool. Each condition is indicative of certain underlying medical issues. Melena is usually associated with upper gastrointestinal bleeding, where the blood gets digested and leads to the black, tarry appearance. This is caused by factors such as gastric ulcers, or esophageal varices. Hematochezia, on the other hand, is typically linked with bleeding in the lower gastrointestinal tract such as the rectum or the colon. Conditions like colorectal cancer or hemorrhoids can result in hematochezia.

Moreover, the presence of stool color variations may be related to other digestive system disorders. A regular stool color is caused by stercobilin, a brown pigment resulting from the transformation of bilirubin by intestinal bacteria. Abnormal stool color, like greenish black meconium in a newborn or a high-fat white ('acholic') stool, might indicate a different problem with the digestive or excretory system.

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