Hematemesis and Melena
Hematemesis is defined as the vomiting of frank blood from a source lying between the esophagus and the duodenum. The ejected blood may be bright red in colour or dark brown in colour. Hematemesis is vomiting of gross blood. It is diagnostic of bleeding from any site proximal to the ligament of Treitz. The dark brown colour is due to the chemical reaction of the acid content of the stomach with hemoglobin of RBC's (coffee ground).
Sources of hematemesis
Hematochezia is defined as the passage of bright red blood.
- Esophagus
- Esophagitis
- Ulcer
- Mallory-Weiss tear
- Esophageal varices
- Stomach
- Gastric ulcer
- Prepyloric ulcer
- Pyloric channel ulcer
- Gastric erosions
- Gastritis
- Varices
- Portal-hypertensive gastropathy
- Gastric cancer
- Polyp
- Dieulafoy lesion
- Duodenum
- Ulcer
- Duodenitis
- Aortoenteric fistula
- Pancreatic pseudocyst
- Post-sphincterotomy
Melena is defined as the passage of black tarry stools due to presence of altered blood. Retention of blood in the digestive system is required for the blood to become black or tarry in appearance.
The passage of dark black, liquid, tarry, metallic-smelling stools. Melenic stools usually indicate bleeding proximal to the right side of the colon. It usually indicates that hemorrhage has remained for > 8hrs in the GI tract. At least 60 ml of blood is required to produce a single black stool. The occurrence of melena without vomiting is due to a lesion beyond the duodenum.
Sources of melena
- All causes of upper gastrointestinal bleeding
- Jejunum and ileum: (Meckel's diverticulum, angiodysplasia, Chron's disease, tumors, bowel infarction).
- Colon: right sided tumors, angiodysplasia, inflammatory bowel disease.
Common Causes of hematemesis and melena
1. Esophagus - Cancer, inflammation of esophagus
2. Stomach - Ulcer, gastritis, aspirin intake, cancer.
3. Duodenum - Ulcer
4. Small intestine - Inflammatory bowel disease, diverticulosis
5. Large intestine - Inflammatory bowel disease, ulcerative colitis, cancer colon, rectal cancer, piles, anal fissures.
Common Symptoms of hematemesis and melena
The symptoms of digestive system bleeding depends on the extent and rate of hemorrhage. Blood loss of less than 500 ml is rarely associated with signs, exceptions include bleeding in the elderly or in an anemic patient. Rapid hemorrhage of greater volume results. In decreased venous return to the heart resulting in decreased pumping of pure blood to tissues. A blood pressure fall of greater than 10 mm Hg usually indicates a 20% or greater reduction in blood volume. When blood loss approaches 40% of blood volume, shock results.
Always consult a doctor.
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