Hematemesis and melena are two distinct signs that often indicate bleeding within the upper part of the gastrointestinal (GI) tract. Understanding their characteristics is important for recognizing potential health concerns. They indicate the presence of blood in the digestive system, signaling a need for further medical attention.
Understanding Hematemesis
Hematemesis refers to the vomiting of blood. The appearance of vomited blood provides clues about the bleeding. When fresh, the vomitus may appear bright red, indicating minimal alteration by digestive processes.
If blood has been in the stomach for some time, it interacts with stomach acid, leading to a darker, granular appearance often described as “coffee grounds.” This darker color results from the partial digestion of hemoglobin in the blood. Hematemesis typically originates from sources within the upper GI tract, which includes the esophagus, stomach, or duodenum.
Understanding Melena
Melena is characterized by dark, black, and tarry stools that often have a distinct, foul odor. This appearance is due to digested blood. The dark color is a result of chemical reactions between hemoglobin in the blood and digestive enzymes and bacteria over time.
Melena indicates a bleed in the upper GI tract, as blood takes time to darken while moving through the intestines. In contrast, bright red blood in the stool, known as hematochezia, suggests bleeding from the lower GI tract, where the blood has not had sufficient time to be digested.
Common Causes of Upper Gastrointestinal Bleeding
Several medical conditions can lead to upper GI bleeding, manifesting as hematemesis or melena. Peptic ulcers are a common cause, involving open sores on the stomach or duodenum lining. These ulcers can erode into blood vessels, causing them to bleed. The presence of Helicobacter pylori bacteria and the use of nonsteroidal anti-inflammatory drugs (NSAIDs) are frequent contributors to peptic ulcer formation.
Esophageal varices are enlarged, fragile veins in the esophagus. They often develop in individuals with severe liver disease, such as cirrhosis, where blood flow through the liver is obstructed, causing pressure to build in these veins, making them prone to rupture and bleeding. Other conditions include gastritis, an inflammation of the stomach lining, and esophagitis, an inflammation of the esophageal lining, both of which can lead to erosions and bleeding. Mallory-Weiss tears, lacerations in the esophagus or at its junction with the stomach, can also cause bleeding, often from forceful vomiting or retching.
When to Seek Urgent Medical Care
Both hematemesis and melena are signs that require immediate medical evaluation. The presence of visible blood in vomit or dark, tarry stools indicates internal bleeding that can range from mild to severe.
Signs of a more severe situation include vomiting large volumes of blood, dizziness, faintness, severe abdominal pain, a rapid heart rate, or confusion. These symptoms suggest significant blood loss that can lead to shock, a condition where there is insufficient blood flow to the body’s organs. If any of these severe symptoms occur, calling emergency services or seeking immediate medical attention is necessary.
Medical Evaluation and Management
Medical professionals diagnose and manage the causes of hematemesis and melena through a structured approach. Initial assessment involves blood tests to evaluate blood loss, check for anemia, and assess clotting ability. An upper endoscopy, where a thin, flexible tube with a camera is passed into the stomach and duodenum, directly visualizes the bleeding source.
Treatment aims to stop the bleeding, address the underlying cause, and provide supportive care. During an endoscopy, the source of bleeding can often be treated directly through methods like injecting medication, applying heat, or placing clips to seal blood vessels. For esophageal varices, endoscopic banding may be performed, which involves placing small rubber bands around the enlarged veins to stop bleeding. Supportive care includes intravenous fluids to replace lost volume and, if necessary, blood transfusions to restore red blood cell count. Medications such as proton pump inhibitors (PPIs) are often administered to reduce stomach acid, which can help ulcers heal and prevent further bleeding.