What’s the Difference Between Hematochezia and Melena?
Medically reviewed by Robert Burakoff, MD
Conditions that cause bleeding in the digestive system can lead to blood leaving the body in stool. When blood in the stool is brighter red, it is called hematochezia, and it could be coming from the lower parts of the digestive system. When the blood is darker, making stool appear black, the blood may be coming from higher up in the digestive system, and it is called melena.
Bleeding in the digestive system can be a symptom of many different conditions, some of which may be serious. Blood in the stool is never normal, and it is a reason to seek care from a healthcare provider.
This article will discuss the differences between hematochezia and melena, including symptoms, causes, diagnosis, and treatment.
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Differences in Symptoms
Blood in or on the stool is a symptom that something is causing bleeding in the digestive system. There are many reasons that blood could be in the stool. The color or volume of the blood is not enough information to know what might be causing it. Sometimes blood in the toilet bowl water can look like it's much more than it really is.
Hematochezia
Hematochezia looks like fresh blood, which is bright red. When blood is brighter, it is coming from the lower end of the digestive system, including the large intestine (the colon and the rectum). Blood leaving the body closer to the end of the digestive system means that it may not be changed much by the digestive process.
The blood may appear in the stool, on the stool as streaks, or there could be bowel movements that appear to be mostly or only blood. How the blood appears may be dependent on what is causing it.
Other signs and symptoms that may occur along with hematochezia are:
Abdominal pain
Diarrhea and/or constipation
Fever
Unintended weight loss
Melena
Melena is blood that comes from farther up in the digestive system, such as in the stomach or the small intestine. It passes through more of the digestive system, losing the oxygen that makes blood appear brighter.
This blood also causes the stool to take on a tarry appearance. Stools that contain blood from the upper digestive system may also be sticky and smell foul (more so than stool that doesn't contain any blood).
Other signs and symptoms that may occur along with melena can include:
Anemia
Difficulty swallowing (if the condition is affecting the esophagus)
What Causes Them?
Bleeding in the digestive system is a symptom rather than a condition itself. There are many potential reasons for bleeding, ranging from relatively minor and treatable conditions to more serious ones that need intensive treatment. This is why it's important to talk with a healthcare provider when blood is present in the stool.
Hematochezia
Hematochezia is caused by a source of bleeding in the lower digestive tract. Some of the conditions that can cause hematochezia include:
Anal fissures: A tear or ulcer in the anal canal can cause pain and bleeding.
Colon and rectal cancer: Tumors in the large intestine may cause bleeding as well as other symptoms such as changes in bowel habits or pain.
Diverticular disease: Diverticula are small outpouchings in the lining of the colon. They can bleed due to chronic injury to the blood vessel (arteriol) in or next to a diverticulum.
Fistula: An abnormal tunnel between two organs or an organ and the skin can cause pain, bleeding, and other symptoms.
Hemorrhoids: Swollen veins in and around the anus, are a common reason for pain, itching, and bleeding.
Inflammatory bowel disease (IBD): Chronic immune-mediated conditions (Crohn's disease and ulcerative colitis) cause inflammation, leading to abdominal pain, bleeding, diarrhea, anemia, and unintended weight loss.
Ischemic colitis: An interruption in blood flow to the intestine can lead to bleeding.
Melena
Several different types of conditions could lead to melena. It's not possible to diagnose a condition with the presence of melena and other symptoms alone. It is important to talk to a healthcare provider about any symptoms so that the cause of the bleeding can be found.
Conditions that can cause melena include:
Cirrhosis with esophageal or gastric varices: A vein in the esophagus or stomach is expanded or widened and could be related to cirrhosis (scarring in the liver).
Erosive esophagitis: When the esophagus (food tube) is irritated or inflamed, it could lead to bleeding.
Gastrointestinal (GI) stromal tumor: A tumor in the upper digestive system is very rare, but it may cause bleeding.
Mallory-Weiss tear: A hole in the lining of the esophagus or stomach may be caused by severe vomiting.
Ulcers (peptic or duodenal): A hole or an erosion in the lining of the stomach or the first part of the small intestine is most commonly caused by infection with a bacteria called Helicobacter pylori (H. pylori).
Vascular gastrointestinal lesions: Abnormalities in blood vessels that people are born with or are caused by another condition such as kidney disease may cause bleeding.
How Are They Diagnosed?
Various tests might be used to find the source of bleeding in the digestive system. Before testing is started, a healthcare provider will take a detailed health history to narrow down the cause of the bleeding. Then, one or more tests might be used to find the source and treat it.
Hematochezia
Blood from a source of bleeding in the lower digestive system may be visible in or on the stool. However, it might not be clear what is causing the bleeding. For that reason, some tests might be used to find the source.
A few of the types of tests that might be used to diagnose bleeding in the lower digestive tract include:
Colonoscopy: A flexible tube with a light and a camera on the end is inserted through the anus and up into the colon to look for the source of bleeding.
Computed tomography (CT) scan: This type of imaging uses multiple X-rays to compose a three-dimensional (3D) image of the structures inside the abdomen and looks for any abnormalities.
Digital rectal exam: A healthcare provider inserts a gloved, lubricated finger into the rectum to feel for any problems and see if there is any bleeding.
Lower GI series (barium enema): This type of X-ray uses barium as a contrast in order to better see the inside of the colon.
Sigmoidoscopy: This is similar to a colonoscopy except that it might be done with or without a preparation and is used to look at the rectum and the last part of the large intestine (the sigmoid colon).
Melena
Diagnostic testing may be used in order to find the source of the bleeding. A healthcare provider will ask about any other symptoms. Based on symptoms and any other factors like personal and family history, a healthcare provider will order one or more tests.
Some of the tests that might be used include:
Angiography: This is a type of X-ray that's done using contrast in order to see blood vessels.
Gastrointestinal bleeding scan (GIBS): This nuclear medicine test is non-invasive and uses contrast to find bleeding in the stomach or intestine.
Balloon enteroscopy: This type of endoscopy can be used to look at the inside of the small intestine.
Blood tests: Blood tests won't be helpful to diagnose the source of bleeding, but it could be used to look for anemia, liver problems, or clotting issues.
Capsule endoscopy: A person swallows a pill with a camera in it, which takes photos as it travels through the digestive tract.
Esophagogastroduodenoscopy (EGD): This test uses a flexible tube that's passed through the mouth and down into the esophagus, stomach, and first part of the small intestine.
H. pylori: A test for an infection with this bacterium might be done because H. pylori can cause ulcers in the stomach and the small intestine.
Stool culture: Culturing a bowel movement is used to check for an infection or other issues that could indicate disease.
How Are They Treated?
It will be important to understand the reason for the bleeding and find out where it is coming from. That way, the right treatment can stop the bleeding and prevent complications.
Hematochezia
Treating hematochezia will depend on the cause of the bleeding. Some of the treatments for common reasons for bleeding in the lower digestive system include:
Anal fissures: Treatment may start with home remedies like changing the diet, taking a sitz bath, or using fiber supplements or a stool softener. Prescription medications and surgery may be used for fissures that are taking longer to heal.
Colon and rectal cancer: Colon cancer may be treated with surgery to remove any polyps or tumors, as well as radiation therapy, chemotherapy, or other medications to treat the cancer or other symptoms.
Diverticular disease: A liquid diet may be recommended for a flare-up, followed by antibiotics if needed, and surgery in rare cases.
Fistula: Some fistulae may be treated with a liquid diet or medication and, when needed, surgery or wound care.
Hemorrhoids: Over-the-counter medications and sitz baths might be used at first, followed by treatment from a provider in an office setting.
IBD: Treating inflammatory bowel disease includes changes in diet and lifestyle, followed by medications and, in some cases, surgery.
Ischemic colitis: Treatment for a mild case includes antibiotics, a liquid diet, intravenous fluids, and pain management, with surgery being reserved for more severe cases.
Melena
A diagnosis to discover the cause of melena is needed before treatment can start. Potential treatments and common causes of melena include:
Cirrhosis with esophageal or gastric varices: Treatment might include endoscopy, with antibiotics, plasma or a transfusion, and other medications as needed.
Erosive esophagitis: Medications to reduce acid, antibiotics, steroids, and pain medication might be used to treat the inflammation and its cause.
Gastrointestinal stromal tumor: Tumors are usually removed surgically, sometimes after medications are first used to shrink the tumor.
Mallory-Weiss tear: Bleeding might stop by itself, or with the use of medications to control it. Rarely, surgery may be used.
Ulcers (peptic or duodenal): Ulcers are usually treated with antibiotics to control the infection, along with changes to diet and lifestyle and medications to reduce stomach acids.
Vascular gastrointestinal lesions: An endoscopic procedure, medications, or surgery might all be used as a treatment, depending on the degree of bleeding.
Summary
Bleeding in the digestive system is never normal. It is a symptom of a condition that needs to be diagnosed. Knowing the difference between hematochezia and melena can help in understanding the general area of the bleeding.
The cause could be common and benign, but it could also be more serious, which is why a diagnosis from a healthcare provider is important. Once the cause of the bleeding is found, a treatment plan can be put into place.
Read the original article on Verywell Health.
