Blood in the stool is a symptom that can be frightening to discover. While it always signals that something in the digestive tract requires attention, the severity of the underlying cause varies widely. The source of the bleeding can range from a minor, easily treatable condition to a serious disease that requires prompt medical intervention. A medical evaluation is always necessary to determine the exact cause and appropriate treatment.
The Significance of Color and Consistency
The color and consistency of the blood offer important clues about where the bleeding is occurring in the gastrointestinal (GI) tract. Bright red or maroon blood, known as hematochezia, typically suggests a bleed in the lower GI tract, such as the colon, rectum, or anus. This blood has not traveled far, so it remains fresh and retains its vivid red color. The presence of bright red blood often indicates a rapid bleed or a source close to the exit.
Dark, black, and sticky stool, referred to as melena, suggests that the blood originated higher up, usually in the upper GI tract, like the stomach or small intestine. The black, tarry appearance results from the blood being chemically altered by digestive enzymes and acid as it passes through the intestines. This process changes the hemoglobin, giving the stool its characteristic dark color and foul odor. Melena is a strong indicator of an upper GI source.
Common Sources of Bright Red Blood
The most frequent causes of bright red blood are conditions affecting the lower rectum and anus. Hemorrhoids are swollen veins in the anal canal or around the anus that bleed when irritated, often due to straining during a bowel movement or chronic constipation. Bleeding from hemorrhoids is typically painless and may appear as streaks on the toilet paper or as blood dripping into the toilet bowl.
Another common source is an anal fissure, which is a small tear in the lining of the anus. Fissures are frequently caused by passing large or hard stools and can be painful, often described as a sharp, burning sensation during and after a bowel movement. The blood is usually bright red and small in volume, often appearing on the surface of the stool or on the wiping tissue. Both hemorrhoids and anal fissures are often managed with simple measures to soften the stool and reduce straining.
Conditions Requiring Medical Intervention
Bleeding that is chronic, recurring, or associated with other symptoms may point to conditions requiring more involved medical intervention. Peptic ulcers, which are open sores on the lining of the stomach or small intestine, are a common cause of upper GI bleeding resulting in melena. These ulcers can erode a blood vessel, and the blood is then digested, leading to the black, tarry stool.
Inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn’s disease, cause inflammation and ulceration throughout the digestive tract, leading to bleeding. Ulcerative colitis affects the colon and rectum, often causing bloody diarrhea and bright red blood, while Crohn’s disease can affect any part of the GI tract. Diverticular disease involves small, bulging pouches, called diverticula, that form on the walls of the colon. Bleeding from a vessel within a diverticulum can be painless and sometimes heavy, leading to bright red or maroon blood.
Colorectal polyps and cancer represent a serious group of potential causes for blood in the stool. Polyps are growths on the lining of the colon or rectum that can bleed, and while many are benign, some can develop into cancer over time. Bleeding from a low-lying polyp or tumor can sometimes present as bright red blood, similar to hemorrhoids. However, a tumor higher in the colon may cause darker blood or microscopic amounts of blood that are not visible. Any change in bowel habits, unexplained weight loss, or persistent fatigue accompanying the bleeding must be investigated promptly.
Diagnostic Steps and Urgent Warning Signs
Anyone who notices blood in their stool should consult a healthcare provider, even if the bleeding is minor and stops quickly. The initial diagnostic process involves a detailed medical history and a physical examination, including a digital rectal exam to check for common causes like hemorrhoids or fissures. Further diagnostic steps may include stool tests to look for hidden blood or infection, and blood tests to check for anemia.
Depending on the suspected location of the bleed, the physician may recommend an upper endoscopy to visualize the esophagus, stomach, and upper small intestine, or a colonoscopy to examine the entire large intestine. These procedures allow for direct visualization and can often treat the source of the bleeding, such as removing a polyp.
Certain warning signs require immediate emergency medical care. These include a large volume of blood or blood clots, feeling dizzy or lightheaded, a rapid heart rate, or experiencing severe abdominal pain. These symptoms indicate a significant loss of blood that needs urgent intervention.