Rectal bleeding, known medically as hematochezia when the blood is bright red, is a common symptom. The presence of blood in the stool is never considered normal, and while the cause is often benign, it always requires a professional medical evaluation. Determining the source of the bleeding is the primary goal of a doctor’s examination, as the symptom can indicate a wide range of conditions from minor irritations to serious diseases. Consulting a healthcare provider is the only way to accurately determine the underlying cause and ensure appropriate care is received.
Assessing the Bleeding: Color and Quantity
The visual characteristics of the blood are the first clues doctors use to pinpoint the location of the bleed within the gastrointestinal tract. Bright red blood typically indicates a source in the lower digestive system, such as the rectum or anus, because the blood has not been digested. Conversely, if the stool appears black and tarry (melena), it generally suggests bleeding from higher up in the digestive tract, like the stomach or small intestine. This dark color results from hemoglobin being chemically altered by digestive enzymes as it passes through the intestines.
Observing the quantity and consistency of the blood is equally important information to relay to a doctor. Small streaks of blood on the toilet paper or a few drops in the toilet bowl often point to a source very close to the anus. A large volume of blood or the presence of blood clots, especially if bright red, suggests a more significant or rapid bleed, often from the colon. Rapid, high-volume bleeding can sometimes cause bright red blood even if the source is higher up, simply because the blood moves through the system too quickly to turn dark.
Common Causes of Rectal Bleeding
The most frequent causes of bright red rectal bleeding originate from the end of the gastrointestinal tract and are generally not life-threatening. Hemorrhoids, which are swollen veins in the anus or lower rectum, are a highly common source. Internal hemorrhoids are typically painless and bleed when strained during a bowel movement, often showing as drops of blood or streaks on the stool. External hemorrhoids, located around the anus, can also bleed but are more likely to cause pain or itching.
Another common cause is an anal fissure, a small tear in the tissue lining the anus. These tears usually result from passing hard or large stools, causing sharp pain during and after a bowel movement. Fissures typically present with a small amount of bright red blood on the tissue or stool.
Inflammation in the lining of the rectum, known as proctitis, can also lead to minor rectal bleeding. This condition can be caused by infections, radiation therapy, or inflammatory bowel disease, resulting in irritation and fragility of the rectal tissue. Another common cause is diverticulosis, where small, bulging pouches called diverticula form in the wall of the colon. A small blood vessel near a diverticulum can rupture, causing painless, often significant, bright red or maroon bleeding.
Serious Causes Requiring Immediate Investigation
Professional investigation is mandatory because rectal bleeding can be the first sign of serious disease, even if the cause is often benign. Colorectal polyps are small growths on the lining of the colon or rectum that can bleed easily. The friction of stool passing over these fragile growths can cause bleeding, which may be bright red or darker depending on the polyp’s location. Some polyps, known as adenomas, have the potential to develop into colorectal cancer, making their detection and removal a primary reason for screening.
Colorectal cancer itself can present with rectal bleeding, often due to the tumor’s fragile, abnormal blood vessels. The bleeding from a cancerous lesion can be mixed in with the stool, appearing darker or maroon-colored. This may be accompanied by other symptoms like a change in bowel habits or unexplained weight loss. Urgent evaluation is required to prevent disease progression, as early detection significantly improves treatment outcomes.
Inflammatory Bowel Disease (IBD), which includes Ulcerative Colitis and Crohn’s Disease, involves chronic inflammation and ulceration of the digestive tract lining. In Ulcerative Colitis, inflammation is confined to the colon and rectum, causing the mucosal layer to become raw and bleed, resulting in bloody diarrhea mixed with mucus. Crohn’s Disease can affect any part of the GI tract, and when it affects the colon, it also causes inflammation and deep ulcers that can lead to bleeding. Severe gastrointestinal bleeding, such as from a large bleeding ulcer or a vascular abnormality called angiodysplasia, also requires immediate medical attention.
Next Steps: When and How to Consult a Doctor
Any instance of rectal bleeding warrants a medical consultation, but certain symptoms require immediate emergency care. If the bleeding is continuous, heavy, or accompanied by severe abdominal pain or cramping, a visit to the emergency room is necessary. Signs of significant blood loss, such as feeling dizzy, faint, or experiencing rapid heart rate, indicate a severe bleed that needs urgent stabilization.
For less urgent, intermittent bleeding, scheduling an appointment with a doctor is the appropriate next step. The doctor will take a detailed history, asking about the color, quantity, and frequency of the bleeding, as well as any associated symptoms like pain or changes in bowel habits. A physical examination, including a digital rectal exam (DRE) and often an anoscopy (a short, lighted tube to view the anal canal), will be performed.
To investigate potential sources higher up in the colon, the doctor may recommend a diagnostic procedure like a colonoscopy. A colonoscopy uses a long, flexible tube with a camera to examine the entire large intestine, allowing the physician to visualize the source of the bleeding and treat it immediately, such as by removing a polyp. Providing a clear, detailed description of the bleeding and any other symptoms is the most valuable information a patient can provide to guide the diagnostic process.