Blood should not appear in the stool or with wiping after a bowel movement. When it does occur, most people are concerned. This can be a worrying symptom but most of the time rectal bleeding is not serious. Nevertheless it is always advisable to have a doctor investigate rectal bleeding further as it can be a sign of serious conditions like colorectal cancer.
Blood from the Rectum
It is not common for there to be excessive bleeding from the rectum and anus. Sometimes rectal bleeding is noticed with a bowel movement. However, in most cases blood in the stool may not be visible (microscopic) and is only detected with diagnostic investigation like a fecal occult blood test (FOBT).
When blood is visible, it may either appear fresh blood or dark blood in the stool. The fresh red blood is known as hematochezia and it may be seen with wiping after a bowel movement. In rare cases the blood may be seen in the toilet during a bowel movement or as bloody diarrhea. Fresh red blood is a sign of bleeding lower down the gut, in the large intestine, rectum or anus.
Dark degraded blood is not always as easily visible. It may cause the stool to appear dark to black in color and tarry. This is known as melena. It is more likely to arise with bleeding higher up in the gut like from the stomach or small intestine. The blood degrades and mixes with stool as it passes down the gut to the rectum. Often it is not evident to the naked eye.
Symptoms with Rectal Bleeding
Profuse bleeding within the lower part of the gastrointestinal tract may mess the toilet bowl with bright red blood. More commonly blood is seen on tissue paper after wiping. Bleeding is a sign of a break in a blood vessel. It is important to take note of other signs or symptoms that accompany rectal bleeding during or after a bowel movement. This may include :
- Pain during or after a bowel movement (character, duration, location, trigger and relieving factors).
- Blood in the stool – fresh blood in stool (hematochezia) or dark blood in stool (melena).
- Mucus in the stool which may be streaked with blood.
- Abnormal stool – watery stool, hard stool or other changes in the color, consistency and volume of stool.
- Nausea and/or vomiting, especially if there is blood in the vomit (hematemesis).
Persistent rectal bleeding and unintentional weight loss, even without any of the other signs and symptoms above, needs to be investigated immediately. It may occur with colorectal cancer.
Causes and Other Symptoms
There are many different causes of rectal bleeding. Although it may seem like a serious sign it is not always due to a serious or life threatening condition. It is important that the exact cause is diagnosed by a medical professional in order for the appropriate treatment to be prescribed.
Rectal bleeding that occurs after an abdominal injury should be considered as a medical emergency. There may be internal bleeding and immediate medical attention is necessary. Left untreated, it could become life threatening within a short period.
Some of the more likely causes of rectal bleeding have been discussed below. The bleeding may occur during or after a bowel movement. It may also precede (occur before) a bowel movement. In severe cases, the underwear may be soiled with blood.
Hemorrhoids are inflamed and enlarged veins in the lower rectum and/or anus. It is one of the most common causes of rectal bleeding. Other symptoms may include an itchy anus, pain or discomfort in the rectum/anus and a palpable sensitive lump in the anal area.
Anal fissures are tiny tears on the skin of the anus. It mainly occurs with constipation or chronic diarrhea. Although the condition is not serious it can cause discomfort and pain with bowel movements. An itchy sensation may also be present and the tears can be visible.
Certain diarrheal illnesses can present with rectal bleeding and even bloody diarrhea. This is seen with more severe infections. The bleeding may not always be from the colon. There can be bleeding higher up in the gut but it moves rapidly through the bowels and does not degrade. Bloody diarrhea needs immediate medical attention.
Inflammatory bowel disease
Inflammatory bowel disease is chronic inflammation of the small and/or large intestine as a result of autoimmune factors. There are two types – Crohn’s disease and ulcerative colitis. Other symptoms include tenesmus (urging to have a bowel movement), stomach cramps and abdominal pain, bloody diarrhea or mucus in stool.
Irritable bowel syndrome
Irritable bowel syndrome (IBS) is a condition where there is abdominal pain with abnormal bowel habit. It is is a functional disorder where the bowel activity is abnormal. There is usually no bleeding from the gut but people with IBS may be prone to hemorrhoids. It is this hemorrhoids that may be responsible for the rectal bleeding.
Diverticulitis is inflammation of small pouches in the colon. These pouches (diverticula) may form during life and is more common in older people. It usually does not cause any symptoms. However, if the diverticula become infected and inflamed then there may be symptoms like rectal bleeding with abdominal pain.
Polyps are growths from the lining of the rectum or colon. These types of growths can occur anywhere in the digestive tract. Most polyps are benign although some may become cancerous over time. Polyps may be asymptomatic for long periods of time. Eventually symptoms like rectal bleeding, red blood in the stool, constipation or diarrhea may become evident.
Colorectal cancer is one of the more serious causes of rectal bleeding. It is sometimes the earliest and only sign of cancer. It needs to be considered as a cause of rectal bleeding especially if there is an ongoing bleed with other symptoms. It is more of a concern in people who are considered at risk of colorectal cancer. Other symptoms may include persistent diarrhea or constipation, lower abdominal discomfort, fatigue and unintentional weight loss.