Medical Director
Senior Consultant, General & Colorectal Surgeon
MBBS (Singapore), MRCS (Edinburgh), MMed (Surgery), FRCS (Edinburgh)
Noticing blood in the toilet bowl or on tissue paper after a bowel movement can be unsettling. Known medically as rectal bleeding or haematochezia, it indicates bleeding somewhere within the digestive tract. Bright red blood often suggests a source in the lower colon or rectum, while dark, tarry stools may point to bleeding from the upper gastrointestinal tract.
Although rectal bleeding should always be assessed by a doctor, it can arise from a range of conditions. Common causes include:
Haemorrhoids
Haemorrhoids, also known as piles, are swollen blood vessels located in the rectum or anus. They often develop due to increased pressure on the veins, which can occur with straining during bowel movements, pregnancy, chronic constipation or sitting for long periods.
Internal haemorrhoids, located inside the rectum, may bleed painlessly. In contrast, external haemorrhoids, situated under the skin around the anus, can be more uncomfortable and may cause itching or swelling.
Anal Fissures
An anal fissure is a small tear or crack in the thin, moist tissue (mucosa) lining the anus. This often happens when passing large or hard stools. The bleeding associated with an anal fissure is often bright red and may be accompanied by sharp pain during bowel movements. Fissures can result from chronic constipation, diarrhoea or trauma to the area.
Colorectal Polyps
Polyps are small clumps of cells that form on the lining of the colon or rectum. Most polyps are harmless (benign), but over time, some can develop into colorectal cancer. They do not always cause symptoms, but when they do, rectal bleeding is one of the more common signs. The bleeding may range from bright red to darker in colour, depending on its location in the digestive tract.
Colorectal Cancer
Blood in stools can sometimes be a sign of colorectal cancer, particularly if it is accompanied by other symptoms such as changes in bowel habits, abdominal pain or unexplained weight loss. This type of cancer can cause bleeding that is either visible or microscopic (invisible to the naked eye).
Inflammatory Bowel Disease (IBD)
Chronic inflammation of the digestive tract, such as ulcerative colitis or Crohn’s disease, can cause damage to the intestinal lining. This often results in bloody diarrhoea, along with other symptoms like abdominal pain, fatigue and weight loss.
Gastrointestinal Infections
Certain bacterial, viral or parasitic infections can inflame the gastrointestinal tract and cause abdominal pain with diarrhoea that may contain blood or mucus. Common examples include Salmonella and E. coli. These infections are often accompanied by fever, nausea and abdominal cramping.
Diverticular Disease
Diverticula are small bulging pouches that can form in the lining of the digestive tract, most often in the lower colon. When a pouch becomes inflamed or infected, a condition known as diverticulitis, or when a nearby blood vessel ruptures, it can lead to noticeable red or maroon blood in the stool.
The Role of Colonoscopy in Detecting the Cause
If you present with rectal bleeding, your doctor may recommend a colonoscopy. This is the gold standard for identifying the exact source of the bleeding, whether it is a polyp, a fissure or inflammation. If polyps are found, they can be removed during the exam, and tissue samples (biopsies) can be taken for further analysis.
When to See a Specialist for Blood in Stools
Any instance of blood in stools should be assessed by a doctor. While not all causes are serious, certain accompanying symptoms require urgent medical attention. These include:
- Heavy or continuous bleeding
- Severe abdominal pain or cramping
- Unexplained weight loss
- Fatigue or symptoms of anaemia, such as weakness or shortness of breath
- Changes in bowel habits, such as prolonged diarrhoea or constipation
- Black or tarry stools, which may indicate bleeding higher up in the digestive tract
Consult Dr Chew Min Hoe for Rectal Bleeding Evaluation
Blood in stools should never be ignored, even if it appears mild or occurs only once. Early evaluation allows the underlying cause to be identified accurately and treated appropriately, reducing the risk of complications and providing reassurance.
At our colonoscopy clinic, patients receive comprehensive colorectal assessment supported by advanced diagnostic tools, including colonoscopy where indicated. Dr Chew Min Hoe provides thorough assessment and evidence-based management for rectal bleeding and other colorectal concerns. With access to advanced diagnostic tools, including colonoscopy, patients receive comprehensive care tailored to their condition. Schedule an appointment to discuss your symptoms and receive a personalised evaluation.