The sighting of blood in the stool has frightened many people, and understandably so. Although it is often caused by a harmless problem such as haemorrhoids, it is important to know that it can be a sign of more serious illnesses. Ignoring this symptom can have serious consequences, so it is vital to be aware of the possible causes and when to seek medical advice.
This guide is designed to help you understand what might be causing your bloody stools. It details the most common causes, associated symptoms, diagnostic procedures and treatment options. Our aim is to dispel unnecessary fears with authoritative, easy-to-understand information and provide clear guidance on when to seek professional help. If you have experienced a similar symptom or simply want to find out more, this article is for you.
What exactly does bloody stools mean?
A bloody stool (also known as haematochezia or melena) means that bleeding has occurred in some part of the digestive tract. The appearance of blood can tell you a lot about the location and nature of the bleeding.
- Fresh, bright red blood (haematochezia): This type of bleeding usually originates from the lower digestive tract, most commonly from the colon, rectum or rectal area. In this case, the blood is not digested and can be seen fresh on the toilet paper or on the surface of the stool.
- Pitch black, tarry stools (melaena): When the bleeding occurs in the upper digestive tract (oesophagus, stomach, small intestine), the blood is digested as it passes through the intestinal tract. The stomach acid and enzymes cause it to turn black, sticky and have a distinctive smell. It is important to note that certain foods (e.g. beetroot, blueberries) or medicines (e.g. iron supplements, bismuth) can also discolour the stools, but this is not true melena.
- Hidden (occult) bleeding: Sometimes the bleeding is so small that it is not visible to the naked eye in the stool. This is called occult bleeding, which can only be detected by special laboratory tests (e.g. faecal blood tests). Often iron-deficiency anaemia is the cause.
Possible causes of bloody stools
Blood in the stool can be caused by a wide range of conditions, from mild, easily treatable problems to serious conditions requiring immediate intervention.
Common, usually benign causes
These are the most common reasons why you may experience blood in your stools. Although they are not usually an indication of a life-threatening condition, a medical check-up is recommended.
- A nodularity (nodus haemorrhoidalis): This is the most common reason. Hemorrhoids are dilated varicose veins around the anus. Internal haemorrhoids usually cause painless, bright red bleeding that appears on toilet paper or the surface of the stool. External haemorrhoids can be painful, especially if they form a blood clot (thrombosed haemorrhoids).
- Rectal tear (fissura ani): Chapping of the skin of the anus, often caused by hard stools or straining. It is characterised by sharp, stabbing pain during defecation and a small amount of fresh red bleeding.
- Diverticulosis: Tiny bumps on the wall of the large intestine (diverticula). These do not cause complaints on their own, but if they become inflamed (diverticulitis) or the blood vessel inside them bursts, they can cause sudden, heavy, painless bleeding. This is a major cause of significant lower GI bleeding in the elderly.
More serious conditions requiring investigation
The following diseases require more attention and a thorough medical examination in all cases.
- Inflammatory bowel diseases (IBD):
- Ulcerative colitis (ulcerative colitis): An autoimmune disease associated with chronic inflammation of the colon, which spreads from the rectum. It is characterised by bloody, pus-filled diarrhoea, frequent, urgent bowel movements and abdominal pain.
- Crohn's disease: It can affect any part of the digestive tract, from the oral cavity to the rectum. Symptoms vary, but abdominal pain, diarrhoea (which may be bloody), weight loss and weakness are common.
- Infectious colitis (infectious colitis): Inflammation caused by various bacteria (e.g. Campylobacter, Salmonella, Shigella, E. coli) or parasites, which may be associated with bloody diarrhoea, fever and abdominal cramps.
- Ischaemic colitis: Inflammation due to insufficient blood supply to a section of the large intestine. More common in older patients with vascular disease. It is characterised by sudden onset of abdominal pain and bloody stools.
- Peptic ulcer (stomach and duodenal ulcer): A wound on the lining of the stomach or duodenum. If the ulcer involves a blood vessel, it can cause bleeding, which takes the form of black, pitchy stools (melaena). In severe cases, blood vomiting (haematemesis) may also occur. The most common causes of ulcers are Helicobacter pylori infection and taking non-steroidal anti-inflammatory drugs (NSAIDs).
- Angiodysplasia: Tiny, abnormal vasodilatations in the mucous membrane of the digestive tract (most often the large intestine). These can bleed easily, usually painlessly. They can cause recurrent or hidden bleeding, especially in older age.
- Polyps and tumours:
- Colon polyps: Mostly benign growths protruding from the intestinal wall. Over time, however, they can become malignant and it is important to remove them. They can cause hidden or visible bleeding.
- Colorectal cancer (colorectal carcinoma): It is one of the most common malignant tumours. Bloody stools can be one of the most important warning signs, especially when associated with altered bowel movements, abdominal pain, unclear weight loss or iron deficiency anaemia.
When should we seek medical advice immediately?
Although bloody stools are not always an emergency, in some cases immediate medical attention is needed. Visit your nearest emergency department if you experience any of the following:
- Large amounts of blood are continuously passed in the stool.
- Bloody stools may be accompanied by dizziness, weakness, fainting, paleness, cold sweats or a rapid pulse (signs of significant blood loss).
- It is accompanied by severe, unremitting abdominal pain or abdominal cramps.
- Vomiting of blood (fresh red or coffee grounds-like) may occur.
- A high fever develops.
Diagnostics: how do you find out the cause?
To make an accurate diagnosis, a gastroenterologist will carry out a thorough examination. Don't be afraid of tests, they are essential for a correct diagnosis and appropriate treatment.
- History taking and physical examination: The doctor will ask you about your symptoms (how long they have been present, the nature of the bleeding, any other complaints you have), your medical history, your medicines and your family history. This will be followed by a physical examination, which will include palpation of the abdomen and a rectal digital rectal examination (RDV). The latter may be a little uncomfortable, but it can provide quick and important information about lesions around the anus.
- Laboratory tests: Blood counts (to detect anaemia), inflammatory parameters, coagulation values and liver function are essential. Stool samples are taken to detect occult bleeding or infection.
- Endoscopic examinations: These are the most important procedures in identifying the source of bleeding. A flexible instrument with a camera (endoscope) can be used to directly view the inner surface of the digestive tract and, if necessary, take a histological sample (biopsy) or treat the bleeding immediately.
- Colonoscopy (colonoscopy): The „gold standard” for investigating lower GI bleeding. The entire colon and the last part of the small intestine are examined. A thorough bowel cleansing is required before the test. From Endomedix Gastroenterology Centre using modern, gentle procedures, even under anaesthesia, to increase the patient's comfort.
- Gastroscopy (gastroscopy): In case of suspected upper GI bleeding (e.g. melaena), the esophagus, stomach and duodenum are examined.
- Imaging studies: If endoscopy is unsuccessful, or in the case of active, severe bleeding, a CT angiogram (CTA) may be needed to show the bleeding vessel using contrast material.
Prevention and lifestyle advice
Many conditions that cause bloody stools can be prevented or the risk reduced through lifestyle awareness.
- A diet rich in fibre: Eating adequate amounts of fibre (vegetables, fruit, whole grains) helps prevent constipation, a major risk factor for haemorrhoids and rectal tears. Fibre may also play a role in preventing colon cancer.
- Drink plenty of fluids: Drinking at least 2-2.5 litres of fluid (mainly water) a day is essential for softening stools and regular bowel movements.
- Regular physical activity: Exercise stimulates bowel function and helps maintain an ideal body weight, reducing the risk of many digestive diseases.
- Participation in screening tests: Colorectal cancer is one of the most easily screened cancers. Regular screening tests (e.g. stool blood test, colonoscopy) are recommended for people over 45-50 years of age, or earlier if there is a family history of polyps. By removing polyps at an early stage, cancer can be prevented.
Leave it to the experts!
Blood in the stool can be a serious cause for concern, but the most important thing is not to panic and ignore the symptom. Early and accurate diagnosis is the key to successful treatment.
From Endomedix Gastroenterology Centre experienced specialists and state-of-the-art diagnostic tools to quickly and reliably identify the cause of your symptoms. Our empathetic, patient-centred approach and gentle examinations, even under anaesthesia, help to ease the fear of interventions.
Don't delay an investigation! Take action for your health and make an appointment for a gastroenterology consultation today!
