Rectal bleeding

Dr. Suvansh Raj NirulaMBBS

December 16, 2020

January 29, 2024

Rectal bleeding
Rectal bleeding

Bleeding through one’s anus, either while defecating or not, is known as rectal bleeding.

Rectal bleeding is usually noticed while using the toilet and may not be associated with other symptoms. Conversely, trace amounts of blood in stools, invisible to the naked eye, may be diagnosed by symptomatology.

Usually, rectal bleeding is benign but can occasionally be due to colon cancer or stomach cancer. Through taking a proper medical history of the patient, physical examination and intelligent investigations, the root cause of the bleed can be diagnosed and treated.

Rarely, massive lower gastrointestinal bleeding can cause hypovolemic shock which needs emergency medical care. (Read more: Hypovolemia symptoms, causes, diagnosis, treatment)

Read on to know more:

What is rectal bleeding?

The rectum is the final segment of the large intestine, through which the remnants of undigested matter, or faeces, is expelled out. Any bleeding that presents through this orifice is referred to as rectal bleeding.

Blood may present either as obvious bleeding (frank blood) or mixed with stool. It is typically noticed by the patient in the toilet pan, mixed with the water in the toilet bowl, on toilet paper after wiping or in faeces.

While in some cases the presence of blood in stool is appreciable by the change of its colour, at other times it is invisible to the naked eye (occult blood) and is only suspected by the doctor based on other symptoms or clinical history.

Based on the principle that blood grows darker with distance traversed through the colon and subsequent action of digestive juices, different colours of stool potentially indicate the site of the bleed.

Although most rectal bleeds are mild; rarely, severe bleeding sufficient to cause hypovolemic shock, due to depleted blood volume, can also occur.

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Types of rectal bleeding (based on colour)

In case of rectal bleeding, the colour of the faeces can help a medical professional determine the source of the bleed. There are at least four different types of rectal bleeding:

  • Frank blood: Rectorrhagia is the fresh bleeding through anus unassociated with passage of stool.
  • Haematochezia: Refers to the passage of fresh bright blood in faeces or with it. It usually indicates a lower gastrointestinal bleed (shorter distance travelled to the anus for expulsion results in a brighter colour) but can also occur concomitantly with massive haematemesis (emission of blood through the mouth or vomiting blood). 
  • Melena: While melena also refers to the presence of blood in stool, in contrast with haematochezia, it presents as dark sticky tarry foul-smelling stools. The darker colour is due to the breakdown of haemoglobin of blood as it descends from the upper gastrointestinal tract (due to upper intestinal bleed or swallowed blood). However, black tarry stools can also be caused by use of iron supplements, consumption of beetroots or by medicines like pepto-bismol.
  • Occult blood in stool: At times, there may be reason to believe that blood loss is, or can, take place undetected in the digestive tract. Common causes for concern are anaemia of unknown origin, liver disease that can give rise to oesophageal varices which in turn could bleed, suspected peptic ulcer and a family history of colonic cancer. The stool sample is tested chemically for the presence of heme (the iron component of blood) and a positive test can prompt further investigations to elucidate the cause of bleeding.

Rectal bleeding causes

Any bleed in the gastrointestinal tract escapes either through the oral or the anal orifice. If the quantity isn’t sufficient for the blood to be appreciable, occult blood may be present in the stool. While lower gastrointestinal bleeds (haematochezia or rectorrhagia) more commonly present at the rectum, bleeds from the upper gastrointestinal tract (melena) can also manifest in stool.

Causes of rectal bleeding in children

Most causes of rectal bleeding in children are benign. Common ones include:

  • Anal fissures: At times due to repeated passage of hard stools, a tear may occur in the thin mucosa that lines the anal canal. This is easily distinguishable and presents with bright red blood. An anal fissure can be very painful. 
  • Volvulus: Sometimes the bowel loop can twist upon itself and get knotted, leading to intestinal obstruction. Signs of volvulus include abdominal pain and distension, bloatingconstipationvomiting and blood in stools.
  • Intussusception: A very common cause of intestinal blockage in young babies, it occurs due to one segment of the bowel telescoping into the adjoining bowel segment. This, too, presents with similar signs of intestinal obstruction. Classically “red currant jelly stools” are present. 
  • Intestinal polyps: These polyps are generally present at birth itself and are often benign (not cancerous). They can cause repeated painless bleeding. 
  • Meckel’s diverticulitis: Meckel’s diverticulum is an aberration of the intestinal wall present in 2% of the population. When it gets inflamed (diverticulitis), rectal bleeding can take place.
  • Gastroenteritis: Bloody diarrhoea known as dysentery can occur in children (read more: stomach infections). 
  • Inflammatory bowel disease: In inflammatory bowel disease—whether it is ulcerative colitis or Crohn’s disease—genetic or immune-linked chronic inflammation and ulceration of the digestive tract occurs. Ulcers may be limited to the colon, as with ulcerative colitis, or be extensively widespread throughout the tract (Crohn’s disease). These ulcers generally bleed. 

Some rarer causes of rectal bleeding in children that should be ruled out include:

  • Necrotising enterocolitis: Necrotising enterocolitis is a very serious condition affecting the gut of premature babies. In this condition, bacteria invade the intestinal walls and cause the tissue to die (necrosis). It is a medical emergency requiring urgent management to save the gut. 
  • Hirschsprung’s disease: A congenital disease in which the neurons (nerve cells) of the nerves in the intestinal muscles are missing. Without these neurons, the muscles do not contract and relax, causing lack of normal intestinal movements (peristalsis). This creates a megacolon, or dilated pouch of intestine with no movement where food collects. 
  • Sexual abuse: This should be ruled out in children, especially younger ones.

Causes of rectal bleeding in adults

Rectal bleeding is more common in adults. While mostly due to benign causes, it can sometimes be due to colon cancer. Common causes are:

  • Haemorrhoids (or piles): Piles are swellings containing dilated blood vessels that may either remain prolapsed or may prolapse only while sitting on the toilet. They are usually painless and may go undetected, unless associated with bleeding (which is described as a “splash in the pan”). Thrombosed piles are painful. While they can regress spontaneously, sometimes surgical management is needed. 
  • Anal fissure: A tear in anal canal mucosa, arising by passing hard stools. This condition can be extremely painful and may require sphincterotomy operation (it is a surgery done to open up or stretch the anal sphincter more).
  • Fistula in ano: An anal fistula could occur because of improper resolution of anal abscesses (collection of pus due to infection). Fistula is an abnormal tract connecting the anal canal to the perianal skin.
  • Diverticular disease: When we don’t eat enough fibre, the pressure inside the intestines rises and portions of the colonic wall outpouch as diverticula, causing diverticulosis. These diverticula may get inflamed (diverticulitis) and can also bleed. 
  • Inflammatory bowel disease (IBD): IBD—ulcerative colitis or Crohn’s disease—can occur in both children and adults. 
  • Colon polyps: Polyps are abnormal finger-like projections in the colon that can be benign or malignant (cancerous). Sometimes the propensity to colonic polyps runs in families and in such cases the probability of progression to cancer is high. 
  • Cancer (colorectal or anal): Colorectal cancer and anal cancer are often associated with an inherited genetic syndrome and run in families. It is imperative to begin screening at a young age because the chance of familial polyps progressing to cancer is very high.

Less common causes of rectal bleeding in adults include:

  • Infectious gastroenteritis: Some stomach bugs can cause blood to appear along with loose stools—these infections are called dysentery. Shigella bacteria is a common causative agent.
  • Coagulation disorders: Blood clotting disorders or health conditions in which the formation of blood clots is impeded. These disorders, such as haemophilia and Von Willebrand’s disease, can give rise to internal bleeding at various sites in the body and that blood can appear in stool. 
  • Angiodysplasia: Rarely, malformed blood vessels in the colon too can give rise to rectal bleeding. This can also occur in children. 
  • Massive upper gastrointestinal bleed: Massive expulsion of blood through the mouth (haematemesis) or swallowed blood can naturally appear in the faeces.

Signs and symptoms of rectal bleeding

Usually, rectal bleeding is mild to moderate. However, sometimes severe bleeding can cause the patient to go into shock. Although usually benign, it can also be associated with malignancy and signs of such. Here are some of the symptoms that may be seen with rectal bleeding:

Anal symptoms: 

  • Pain: extreme pain could be a sign of anal fissures
  • Soreness
  • Itching: common with haemorrhoids 

Occult bleeding is suspected by signs and symptoms of anaemia

Mild to moderate bleeding can be seen as presence of blood or change in colour of bowel movements.

  • Frank bleeding: Presence of fresh bright blood unrelated to faeces; often this occurs due to anal fissures, haemorrhoids and polyps. 
  • Hematochezia: Bright red blood, either coating faeces or mixed with it. Lower gastrointestinal bleeds due to piles, fissures, fistulae, polyps or even rectal cancer should be suspected. 
  • Melena: Dark tarry black foul-smelling stools that stick to the toilet bowl. Suspicion of upper gastrointestinal bleeds caused by peptic ulcer disease, liver disease (with portal hypertension or rise in blood pressure in the portal vein that connects the digestive organs to the liver—this, in turn, could give rise to esophageal bleeding) and stomach cancer arise. 

These are the signs to look out for for massive bleeding associated with hypovolemic shock:

  • A significant amount of dark or bright blood 
  • Falling blood pressure: Systolic blood pressure (the higher number on the blood pressure machine) below 90mm of mercury (mmHg) (normally it is between 90 mmHg and 120 mmHg)
  • Initial drop in haematocrit and haemoglobin less than 6 grams per decilitre (g/dL) of blood (normal values are 13.5-17.5 g/dL for men and 12-15.5 g/dL for adult women)
  • Continued bleeding for three days or more
  • Rebleed within a week
  • A requirement of two units or more for blood transfusion

Massive lower gastrointestinal bleeding requires immediate hospital admission.

Malignancy could be associated with:

  • Unexplained weight loss
  • Altered bowel habits
  • Tenesmus: A sensation of incomplete emptying of bowels while defecating 
  • Family history of colon cancer or polyposis

Diagnosis of rectal bleeding, how can you tell when to seek medical advice when there are so many reasons why faeces change colour and so many potential causes of blood in stool or bleeding from the anus?

You should consult with a doctor if bleeding is present with:

  • Changed stool colour
  • Abdominal pain 
  • Vomiting
  • Altered bowel habits and tenesmus
  • Prolonged or severe diarrhoea 
  • Weight loss
  • The bleeding is getting worse

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Visit the emergency department if:

  • There is massive bleeding 
  • Bleeding from other sites
  • Trauma
  • You are feeling faint or dizzy (read more: fainting or syncope)
  • You’ve been taking blood thinners

Based on relevant history (including family medical history and anticoagulant drug history), presentation, and physical examination, a clinical diagnosis can be made. To confirm and further elucidate the cause of rectal bleeding, to treat it, further investigations are done.

Examination for rectal bleeding: 

The doctor may conduct the following examinations to identify the reason for rectal bleeding:

  • General examination: The doctor would check for signs of pallor (due to anaemia), cardiovascular changes of shock (low blood pressure, bounding fast pulse) and weight loss.
  • Abdominal examination: Any signs of liver disease (dilated veins around umbilicus, enlarged liver, etc.) and abnormal masses or lumps (stomach cancer, etc.) are noted. 
  • Rectal examination:
    • Digital rectal examination is a must to confirm rectal bleed as well as rule out obvious masses in the rectum. 
    • Proctoscopy can supplement digital rectal examination and allows better visualisation of piles
    • Flexible sigmoidoscopy: A flexible tube with camera is inserted through the rectum to visualise the tract up till the colon. Helps rule out causes of lower gastrointestinal bleeding other than piles, fissures and fistulae. 
    • Colonoscopy is a definitive and unpleasant investigation reserved for individuals over 40 with suspicion of cancer or those in shock. A colonoscopy allows visualisation of the entire colon and permits biopsy sampling. In case your doctor suggests a colonoscopy, you can prepare for it by following the instructions given by your doctor such as:
      • Eat low-fibre light meals for three to four days leading up to the procedure
      • Only consume clear liquid food (avoid dairy products and coloured juices) the day before the procedure to prevent discolouration of the intestines
      • Strong laxatives are given in two doses, one at night and one six hours before the procedure. Forceful diarrhoeabloating and cramps may occur. 

Investigations for rectal bleeding may include:

  • Blood tests:
  • Stool examination:
    • Colour and appearance indicate possible location of bleed
    • In faecal occult blood test, a small stool sample is tested with a reagent to check for the presence of heme iron in stool
  • Imaging: Classical signs for many causes of rectal bleeding exist in radiodiagnosis. 
    • X-ray: Characteristic mid-gut rotation of volvulus is picked up amongst other problems. 
    • Ultrasound: typical signs of intussusception, volvulus, and diverticulitis exist. Tumours may also be seen. 
    • Computed tomography (CT scan): Better visualisation and description of dimensions of tumours and other causes.

Rectal bleeding treatment

Most cases resolve spontaneously, for others, one or more of the following may be recommended by a doctor:

  • Home management: In young patients with minimal bleeding, with doctor’s advice, home remedies may be useful:
    • Drink plenty of fluids
    • Avoid alcohol to prevent dehydration 
    • Increase fibre in diet
    • Reduce straining while defecating
    • Don’t sit on the toilet for too long
    • Cleanse anal region well
    • Sitz baths: sitting in warm water with the buttocks submerged relieves pain and itching
  • Medical management:
    • Pain relief
    • Stool softeners and laxatives: treat constipation 
    • Anti-inflammatory drugs like aminosalicylates (sulfasalazine, mesalamine), steroids, immunomodulators (azathioprine, methotrexate) and injectables like infliximab are used to control inflammatory bowel disease
    • Antibiotics may be prescribed for infectious gastroenteritis and dysentery. It is important not to self-medicate. If you are prescribed antibiotics, make sure to go and see the doctor at the completion of the course. Your doctor will be able to advise on whether to continue the medication for a while longer or if the infection has cleared. This is important to get well properly and avoid antibiotic resistance.
    • Aspirin: Low dose aspirin is used to prevent colon cancer in familial polyposis patients. Continued use of aspirin is not recommended without the express recommendation of your doctor.
  • Surgical management: This remains the definitive management for congenital anomalies, polyps and tumours. Sometimes surgical intervention in benign anal conditions like piles, fissures and fistulae are necessary.
  • Emergency management: Acute lower gastrointestinal bleeding with shock calls for an upper gastrointestinal endoscopy, while the shock is corrected simultaneously, followed by colonoscopy, if needed, to identify the site of bleed. As soon as the site is located, angiography is done. Emergency surgery may be needed to stop bleeding.

Prognosis or outcome in rectal bleeding

Prognosis depends on the cause of bleeding. While benign causes of rectal bleeding either resolve spontaneously or are managed effectively with medical or surgical intervention, the average five-year survival rate with colorectal cancer is around 60%. However, it dips to 15% if the cancer has spread.

Medicines for Rectal bleeding

Medicines listed below are available for Rectal bleeding. Please note that you should not take any medicines without doctor consultation. Taking any medicine without doctor's consultation can cause serious problems.