Over 80% of people will experience rectal bleeding at some point in their lifetime. The causes of such bleeds are multiple and most often the underlying problem is not a serious one. However, this is not always the case – bleeding from your bowels should always be reported to your doctor so that an accurate assessment of your bleeding can be made.

Find here information on the potential causes of rectal bleeding, the tests available to confirm the diagnosis and some general guidelines on how to access help when you experience rectal bleeding.

What types of rectal bleeding occur?

Rectal blood can be visible to the human eye (overt) or invisible (occult). Visible blood may be fresh, easily recognisable blood just like the blood that we see when we cut or graze our skin and typically separate from the faecal waste. Fresh blood is often evident on tissue paper when wiping or might drip from the anus. In some individuals it might even splatter the toilet bowl quite alarmingly. Visible blood can also emerge in the form of older blood – often a darker purple-to-black colour and usually passed as a motion comprising mostly blood. Occult bleeding is not visible to the naked eye since the blood is hidden within the faeces. A sample of faeces is submitted to a laboratory and analysed for the presence of blood residue.

What causes rectal bleeding?

Bleeding from the bowels is never a spontaneous event – it only occurs when there is an underlying abnormality, whether it be a harmless one or a sinister one. The majority of the abnormalities that lead to bleeding are harmless ones, but only investigations can confidently distinguish between the two.

A list of some of the more common conditions causing bleeding are shown below. This list is not complete and is provided in no particular order of the likelihood of bleeding sources:

• Haemorrhoids (piles)

• Fissures (a tear or crack in the anal skin)

• Colitis (inflammation of the colon) or proctitis (inflammation of the rectum)

• Diverticular disease (little pouches or pockets in the wall of the bowel)

• Diverticulitis (inflammation in the diverticular disease)

• Angiodysplasia (small clusters of blood vessels within the bowel lining)

• Ulcers (shallow craters in the gut lining)

• Gastritis (inflammation of the stomach lining)

• Duodenitis (inflammation of the duodenum)

• Oesophagitis (inflammation of the oesophagus)

• Polyps (benign growths that can sometimes evolve into cancer)

• Cancer (malignant growths that can spread)

Many of these conditions will cause more than just bleeding alone and some will be evident during a routine consultation. Your doctor will often narrow down the list of potential causes by seeking more details about your recent health and by examining you.

When should I seek medical help?

We encourage you to report rectal bleeding to your doctor promptly, since the source of bleeding should never be presumed without the benefit of a detailed history, a careful examination and the knowledge of how to reliably risk stratify patients who experience rectal bleeding. Even in the hands of experts it is impossible to guarantee that bleeding is innocent (or not) but at least the likelihood of being correct is improved. Overall, it is better to err on the side of safety – too often patients guess incorrectly about what is at fault or they procrastinate too long whilst a serious condition progresses. Bowel cancer screening programs remind us that some bowel cancer patients were oblivious to the presence of their cancer i.e. they had no clue that there was a serious problem going on within them. If you experience bleeding, chat to your doctor without undue delay.

What investigations might be required?

Rectal bleeding tests are performed to confirm the locality of the bleeding point and identify what is producing the bleeding.

• If the bleeding is purely fresh blood and in isolation from any other symptoms, your specialist will probably perform a “proctoscopy” or a “rigid sigmoidoscopy” inspection of the anus and rectum. A proctoscopy is a short plastic inspection tube with a torch light that is gently inserted via the anus with lubricant to inspect the lower rectum and the anal canal.

• Bleeding that is arising from high up in the digestive system usually manifests with only occult (invisible) blood in the waste or with anaemia. If bleeding from high-up in the digestive system is suspected, you are likely to be offered a “Gastroscopy” test.

• Inspection of the lower colon and rectum can be achieved by a “flexible sigmoidoscopy” procedure.

• Full inspection of the rectum and colon requires complete clearance of waste from the bowel. The empty bowel must then be inflated a little so that the walls are smoothly outlined for an inspection. This is achieved in two possible ways: “Colonoscopy” or “CT colonography”.

It is challenging to pinpoint where bleeding conditions in your small intestine are situated. No camera scope can inspect the full length of the small intestine, only the first 30cm and the last 20cm (at best) of an organ early 3 metres long. If your small intestine requires evaluation, this can be done in one of three ways:

Radiological imaging

A CT scan of the small intestine (known as a “CT enterogram”) or an MRI scan of the small intestine (known as an “MR enterogram”) can be performed. These scans involve you drinking a dye, or having a dye injected via a vein, and a subsequent scan. The procedure is painless and usually over within 15-45 minutes.

Laparoscopic techniques allow an excellent view of the pelvic floor and enable accurate identification of the pelvic floor defects. Laparoscopic surgery is less invasive than other procedures. It minimises the extent of vaginal repair, thus reducing the risk of painful internal scars.

As with all laparoscopic procedures, hospitalisation is comparatively short, pain is minimised and recovery is fast.

Indirect chemical testing

Most parts of the digestive tract will produce a chemical called “Calprotectin” whenever it is diseased. The chemical doesn’t specify which disease is at fault or where the disease is located, but the presence of excessive Calprotectin within your stool may be helpful to highlight that there might be a disease process in the parts that couldn’t be reached by cameras. Calprotectin is fairly reliable in reassuring (if it is normal) or flagging something problematic (if it is substantially elevated).

PillCam

This is a tiny camera installed in a capsule that is then swallowed. As the capsule passes through the digestive system it takes 2-6 photographs of the intestine every second. These photos are transmitted to a data capture device that you carry with you for a few hours. The combined photo frames produce a video “tour” through your intestine and the video is viewed by your doctor to spot any sources of your bleeding.

Read more about our PillCam testing here

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Your specialist will discuss these options with you during a consultation. They will make recommendations for the most appropriate tests for your circumstances and they work their way through potential tests in a logical and pragmatic way using the best international literature to guide their choice of test for you. We always strive to choose the simplest, safest, most effective, most efficient and most reliable test to find solutions to your problems.