The problem: Rectal bleeding Vet’s advice
My three-year-old Labrador seems as happy as Larry but occasionally there is a spot of blood on his poo. Does this mean cancer?
In short, no. Tumours of the bowel can certainly cause bleeding but given his age, breed and otherwise good health, it is unlikely that cancer is the cause of this relatively common problem. In my opinion, there are two conditions that should be considered initially but, of course, you should take specific veterinary advice following examination.
Colitis
Colitis (or inflammation of the lower bowel or colon) is also known as Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS). Call it what you will, it is a common cause of diarrhoea in dogs, though it may just be associated with blood and/or mucus in faeces. Affected dogs will digest and absorb nutrients properly (so generally look fine) but there is malfunction of the colon, whose job it is to create a normal stool. The result is fairly simple: • Damage to the lining of the colon results
in inflammation •Hypermotility occurs, so faeces are passed more frequently • Failure to absorb water and electrolytes • Stimulation of goblet cells means more
mucus production • The inflamed colon bleeds • Soft, shiny bloody faeces with ‘faecal urgency’ occur In very mild cases (perhaps your dog) an owner might simply notice a spot of blood but in others, vomiting (associated with the colon and not the stomach) and chronic diarrhoea with frequent straining can occur. It is interesting to note that on many occasions owners actually report to us that they think their dog is constipated, as it pushes so much. Causes of colitis in dogs are myriad but the common ones are: • Food allergy • Bacterial infections – campylobacter,
salmonella, clostridia • Parasites – whipworm, giardia • Stress – boarding, change of environment • Sudden alterations of diet – introduction of
meat, offal, etc • Inappropriate consumption of decayed
dead stuff • Rubbish and foreign body consumption • Complicated immune mediated conditions Of course, there is a diagnostic pathway that can be followed but most dogs will respond to 24 hours of starvation followed by careful identification of the underlying cause. This may require supervision when walking, a change of diet, worming, antibiotic use (especially after bacterial culture of faeces) or perhaps an alteration of dietary fibre levels. Given your dog’s apparently mild symptoms, it may be worth adding fibre (try Pro-fibre) to each meal.
Chronic colitis that proves unresponsive to simple treatment can be very frustrating as relapses (as seen in humans with IBD and IBS) are common. We have many patients who just cannot tolerate any change whatsoever in their diet or circumstances without deteriorating.
Rectal polyps
Although less common, the symptoms you describe could be caused by a rectal polyp. These are usually benign (especially if they are small) and are simple flap-like extensions of the rectal wall. Sometimes, they will appear through the anus at the end of the dog passing a stool then disappear again, so it is well worth looking closely around this time. (Please explain to your neighbours what you are doing!) Your friendly vet should be able to feel polyps with a well-oiled and gloved finger.
Removal of rectal polyps is generally quite simple – if you can reach them. Under general anaesthesia, the polyp is pulled out through the anus and the neck ligated. I do hope that you find the source of your dog’s problem.
“Many patients can’t tolerate a change in diet”