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It can be terrifying to discover that your cat has blood in its stool. The presence of blood in the stool, or “hematochezia” can be a result of a minor intestinal upset, or a symptom of many more serious medical conditions.

Bleeding in the lower intestines, such as the colon and the rectum, generally causes hematochezia. It is characterized by the presence of bright, frank blood in the feces. Hematochezia should not be confused with melena, the passage of dark, tar-colored feces, caused by bleeding that occurs higher up in the intestinal tract.

If your cat has blood in its stool on only one occasion, and otherwise appears to be eating, drinking and acting normally, the cause may simply be a minor gastrointestinal upset, such as eating too much, eating a unfamiliar food, or eating something that does not agree with him. Some cats are especially sensitive to stress, and any sudden change in environment, such as adding a new pet to the household, having a baby or even a schedule change can induce colitis. Changing food brands suddenly can also cause this condition, as cats often require a gradual change of food in order to adjust without complications.

However, if your cat has any repeated episodes of blood in the stool, if he appears lethargic or depressed, or the blood is accompanied by diarrhea or vomiting, it can be a sign of a severe medical problem requiring veterinary assistance.

The most common cause of blood in the stool in cats is colitis, or inflammation of the colon. Colitis is a symptom of various gastro-intestinal disorders, and identifying the cause of the inflammation can be difficult.

When colitis occurs, inflammation of the colon causes the cells in the lining of the intestines to separate, becoming permeable and allowing water and secretion to leak out. Motility of the gut is affected, as is the ability of the colon to absorb water and store feces. This leads to frequent diarrhea, often with mucous and blood, as the food in the intestines passes through the colon before nutrients and water are utilized by the body.

Aside from blood in the stool, cats with colitis will defecate frequently, with very little stool actually being passed, and strain repeatedly in the litterbox. Because the biggest complication of colitis is rapid dehydration, veterinary attention should be sought anytime your cat has blood in its stool and diarrhea. Your veterinarian can treat the dehydration, as well as help to identify and treat the underlying causes.

Parasites are a common cause of colitis and bloody stools in kittens. Kittens typically acquire roundworms through the milk of an infected mother. Adult cats can acquire the parasite by eating a rodent or other animal that was affected with the parasite. These long, spaghetti like parasites can cause severe signs in young animals, including vomiting, diarrhea, bloody stools, coughing and gagging. If left untreated, the worms can cause pneumonia, intestinal obstructions and death.

Protozoa infections, such as Giardia and Coccidia, occur when a single-celled parasite is ingested via contaminated soil, food or water. This parasite can cause an array of gastrointestinal issues, from an occasional bout of soft stools to a severe episode of vomiting, diarrhea and hematochezia.

In unvaccinated cats and kittens, feline Panleukopenia can be a devastating disease. Also known as feline distemper, Panleukopenia is caused by the parvovirus and is highly contagious from cat to cat. It is of especially great concern in shelters, catteries and boarding facilities where it can remain active and infectious in the environment for months or even years. The virus is especially dangerous to kittens who have not fully developed their immune systems, and can cause a high fever, vomiting, nasal discharge, respiratory signs, diarrhea, hematochezia, dehydration and death.

In older cats that develop hematochezia, one of the main concerns is inflammatory bowel disease. Cats with IBD develop a chronic level of inflammatory cells in the gastrointestinal tract, and can affect the mucosa of different areas: the small intestine (enteritis), colon (colitis) and stomach (gastritis).

Unlike colitis that occurs due to a temporary intestinal upset, cats with IBD develop an inflammatory response in their intestines that does not resolve. The exact causes are unknown, but its origin has been linked to food sensitivities, bacteria in the intestinal tract, and immune system dysfunctions.

Left untreated, in the short run IBD can lead to poor digestion and nutrient absorption, as well as abdominal discomfort. Over time, the chronic inflammation can lead to scaring of the mucosa, and studies have shown that the scaring often leads to the development of lymphoma, a type of cancer, in the intestines.

Blood in the stool can also be attributed to more external causes, such as trauma to the rectum, anal gland abscesses, or tumors and polyps in the rectum.

If your cat has had more than one episode of blood in its stool, a veterinarian should examine him or her to rule out possible causes. Routine fecal screening can help to detect and eradicate internal parasites before they are able to cause severe damage to your pets’ intestinal tract. In addition, a fecal cytology can detect the presence of bacteria such as salmonella in the feces. A complete blood count (CBC) and blood chemistry analysis can help to access your cats general level of health, and may provide clues to possible viral or other causes.

Radiographs may be recommended to rule out an intestinal obstruction or blockage, and an ultrasound exam can help to diagnose any potential tumors, as well as access the condition of the intestines. If the bowel appears thickened, scarred or abnormal on the ultrasound, your veterinarian may recommend further tests to see if IBD, or even lymphoma may be causing your cats symptoms.

Regardless of the cause of the blood in the stool, cats that are having repeated episodes of diarrhea or vomiting may need to be hospitalized so that their dehydration can be corrected with IV fluids, and that medicine can be administered to control vomiting. Depending on the cause of the hematochezia, treating your cat may be as simple as administering a dewormer or changing his food, but only your veterinarian can determine what is causing your cats symptoms.


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