By Dr. Becker
I've written several articles here at Mercola Healthy Pets about vomiting cats. My position has always been that chronic vomiting, even when it involves hairballs, is not "normal" behavior and requires investigation.
Fortunately, in recent years researchers have begun looking into the problem of persistent feline vomiting and its causes. In November 2013, a study was published in the Journal of the American Veterinary Medical Association (JAVMA) titled "Diagnosis of chronic small bowel disease in cats: 100 cases (2008–2012)."1 The study was conducted by a team of veterinarians and pathologists from the Alamo Feline Health Center in San Antonio, Texas Veterinary Pathology, and the College of Veterinary Medicine at Michigan State University.
Newly Published Study Yields Stunning Results
The study involved 100 pet cats with symptoms of chronic vomiting, weight loss, chronic diarrhea, or a combination. The authors of the study, led by Dr. Gary Norsworthy, owner of the Alamo Feline Health Center, reached the stunning conclusion that "chronic small bowel disease likely is the cause of these clinical signs in hundreds of thousands of cats."
According to Dr. Norsworthy, in his experience the top four excuses both cat owners and veterinarians offer for chronic vomiting are:
- "He eats too fast."
- "She has a sensitive stomach."
- "It's just hairballs."
- "He's just a puker."
As a result, the traditional veterinary approach to treating the problem has involved cat food formulas for "sensitive stomachs," hairball or hypoallergenic diets, medications for hairballs, and drugs for nausea and vomiting. Some combination of these approaches usually brings symptomatic relief, but rarely is the problem entirely resolved. And often symptoms return or increase over time.
Study Reveals 99 Out of 100 Cats Had Either Inflammatory Bowel Disease or Lymphoma
Norsworthy and his associates set out to determine if chronic small bowel disease was present in the 100 cats with the symptoms noted above, as well as thickening of the small bowel wall.
The kitties in the study received abdominal ultrasound exams to measure small bowel wall thickness in several places. If one or more measures exceeded a certain thickness, biopsies were performed to examine all layers of the bowel wall. The liver and pancreas were also biopsied.
The final diagnosis of the 100 cats revealed that only one had a normal small bowel. Forty-nine had enteritis (primarily inflammatory bowel disease – IBD), and the remaining 50 had one or more types of small bowel cancer. Lymphoma was present in 46 of 50, small cell neoplasia in 39, lymphoblastic neoplasia in 7, mast cell disease in 3, and adenocarcinoma in 1.
The kitties with lymphoma were slightly older than those with enteritis, and evidence suggests that chronic IBD progresses to lymphoma in some cats. This is why it's so important to thoroughly investigate chronic vomiting in kitties.
Dr. Norsworthy's theory is that the presence of vomiting alone or vomiting with weight loss indicates that small bowel thickening causes hypomotility, which is deficient motility or movement of all or part of the GI tract. Ingested hair and food move through the cat's bowel at an abnormally slow speed. As more is ingested, the full bowel causes reflux vomiting. The thicker the bowel wall gets, the less nutrients are absorbed, which results in weight loss coupled with increased hunger. These are classic signs of intestinal lymphoma in cats.
Hairballs May Actually Be a Sign of Chronic Small Bowel Disease
Dr. Norsworthy also believes that hypomotility of the small bowel is the cause of hairball formation. Many of the cats in the study threw up hair or hairballs over 50 percent of the time. In cats with small bowel disease, ingested hair moves slower than normal through the digestive tract, resulting in hairball formation.
"I am convinced that the vomiting of hairballs is a sign of chronic small bowel disease if it occurs twice a month or more in any cat; or if it occurs once every two months or more in shorthaired cats; or if it occurs in cats that are not fastidious groomers, i.e., presented with many mats in their hair coats or with heavy dandruff," says Norsworthy.
He recommends that veterinarians proactively ask clients with cats about chronic vomiting. As discussed earlier, many cat owners consider chronic vomiting to be normal behavior and are not likely to mention it without prompting. Sadly many vets also assume some cats are just more prone to vomiting and don't address this symptom as a reason for concern.
Best Diagnosis of Small Bowel Disease Requires Surgical Biopsy
Norsworthy recommends surgical biopsy over endoscopy in suspected cases of small bowel disease for two reasons. Number one, over 75 percent of the cats in the study had segmental disease -- meaning sections of healthy bowel were interspersed with sections of diseased tissue -- that was confirmed by visual examination during surgery. In addition, according to Dr. Norsworthy, many cats had disease in areas that were not accessible with endoscopic biopsy tools.
Secondly, endoscopic biopsies usually contain only mucosal tissue, and pathologists prefer to look at all the layers of tissue, especially in ambiguous cases. In a future report, Dr. Norsworthy will discuss the differing treatment responses and prognosis for cats with mucosal lymphoma vs. cats with lymphoma that has penetrated deeper into the bowel wall.
Dr. Norsworthy feels "It is time to quit accepting our timeworn excuses and treating these cats symptomatically." He advises pet owners and veterinarians to get a diagnosis so these kitties can be treated appropriately, potentially preventing cases of IBD from progressing to lymphoma.
Now Let's See Some Research on the Root Cause of Chronic Small Bowel Disease in Today's Cats
Dr. Norsworthy's study sheds some much-needed light on what seems to be a very common cause of chronic vomiting in pet cats -- small bowel disease. The downside to pursuing a confirmed diagnosis, of course, is the invasive nature of surgical biopsies, as well as the cost.
And while the study addresses a probable root cause of chronic vomiting, it doesn't address potential root causes of small bowel disease in, by Dr. Norsworthy's calculations, hundreds of thousands of cats. The study also doesn't address lifestyle issues. Is small bowel disease a problem of wild cats as well? Cats living in feral colonies? Free-roaming cats? Or is it a problem primarily of housecats?
My guess is it's the latter. And more specifically, it's very likely a problem of housecats fed processed cat food -- primarily kibble. The vast majority of affordable commercial cat food is grain-based. The digestive tracts of cats, who are obligate carnivores, are not designed to process grain. It's reasonable to think a decade or so of eating a biologically inappropriate diet containing a host of GMOs (genetically modified organisms) might cause serious digestive disease.
In addition, most commercial pet foods contain a long list of additives and preservatives, not to mention the potentially toxic changes that take place in the actual food ingredients during processing. It's entirely possible some of the chemicals present in processed cat food cause degenerative changes in the feline digestive tract over time. Pet food trials, after all, do not follow animals from weaning to death. The food most pets eat was tested over a period of weeks before hitting store shelves. If it didn't cause obvious, immediate problems for the animals testing it, it was considered safe.
If you're interested in learning how to feed your obligate carnivore kitty the species-appropriate food her body is designed to effortlessly digest and absorb, there's a wealth of information on the topic here at Mercola Healthy Pets. I recommend you start with my three-part video series on raw pet food diets:
Part 1 - "The Feeding Mistake Linked to the Cause of Most Disease - Are You Making It?"
Part 2 - "The Biggest Myths About Raw Food (and Why They're Mostly Nonsense)"
Part 3 - "Common Feeding Mistakes That Can Harm Your Pet"