Chronic Vomiting and Weight Loss in Cats
It is quite common for older cats (over age 7 years) to occasionally vomit or have diarrhea.
Sometimes just throwing up hairballs twice monthly can be a sign of serious intestinal disease.
When older cats vomit too frequently, more than 2-3 times per month, and they lose
weight, they have a medical problem. Please notify us immediately if this describes
Inflammatory Bowel Disease (IBD)
and Intestinal Lymphoma
Vomiting in the cat is not usually a problem of the stomach, but more likely a disease of the small
intestine. IBD and Lymphoma both cause thickening of the intestinal wall that results in a much
smaller food capacity and the inability of food or hairs to pass through.
The intestine is like a flimsy muscular balloon. When filled with food the intestine stretches open and
then it contracts. When it contracts, it pushes food forward. When it is thick, like a garden hose, in
disease and cannot balloon out, the intestinal contractions are not forceful enough to push food
forward. The cat‘s intestine and stomach fill up and then the cat vomits the food back up. Because the
intestines are so thickened, nutrients cannot absorb from the intestines into the blood. Many of these
cats are very hungry and will eat more often, then vomit.
Studies have shown that approximately 75% of older cats with frequent vomiting and weight loss have
either IBD or intestinal Lymphoma in about equal numbers. Approximately 25% of cats with vomiting
and weight loss can have one or more of a variety of other causes for this syndrome. These include a
local reaction in the intestines to a food component (food allergy), intestinal parasites, and other
diseases of old age like hyperthyroidism, kidney disease, or liver disease.
Inflammatory Bowel Disease (IBD) is a progressive problem in cats as inflammatory cells and fluid
thicken the bowel wall. It worsens as time goes by. Vomiting and diarrhea become more persistent and
the cats may lose more weight. Some cats lose their appetite, while others become more hungry.
Inflamed lower intestines bleed, so mucus, straining and flecks of bright blood may be present on the
cat's stool. When the majority of the pathology is higher up the digestive tract (closer to the stomach),
cats usually pass very large stools with little or no discomfort, no straining, no bright blood and little or
no mucus. Here is a link to a webpage describing IBD in more detail.
The other, more serious cause of these signs and symptoms is Intestinal Lymphoma, which is a cancer
of the small intestines unique to the cat. Cats with IBD can have a long life expectancy with treatment,
but 50% of cats with Intestinal Lymphoma do not survive more than a year without some kind of
treatment. It is extremely important to know what the disease is so we can properly treat it. New
medical treatments for intestinal Lymphoma can add several good months or years to your cat’s life.
Intestinal lymphoma is becoming one of the most commonly diagnosed cancers in cats. The intestine
is the largest organ in the body designed to fight off foreign invaders. The immune cells called
Lymphocytes are normally found within all the layers of the intestine in small numbers or in patches.
When the cancers start, the cancerous Lymphocytes are widely scattered along the intestine (diffuse)
and they cannot be felt, like a large solitary tumor could be felt. Sometimes this tumor will spread to
nearby tissues, like the liver and the pancreas resulting in a syndrome called triaditis. That is why we
take samples of the liver and pancreas when we diagnose these cats. Intestinal Lymphoma is not
associated with Feline Leukemia virus or the Feline Immunodeficiency virus, more common in
INTESTINAL LYMPHOMA The Stomach (S) Small Intestine (SI) and Large Intestine (LI). Notice that
Lymphoma is most often found in parts of the small intestine (SI) depicted in red. This also shows the
normal bowel wall (Nm) and the abnormally thickened bowel wall filled with cancer cells (Abn).
Only 50% of cats with Lymphoma survive one year without treatment. Cats with IBD have longer
survival. From Veterinary Pathology Journal.
Diagnostic Testing for IBD and Lymphoma
In all cats, we will do blood tests as a part of the diagnostic workup to rule out some of the other less
common diseases that can cause similar symptoms. In some outside cats, we will do 30 days of
intestinal parasite treatments, while in other cats we will do a diet trial for 6 weeks to rule out a food
There are no blood tests that can detect either IBD or Intestinal Lymphoma. It is diagnosed by
"excluding" the other causes of vomiting and weight loss.
An ultrasound examination of the intestines is highly recommended so that we can confirm thickened
segments of the small intestine. In most of these cats, we will examine 4 or 5 segments of the small
bowel because the disease can be present in one part of the intestine but not in others. Ultrasound is a
very rapid and non invasive method of determining if the walls are thickened so we can proceed to
other more invasive tests.
Because there is no way to feel for these thickened bowel segments, the only way to be sure of the
diagnosis of these 2 conditions is through intestinal biopsy, which requires surgery. We will open up
the cat's abdominal cavity and inspect the intestines, liver and pancreas tissues. Then 4 – 6 small
intestinal biopsies are taken from several thickened parts of the small intestine. We also take surgical
biopsy samples of the pancreas, and liver.
Then these suspect tissues are sent to a pathologist who will examine them and determine if there is any
disease present, if it is IBD, intestinal Lymphoma, or both. Some cats initially diagnosed with IBD that
fail to respond to treatment are subsequently diagnosed with intestinal lymphoma. Some cats that have
negative pathology reports will show disease within 6 months. There is mounting evidence that long
standing IBD can result in intestinal Lymphoma later on.
Once the cat’s diagnosis is established, then treatment can be chosen to help reduce vomiting and to
help the cat re-gain weight.
Treatment of Inflammatory Bowel Disease
In IBD, the cat is treated with high dose continuous prednisolone tablets or liquid tapered off as
symptoms begin to disappear. Vitamin B-12 injections are given at home by the owner to help
stimulate the appetite and to replace the lost B-12 from the poor absorption in the diseases intestines.
These are given twice weekly until the cat is eating without vomiting and begins to re-gain weight,
then it is reduced to once weekly. Probiotics are beneficial bacteria sprinkled on the food daily for 30
days to re-establish the normal balance of bacteria that should be in the intestines. In addition, a special
hypoallergenic diet that is low in carbohydrates but high in protein is fed. We have several types of this
diet, so we offer trial sizes of each of these diets to see which one your cat prefers.
Treatment of Intestinal Lymphoma
For intestinal Lymphoma, the treatment is similar to the IBD treatment, but another medication called
Lomustine is added to help shrink the Lymphoma. This is a very well tolerated oral drug in cats but it
can result in some hair loss. Another side effect is that it can depress the bone marrow that makes the
white blood cells. Before each monthly treatment a blood count is done to measure the white blood
cell count to make sure it is OK to give the medication. So once monthly, a blood count is done, shot
of a long acting prednisolone is given and the Lomustine is administered by the veterinarian. After 6
monthly treatments, the cat is assessed to monitor weight gain and the frequency of vomiting. If the
cat is doing better then the treatment reduced to every 2 months. Sometimes we need to use drugs that
help quiet the vomiting for few weeks at the start of the treatment.