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It is a widely believed myth that vomiting in cats is normal. Even in cats that look completely healthy, frequent vomiting can be a sign of disease. If your cat vomits more than twice a month, or if the frequency of the vomiting is increasing, or if they have lost weight then we strongly recommend that this is investigated.

Causes of Vomiting

There are many causes of vomiting in cats. Cats that tend to eat grass or other hard to-digest plants may frequently vomit. Restricting them from access to grass may solve the problem. However often the vomiting can be due to a more serious underlying disease which needs to be diagnosed in order to treat it specifically.

Some of the most frequently diagnosed conditions include:

• Dietary intolerance and dietary hypersensitivity. These cats will generally respond to a strict hypoallergenic or elimination diet.
• Inflammatory bowel disease
• Chronic gastritis
• Gastric and intestinal obstructions
• Gastric and intestinal cancer (lymphoma, adenocarcinoma, mast cell tumours)
• Intestinal polyps
• Fur balls. Although it is thought that cats who suffer from severe fur balls are likely to have an underlying intestinal disorder that affects the motility of the gut.
• Parasites such as intestinal worms. This is a very uncommon cause of vomiting in adult cats

Diagnostic tests

There are many diagnostic tests that can be performed to investigate for the long list of possible causes of your cat’s vomiting. After performing a thorough physical examination on your cat, our vet will recommend which tests to start with and then on the basis of the results, may recommend further testing.

In most cases, we will start off with performing a comprehensive blood and urine test to check for organ function, and in older cats we will also check their thyroid hormone levels. We may also need to examine the faeces, especially in younger cats.

Most cats will also require imaging to be performed to look for structural disease. This may involve taking x-rays of the abdomen with or without barium contrast and performing an abdominal ultrasound.

Ultrasound is the most useful non-invasive tool for assessing feline diseases that affect the stomach and small intestines. Our high frequency, high resolution ultrasound machine is capable of measuring increases in the thickness of the intestinal layer right down to the tenth of a millimetre. If intestinal thickening is found, there are two primary possible diagnoses: inflammatory bowel disease (IBD) and lymphoma, although about 5% of the time another disease will be found.

If intestinal thickening is observed on ultrasound, the only way to diagnose either is by obtaining full thickness biopsy samples of the small intestinal wall via abdominal surgery. Endoscopic biopsies are rarely recommended in cats because the biopsy obtained only samples the internal surface layer of the intestines. Most pathology in the cat’s intestine is found in the deeper layers.

Biopsies are sent to a veterinary pathologist who will determine if either IBD or lymphoma is present and can further classify the type of each. Once a final diagnosis is made, a specific treatment plan can be made and we can determine the prognosis.

Inflammatory bowel disease

Inflammatory bowel disease (IBD) affects about 50% of cats that have significant intestinal thickening. IBD occurs because of chronic inflammation of the gastrointestinal tract and can be caused by a number of diseases including bacterial and parasitic infections, and food allergies. However, in many cases the cause of IBD remains unknown or “idiopathic”. Current theories suggest that idiopathic IBD may be due to a breakdown in the relationship between the normal bacteria that reside in the gastrointestinal tract and the immune system of the gastrointestinal wall.

Inflammation in the intestinal wall interferes with digestion of food and absorption of nutrients. Cats with advanced IBD commonly have a history of weight loss coupled with an increased appetite as they attempt to make up for their weight loss and nutrient deficiencies. Poor motility of the thick intestines is associated with vomiting.

The mainstay of treatment for IBD involves dietary management with a hypoallergenic diet combined with use of immunosuppressive drugs. Most cases are initially started on corticosteroids such as prednisolone however in severe cases they may also need more potent drugs such as chlorambucil. Additional supportive treatments for IBD can include probiotics and vitamin B12 injections. Many cats will also be given a short course of anti-parasitic drugs and antibiotics.

IBD is not considered a curable disease, but proper treatment can control the disease and stop or slow the vomiting and weight loss. Overall, the prognosis is very good.

Lymphoma

Lymphoma is caused by cancer of the lymphoid tissues. Lymphoid tissue is found in lymph nodes, the tonsils, the spleen, the stomach, and the intestine. The greatest concentration is in the small intestine, so lymphoma is common in this location. Lymphoma accounts for about 45% of the cases of intestinal wall thickening, and it occurs in two forms: small cell lymphoma and lymphoblastic or large cell lymphoma. Biopsy is needed diagnose lymphoma and to distinguish between its different forms.

Lymphoma is the most responsive cancer we see in cats and up to 90% of cases undergoing treatment will experience complete remission with minimal side effects. Most treatments will involve the use of a combination of chemotherapy drugs called a “protocol”. Cats do not tend to experience the array or degree of side effects that humans do and very rarely experience nausea or vomiting. Many owners are surprised and relieved to see almost all cats undergoing chemotherapy treatment go through their protocol with minimal to no side effects.

Suppression of the bone marrow can occur with any chemotherapeutic drug however we see this very infrequently in our feline patients. We will carefully monitor your cat’s bone marrow function by taking regular blood samples to check the white blood cell counts. If their cell counts drop too low, we will withhold giving any further chemo treatment until their blood count returns to normal.

Hair loss does not occur commonly in cats undergoing chemotherapy. This is because chemotherapy only affects hair that grows continually. Body hair in cats does not grow continually however some cats may lose their whiskers with some treatments. Hair re-growth from shaved areas does tend to be sparse whilst on chemotherapy treatment.

It is important that we have realistic goals when treating cancer, and thus you will often hear the term “remission” used more than “cure”. Even in people with lymphoma, the word “cure” is not used for lymphoma. Remission in cats means that vomiting or diarrhoea stops, their appetites return to normal, lost weight is regained, and the small intestinal wall returns to normal thickness.

Treatment for the two types of lymphoma carries different prognoses. Cats with lymphoblastic lymphoma have a lower success rate; fortunately, only about 15% of the lymphoma cases are of this type. Although many cats respond well to treatment, the prognosis is always guarded. Cats with small cell lymphoma have a much better success rate. In our experience, about 70% to 75% will go into remission. The average time of remission is about two years, although we have seen cats live more than four years in remission.

Is vomiting hairballs really normal for cats?

There is no doubt that some cats, especially those with long hair, swallow so much hair during their normal grooming process that hairballs can develop in their stomach and in these individuals vomiting hairballs can be considered to be normal. However, that is not the case in all cats. A significant number of cats that vomit hairballs have underlying stomach and intestinal disease. IBD and lymphoma often lead to a motility disorder of the gastrointestinal tract. The thickened stomach wall and intestinal loops are unable to move hair through the digestive tract at its normal speed. This slower movement results in abnormal hair collection in the stomach or intestines, resulting in hairball formation.

If you notice your cat vomiting hairballs and they are not long-haired, or they are a poor groomer, or the vomiting of hairballs occurs more than twice a month then further investigation including an abdominal ultrasound is recommended.

If the intestines are found to be normal, a hairball diet or a hairball medication is definitely indicated. These diets are usually high in soluble fibre that attracts fluid to itself as it goes through the digestive tract. This softer, moister stool will carry hair through the digestive tract and out with the stool. The medications are lubricants or stool softening agents that also help to move hair through the digestive tract.

Stopping the conversion to cancer

A very important reason not to ignore your cat vomiting hairballs is that there is mounting evidence that untreated IBD may transform into intestinal lymphoma. If a cat has IBD and that is what is causing hairball formation, delaying treatment for their IBD may allow it to transform into lymphoma. Many cats that have been vomiting for months to years are found to have lymphoma. The abdominal ultrasound study is eventually performed because either weight loss becomes substantial or the frequency of vomiting increases which triggers the investigation process. In reality, most of the time that the cat was vomiting hairballs he or she had developed IBD, and then with time it transformed into lymphoma. When lymphoma developed, the signs became severe enough to seek a cause.

Therefore, whilst treating hairballs with special diets or medications may reduce your cat’s vomiting and control hairballs even if the underlying disease is IBD, it can still progress to lymphoma. Early diagnosis and treatment of IBD is strongly recommended as it is likely to dramatically reduce the risk of possible progression to lymphoma.

Disclaimer: Please note that the information provided on this page does not replace the advice of your veterinarian. If you are concerned about your cat’s health in any way, we strongly recommend you seek veterinary advice. 

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