Feline inflammatory bowel disease (IBD) is a chronic condition affecting a cat’s gastrointestinal tract, leading to irritation and inflammation. This inflammation infiltrates the GI tract walls, causing them to thicken and impairing the cat’s ability to properly digest and absorb food. While cats of any age can develop IBD, it is most commonly diagnosed in middle-aged to older cats. The exact cause remains unknown, but current research points to a complex interplay between the immune system, diet, intestinal bacterial populations, and environmental factors. Genetic predispositions within the immune system are also considered potential contributors, drawing parallels to IBD in humans and dogs.
IBD can manifest in various forms depending on the affected part of the GI tract and the type of inflammatory cells involved. Gastritis occurs when the stomach is inflamed, enteritis when the small intestine is affected, and colitis when the large intestine (colon) is inflamed. The most prevalent form, lymphocytic plasmacytic enteritis, is characterized by the invasion of inflammatory lymphocytes and plasma cells into the small intestine. Eosinophils, a type of inflammatory white blood cell, are also frequently implicated in feline IBD. While they can sometimes be the predominant cell type, as seen in eosinophilic gastroenteritis, they are more often found as part of a mixed inflammatory cell population. Less common forms include neutrophilic IBD (involving neutrophils) and granulomatous IBD (involving macrophages). In some instances, IBD may be associated with inflammation in other abdominal organs, such as the liver and pancreas.
Clinical Signs of Feline IBD
The common signs associated with feline IBD are broad and can include vomiting, unexplained weight loss, diarrhea, the presence of blood in stools, lethargy, and a reduced appetite. The severity and frequency of these signs can vary significantly, and the most prominent symptoms often depend on which sections of the GI tract are most affected. For instance, inflammation in the stomach or the upper parts of the small intestine is more likely to result in persistent vomiting. Conversely, inflammation predominantly in the colon tends to cause diarrhea, which may or may not be accompanied by blood.
Diagnosing Inflammatory Bowel Disease in Cats
Diagnosing feline IBD is a comprehensive process because many of its symptoms overlap with those of other feline diseases. Your veterinarian will likely initiate a thorough diagnostic workup, which may include baseline blood tests, fecal examinations, X-rays, and an abdominal ultrasound. These initial tests help rule out other potential conditions such as metabolic diseases, feline leukemia virus (FeLV) infection, parasitic or bacterial infections, hyperthyroidism, and certain types of cancer. Intestinal lymphoma, a serious form of cancer, can be particularly challenging to differentiate from IBD in cats. Additionally, your veterinarian may measure blood levels of B vitamins like B12 and folate, as IBD can impede their absorption from the GI tract. A hypoallergenic food trial might also be recommended to assess the possibility of a food allergy contributing to the symptoms.
A definitive diagnosis of feline IBD hinges on obtaining an intestinal or gastric biopsy and examining the tissue microscopically. A diagnosis of IBD is confirmed by the presence of an increased number of inflammatory cells within the intestinal wall. The specific types of inflammatory cells identified will help determine the subtype of IBD and guide the subsequent treatment plan. Gastrointestinal biopsies can be performed either through endoscopy, a procedure using a flexible camera inserted via the mouth or rectum, or through abdominal surgery. While endoscopy is less invasive, surgery may be preferred if concurrent liver or pancreatic disease is suspected, allowing for biopsies of these organs as well. Both endoscopic and surgical biopsies require general anesthesia, and the associated risks must be carefully considered when deciding on the diagnostic approach.
Treatment Strategies for Feline IBD
Veterinary treatment for feline IBD typically begins with addressing any potential intestinal parasites, if not recently treated, followed by a combination of dietary modifications and medication. There isn’t a one-size-fits-all treatment, and your veterinarian may need to experiment with various diet and medication combinations to find the most effective therapy for your cat.
Dietary Management
Given that dietary allergens can contribute to IBD, your veterinarian may suggest a food trial using hypoallergenic diets. These specialized diets are formulated with novel protein or carbohydrate sources that your cat has not been exposed to previously. Common initial choices include diets based on rabbit, duck, or venison. If symptoms do not improve with a hypoallergenic diet, your cat might benefit from diets that are high in fiber, low in fat, and easily digestible. It can take several weeks, or even longer, for cats to show improvement after a dietary change. Crucially, during any food trial, all other food sources, including table scraps, flavored medications, and treats, must be completely eliminated to ensure the trial’s accuracy.
Medical Treatment
Metronidazole is often recommended as a first-line medical therapy alongside dietary modifications. This medication possesses antibiotic, anti-inflammatory, and antiprotozoal properties, and is generally well-tolerated. However, some cats may experience a loss of appetite when taking metronidazole.
If dietary changes or metronidazole prove insufficient, corticosteroids, which are powerful anti-inflammatory and immune-suppressing agents, may be prescribed. These can be used alone or in conjunction with metronidazole. Cats on corticosteroids require close monitoring due to potential side effects such as diabetes and immune suppression. Nevertheless, cats typically tolerate these medications well when administered at appropriate dosages. Corticosteroids are usually given orally, starting with a higher dose that is gradually reduced over several weeks. For cats that refuse oral medication or experience severe vomiting, your veterinarian may administer the drugs via injection.
In cases where standard medications do not effectively control IBD symptoms, more potent immunosuppressive drugs like chlorambucil or azathioprine might be necessary. These medications can suppress the production of white blood cells, red blood cells, and, less commonly, platelets in the bone marrow. Cats receiving these drugs require meticulous monitoring by a veterinarian. Emerging therapies for IBD also include prebiotics, which encourage the growth of beneficial gut bacteria, and probiotics, which introduce beneficial bacterial strains to support GI health. Adding soluble fiber, such as psyllium, to the diet of cats with inflammatory colitis can be beneficial. Furthermore, supplementation with folate or vitamin B12 is recommended if an affected cat is found to be deficient in these essential B vitamins.
Prognosis for Cats with IBD
Feline IBD can often be managed effectively, allowing affected cats to lead healthy and comfortable lives. However, even with diligent management, symptoms may recur intermittently. Maintaining control of the disease requires strict adherence to prescribed dietary and medical therapies. Consistent monitoring by both the veterinarian and the owner is also crucial for assessing relapses and adjusting the dosages of long-term medications as needed.
