How to Treat Feline Inflammatory Bowel Disease
When addressing feline inflammatory bowel disease (IBD), the key to effective treatment is starting with the correct diagnosis.
Feline IBD is the histopathologic diagnosis of an idiopathic condition; therefore, before initiating potentially lifelong treatment with immunomodulatory drugs that may incur significant adverse events, several important causes of chronic enteropathy must be ruled out.
Endoscopic image of duodenum showing a large ulcerated area of mucosa in a 10-year-old spayed DSH presented for chronic diarrhea and weight loss. Histopathologic diagnosis was severe inflammatory bowel disease with necrotic ulcerated tissue.
How I Treat Feline IBD
Make diagnosis
Initiate a stepwise approach to treatment
Initiate dietary intervention
Adjust vitamin intake
Administer medical treatment
Assess therapy; readjust if necessary
1. Make diagnosis
Rule Out Common Causes
Rule out common causes of chronic enteropathy
Consider differentials for chronic enteropathies in cats:
Food sensitivity, food allergy, or food-responsive disease
Intestinal parasitism
Medication effects or adverse events
Plant or toxin intoxication
Extraintestinal disease (eg, hyperthyroidism, chronic kidney disease, cholangitis, triaditis, infection)
Alimentary neoplasia
Antibiotic-responsive enteropathy
While this is recognized in dogs, whether it occurs in cats is unclear
Exocrine pancreatic insufficiency (rare)
Pursue Histopathologic Diagnosis
Note that IBD requires a histopathologic diagnosis
This may take considerable effort and expense, anesthesia, and referral
Determine whether signs result from idiopathic IBD or a neoplastic condition (eg, lymphoma, adenocarcinoma)
Expect (and inform clients) that the pathologist may use technologically advanced diagnostics and extract all available information from the biopsy sample
If client constraints preclude histopathologic diagnosis, initiate treatment after ensuring the client understands the potential pitfalls of treating without a definitive diagnosis
Perform Histopathology or Refer to a Pathologist
Perform the following, or see that a pathologist can perform:
Histopathology
Mucosal/submucosal (endoscopic biopsy) or full-thickness (surgical biopsy)
Villus blunting or fusion, edema, lymphatic dilation, cryptal hyperplasia, fibrosis
Lymphocytic infiltration (intraepithelial, submucosal, muscularis, serosal)
Immunohistochemistry (T cells, B cells, CD3e, CD79a)
PCR for clonality by PCR antigen receptor rearrangement (PARR) and flow cytometry
2. Initiate a stepwise approach to treatment
Let the patient’s clinical condition dictate urgency of treatment decisions
Start with basic intervention and advance to more powerful treatment combinations
As each component of treatment may have an individual effect, judge efficacy with a brief period of observation and assessment at each stage before adding to the therapeutic mixture
Poor prognostic indicators (eg, hypoalbuminemia, weight loss) may dictate a more aggressive initial approach
A 7-year-old spayed DSH was presented for chronic diarrhea, intermittent vomiting, and weight loss. Although endoscopy revealed some mucosal irregularities, there were no marked gross abnormalities. Histopathology revealed moderate lympho-plasmacytic IBD, and the cat responded well to a hypoallergenic diet, prednisolone, and cobalamin supplementation.
3. Initiate dietary intervention
General
Initiate hydrolyzed or hypoallergenic diets to decrease antigenic stimulation of the GI tract
Although idiopathic IBD is not a food allergy or food-responsive disease, dietary intervention remains an important treatment component
Antigenic stimulation by dietary components, most likely the protein portion, may contribute to the abnormal immune-inflammatory environment of the intestinal tract
Match diet with patient (ie, palatability, wet/dry, client preferences)
Assess effect after a 1–2 week trial; adjust accordingly
May require multiple adjustments
Inform client that numerous commercial diet options are available
Advise clients who prepare their own pet food to use careful, consistent attention for a complete and balanced diet that provides a single-source protein and single-source carbohydrate
Fiber
Add fiber to patient’s diet
For large bowel diarrhea, add both soluble and insoluble fiber in moderation (eg, canned pumpkin, psyllium)
Fiber, both soluble and insoluble, appears to have several beneficial properties and is most frequently used in cases where large bowel diarrhea is a prominent sign
Prebiotics & Probiotics
Institute prebiotics, which are included in most specialized commercial pet foods
Institute probiotics from a reputable veterinary source
The product chosen must contain billions of live organisms when ingested, and the formula must survive GI passage
Probiotics appear beneficial for many cats with chronic enteropathies of various causes, including idiopathic IBD
Probiotics are generally safe and unlikely to cause harmIt is unclear whether different probiotics are needed for different conditions
It is unclear whether different probiotics are needed for different conditions
4. Adjust vitamin intake
Measure cobalamin (ie, vitamin B12) and folate levels
Administer cobalamin at 250 μg SC q7days for a month before tapering
Studies have demonstrated that many cats with chronic GI disease have suboptimal levels of cobalamin
Feline cobalamin levels are measured in a fasted sample
Although cobalamin supplementation is often instituted based on assumption, the actual number is still important
It appears that the lowest cobalamin levels usually appear in either severe cases of IBD or in cases of GI lymphoma
Administer folate supplementation, 0.5–1.0 mg PO q24h, if indicated
5. Administer medical treatment
Corticosteroids
Administer prednisolone at 1–3 mg/kg q24h before tapering
Prednisolone, preferred over prednisone in cats, remains the pharmaceutical cornerstone of treatment for feline idiopathic IBD
Cats are less prone to adverse events caused by corticosteroids side effects than dogs, but it is still a powerful corticosteroid and long-term use can have deleterious consequences in this species
Maintain contact with the clients and patient
Once signs have remained absent for 1–2 weeks, taper prednisolone dose 25% every 2–4 weeks until administration is q48h; it is rarely discontinued
Consider Corticosteroid Alternatives
Consider budesonide (corticosteroid alternative) at a 0.5–1.0 mg/cat PO q24h starting dose
Theoretically, budesonide has a high first-pass removal by the liver with minimal systemic consequence
Note that some cats appear to respond differently to different glucocorticoids; if prednisolone is not effective, dexamethasone or betamethasone is worth trying
Evidence is anecdotal and mixed for budesonide, dexamethasone, and betamethasone
6. Assess therapy; readjust if necessary
Assess & Readjust: 1
Assess the patient
Dietary intervention, vitamins, and corticosteroids are generally sufficient
If necessary, reconsider diagnosis
Therapeutic failure at this point suggests poor client compliance or inadequate workup
This makes biopsy imperative
This may be indicative of an inaccurate diagnosis, such as GI lymphoma, low-grade alimentary lymphoma or other GI neoplasia, or other concurrent diseases
The potential causes of enteropathies may not have been adequately ruled out
Consider other immunomodulatory drugs in IBD cases refractory to traditional therapy
Consider chlorambucil (for low-grade GI lymphoma; 2 mg/cat q2–3days)
Monitor CBC
Consider cyclosporine (5 mg/kg q12–24h)
Monitor for anorexia and vomiting
If necessary, administer an antibiotic (eg, tylosin at 10 mg/kg PO q8h)
Assess & Readjust: 2
Consider concurrent diseases
Cats are notorious for concurrent disease; the most relevant in cases of feline idiopathic IBD are chronic pancreatitis and cholangitis, forming the triad termed triaditis
Treat for chronic pancreatitis
Includes analgesia, adequate calories +/- appetite stimulant, and maintaining perfusion by optimizing ongoing hydration
Treat for cholangitis (neutrophilic, lymphoplasmacytic)
Text at a Glance
Rule out common known causes of chronic GI disease first.
Idiopathic IBD is a histopathologic diagnosis.
Dietary intervention is the first order of treatment.
Measure and supplement cobalamin as needed.
Prednisolone is the pharmaceutical foundation of treatment.
Dietary intervention, cobalamin, and prednisolone are generally sufficient.
Therapeutic failure may suggest poor compliance, inadequate workup, GI neoplasia, or other concurrent diseases; biopsy is then necessary.
Ready, Aim, Fire!
Proceed with conclusive diagnosis
Start with basic intervention and continue to more powerful treatment
Brief periods of observation and assessment after each treatment plan are beneficial
Proceed without conclusive diagnosis
Client constraints may prevent histopathologic diagnosis
Treatment can be initiated with client understanding of potential complications
CRAIG B. WEBB, DVM, PhD, DACVIM (Small Animal), is associate professor at Colorado State University, where he is head of the medicine section and is a gastroenterology specialist. He frequently gives CE lectures and runs wet lab courses on GI diseases, including a special NAVC session on GI endoscopic techniques. Dr. Webb earned a PhD in neuroscience and, following an internship at Alameda East Veterinary Hospital, trained as a small animal internal medicine resident at Colorado State University. Dr. Webb earned his DVM from University of Wisconsin-Madison.
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