Inflammatory Bowel Disease (IBD) & Chronic Enteropathy

Signs vary depending on where in the GI tract the inflammation is most active:

• Intermittent or persistent vomiting — may occur hours after eating or on an empty stomach (bile-tinged)
• Chronic diarrhea — watery large-bowel diarrhea, or soft, poorly formed small-bowel stool
• Progressive weight loss despite a normal, reduced, or even increased appetite
• Poor body condition and muscle wasting over weeks to months
• Borborygmi (loud intestinal gurgling) and gas
• Intermittent hyporexia (reduced appetite) or episodes of complete food refusal
• In cats: chronic vomiting with or without hairballs, gradual muscle loss along the spine
• Protein-losing enteropathy (PLE) in severe cases — fluid accumulation in the abdomen (ascites) or legs (edema) caused by loss of albumin through the damaged intestinal wall

Many owners notice the signs wax and wane over months before seeking evaluation, attributing them to stress or a sensitive stomach. Persistence is the key indicator that something structural is driving the problem.

Chronic enteropathy results from a complex interplay of genetics, diet, the intestinal microbiome, and immune regulation. Known contributors include:

• Food antigens — dietary proteins that trigger an abnormal mucosal immune response; common offenders include beef, chicken, dairy, and wheat, though any protein can be responsible
• Dysbiosis (microbiome imbalance) — an altered bacterial community in the gut, sometimes triggered by prior antibiotic use, illness, or stress
• Genetic predisposition — Soft Coated Wheaten Terriers, Basenjis, Border Collies, and Norwegian Lundehunds have breed-specific enteropathies; German Shepherd Dogs are over-represented in IBD and EPI; Yorkshire Terriers are prone to protein-losing enteropathy
• Immune dysregulation — in true IBD, the immune system mounts an inappropriate sustained attack on normal intestinal flora or structural proteins
• Secondary factors — prior infections (Giardia, Salmonella), intestinal parasites, and chronic stress can all destabilize the gut environment and predispose to ongoing inflammation

Intestinal lymphoma (low-grade) in cats can closely mimic IBD on exam and ultrasound; distinguishing the two requires biopsy, which is why histopathology is the gold standard when the diagnosis is uncertain.

Diagnosis is stepwise — each tier rules out simpler causes before advancing to more invasive testing. This structure also reveals the most treatable cause first, minimizing both cost and patient stress.

• Fecal examination and PCR panel: rules out parasites (Giardia, hookworms, Tritrichomonas in cats) and enteric pathogens as a primary or contributing cause
• Complete blood count and chemistry panel: evaluates protein levels (albumin, total protein), inflammation markers, liver and kidney function, and evidence of protein-losing enteropathy
• Serum cobalamin (B12) and folate: low B12 reflects small intestinal malabsorption and identifies pets that need supplementation; the combination helps localize the affected intestinal segment
• Serum TLI (trypsin-like immunoreactivity): screens for exocrine pancreatic insufficiency, which can coexist with or mimic enteropathy
• Abdominal ultrasound: evaluates intestinal wall thickness and layering, mesenteric lymph nodes, and rules out focal masses or foreign material; thickened, layered walls are a hallmark of IBD, while a loss of wall layering suggests lymphoma
• Dietary trial: 6–8 weeks on a strict hydrolyzed or novel-protein diet; response (or lack of response) is diagnostically informative and may be curative in food-responsive cases
• Endoscopic biopsy: the definitive diagnostic step; on-site upper and lower endoscopy at our hospital allows direct visualization and biopsy of the duodenum, ileum, and colon under anesthesia, providing tissue for histopathology to classify the type and severity of inflammation

Treatment is matched to the type of enteropathy identified and the severity of the patient's disease.

• Dietary modification: hydrolyzed protein diets (proteins broken into fragments too small to trigger an immune response) or novel-protein diets (single protein source the pet has never eaten) are the first-line treatment for food-responsive enteropathy and the dietary backbone for all IBD management
• Cobalamin (B12) supplementation: subcutaneous or oral B12 is given to all patients with documented deficiency; correcting B12 improves intestinal cell health, appetite, and response to other treatments
• Antibiotic therapy: short courses of metronidazole or, in specifically antibiotic-responsive cases, tylosin are used when dysbiosis is a primary driver; long-term antibiotic use is avoided to protect the microbiome
• Immunosuppressive therapy: prednisolone (a corticosteroid) is the backbone of true IBD treatment; budesonide (a locally acting steroid with fewer systemic effects) is used when systemic side effects are a concern; chlorambucil combined with prednisolone is the first-line protocol for cats with IBD or low-grade lymphoma
• Azathioprine or cyclosporine: second-line immunosuppressants used to reduce the steroid dose in dogs that require long-term therapy
• Supportive care during flares: anti-nausea medications (maropitant), appetite stimulants, and IV or subcutaneous fluids when dehydration or anorexia is significant

Many pets with food-responsive or antibiotic-responsive enteropathy achieve full clinical remission. Those with true IBD are managed for the long term but can live excellent, comfortable lives with appropriate therapy and regular monitoring.

If your dog or cat has had vomiting, diarrhea, or weight loss for more than two to three weeks — even if the signs seem mild or intermittent — that timeline alone warrants a structured evaluation. Chronic enteropathy is progressive without treatment, and protein-losing enteropathy can become a medical emergency if albumin levels fall far enough. Dr. Norman's internal medicine expertise means complex cases are managed in-house from ultrasound to endoscopy to long-term immunosuppressive protocols without the cost and delay of multiple specialty referrals. Book an appointment and let us work through the diagnostic ladder systematically — from the simplest, most treatable cause to a definitive biopsy-based diagnosis when needed.