A 4-year-old male neutered domestic longhair cat was presented to Cornell’s Emergency Service with a 4-day history of anorexia and an episode of open-mouth breathing the day of presentation. Beginning at 6 months of age, he was treated for inappetence and intermittent diarrhea with grain-free and sensitive-stomach diets, vitamin B-12 injections, metronidazole, and FortiFlora; however, his clinical signs did not resolve.

On initial presentation, he was in thin body condition with tachypnia, pale mucous membranes, and thickened loops of intestine. Because of severe anemia (11%, normal: 31-48%) and elevated lactate (7.57mmol/L, normal: <2.0mmol/L), a transfusion of feline packed red blood cells was administered. Abdominal ultrasound showed severe diffuse gastroenteropathy, mild peritoneal effusion, and mild lymphadenopathy. Hematology consistently showed a severe regenerative anemia and severe leukocytosis with an increase in all white blood cells. Primary differentials were alimentary lymphoma, intestinal mast cell tumor, and inflammatory bowel disease (IBD). After a week of supportive therapy, the anemia improved and he was sent home with amoxicillin/clavulanic acid, omeprazole, diphenhydramine, and maropitant.

A week later, endoscopic mucosal pinch biopsies of stomach and duodenum confirmed a clinical diagnosis of IBD. He was put on a regimen of dexamethasone and pradofloxacin, followed by chlorambucil. As of about one week after starting this therapy, diarrhea remained but owners were happy with their cat’s progress.