Contributors: Julien Bazelle, Ed Hall, Kenneth Simpson

 Species: Feline   |   Classification: Miscellaneous


  • Most common cause of chronic vomiting Vomiting and diarrhea Diarrhea: overview.
  • Cause: any idiopathic inflammatory condition of the small or large intestine:
  • Signs: chronic gastroenteritis (diarrhea and vomiting), weight loss.
  • Characterized by infiltration of gastrointestinal tract with inflammatory cells including:
    • Lymphocytes.
    • Plasma cells.
    • Eosinophils.
    • Macrophages.
    • Neutrophils.
  • Diagnosis: idiopathic nature makes it a diagnosis of exclusion.
  • Treatment: dietary change, immunosuppressive therapy (prednisolone/azathioprine/chlorambucil).
  • Prognosis: good with appropriate treatment.
    Print off the owner factsheet on Inflammatory bowel disease  Inflammatory bowel disease  to give to your client.


  • Underlying cause unknown but immune mechanisms involving the response of the gut-associated lymphoid tissue (GALT) implicated:
    • Genetic factors, eg major histocompatibility type.
    • Specific defects in the immune system.
    • Mucosal and/or systemic infection (viral, bacterial or parasitic).
    • Abnormal or inappropriate antigen presentation.
  • Complement activation, mast cell degranulation and T-cell and macrophage activation   →   active inflammation.
  • Location and relative amount of inflammatory mediators depend on inciting factors and immune response   →   variable clinical and pathological presentations.
  • Possible progression from IBD to lymphoma Lymphoma  in some cases.
  • Hypersensitivity to luminal dietary or microbial antigens implicated.
  • IBD is often found concurrently with other diseases, such as cholangiohepatitis Liver: cholangitis, and Pancreatitis Pancreatitis. The concurrent occurrence of these three disorders in cats is termed "triaditis".


  • Chronic/recurrent vomiting.
  • Chronic/recurrent diarrhea Diarrhea: dietary (small or large intestinal).
  • Tenesmus, hematochezia, mucoid stools.
  • Anorexia Anorexia or ravenous appetite.
  • Weight loss.
  • Lethargy.
  • Unkempt coat.
  • Aggressive behavior.




Hormone assay


  • FeLV antigen FeLV test and FIV antibody testing FIV test (may be part of panel when investigating weight loss).


Fecal analysis

Therapeutic trials

  • For diet-responsive conditions (rarer in cats than in dogs).
  • For antibiotic responsive conditions (rarer in cats than in dogs).



  • +/- thickened GIT Ultrasonography: GI system. Older cats with thickened muscularis layer more likely to have lymphoma than IBD (Zwingenberger et al, 2010).
  • Raised lymph nodes.
  • +/- hepatic/pancreatic abnormalities.


  • To examine intestinal mucosa - often granular, friable lesions or erosions Flexible endoscopy      Gastroscopy.
  • May be normal - lesions can be microscopic.


  • Intestinal biopsy is the only method of definitive diagnosis. Endoscopic biopsy safest; surgical biopsy to assess muscularis and to sample pancreas/liver.
  • Biopsy several sites (6-15 depending on quality of biopsies) because signs do not always correlate with site of pathology. Biopsy of both duodenum and ileum increases likelihood to reach diagnosis.
  • Lymph node biopsy/aspirate Cytology: lymph node aspirate should be taken if lymphadenopathy Lymphadenopathy is detected.
  • Usually lymphocytic-plasmacytic or eosinophilic infiltrate predominates.
  • In chronic cases mucosal villus atrophy and fibrosis may be severe.
  • Sometimes difficult to differentiate lymphocytic inflammation with low grade small cell lymphoma Lymphoma. Assess immunohistopathology for immunophenotyping or polymerase chain reaction (PCR PCR (Polymerase chain reaction)  ) results for B and/or T cell clonality (Kiupel et al, 2011).
  • Liver and pancreas histopathology: lymphocytic-plasmacytic inflammation.

Differential diagnosis