Contributors: Julien Bazelle, Ed Hall, Ken Harkin

 Species: Canine   |   Classification: Miscellaneous

Introduction

  • 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 (rarely).
  • Diagnosis: idiopathic nature makes it a diagnosis of exclusion.
  • Treatment: dietary change, immunosuppressive therapy (prednisolone/cyclosporine/chlorambucil).
  • Prognosis: good with appropriate treatment.
    Print off the owner factsheet on Inflammatory bowel disease Inflammatory bowel disease to give to your client.

Pathogenesis

  • Breed predisposition: Shar-Pei Chinese Shar Pei , Yorkshire terrier Yorkshire Terrier , German Shepherd dog German Shepherd Dog.
  • 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, eg decreased IgA (Maeda et al, 2013).
    • Mucosal and/or systemic infection (viral, bacterial or parasitic).
    • Abnormal or inappropriate antigen presentation, eg mutation of Toll-like receptors.
  • 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.
  • Hypersensitivity to luminal dietary or microbial antigens implicated.

Signs

Diagnosis

  • Baseline information is necessary to exclude other causes.

Hematology

Biochemistry

Urinalysis

Fecal analysis

Therapeutic trials

  • For diet-responsive conditions.
  • For antibiotic responsive conditions.

Radiography

  • See abdominal radiography Radiography: abdomen.
  • Plain and contrast films.
  • Usually unremarkable or non-specific findings (mucosal irregularities or thickened bowel segments).

Abdominal ultrasound

Endoscopy

  • To examine intestinal mucosa Enteroscopy.
  • Gastric ulcerations Gastroscopy - particularly in pyloric region (cf normal).
  • May be normal - lesions often microscopic.

Histopathology

  • Intestinal biopsy is the only method of definitive diagnosis. Endoscopic biopsy safest, surgical biopsy more representative.
  • 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 should be taken if lymphadenopathy Lymphadenopathy is detected.
  • Usually lymphocytic or eosinophilic infiltrate predominates.
  • Possible signs of secondary lymphangiectasia.
  • In chronic cases mucosal villus atrophy and fibrosis may be severe.

Differential diagnosis

Treatment

  • Diet:
    • Reduce antigenic load, increase fiber.
    • Highly digestible, gluten-free diet.
    • Moderate fat restriction.
    • Supplementation with medium chain triglycerides Fat may help.
    • Feeding prescription hypoallergenic diets may help.
    • Supplementation with folates and cobalamin may be required.
  • Prednisolone Prednisolone 0.5-2.0 mg/kg (in severe cases) BID PO for 2 weeks, then tapering dose. Budesonide Budesonide (Dye et al, 2013).
  • In refractory cases,it may be helpful to use prednisolone in combination withcyclosporine Ciclosporin (5-10 mg/kg SID-BID) or chlorambucil Chlorambucil (1.5 mg/m2 EOD).This is considered more efficient than prednisolone andazathioprine Azathioprine 1-2 mg/kg SID. Treat for 14 days then alternate days PO for 3-4 months (Dandrieux J R et al, 2013).
  • Antibiotics - to reduce antigenic load, eg metronidazole Metronidazole 10-15 mg/kg PO BID, oxytetracycline Oxytetracycline tylosin Tylosin.
    Metronidazole may suppress cell-mediated cellular responses in addition to its antiprotozoal and antibacterial effects. May not improve outcome when combined with steroid therapy.
  • May be possible to wean patient off therapy after 3-4 months and maintain by dietary manipulation alone.