Inflammatory Bowel Disease

Signalment

• No sex predisposition
• More common in middle-aged dogs and cats

Description

Inflammatory bowel disease (IBD) is an idiopathic group of disorders characterised by intestinal inflammatory changes associated with persistent or recurrent gastrointestinal signs. IBD can affect any part of the intestines and is classified according to the predominant cellular inflammatory infiltration. Several histological types have been recognised, which are:

• Lymphocytic - Plasmacytic Enteritis (most common)
• Eosinophilic Enteritis

The underlying cause of IBD is currently unknown. It may reflect an exaggerated or inappropriate response by the immune system to dietary, bacterial or self-antigens.

Diagnosis

Clinical Signs

• Vomiting (most common sign in cat)
• Diarrhoea; small or large intestinal
• Haematoemesis or haematochezia (more severe cases)
• Weight loss
• Abdominal discomfort or pain
• Excessive borborygmi
• Variable appetite; incrased or decreased
• Hypoproteinaemia or ascites
• Thicked intestinal loop

Laboratory Tests

Haematology

• Neutrophilia ± mild left shift in LPE
• Eosinophilia
  • Not always present in EGE

Biochemistry

• Panhypoproteinaemia
• Hypocholesterolaemia
• Mild increased in liver enzymes, secondary to intestinal inflammation

Other Tests

• Faecal analysis should be carried out to rule out parasitic causes such as hookworms, whipworms and Giardia
• Serum folate level decreases with proximal small intestitnal inflammation
• Serum cobalamin level decreases with distal small intestinal inflammation

Diagnostic Imaging

• Plain radiography is used for evaluate for anatomic abnormalities.
• Contrast study is only of value if there is a severe mucosal disease.
• Ultrasonography may reveal thickening of intestinal wall and mesenteric lymphadenopathy.

Histopathology

A biopsy of the intestine is required for a definitive diagnosis of IBD. A non-invasive biopsy may be taken via endoscopy by this limits where the samples can be taken from as the jejunum and ileum in not easily accessible. Exploratory laparotomy and full thickness may sometimes be preferred.

Treatment

• Dietary modification
  • An elimination diet should be instigated. The patient should be fed strictly a protein source that the patient was never exposed to. Clinical signs should resolve within 1-2 weeks.
  • Folate and cobalamin supplementation may be required if the levels are subnormal.
• Antimicrobials such as Metronidazole at 10-15 mg/kg BID for 3-4 weeks may be given to mild to moderate cases, and especially in cats
  • The mucosal damage caused by IBD may decrease the animal's ability to manage to intestinal flora and secondary ARD has been reported.
• Immunosuppressive therapy
  • This should be considered if antimicrobial therapy alone is inadequate.
  • Prednisolone at 2.2mg/kg/day PO for 10 days. Then gradually taper to EOD.
  • Azathioprine or Cyclosporine can be given alternatively if non-responsive or poor tolerance to steroid.

References

• Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company.
• Hall, E.J, Simpson, J.W. and Williams, D.A. (2005) BSAVA Manual of Canine and Feline Gastroenterology (2nd Edition) BSAVA
• Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.