Inflammatory Bowel Disease in Cats

Inflammatory bowel disease (IBD) is a group of gastrointestinal disorders caused by infiltration of the bowel by inflammatory cells. This infiltration thickens the bowel lining and interferes with the absorption of food and motility of the bowel. The cause of IBD is unknown, but the immune system is thought to play an important role.

IBD is classified according to the type of inflammatory cells infiltrating the gastrointestinal wall. The most common form is called lymphocytic - plasmacytic IBD, where lymphocytes and plasma cells are the primary types of inflammatory cells present. Less common forms are eosinophilic and neutrophilic IBD.

CLINICAL SIGNS

IBD may present with a variety of clinical signs, including vomiting, diarrhoea and variable appetite. Weight loss is the most common clinical sign for feline IBD. Although cats of any age can be affected, middle-aged or older cats are more susceptible.

DIAGNOSIS

To rule out other potential causes of vomiting, diarrhoea, weight loss or reduced appetite, the following diagnostic tests may be performed:

1. Blood and urine tests
2. Faecal examination
3. Abdominal ultrasound
4. Biopsy - Biopsies are required to obtain a definitive diagnosis. Biopsy specimens can be obtained either by endoscopy or abdominal surgery. Surgical biopsies are usually of better quality. Both procedures require general anaesthesia.

TREATMENT

A combination of diet and medical therapy will successfully manage IBD in most cats.

1. Dietary Management 

Diet is a critical component of therapy, as sensitivity to food antigens is thought to contribute to the gastrointestinal inflammation mostly in younger patients. Several balanced commercial diets  which contain either a novel or or partially hydrolysed protein source are available, Royal Canin hypoallergenic and Delicate Care duck and kangaroo dry food. Intestinal prescription diets are more readily digestible and allow for more calories & nutrition to be absorbed by the diseased intestine.

Home-made diets are an alternative. Ideally, the diet should contain a single source of protein not normally consumed by the cat, such as lamb, duck, turkey, rabbit or venison. The addition of a fibre source, such as psyllium (Metamucil Fibresure) may assist. It may take 6-8 weeks or longer for cats to improve after a dietary change. During this trial feeding period, all other food sources, such as other commerical dry and tinned foods and table scraps, must be eliminated from the diet. These diets often require a veterinary Nutritionist to ensure the diet is complete and balanced.

2. Medical Therapy

• Metronidazole - can be effective in some cats with mild IBD. Metronidazole is an antibiotic, but has also been reported to inhibit cell-mediated immunity.
• Corticosteroids - are commonly used to treat cats with IBD. Corticosteroids have potent anti-inflammatory and immunosuppressive properties with relatively few side effects in cats. Oral prednisone is the corticosteroid used most frequently. Budesonide, a local acting anti-inflammatory capsule is also available, if oral prednisolone is contraindicated due to other medical conditions. Injectable corticosteroid therapy can be used in cats that are too difficult to medicate orally, or if vomiting and malabsorption is severe.
• Vitamin B12 (cobalamin) injections - cats with IBD may be unable to absorb vitamin B12 in their intestines, which can result in deficiency. Injections are typically administered weekly  for 6 weeks, then fortnightly for 6 weeks, then monthly.
• In refractory cases of IBD, immunosuppressive drugs may be recommended, such as chlorambucil, cyclophosphamide or cyclosporine. Use of these medications necessitate close monitoring.

PROGNOSIS

With appropriate dietary and medical therapy, IBD is often controllable, but rarely curable. Concurrent liver or pancreatic involvement can lead to a less favourable prognosis. Relapses can occur if the treatment regimen is not strictly followed.