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Inflammatory Bowel Disease (IBD) usually refers to a chronic inflammatory
disease anywhere in the gastrointestinal (GI) tract, including the
stomach, small intestine (duodenum, jejunum, ileum), and large intestine
(colon) The term implies a process of long duration as opposed to sudden
onset.
Because IBD affects many
areas of the GI tract it probably has many different causes.
More traditionally, IBD has referred to chronic inflammation of the
small or large bowel excluding the stomach. The disease is classified by
the predominant inflammatory cell found invading the wall of the bowel.
Such classification may allude to its cause. However, this method of
grouping is not always possible and location of the lesion will help its
classification.
IBD is usually found in younger dogs but, it can extend to middle age
dogs. There is no strong relationship by breed however, IBD does seem to
affect some breeds more often than others.
The most common form of IBD is lymphocytic-plasmacytic IBD (LPIBD). This
term describes the cells that are found microscopically when a biopsy of
the lesion is examined. Most biopsies are obtained by abdominal surgery or
by endoscopy if available. Biopsies are important to rule out other causes
such as: dietary hypersensitivity, lymphoma, histoplasmosis (a fungus),
bacterial infection or overgrowth, and malassimilation problems. The
predominant cell type, lymphocytes and plasma cells represent a chronic
stimulation of the immune system.
Because of this response, IBD is typically thought of as an immune
mediated disease and therefore treated with the various immunomodulating
therapies. Current thoughts are that the GI tract has been sensitized by
some bacteria or food antigens that determines the ongoing immune
response. Complexes are formed from antibodies against food antigens,
bacteria or bacterial by-products. These antigen-antibody complexes (ABC)
induce the release of destructive chemicals into the area and tissue
destruction results. The destruction is indiscriminate. The quantity of
ABC¹s produced may influence the long standing nature of the disease.
Signs of IBD are dependent on the location of the problem. Disease in the
stomach or upper small intestine are frequently associated with chronic
vomiting and weight loss. Diseases of the jejunum, ileum, and colon are
associated with chronic diarrhoea, weight loss and infrequent vomiting.
Small bowel diarrhoea is often watery with a large volume of faeces and
the patient acts sick. Large bowel diarrhoea is associated with straining,
some blood, mucus, small volume of faeces and frequent attempts to
defecate.
Once IBD is suspected, strict dietary changes are fundamental for long
term results. Often diet will control the disease but in the majority of
cases anti-inflammatory drugs are added to quiet the immune system. Often,
the use of anti-inflammatory drugs at the beginning is enough with
controlled diet to stabilize the chronic inflammation. However, the
disease in most cases goes into periods of remission with repeated flare
ups. Certain breeds (Wheaton Terriers and Basenjis) are more predisposed
to progressive disease.
Diet is chosen to produce the least amount of ABC stimulation. A true
hypoallergenic diet should contain a very good single protein source that
is highly digestible, so as not to be available for immune stimulation.
There are now commercial diets available through veterinarians and some
knowledgeable pet food stores that contain only one source of a
hypoallergenic protein such as lamb, rabbit, turkey, venison, fish or
duck.
Many diets listed as hypoallergenic contain other ingredients and caution
is order. These are usually combined with a good source of carbohydrates
such as rice or potatoes. Commercial diets insure that essential vitamins,
minerals and fatty acids are included. Fibre is often a vital component of
long term care. quality fibre aids in the development of beneficial
colonic flora and enhances the digestive process. In addition, diets free
from preservatives and food additives may provide relief for some patients
that are sensitive to these chemicals.
Anti-inflammatory therapy involves immunosuppressive drugs, metronidazole,
or Salycilates. The mainstay of anti-inflammatory drugs are
corticosteroids. Prednisone and methylprednisolone are powerful
anti-inflammatory drugs that can produce impressive results. They have
minor short term side effects that include increased drinking, eating and
urinating. Long term, these drugs can cause Cushings disease if alternate
day therapy can not be achieved for control of IBD. If prednisone is used
for anything other than a very short period, it is very important that you
must ensure that you give Calcium and Vitamin D supplements.
Sulfasalazine is commonly
used to control large bowel IBD. It has no long term side effects, however
it can cause a dry eye syndrome and occasionally will cause salicylate
toxicity. Metronidazole is used because it is anti-inflammatory,
anti-protozoan, and is a good antibacterial for the small bowel. The only
side effect is vomiting.
Other drugs that are being
tried include cyclosporine and eicosapentanoic acid, a fatty acid found in
fish oil. Eicosapentanoic acid (Derm Caps) is a drug often used in
veterinary medicine to decrease the inflammatory response of inhaled
allergies. The only side effects are a shiny coat.
IBD involves a great deal of patience by the dog owner but most dogs will
gain relief with some variation of therapies. The disease is life long and
will require regular attention. |
