以下的資料是有關狗狗的IBD的。和人類的其實差不多。
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Source: Inflammatory Bowel Disease in Dogs
Inflammatory Bowel Disease in Dogs
What is Inflammatory Bowel Disease?
Inflammatory Bowel Disease (IBD) is a disorder in which one or
more sections of the gastrointestinal tract have become invaded with
inflammatory cells. Over time, this inflammation causes the intestine
to become less efficient at absorbing nutrients from digested food and
weight loss, vomiting or diarrhea often result. Early signs are often
subtle which allows IBD to go undiagnosed for months to years until the
dog begins to develop more serious symptoms.
IBD is not a specific diagnosis as there are several types of IBD
recognized. The different types of IBD are characterized by the type
of cell that is causing the inflammation and the specific
section of the gastrointestinal tract that is affected. There are many
causes of gastrointestinal inflammation that are not "true IBD" and your
veterinarian must investigate these possibilities before confirming a
diagnosis of IBD.
How Does a Dog Develop IBD?
The cause of IBD is poorly understood. It appears that genetics,
diet, intestinal infection and abnormalities of a dog's immune system
all play a role. The intestine is responsible for processing large
amounts of food and bacterial particles called antigens. Antigens can
be recognized by a dog's body as "foreign" and cause an abnormal
allergic (immune-type) response. The end result is that the lining of
the intestine is invaded with inflammatory cells and this inflammation
interferes with the ability to digest and absorb nutrients.
Common antigens in the intestine include proteins and
preservatives from the food, parasites, viruses or bacteria, and
ingested foreign material (toys, garbage, etc). Any of these antigens
can start an abnormal immune response but eventually the inflammation
continues even when the antigen is no longer present. In most
instances, an exact underlying cause cannot be identified and this is
called idiopathic (or true) IBD.
What are the symptoms of IBD?
Occasional vomiting and diarrhea that occur over weeks to years
are the most common signs of IBD in dogs. These symptoms may be
responsive to brief changes in diet or short courses of antibiotics, but
eventually return. The signs are usually slowly progressive but can be
severe and sudden in onset in advanced stages of the disease. A
combination of symptoms is most common in dogs with IBD as the stomach,
small intestine and colon may be involved.
Stomach inflammation (called gastritis) typically causes loss of
appetite and vomiting. Vomit may contain undigested food, partially
digested food, clear or brownish liquid or even a small amount of blood.
Inflammation of the small intestine (called enteritis) often
causes vomiting, diarrhea and weight loss. Vomit may be clear liquid,
yellow or green bile, foam or food. Diarrhea is usually soft to watery,
large volume and occurs one to three times daily. The small intestine
is the main area of nutrient absorption and with chronic inflammation
nutrient malabsorption often results. Affected dogs will frequently
exhibit weight loss, lethargy and general unthriftiness.
Colon inflammation (called colitis) most often causes diarrhea.
The diarrhea is usually of small volume and very frequent (up to ten or
more times per day). Dogs with colitis often strain to defecate and
have blood or mucus in the stool. These dogs usually remain active,
have a healthy appetite and do not lose weight.
How is IBD diagnosed?
There are many causes of vomiting and diarrhea in dogs and the
most difficult part of diagnosing IBD is eliminating other
possibilities. A complete blood count, chemistry panel, urinalysis,
fecal examination and culture, x-rays of the chest and abdomen and
sometimes abdominal ultrasound are used to screen for metabolic
disorders (such as liver, kidney, pancreas or thyroid disease);
intestinal parasites (including Giardia and Cryptosporidia); bacterial,
fungal or viral infections; dietary allergies; foreign bodies and
cancer. Specialized blood tests such as cobalamine and folate are often
recommended to determine the severity of intestinal malabsorption.
If all screening tests fail to reveal an underlying cause for the
recurrent gastrointestinal signs, IBD is suspected and biopsy of the
intestines is required to make a definitive diagnosis. Obtaining
biopsies involves anesthesia and either surgery or endoscopy. Surgery
allows adequate viewing of all sections of the intestine and deeper
biopsies can be obtained for the most accurate diagnosis. Endoscopy
allows your veterinarian to look at the inside of the stomach and
intestines without surgery by using a fiber-optic scope with a built-in
biopsy instrument. Endoscopy has the advantage of being much less
invasive; however, it is not appropriate for all patients as it cannot
reach some portions of the small intestine.
Intestinal biopsies must be sent to a laboratory for microscopic
examination. A pathologist will report the changes as mild, moderate or
severe IBD and describe the inflammatory cell that is present (see
Table 1). This confirms the type and severity of IBD present and helps
your veterinarian determine the best treatment plan for your dog.
How is IBD treated?
Most dogs with true IBD require medication in addition to dietary
management to have complete resolution of symptoms. If dietary
management alone results in complete improvement a diagnosis of IBD
caused by an adverse reaction to food is made.
Diet
Highly digestible diets are usually recommended for dogs with IBD
because nutrients from these diets are more completely absorbed and the
amount of diarrhea will be minimized. Diets that contain a single
protein source never previously eaten and a carbohydrate source that is
unlikely to be antigenic (such as potato) may also be recommended.
Commercial products are available or your veterinarian can advise you on
a homemade dog food recipe. An appropriate diet must be fed for eight
to twelve weeks before a positive affect may be seen.
Fiber supplementation is recommended for IBD that affects the
colon. Dietary fiber improves stool consistency and produces fatty
acids that nourish the colon and discourage the growth of harmful
bacteria.
Medication
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Corticosteroids (aka steroids, cortisone,
prednisone) are the mainstay of therapy for IBD. Corticosteroids
inhibit the inflammatory process and reduce the inflammation within the
intestine. As steroids have potentially severe side effects, the goal
of therapy is to gradually adjust the dose to the lowest possible amount
that controls symptoms. Over time, many dogs can be weaned off
steroids completely and be maintained on diet alone.
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There are several other anti-inflammatory medications
available and you should ask your veterinarian if any of them are right
for your dog. Metronidazole is an antibiotic that helps restore the
normal balance of intestinal bacteria and also has anti-inflammatory
properties. The beneficial effects of metronidazole can sometimes
reduce the dosage of steroids that are needed. Dogs with severe cases
of IBD often need more aggressive anti-inflammatory therapy.
Azathioprine, chlorambucil and cyclosporine are examples of drugs that
reduce inflammation by suppressing the immune system.
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Some dogs benefit from antacid, anti-nausea or anti-diarrheal
therapy. Your veterinarian can advise if any of these are right for
your dog.
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Studies in humans suggest that supplementation of omega-3 fatty acids helps decrease inflammation within the gastrointestinal tract. Although more research needs to be done to fully determine their benefit in dogs with IBD, it is a reasonable treatment option.
What is the long term prognosis for dogs with IBD?
IBD can be controlled, but not cured. All patients with IBD will
require a strict diet and possibly anti-inflammatory medication to
manage their disease. Most dogs with IBD do well for many years while
others require alterations in therapy every few months to treat
flare-ups and recurrent symptoms. Unfortunately, a few dogs will fail
to respond to treatment and some severe forms of IBD can progress to
intestinal cancer.
Keep your dog with IBD on the right track—have your veterinarian
examine him or her several times each year to ensure no problems arise
because of disease or medication.
Donna Spector, DVM, DACVIM,is a renowned,
board-certified Veterinary Internal Medicine Specialist who has
practiced at the Animal Medical Center in New York City and other
leading institutions. She is an active member of the American Veterinary
Medical Association (AVMA) and the American Holistic Veterinary Medical
Association. Dr. Donna has written and lectured extensively on topics
including nutrition, diabetes, gastrointestinal disorders, kidney
failure and respiratory disease. She is widely recognized for her role
as consulting veterinarian to HALO, Purely for Pets, her TV appearances
with Ellen DeGeneres and her widely-quoted pet health advice in print
and on radio. Dr. Donna performs medical, nutrition and weight loss
consultations for dogs and cats through her web-based veterinary
consulting service, www.SpectorDVM.com.
