Inflammatory bowel disease: Why the prognosis is often guarded
Inflammatory bowel disease is the term used to describe a diverse group
of intestinal disorders in dogs and cats. These disorders are
characterized by the abnormal accumulation of inflammatory cells in the
mucosa or lining of the intestine.
The most common type of inflammatory bowel disease in dogs and cats is
called lymphoplasmacytic enteritis. The reason plasma cells and
lymphocytes (cells produced in lymphoid tissue) accumulate in the lining
of the intestine is not clear but is thought to involve an immunological
reaction to antigens present in food, bacteria, or parasites.
Veterinarians diagnose lymphoplasmacytic enteritis by ruling out
metabolic, parasitic, infectious, and pancreatic causes of small-bowel
disorders and also by obtaining biopsies, which demonstrate the abnormal
accumulation of inflammatory cells. The exclusion of known causes of
intestinal inflammation such as dietary sensitivity and infestation by
internal parasites suggests a diagnosis of idiopathic inflammatory bowel
disease.
The veterinarian evaluates the degree of cellular accumulation and
categorizes this as mild, moderate, or severe. The extent of
inflammation varies and can range from the duodenum (the first part of
the small intestine) to the rest of the small and large bowel. A very
severe form of this disease has been found in Basenjis.
Clinical signs
The most frequently observed clinical signs in dogs and cats with
lymphoplasmacytic enteritis are chronic diarrhea (large volume)
accompanied by weight loss or vomiting. The pet owner can help the
veterinarian diagnose the disease by describing the type of diarrhea.
Lymphoplasmacytic enteritis of the small intestine is characterized by
small bowel disorder, which involves a large volume of stool, a mild
increase in frequency of defecation, and little or no straining, mucus,
or blood present. The vomit often contains bile, and in cats it
frequently contains hairballs. If the large bowel is involved, there may
be mucus, blood, and straining at defecation with little matter produced
(tenesmus).
There are other clinical signs such as changes in appetite, excessive
burbling noises in the intestine (borborygmi), and abdominal discomfort.
It is important for owners to understand that the severity of
inflammatory bowel disease is variable, ranging from intermittent
diarrhea and vomiting in mild cases to intractable diarrhea, refusal to
eat, and weight loss in severe cases. The severity of the disease is
believed to reflect the degree of cellular infiltrate into the intestine
. In addition to these signs, the veterinarian may also note a
thickening of the intestine (with or without enlarged lymph nodes),
marked weight loss, and the accumulation of fluid in the abdomen
(ascites). Animals that have very low plasma protein may also show signs
of tissue swelling due to edema formation.
Treating the disease: dietary factors
Mild to moderate intestinal inflammation may be associated with dietary
sensitivity, food intolerance, parasites (for example, giardia), and
even small intestinal bacterial overgrowth.
The veterinarian may decide to put the dog or cat on a special diet to
determine if dietary sensitivity or intolerance is present. After all
factors have been taken into consideration, the pet is usually fed a
highly digestible diet that is restricted in tat, is gluten-free, and is
limited to a single protein source. Up to six weeks may be required to
see a response to this therapeutic trial.
A trial lasting 21 days of antibiotics may be warranted if small
intestine bacterial overgrowth is suspected. (Cat owners should know
that dietary modification is seldom effective in cats with inflammatory
bowel disease and, furthermore, intestinal bacterial overgrowth has not
been recorded in cats.)
Dietary factors to consider are additives, preservatives, protein
digestibility, protein source, and dietary fiber.
Some pet foods are labeled hypoallergenic if they contain no additives
and preservatives. Although some pets are allergic to foods with
additives and preservatives, there appears to be no hard scientific
evidence that most pets react this way, nor is there evidence that
additives and preservatives are in and of themselves likely to cause
allergic reactions. But weighing in on the side of cautious management,
they are excluded from trial diets.additives and preservatives are in and of themselves likely to cause
allergic reactions. But weighing in on the side of cautious management,
they are excluded from trial diets.
Pet owners should again be reminded that the mere absence of additives
and preservatives does not make a food hypoallergenic.
Protein digestibility, meaning that the food contains an adequate amount
of highly digestible protein; is important because protein that is
poorly digestible may cause antigenic stimulation and may promote
inflammatory bowel disease.
Protein digestibility, meaning that the food contains an adequate amount
of highly digestible protein; is important because protein that is
poorly digestible may cause antigenic stimulation and may promote
inflammatory bowel disease.additives and preservatives are in and of themselves likely to cause
There are no protein sources that are in and of themselves
hypoallergenic. This includes lamb. Much depends on the dietary history
of the pet. That is, the protein source in the hypoallergenic diet must
be a food that the pet has not encountered before, i.e., tofu, cottage
cheese, and lamb, along with rice. The owner is usually advised to use
only one of the novel protein sources, and if the pet improves, then
switch to a commercially available ration with that protein source. An
important piece of advice: check the label and avoid rations that list
several protein sources.
Fortunately, the market offers an increasingly diverse array of novel
protein sources, including rabbit, venison, and duck, along with the
more familiar lamb, chicken, and rice.
Drug therapy for lymphoplasmacytic enteritis
The administration of immunosuppressives is often required for patients
who fail the dietary trials described, for patients with moderate to
severe infiltrates, and for patients that develop a condition called
hypoproteinemia, a deficiency of protein in the blood due to protein
leakage from the gut.
Oral prednisolone is the initial drug of choice. It is usually
administered at an immunosuppressive dose for two to three weeks, then
decreased by 50 percent every two to three weeks and eventually
continued on an alternate day basis for two to three months. The
antibiotic tylosin is frequently administered at the same time.
If clinical response is poor or if the adverse effects of
corticosteroids are troublesome, further immunosuppression can be
achieved by adding azathioprine (Imuran) to the regimen. In dogs,
azathioprine is
usually given every five days and then on a schedule that alternates it
with prednisolone. Cats are more sensitive to azathioprine and require a
reduced dose. The veterinarian will want to monitor the pet's complete
blood count every two to four weeks when azathioprine is given. Another
drug, metronidazole, can also be used in conjunction with steroids and
has effects on bacteria and the immune system.
Successful treatment is accompanied by a decrease in diarrhea and
vomiting followed by weight gain and an increase in plasma proteins.
Once a patient has had from two to three months of remission of clinical
signs it may be possible to gradually withdraw the immunosuppressive
therapy. If signs recur,
however, daily medication is continued until they resolve, then the
medication is gradually reduced. In
patients that respond poorly to therapy or go into relapse after an
initial response, the veterinarian, may want to reassess* the patient
and consider taking additional intestinal biopsies to rule out the
presence of alimentary lymphosarcoma, a malignant tumor of the lymphoid
tissue.
What's new in drug therapy
There has been progress in developing new drugs to treat inflammatory
bowel disease and related problems in humans, but unfortunately few of
these new drugs are available or practical for use in dogs and cats.
Cyclosporine, the extraordinary immunosuppressant that made organ
transplantation a lifesaver for thousands of humans, has had moderate
success as a treatment for human bowel disease (in this case, Crohn's
(disease). The drug has serious side effects and is costly, factors that
make its use in pets unlikely.
The antihypertensive drug clonidine has been used with success in humans
, but there is no report of its use in dogs or cats. Finally, the use of
the acid found in fish oil for skin diseases in dogs and cats has led to
the speculation that fish oil might also benefit pets with inflammatory
bowel disease. Although there is a fish oil drug available for humans
with inflammatory bowel disease, the drug has not been evaluated in dogs
or cats.
Prognosis
The owner of a dog or cat with lymphoplasmacytic enteritis should
understand that the prognosis for recovery depends on the severity of
the condition. Prognosis is also quite variable with many patients
requiring prolonged treatment with glucocorticoid and diet modification.
In the absence of accurate criteria for predicting response,
veterinarians tend to give a guarded prognosis when treating the disease
..
Focus on dietary fiber
If you believe all the labels you read, you could come away convinced
that fiber in the is absolutely necessary for health, well-being and
disease-free longevity. But all the hype aside, can an increase in
fiber in the diet of a dog or cat either prevent or help manage
inflammatory bowel disease?
To begin with, the role of fiber has not been well studied, although
some experts believe that an increase in fiber is likely to be useful in
some cases. But no one claims that fiber can cure a case of inflammatory
disease.
Dr. Michael D. Willard of Texas A&M notes that some of the known effects
suggest some potential benefits. For example fiber increases the
activity of the colon and speeds up transit time, increases fecal output
and improves stool consistency. This combined action may be of some
benefit in certain cases of bowel disease, as has been reported to happen with human patients.
In spite of this evaluation other experts take more guarded approach. Dr
P. J. Markwell and Dr. I. E. Maskell, both of the highly regarded
Waltham Centre for Pet Nutrition in Great Britain, say that high fiber
diets are not indicated in gastric diseases. However, they agree that
fiber may be beneficial in some cases, mainly for the reasons already
given. Fiber normalizes fecal transit time and fecal water content.
Fiber may also increase gastrointestinal tissue weight.
The owner of a dog or cat with inflammatory bowel disease is advised not
to try to increase fiber content of the pet's diet by, say, giving , it
a helping of one of the high-fiber breakfast cereals. That's because
most commercial breakfast cereals contain only 2 to 4 grams of fiber per
cup, and many contain excessive, sugar and gluten The safest route is to
have the veterinarian decide if fiber is of possible benefit in an
individual case of inflammatory bowel disease. A homemade high-fiber
diet could be prepared by the owner or , a better choice, prescription
diet can be such diets are specially formulated with anywhere from 12 to
25 percent more fiber than is in an average commercial food (which
usually contains from 1 to 4 percent fiber). In addition prescription
diets have the special advantage of being consistent, which is not
always the cases with a diet being prepared in the home.
Clinical signs
The most frequently observed clinical signs in dogs and cats with
lymphoplasmacytic enteritis are chronic diarrhea (large volume)
accompanied by weight loss or vomiting. The pet owner can help the
veterinarian diagnose the disease by describing the type of diarrhea.
Lymphoplasmacytic enteritis of the small intestine is characterized by
small bowel disorder, which involves a large volume of stool, a mild
increase in frequency of defecation, and little or no straining, mucus,
or blood present. The vomit often contains bile, and in cats it
frequently contains hairballs. If the large bowel is involved, there may
be mucus, blood, and straining at defecation with little matter produced
(tenesmus).
There are other clinical signs such as changes in appetite, excessive
burbling noises in the intestine (borborygmi), and abdominal discomfort.
It is important for owners to understand that the severity of
inflammatory bowel disease is variable, ranging from intermittent
diarrhea and vomiting in mild cases to intractable diarrhea, refusal to
eat, and weight loss in severe cases. The severity of the disease is
believed to reflect the degree of cellular infiltrate into the intestine
. In addition to these signs, the veterinarian may also note a
thickening of the intestine (with or without enlarged lymph nodes),
marked weight loss, and the accumulation of fluid in the abdomen
(ascites). Animals that have very low plasma protein may also show signs
of tissue swelling due to edema formation.
Treating the disease: dietary factors
Mild to moderate intestinal inflammation may be associated with dietary
sensitivity, food intolerance, parasites (for example, giardia), and
even small intestinal bacterial overgrowth.
The veterinarian may decide to put the dog or cat on a special diet to
determine if dietary sensitivity or intolerance is present. After all
factors have been taken into consideration, the pet is usually fed a
highly digestible diet that is restricted in tat, is gluten-free, and is
limited to a single protein source. Up to six weeks may be required to
see a response to this therapeutic trial.
A trial lasting 21 days of antibiotics may be warranted if small
intestine bacterial overgrowth is suspected. (Cat owners should know
that dietary modification is seldom effective in cats with inflammatory
bowel disease and, furthermore, intestinal bacterial overgrowth has not
been recorded in cats.)
Dietary factors to consider are additives, preservatives, protein
digestibility, protein source, and dietary fiber.
Some pet foods are labeled hypoallergenic if they contain no additives
and preservatives. Although some pets are allergic to foods with
additives and preservatives, there appears to be no hard scientific
evidence that most pets react this way, nor is there evidence that
additives and preservatives are in and of themselves likely to cause
allergic reactions. But weighing in on the side of cautious management,
they are excluded from trial diets.
Pet owners should again be reminded that the mere absence of additives
and preservatives does not make a food hypoallergenic.
Protein digestibility, meaning that the food contains an adequate amount
of highly digestible protein; is important because protein that is
poorly digestible may cause antigenic stimulation and may promote
inflammatory bowel disease.
There are no protein sources that are in and of themselves
hypoallergenic. This includes lamb. Much depends on the dietary history
of the pet. That is, the protein source in the hypoallergenic diet must
be a food that the pet has not encountered before, i.e., tofu, cottage
cheese, and lamb, along with rice. The owner is usually advised to use
only one of the novel protein sources, and if the pet improves, then
switch to a commercially available ration with that protein source. An
important piece of advice: check the label and avoid rations that list
several protein sources.
Fortunately, the market offers an increasingly diverse array of novel
protein sources, including rabbit, venison, and duck, along with the
more familiar lamb, chicken, and rice.
Drug therapy for lymphoplasmacytic enteritis
The administration of immunosuppressives is often required for patients
who fail the dietary trials described, for patients with moderate to
severe infiltrates, and for patients that develop a condition called
hypoproteinemia, a deficiency of protein in the blood due to protein
leakage from the gut.
Oral prednisolone is the initial drug of choice. It is usually
administered at an immunosuppressive dose for two to three weeks, then
decreased by 50 percent every two to three weeks and eventually
continued on an alternate day basis for two to three months. The
antibiotic tylosin is frequently administered at the same time.
If clinical response is poor or if the adverse effects of
corticosteroids are troublesome, further immunosuppression can be
achieved by adding azathioprine (Imuran) to the regimen. In dogs,
azathioprine is usually given every five days and then on a schedule that alternates it
with prednisolone. Cats are more sensitive to azathioprine and require a
reduced dose. The veterinarian will want to monitor the pet's complete
blood count every two to four weeks when azathioprine is given. Another
drug, metronidazole, can also be used in conjunction with steroids and
has effects on bacteria and the immune system.
Successful treatment is accompanied by a decrease in diarrhea and
vomiting followed by weight gain and an increase in plasma proteins.
Once a patient has had from two to three months of remission of clinical
signs it may be possible to gradually withdraw the immunosuppressive
therapy. If signs recur,
however, daily medication is continued until they resolve, then the
medication is gradually reduced. In
patients that respond poorly to therapy or go into relapse after an
initial response, the veterinarian, may want to reassess* the patient
and consider taking additional intestinal biopsies to rule out the
presence of alimentary lymphosarcoma, a malignant tumor of the lymphoid
tissue.
What's new in drug therapy
There has been progress in developing new drugs to treat inflammatory
bowel disease and related problems in humans, but unfortunately few of
these new drugs are available or practical for use in dogs and cats.
Cyclosporine, the extraordinary immunosuppressant that made organ
transplantation a lifesaver for thousands of humans, has had moderate
success as a treatment for human bowel disease (in this case, Crohn's
disease). The drug has serious side effects and is costly, factors that
make its use in pets unlikely.
The antihypertensive drug clonidine has been used with success in humans
, but there is no report of its use in dogs or cats. Finally, the use of
the acid found in fish oil for skin diseases in dogs and cats has led to
the speculation that fish oil might also benefit pets with inflammatory
bowel disease. Although there is a fish oil drug available for humans
with inflammatory bowel disease, the drug has not been evaluated in dogs
or cats.
Prognosis
The owner of a dog or cat with lymphoplasmacytic enteritis should
understand that the prognosis for recovery depends on the severity of
the condition. Prognosis is also quite variable with many patients
requiring prolonged treatment with glucocorticoid and diet modification.
In the absence of accurate criteria for predicting response,
veterinarians tend to give a guarded prognosis when treating the disease
..
Focus on dietary fiber
If you believe all the labels you read, you could come away convinced
that fiber in the is absolutely necessary for health, well-being and
disease-free longevity. But all the hype aside, can an increase in
fiber in the diet of a dog or cat either prevent or help manage
inflammatory bowel disease?
To begin with, the role of fiber has not been well studied, although
some experts believe that an increase in fiber is likely to be useful in
some cases. But no one claims that fiber can cure a case of inflammatory
disease.
Dr. Michael D. Willard of Texas A&M notes that some of the known effects
suggest some potential benefits. For example fiber increases the
activity of the colon and speeds up transit time, increases fecal output
and improves stool consistency. This combined action may be of some
benefit in certain cases of bowel disease, as has been reported to hap
pen with human patients.
In spite of this evaluation other experts take more guarded approach. Dr
. P. J. Markwell and Dr. I. E. Maskell, both of the highly regarded
Waltham Centre for Pet Nutrition in Great Britain, say that high fiber
diets are not indicated in gastric diseases. However, they agree that
fiber may be beneficial in some cases, mainly for the reasons already
given. Fiber normalizes fecal transit time and fecal water content.
Fiber may also increase gastrointestinal tissue weight.
The owner of a dog or cat with inflammatory bowel disease is advised not
to try to increase fiber content of the pet's diet by, say, giving , it
a helping of one of the high-fiber breakfast cereals. That's because
most commercial breakfast cereals contain only 2 to 4 grams of fiber per
cup, and many contain excessive, sugar and gluten The safest route is to
have the veterinarian decide if fiber is of possible benefit in an
individual case of inflammatory bowel disease. A homemade high-fiber
diet could be prepared by the owner or , a better choice, prescription
diet can be such diets are specially formulated with anywhere from 12 to
25 percent more fiber than is in an average commercial food (which
usually contains from 1 to 4 percent fiber). In addition prescription
diets have the special advantage of being consistent, which is not
always the cases with a diet being prepared in the home.