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Histiocytic Ulcerative
Colitis
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Canine
histiocytic ulcerative colitis (CHUC) is a chronic debilitating disease
which is characterized by inflammation and ulceration of the innermost
lining of the colon. Ulcerative colitis affects only the colon. This
form of colitis is particularly ulcerative and involves infiltration of
the tender colon lining with cells called histiocytes. These cells are
the cells that are normally called into the scene of inflammation
relatively late so that they can absorb the dead cells and debris that
have been created by the inflammatory event.
Research has shown that in ulcerative colitis, the body's defenses are
operating against some substances in the body, perhaps in the digestive
tract, which the body recognizes as foreign. These foreign substances
(antigens) may themselves cause the inflammation to begin or to
stimulate the inflammatory process to continue without control.
Dogs with this
condition typically show symptoms at an early age (less than 2 years)
and become more debilitated than typical colitis patients. The first
symptom of ulcerative colitis is normally a progressive loosening of
the stool. The stool is generally bloody and mucoid and can be
associated with
crampy abdominal pain and severe urgency to have a bowel movement. The
diarrhea may begin slowly or quite suddenly. In addition there may be
skin lesions, pain in the joints and failure to grow properly. The dog may lose
weight and become debilitated later on in the disease. It
is currently believed that this condition results from an inappropriate
immune response against the common bacteria of the colon. Dogs with
this form of colitis do not respond well to the usual remedies listed
above but instead seem to show an excellent response to the antibiotic
enrofloxacin. This antibiotic is particularly effective against gram
negative bacteria (so classified because their cell wall's staining
properties when tested). It has thus been inferred that these bacteria
are at the root of the problem.
Histiocytic
ulcerative colitis can be confirmed by biopsy of the colon or by
colonoscopy, although signs of
colitis in a young dog are highly suggestive of this condition.
Other tests may also be performed to rule out other causes of colitis
such as bacterial infections. Unfortunately this type of colitis tends
to recur and it is often a progressive disease which is ultimately
uncontrollable. Treatment often involves the use of corticosteroids
such as prednisone. Drugs such as sulfasalazine, metronidazole and
tylosin may also be used. It may be worth trying complimentary
treatments in conjunction with these drugs.
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What
is histiocytic ulcerative colitis?
Colitis means
inflammation of the large intestine. Histiocytic colitis is one form of
inflammatory bowel disease (IBD), in this case associated with
infiltration of inflammatory cells (histiocytes) into the intestinal
wall which is thought to be due to a defect in immune regulation. The
result is chronic large bowel diarrhea.
This disorder
has some similarities to Crohn's disease in people.
How
is histiocytic ulcerative colitis inherited?
unknown
What
breeds are affected by histiocytic ulcerative colitis?
boxer, French
bulldog
For many breeds
and many disorders, the studies to determine the mode of inheritance or
the frequency in the breed have not been carried out, or are
inconclusive. We have listed breeds for which there is a consensus
among those investigating in this field and among veterinary
practitioners, that the condition is significant in this breed.
What
does histiocytic ulcerative colitis mean to your dog & you?
This condition
generally develops in young dogs (less than 1 year). Because this is a
problem in the large intestine, your dog will have signs such as an
increased frequency of passing stool (although the volume may be
normal), straining to defecate, and the presence of blood or mucous in
the stool. There is usually an increased sense of urgency for your dog,
which often means "accidents" in the house. There may be intermittent
vomiting, lethargy, loss of appetite and weight loss.
How
is histiocytic ulcerative colitis diagnosed?
There are many
disorders that cause chronic diarrhea in dogs, so diagnosis is not
simple. Your answers to questions about frequency and appearance of the
increased stool will help point your veterinarian towards large bowel
disease. S/he will do blood and fecal tests for parasites, bacterial
infections and other possible causes. An intestinal biopsy is necessary
for a definitive diagnosis of histiocytic ulcerative colitis. This
involves surgical removal of small samples of your dog's intestinal
wall for examination by a veterinary pathologist.
For
the veterinarian: Colonoscopy may
show evidence of the disease (increased mucosal granularity, friability
and diffuse erosions) but histopathology is necessary for a definitive
diagnosis, and will show a mixed inflammatory cellular infiltrate
with PAS-positive histiocytes.
How
is histiocytic ulcerative colitis treated?
This disorder is
difficult to control. Treatment consists of dietary management, and
immunosuppressive and anti-inflammatory drugs to reduce the intestinal
inflammation. The diet should be free of additives and preservatives
and contain an adequate (but not excessive) amount of highly digestible
protein, with supplementation of fiber. Your veterinarian will
recommend an appropriate commercial diet or provide a recipe for a
homemade diet that meets these requirements.
For
the veterinarian: Treatment is largely
empiric. Anti-inflammatory drugs such as corticosteroids,
sulfasalazine, and metronidazole are used, often in combination. Other
immunosuppressive drugs may be tried if prednisone fails. Newer drugs
are also being tried for treatment of Crohn's disease in people, that
may prove useful in dogs.
Breeding
advice
Affected dogs
should not be bred and until more is known about inheritance of this
disorder, it is prudent to avoid breeding their parents and siblings as
well.
FOR MORE INFORMATION ABOUT THIS
DISORDER, PLEASE SEE YOUR VETERINARIAN.
Resources
Dimski, D.S. 1995. Therapy of inflammatory bowel disease. In J.D.
Bonagura and R.W. Kirk (eds.) Kirk's Current Vet. Therapy XII Small
Animal Practice. pp. 723-728. W.B. Saunders Co., Toronto.
Jergens, A.E. and Willard, M.D. 2000. Diseases of the large intestine.
In E.J. Ettinger and E.C. Feldman (eds.) Textbook of Veterinary
Internal Medicine, Chapter 138. W.B. Saunders Co., Toronto.
Copyright © 1998 Canine Inherited
Disorders Database. All rights reserved.
This database is a joint initiative of
the Sir James Dunn Animal Welfare Centre at the Atlantic Veterinary
College, University of Prince Edward Island, and the Canadian
Veterinary Medical Association.
Permission to reprint is granted by
Alice Crook, DVM Coordinator, Sir James Dunn Animal Welfare Centre
Atlantic Veterinary College University of Prince Edward Island
