With this
condition, there is dilation of the esophagus due to a loss of normal
peristaltic function. Peristalsis is the process by which waves of
muscular contraction move along the contents (food in this case) of
tubular organs. Animals with megaesophagus regurgitate undigested food
shortly after eating.
Dogs may be born with esophagus or they may develop
it later in life. It is commonly seen with other disorders such
as myasthenia gravis and peripheral neuropathies
How is megaesophagus inherited?
This is an autosomal recessive trait in the wire-haired fox terrier,
and autosomal dominant in the miniature schnauzer.
The mode of inheritance has not been determined for other breeds
that are predisposed to this condition.
What breeds are affected by megaesophagus?
Chinese shar pei, German shepherd, Great Dane, greyhound, Irish setter,
miniature schnauzer, wire-haired fox terrier.
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 megaesophagus mean to your dog & you?
Although it may not be noticed until young adulthood, this disorder is
usually first recognized in puppies around the
time of weaning. Affected pups regurgitate food, fail to thrive,
and may develop respiratory difficulties associated with aspiration
pneumonia due to inhalation of food particles. Signs include laboured
breathing, fever and lethargy, and nasal discharge.
Some dogs appear to gradually outgrow this condition (by a year or so),
while in others there is no improvement.
How is megaesophagus diagnosed?
Regurgitation of undigested food shortly after eating is the main sign
with this disorder. Your veterinarian will take
chest x-rays to determine if your dog has megaesophagus, and perform
other laboratory tests since there are several conditions that may
be associated with this disorder.
For the veterinarian: Since megaesophagus may be associated with
many different conditions, the diagnostic work-up should include
CBC, biochemical profile, urinalysis and survey thoracic radiographs in
all cases.
How is megaesophagus treated?
If an underlying cause can be identified, treatment may improve
esophageal function. There is no specific treatment
for the megaesophagus itself, but it can usually be managed by feeding
small, frequent, high-caloric meals from an elevated location so
that gravity assists the passage of food. Different consistencies
of foods can be tried to determine which causes the least
regurgitation.
Some dogs appear to outgrow the problem, while in others there is no
improvement and feeding management is required for life. Your
veterinarian will discuss with you possible complications that you must
watch out for, the most serious of which is aspiration pneumonia.
Breeding advice
Affected wire-haired fox terriers, their parents (carriers of the
trait) and siblings (suspect carriers) should not be bred. Affected
miniature schnauzers should not be bred.
In other breeds in which inheritance is unknown, it
is safest to avoid breeding affected dogs, their parents and siblings.
FOR MORE
INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.
Resources
Twedt, D.C. 1995. Diseases of the esophagus. In E.J. Ettinger and E.C.
Feldman (eds.) Textbook of Veterinary Internal Medicine, pp.1124-1142.
W.B. Saunders Co., Toronto.
Jenkins, C.C. and Mears, E.A. 1996. What's new in the diagnosis and
management of megaesophagus. ACVIM-Proceedings of
the 14th Annual Vet. Med. Forum, p. 585-586.
Copyright
© 1998 Canine Inherited Disorders Database. All rights reserved.Revised: April 27, 2001.
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. reprinted with kind
permission from:-
Alice
Crook, DVM,Coordinator, Sir James Dunn Animal Welfare Centre, Atlantic
Veterinary College,University of Prince Edward Island, 550 University
Ave.Charlottetown, PEI C1A 4P3