Yorkie
Health
Health Problems Known
in the Breed
(More information about each disease coming soon) |
Eyes |
Patellar Luxation |
Liver Shunt
Dogs with liver shunts often have grave and occasionally deadly
consequences. A liver shunt, also known as a portosystemic shunt, is a
typical fetal blood conduit that avoids liver tissue while still in the
womb, enabling the mother's body to remove toxins for the developing
child. However, in certain animals, the shunt stays open after birth,
impairing the animal's ability to function as a liver, slowing its
growth, and ultimately leading to the deaths of several affected
animals. Conventional surgical methods can be used to repair congenital
portosystemic shunts, but an ameroid constrictor—a thin metal ring
shaped like a C—is implanted as an alternative by a team of researchers
at the University of Tennessee several years ago. Over a period of
weeks, the shunt gradually closes down as a result of the constrictor
fitting around it. Compared to conventional procedures, dogs undergoing
this kind of surgical repair typically experience shorter surgeries and
less postoperative problems. |
Microvascular Dysplasia (MVD)
Describe MVD.
When Too Little Blood Is Reaching the Liver August 07, 2000
Written by Diplomate ACVIM Celeste A. Clements, DVM
Small breed dog owners and veterinarians should be alert for any
symptoms of a liver issue that has been identified by pathologists for
about 15 years but has only recently been identified by veterinary
internists.
The congenital condition known as hepatoportal microvascular dysplasia,
or MVD, affects the blood supply to the liver. Dogs that inherit this
issue may become very sick; among the more severe symptoms of the
illness are coma, seizures, and odd behavior. This issue is
particularly common in Yorkshire and Cairn terriers.
Dogs with MVD don't receive enough blood flow to their livers. A robust
liver cleanses and detoxifies blood that is returned from the
abdomen's components. The portal vein, which has seven main tributaries
and branches throughout the liver lobes, is the route by which blood
enters the liver. The liver will not develop normally and its function
will be impacted by an abnormal or insufficient blood supply; the
severity of the issue actually depends on how severe the deformity is.
Blood that is unable to enter the liver through the proper channels is
"shunted" or diverted.
An enigmatic illness
There are other congenital liver abnormalities brought on by an
inadequate blood supply besides MVD. Because a portosystemic vascular
anomaly, or PSVA, bypasses all or part of the liver, the blood supply
may appear noticeably abnormal. With MVD, however, the anomaly is only
noticeable at the microscopic level, which is why it can be difficult
for veterinarians to track at times.
The veterinarian might miss the disease because it is so subtle. In the
event that the dog does exhibit symptoms of disease, these typically
include increased thirst and urination, food intolerance, or behavioral
abnormalities that could be attributed to the impact of metabolic waste
products and dietary toxins on the brain. Most patients with
significant blood shunting have hepatic encephalopathy, a disorder
caused by an excess of metabolic byproducts in the blood that the liver
is normally able to filter out.
Other symptoms include a coma or seizures, incoordination, depression
or confusion, and apparent blindness. Puppies with "shunts" frequently
exhibit dementia or strange behavior after eating; more subdued MVD
patients in dogs may exhibit symptoms.
Looking into MVD
Bile acid profiles have gained popularity as a noninvasive method of
identifying liver functional abnormalities, including circulatory
problems. When measured jointly, the amount of bile acids in the fed
and fasted, or postprandial, states provide a valuable indicator of
clinically significant liver disease.
The liver produces bile acids, which are then kept in the gallbladder
as part of bile. In order to facilitate digestion, bile enters the
intestinal tract when the gallbladder empties due to hormonal or
chemical signals triggered by eating. A large portion of the bile salts
are reabsorbed into the bloodstream at the ileum, the end of the small
intestine, along with other metabolic byproducts.
They then enter the portal circulation and are directed toward the
liver.
Bile salts are drawn from the blood and circulated in dogs with healthy
livers. However, if the patient has bile retention, decreased liver
mass, or impaired hepatoportal circulation, the level of bile acids
will be elevated.
However, a dog with a high level of bile salts does not necessarily
have MVD. Since there is a lot of overlap between the various liver
diseases, additional diagnostic procedures such as liver biopsy,
nuclear scintigraphy, or dye studies are often required in order to
distinguish between the diseases.
Noninvasive methods such as nuclear scintigraphy can be used to
evaluate the presence of shunting in dogs exhibiting abnormal blood
circulation to the liver. An enema labeled with a radioisotope is given
during this process
The colon absorbs this radioisotope through circulation, and in healthy
dogs, the labeled blood is delivered to the liver; in shunt-affected
dogs, it is delivered to the heart. It is possible to compare the entry
of labeled blood into the liver and the heart thanks to computer
technology. Although the technique is rarely able to localize the
abnormal circulation, estimates of the shunt fraction are generally
considered reliable. Surgical correction of the portosystemic vascular
anomaly is unlikely if the shunt fraction is less than or equal to
fifteen percent.
A definitive diagnosis of an issue with blood flow to the liver can be
made with a dye study
A dye study test for MVD will reveal blunted portal vein branches,
uneven distribution of contrast within the liver tissue, and
persistence of contrast within the liver tissue. These operations are
carried out on a sedentary patient, usually in conjunction with hepatic
visualization or liver sampling surgery. Contrast studies, sometimes
known as portography, are infrequently carried out even if an anomalous
blood vessel is found grossly.
Options for treatment
If done before the dog reaches two years of age, surgical correction of
the shunting vessel through banding or ligation is successful in most
cases. Improved liver function and a more normal blood flow pattern are
attained, but in certain patients, microscopic circulatory
abnormalities may linger, making establishment of of an entirely
typical condition.
Dogs with MVD are not able to have their liver dysfunction corrected,
in contrast to dogs with PSVA. Dogs exhibiting symptoms of the disease
are treated with diets low in dietary protein, oral antibiotics to
suppress intestinal bacterial growth, and lactulose to lower intestinal
absorption of ammonia, which is one of the major causes of hepatic
encephalopathy. For the majority of dogs, effective sign control should
allow for a good quality of life. However, some people will still
experience progressive liver dysfunction, portal hypertension, and an
accumulation of fluid in the abdomen as a result.
For asymptomatic patients, there is no need for treatment; however, all
dogs with MVD may be more susceptible to negative reactions to drugs
that the liver processes. When giving prescription or over-the-counter
medications, exercise caution, and when making anesthesia plans. It's
unknown if MVD makes people more susceptible to infections or
inflammatory diseases that cause liver disease.
Catching it early It's best to identify dogs with MVD as soon as
possible. It's critical to stop the illness from proliferating and from
being confused with other conditions that may eventually result in
liver failure. A high-risk population of Cairn and Yorkshire terriers
may exist; other small breeds with documented cases of MVD include the
miniature schnauzer, Lhasa apso, dachshund, Maltese, bichon frise, and
poodle.
Puppies or young small breed dogs who have consistently elevated serum
bile acids but are otherwise healthy should be suspected of having the
issue. For patients who may be suspects of of PSVA or MVD, though it
might not always be easily accessible. Furthermore, the test only
detects gross shunting and cannot conclusively confirm or rule out
microscopic abnormalities. The only way to conclusively diagnose MVD is
with a liver biopsy that is both decent in quality and size.
Most patients can safely have liver biopsies done, but each patient
should have their risks evaluated and any potential benefits weighed
against them. In dogs with only abnormal test results, it is far more
difficult to justify the liver biopsy procedure, even though it may be
necessary for symptomatic patients with high bile acids. A liver biopsy
as well as a visual assessment of the liver and portal circulation may
be taken into consideration if spaying is planned for female dogs who
are at risk.
MVD is still considered a tentative diagnosis in certain cases, which
makes sense as long as no surgically treatable issue is missed.
Researchers studying diseases that are difficult to "pin down," like
MVD, are still studying the condition.
The condition known as hepatic microvascular dysplasia is characterized
by the microscopic mixing of venous and arterial blood within the
liver. This condition is also known as hepatoportal microvascular
dysplasia, so you can search for information under either name.
Although it has been identified in several small dog breeds, Cairn and
Yorkshire terriers appear to be particularly affected by this condition.
Most dogs with this illness probably don't exhibit any obvious clinical
symptoms linked to the microvascular dysplasia and are identified, for
whatever reason, when bile acid response testing is carried out to rule
out liver disease. Unfortunately, some dogs with this condition do
exhibit clinical signs. These signs can include urinary tract disease
linked to ammonium biurate cystals in the urinary tract, which form as
a result of liver problems, gastrointestinal issues, or seizures or
other disorders of the central nervous system.
The first clue that this illness is present is typically provided by
abnormal bile acid response testing. It is also possible for
portosystemic shunts to cause elevated bile acid levels. When thinking
about the possibility of hepatic microvascular dysplasia, it is
necessary to rule out that possibility. A liver biopsy helps to rule
out other liver diseases, which provides additional evidence for the
existence of this condition.
When canines possess microvascular dysplasia without exhibiting any
symptoms, and their prognosis is excellent. Therapy is not necessary in
many situations. When dietary therapy and medication are used to manage
clinical signs in dogs that are diagnosed, the signs can frequently be
controlled. The goal of the dietary therapy is cutting back on too much
protein in the diet as well as medications like lactulose and
antibiotics like metronidazole or neomycin that are used to lower the
body's ammonia levels in the digestive tract. Patients with clinical
signs of hepatoportal microvascular dysplasia have varying prognoses.
Certain dogs respond favorably to therapy and have lifespans that are
average or almost average. Others have seen a gradual worsening of
their clinical symptoms. I'm not aware of any
technique for forecasting a patient's prognosis.
Many lower-protein diets, such as Purina's NF diet, the Hills k/d (tm)
and l/d (tm) diets, and others, may be beneficial. The dosage of
lactulose is tailored to each patient's requirements by utilizing it to
produce a formed, but soft, stool. The standard dosage for neomycin and
metronidazole is 22 mg/kg of body weight and 7.5 mg/kg, respectively,
given twice daily. This dosage of metronidazole is less than what is
prescribed for a number of other illnesses. These are the two most
often mentioned antibiotics, though I have seen recommendations for the
use of other antibiotics. |
Protein-Losing Enteropathy (PLE)
What is Protein Losing Enteropathy?
Protein-losing enteropathy is the term for excessive loss
of plasma and proteins into the gastrointestinal (GI) tract. Any
ailment that harms the GI tract's lining may be the cause. Intestinal
lymhangiectasia, immunoproliferative enteropathy, protein-losing
enteropathy, and nephropathy in the soft-coated wheaten terrier are
among the protein-losing enteropathies that are believed to have an
inherited component. The latter disorder is associated with renal
protein loss and is hypothesized to be related to bad dietary reactions
(see also familial renal disease).
How are nephropathy and protein-losing enteropathy inherited? There's a
chance of autosomal recessive inheritance.
Which breeds are afflicted with nephropathy and protein-losing
enteropathy? soft-coated terrier made of wheat
What does nephropathy and protein-losing enteropathy mean for you and
your dog? It's
possible for your dog to gradually lose weight or not gain any weight
at all. Fluid loss from the circulation into the limbs, the belly, or
the chest results from the loss of protein into the colon. Your dog can
appear bloated in the legs and/or abdomen and have breathing
difficulties. The loss of protein, moisture, and fat into the intestine
may result in sporadic or chronic diarrhea. Your dog's drinking and
urinating will rise if their kidneys lose protein.
How are nephropathy and protein-losing enteropathy diagnosed? Your
veterinarian will probably suspect one of the disorders that cause loss
of proteins into the stomach if your dog exhibits the symptoms listed
above. It's essential to do laboratory testing and an intestinal biopsy.
How are nephropathy and protein-losing enteropathy treated? This is an
incurable condition, but it can be effectively treated by both you and
your veterinarian. Reducing the amount of proteins lost into the
intestine and getting your dog's protein levels back to normal are the
main objectives of therapy. This is accomplished by reducing intestinal
wall inflammation with food and medication. Dogs suffering from
protein-losing enteropathy should eat a diet low in fat and high in
quality protein. These requirements can be met by commercial
prescription diets, or your veterinarian can provide you with
information on how to make a low-fat diet at home. In any scenario,
because of the inadequate absorption of fat that occurs in dogs, you
will need to add fat-soluble vitamins to their diet.
Corticosteroids may lessen inflammation, which in
turn may lessen protein loss and the accompanying diarrhea.
Advice on breeding
Dogs that are affected shouldn't be put up for breeding. Parents, who
are regarded as carriers, and siblings, who are regarded as suspect
carriers, should not be used for breeding because the inheritance is
believed to be autosomal recessive.
SEE YOUR VETERINARIAN FOR MORE DETAILS ABOUT THIS DISORDER.
Materials
Sherding, R.G., Batt, R.M., and Burrows, C.F. 1995. small intestinal
diseases. Pages 1224–1225 of Textbook of Veterinary Internal Medicine,
edited by S.J. Ettinger and E.C. Feldman. Toronto's W.B. Saunders Co.
Protein-losing enteropathy, Proceedings of the 16th ACVIM Forum, pp.
419–421, Williams, D.A. 1998
Canine Inherited Disorders Database Copyright C 1998. Reserved rights
apply. Updated:
The Canadian Veterinary Medical Association, the Atlantic Veterinary
College, University of Prince Edward Island, and the Sir James Dunn
Animal Welfare Centre collaborated to create this database.
|
Encephalitis |
Degenerative Myelopathy
(DM) |
Hyperuricosuria |
Kidney Disease |
Collapsing
Trachea |
|