Liver
Disease:
Signs, Symptoms, and Diagnosis.
Column written by: Dr. Fleming, Sherwood Animal
Clinic (Regina, Saskatchewan, Canada)
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This topic is as big as the states of Alaska and Texas combined. I
really cannot do it justice in a short essay, but I think it
deserves some mention, if only to give the pet owner some
understanding as to the difficulties involved when a veterinarian is
faced with a case of possible liver failure.
If you asked ten people on the street what they knew about "liver",
I would bet that the only consistent answer you would get is that it
tastes really bad unless the cook really knows his stuff. The best
description of the liver I can give you is that this organ is the
main industrial centre of the body. The liver processes raw
materials, manufactures the building blocks of the body, recycles
the old to make new, and detoxifies the industrial waste of the
body. In short the liver is involved in just about every biochemical
process required to run e body. As a result of this relationship,
liver disease can affect just about any other part of the body and
thus the symptoms of liver disease are typically unpredictable and
non- specific. Furthermore, because the liver acts as a "biochemical
cross roads" for the body, it is affected by a wide range of
diseases, including viral and bacterial infections, degenerative and
neoplastic disease, and toxic insults. It is estimated that three
per cent of all disease seen by veterinarians is liver based.
The liver has a double edged nature which, while being life
preserving, makes diagnoses and treatment of liver disease extremely
difficult. The liver has a tremendous reserve capacity, which means
that it can easily perform it's duties with up to 70 to 80 per cent
of the liver mass affected by disease. While it certainly is a
benefit that our liver can keep us alive despite an overwhelming
infection or a massive tumour, it also means that the disease is
well advanced and possibly untreatable before any symptoms are
noted. We all know that disease is most easily conquered early, but
the very nature of the liver makes this an impossible task. One
thing about livers though: they are the only organ in the body which
is capable of complete regeneration and thus is we do manage to
successfully treat the disease, there is a chance of complete
recovery.
Because of the complexity of this topic, I am going to cover it
using very abbreviated point form. I will try to skip over the
experimental theories and the more esoteric points and keep to the
meat of the topic.
Common Presenting Symptoms
All, some, or only one of these signs may be present.
Intermittent recurrent abdominal or gastrointestinal upsets. loss of
appetite, vomiting, diarrhea, constipation.
Progressive depression or lethargy. does not want to play anymore or
refuses to go for walks.
Swollen belly with a "fluid filled" look. This is also known as
ascites and is actually fluid accumulation in the belly due to
circulation alterations in the abdomen.
Pale gray feces. Bile pigments are what gives poop it's
characteristic brown colour and if the liver is not processing bile
properly, the feces will not get their colour.
Orange urine. The improper processing of bile results in the
excretion of bilirubin in the urine in high amounts, thus orange
urine.
Jaundice, also known as icterus. Any pale or white skin or visible
tissue takes on a yellow hue. Again the biliary pigments are
accumulating in the body because the liver is not processing them.
Rarely: bleeding problems. Many of the proteins required for proper
blood clotting are created in the liver. Remove these proteins and
blood clotting decreases.
Hepatic encephalopathy, or severe neurological signs. behavioural
changes, seizures, aimless pacing or circling, head pressing. May be
associated with meal time.
Pain associated with the abdomen. This is due to the stretching of
the liver capsule. May be noted when the dog is lifted around the
belly or when the veterinarian probes (palpates) the abdomen. The
veterinarian may also notice a swollen liver while palpating with
some of the more acute liver diseases.
Chronic weight loss or wasting. The liver processes all the building
blocks. If it fails to process, the body fails to maintain itself.
Increased water consumption and urination. Most likely due to
dramatic shifts in serum and kidney salt balances. May be
behavioural too.
Points on notable symptoms.
1. Bile pigment processing. Bile is a complex mixture of organic and
inorganic compounds. It is primarily responsible for alkalizing the
intestinal contents (acidic from the stomach),emulsifying the
dietary fat, and prevention of putrefaction of digestive material.
Bilirubin, one of the bile pigments, is derived from the break down
of hemoglobin, the oxygen carrying molecule carried in our red blood
cell. Bilirubin is quite toxic, but it usually binds to a protein
called albumin, which harmlessly carries it to the liver for
detoxification and excretion. Albumin is made in the liver. Liver
failure results in poor bilirubin processing and decreased albumin
manufacturing, which results in a dangerously high level of free
floating bilirubin.
The liver excretes the bilirubin after binding it to an amino acid
into the bile duct system. Eventually the conjugated bilirubin
enters the digestive tract, where the intestinal bacteria break it
down to a harmless product called urobilinogen. Urobilinogen, after
complete digestion in the intestines, is brown, therefore the feces
tend to be brown.
Jaundice, also known as icterus, results from the accumulation of
conjugated and unconjugated bilirubin in the body tissues. This
becomes visible to the veterinarian, especially around the whites of
the eyes and on the pale areas of the gums.
2. Important biological functions:
• a. hormone metabolism. The liver is both the target organ for many
of the body's hormones and the recycling centre for most of the
hormones. Some of the symptoms stemming from liver failure may mimic
a major hormonal imbalance.
• b. vitamin metabolism. Practically all the vitamins consumed in
our diets are either directly involved in liver function or require
liver aided transformation to be used in the body. This includes
Vitamin C, the B vitamins, Vitamins A, D, E and K. Vitamin K is
important to maintain blood clotting and requires hepatic
transformation from the inactive form to the active form.
• c. Red blood cell maintenance. In the mature dog the liver plays
an active role in the removal of aged or damaged red blood cells
from circulation. It is also active in the metabolism of hemoglobin
and the storage of iron. Abnormalities in red blood cell structure
is one of the harbingers of liver disease. Anemia may be present in
chronic liver disease.
• d. Hemostasis or blood clotting ability. Most of the proteins
involved in the creation of a functional blood clot are made in the
liver. The clotting system is an extremely complex, interlocking
system ; remove some of the factors involved and you end up with a
tendency to bleed or hemophilia.
• e. Carbohydrate and fat metabolism:
Sugars, or carbohydrates are the basic fuel of the body. The liver
is the primary centre for processing of the sugars into the form
immediately required. The liver is also responsible for the
destruction of insulin, the hormone directly involved with the
cellular absorption of blood sugars. Alterations in liver function
often do not affect blood sugar levels until much of the liver has
been destroyed.
Fat metabolism is extremely complex due to the vast number of
functions fat carries out in the body. The liver sits at the centre
of those many functions.
Cholesterol is probably the most common fat based product in the
body, being the major component in the cell wall, the basis for the
steroid hormones and bile pigments, and the precursor of vitamin D.
Any disease in fat metabolism can adversely affect the liver, and
any disease in the liver can result in problems in fat metabolism.
An example of this is the "fatty liver syndrome" we see in cats,
whereas the rapid mobilization of fat stores during starvation
results in an overtaxed liver and eventually liver failure.
Protein synthesis:
The liver manufactures many of the proteins involved in the body
functions. The major protein is albumin, which is required for
transport of many nutrients and toxins (i.e. bilirubin). Albumin is
also responsible for keeping the serum concentration constant, which
is important with regards to serum fluid and salt balance. (also
known as "oncotic pressure") Also synthesized in the liver is the
globulin series, which are responsible for numerous biochemical
reactions throughout the body. Elevations of select globulins may
indicate a particular hepatic pathology.
The building blocks of proteins are the amino acids. The liver is
also primarily involved in processing of dietary amino acids to
modify them into required or useful forms.
Some of the amino acids require direct hepatic metabolism, while
others can be used by the body unchanged. Experimental efforts have
been made to diagnose and track liver disease based on the relative
proportion of the various amino acids to each other. In liver
failure the amino acids requiring hepatic alterations prior to use
should climb in concentration as compared to those amino acids
unaffected by the liver.
Important Liver Enzymes
Traditionally the medical practitioner has measured the relative
concentration of several enzymes which may indicate alterations in
liver health. The following enzymes typically change values in the
face of liver failure:
Alanine Aminotransferase: ALT. Liver specific in the dog and cat.
Cell damage will cause elevations of A-LT due to leakage. The
elevation of the enzyme correlates with the number of cells damaged.
Falling levels of ALT may indicate recovery or may indicate a
failing number of functional liver cells. Rapid increases in ALT may
indicate an acute process, while slow increases may indicate bile
duct obstruction.
Aspartate Aminotransferase: AST, an enzyme seen in the liver, heart,
kidney, skeletal muscle and brain. The half life of the AST in the
blood stream is much shorter than that of ALT, therefore the values
of AST tend to drop more rapidly once liver function is resumed. AST
elevations and ALT elevations should parallel each other in liver
disease.
Alkaline Phosphatase. This enzyme is present in many tissues,
therefore it is not very specific in liver disease, but it appears
very early in the progress of liver disease, therefore it is
considered quite sensitive. ALP tends to be slightly more specific
in the cat, but not quite as sensitive. A similar enzyme or isoenzyme is secreted as a result of high levels of cortisone,
therefore an effort must be made to separate Cortisole induced ALP
or CALP and normal ALP. Liver ALP is released from the liver when
many anticonvulsant drugs are administered to the dog. A similar
sensitivity has not been noted in the cat.. This must be taken into
account when evaluating ALP levels. ALP levels typically are greatly
elevated in the young, growing animal and therefore a veterinarian
should not mistake any elevations as disease in a young animal.
Gamma Glutamyltransferase GGT: This enzyme is has it's highest
concentration in the kidneys and pancreas, but it is also found in
the liver and other organs. The major proportion of GGT in the serum
seems to come from the liver. Elevations of GGT in disease seem to
stem from new synthesis rather than leakage, therefore the changes
seen due to disease are not spectacular. Large elevations of GGT are
more commonly associated with pancreatitis and bile duct
obstruction.
Bile Acids:
These series of organic acids circulate almost entirely in the
localized blood flow between the intestines and the liver (a.k.a.:
the Portal system). The flow is typically from the liver, into the
bile duct system, then excretion into the intestines to aid
digestion after a meal, to be re- absorbed into the portal system
and recycled by the liver. Very little of the bile acids escape form
the portal circulation system into the rest of the body. Leakage is
considered abnormal and is a sure sign of a liver abnormality. This
is one of the most sensitive tests available to diagnose liver
disease. While the liver does actually manufacture this product, it
has tremendous reserve capacity and can easily meet the bodies
demand for bile acids despite severe disease. As a result of this
reserve, the bile acid levels do not typically drop due to liver
disease.
Ammonia and Urea:
Ammonia is a by product of digestion of protein in food and the
catabolism of nitrogen based organic materials in the body. Eighty
per cent of ammonia is delivered to the liver and converted to urea.
In patients with liver insufficiency the ammonia is not detoxified
to urea, but enters the circulation to act as a central nervous
system depressant.
In patients with a severely reduced liver function we may see a true
intolerance of ammonia and thus neurological signs after a heavy
protein meal or we may see substantially reduced urea levels. This
is a late sign in liver disease, only seen after 60 to 70 per cent
of the liver function is gone.
Ascites development:
This is the accumulation of fluid in the abdominal cavity and
results from several factors. Simply put liver disease tends to
alter the blood pressure in the portal system, the albumin and salt
concentration in the serum, the water retention in the body, the
function of the surrounding organs and the permeability of the
portal vessels. As a result of all these factors, fluid tends to
build up in the abdomen and the animal gets a big, swollen, fluid
filled belly.
Electrolyte and Acid-Base disorders.
Common side effect of liver disease due to a multiple of factors
leading from metabolic disorders. Enough said.
Gastrointestinal Ulceration and Hemorrhage:
Again a sequellae to liver disease which may confuse the
veterinarian. He may think he is treating a simple ulcer and miss
the liver disease.
Hepatic encephalopathy.
Simply described as severe neurological dysfunction due to advanced
liver disease. Has been linked to the accumulation of biological
toxins, including ammonia, alterations in the blood brain barrier,
alterations in the neuroreceptors in the brain, and decreased blood
sugar.
Diagnosis of Liver Disease
Having gone into such detail prior to this, I hope this section will
be short and to the point. I hope most of my statements here will
naturally flow from points made above.
1. Examination, specifically noting signs which may indicate liver
disease. Periodic ascites, intolerance of a high protein diet,
icterus, chronic weight loss, abnormally coloured feces or urine,
bleeding disorders, chronic illness, and all that has been mentioned
above. Sometimes urinary crystals formed from the improperly
metabolised proteins and amino acids may indicate liver disease.
2. Extensive blood work:
- A complete blood count to check for anemia and blood cell
abnormalities.
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- A complete chemistry screen, including ALT, ALP, AST, bilirubin,
glucose, urea, electrolyte levels, albumin, globulin and bile acid
levels. The bile acid levels should be checked on a empty stomach
and two hours after feeding. All these values , with the exception
of the bile acids, usually are included on a standard Small Animal
Data Base Screen.
- A complete urine analysis. Check urobilinogen levels, bilirubin
levels, glucose levels, protein levels. Again all this is usually on
a standard urinalysis panel.
- Radiograph the abdomen. X rays can show increased liver size,
decreased liver size liver abscesses, abnormal mineralization , and
circulatory abnormalities (using special dyes)
- Ultrasound the liver. Perfect technique for visualizing the
circulation of the liver, the bile duct system, the density of the
liver tissue, the size of the liver.
- Biopsy of the liver. While this is a surgical technique, it is the
ultimate for diagnoses, since it allows us to directly examine and
test liver tissue, give an absolute diagnoses and hopefully a final
treatment regime. Biopsies can be taken by full laparotomy, where
the surgeon actually looks at the liver and removes a small piece,
or they can be done by a biopsy needle guided by ultrasound through
the body wall. The liver will regenerate any piece removed,
therefore liver biopsy is usually a low risk procedure in capable
hands.
Specific Diseases of the Liver
Infectious Hepatitis
Typically caused by either an adenovirus or a herpes virus.
Transferred from dog to dog by oral contact and ingestion. Usually
only causes a transient non specific illness characterised by
lethargy vomiting, diarrhea and fever. Sometimes develops into a
full blown case of severe hepatitis with many of the symptoms
previously noted. Treatment is geared to support while the body
fights off the bug. Prevention is by vaccination.
Another syndrome has been seen in England called Canine Acidophil
hepatitis. Typical signs of hepatitis are present, but the case may
take a very chronic course, lasting over a period of years. No
specific viral organism has been identified, therefore no vaccine or
treatment is available.
No specific virus causes hepatitis in cats, but the feline corona
virus responsible for Feline Infectious Peritonitis will cause a
hepatitis in some cases. Diagnoses by biopsy. No treatment. Mediocre
vaccine.
Several bacterial causes of hepatitis are known. Treatment is based
on a proper diagnoses and appropriate antibiotic use. There is good
proof that the bacteria is a normal inhabitant of the liver and only
becomes a problem when the liver is injured form other causes. There
are notable exceptions.
Blastomycosis, histoplasmosis and coccidiomycosis are fungal
infections seen in various parts of the country (usually associated
with river systems) Difficult to treat.
Leptospirosis is a bacterial infection common in wildlife and
transferable to domestic animals and people through contaminated
water. Dangerous, possible fatal, but the vaccine is quite good for
prevention.
Tuberculosis is still around and is considered transmissible to
humans.
Certain parasites will infect the liver. Typically the likelihood of
parasitic infestation depends on the area you live in. Diagnoses is
often based on symptoms, fecal examination, and standard diagnostic
techniques for liver disease. Treatment is the use of appropriate
parasiticides.
Liver Disease Secondary to other Disease
Acute pancreatitis: the close proximity of the pancreas to the liver
and the bile ducts results in some degree of hepatitis whenever
there is a case of pancreatic inflammation. Treat the pancreatitis
and the liver disease will regress.
c bowel disease: the chronic inflammation of the bowel allows portal
absorption of toxic intestinal products and bacteria. treat the
colitis.
Shock, anemia, and congestive heart failure. All these result in
severe loss of blood circulation to the liver and lack of oxygen.
The liver disease is rarely of primary concern as the primary causes
of the problem are most likely going to kill the animal prior to
liver failure.
Abdominal trauma: tears, bruising, biliary leakage, hepatic
bleeding. Correction of these problems would require surgical
intervention, assuming a timely diagnoses. Simple bruising of the
liver will heal unaided, with only a transient increase in the
hepatic enzymes.
Feline Hyperthyroidism: many of the symptoms of hyperthyroidism and
hepatitis are the same and in fact the hyperthyroidism will cause
elevations in the liver enzymes. The thyroid level of any cat
presenting with symptoms suggestive of liver failure should be
checked. The hepatitis will resolve once the hyperthyroidism is
treated.
Chronic Hepatitis
Copper storage diseases in Beddlington terriers, Doberman pinschers,
and West Highland white terriers. These are all genetically
inherited diseases which result in abnormal and toxic levels of
copper to be stored in the liver. The course of the disease is
variable, some presenting with acute hepatitis, many presenting in
end stage cirrhosis of the liver. Diagnoses is based on liver
biopsy. Treatment requires the use of copper binding drugs, anti
inflammatory to decrease liver inflammation, dietary modification to
limit copper uptake.
Chronic Active Hepatitis: In humans there is a chronic form of
hepatitis characterised by chronic elevation of liver enzymes and
biopsy samples showing scarring and active inflammation. The
underlying cause for this entity falls into one of three categories:
viral induced, toxin induced, and immune mediated. There is some
question as to whether a similar syndrome exists in dogs. There has
been cases which did show chronic elevation of the liver enzymes
over weeks to months), symptoms characteristic of liver disease ill
defined malaise), and a response of anti inflammatory treatment to
limit the ongoing inflammation and scarring of the liver. At this
time recommendations for treatment are that moderate or intermittent
disease should only receive supportive therapy or basic nursing,
while deteriorating chronic cases should receive steroid based anti
inflammatory. If the case shows poor response, biopsies should be
referred to a pathologist for evaluation in an attempt to find the
underlying cause. In some cases it may be necessary to use strong
immune suppressant drugs to stop the destruction of the liver.
Leptospirosis associated chronic hepatitis: An example of bacterial
infection leading to chronic disease. Diagnoses by biopsy and
identification of the pathogen. Treatment by antibiotics.
Infectious Canine Hepatitis associated chronic hepatitis. Exposure
to the virus responsible for ICH leads to chronic active hepatitis
due to an ongoing immune system malfunction. Diagnoses by biopsy and
the use of special stains to demonstrate the viral antigens in the
liver.
Lobular dissecting hepatitis: rare disease diagnoses by biopsy.
Hepatoportalfibrosis: Disease primarily of the blood supply to the
liver. Diagnosed by very specialized radiograph techniques which
measure and visualize the blood flow through the liver. Biopsy
critical for diagnosing location of lesion.
Toxic liver injury: Primary disease is caused by the ingestion ,
injection, or inhalation of a toxic substance which adversely
affects the liver. Due to the central nature of the liver with
regards to detoxification of chemicals, it is no surprise that many
are harmful to the liver. Factors contributing to the disease are:
females more susceptible, fatty diets more dangerous, continuous
exposure, high levels of exposure to toxins. Exposure results in
death and inflammation of the liver cells, followed by replacement
of damaged tissue by fibrous scarring. This can be a self
perpetuating cycle, resulting in cirrhosis of the liver.
Toxins include many common drugs, such as acetaminophen, ASA,
anabolic steroids, chemotherapy drugs, some antibiotics,
glucocorticoids, anaesthetics, parasite control drugs, and
phenylbutazone. Some of the drug induced hepatitis is a predictable
side effect of the drug, while other incidences of hepatitis are
considered an unpredicted or abnormal side effect of the drug. This
is difficult to diagnose unless there is a known exposure to the
drug or toxin and the appropriate tests are taken. Biopsy will
confirm liver destruction, inflammation, and fibrosis, but it will
not single out the causative agent.
Glucocorticoid Hepatopathy dogs seem abnormally sensitive to
glucocorticoid drugs ("cortisone") and will develop typical lesions
in the liver after multiple dose therapy or long term over
production of intrinsic cortisone by the adrenal gland (Cushing's
disease). Lesions are fairly typical and the rare animal which shows
liver associated symptoms during glucocorticoid therapy will improve
with the removal of the steroids. Liver associated lesions may take
weeks to months to heal.
Anticonvulsant associated hepatopathy; Phenobarbital, primidone,
phentoin. May cause liver disease in 6 to 15 % of all dogs on anti-convulsant
therapy. Inflammation seems related to dose. Degree of disease is
variable and unpredictable. Diagnoses based on history, symptoms,
laboratory tests, and biopsy. Treatment is removal of offending
agent.
Cirrhosis: This is the end point of chronic, active hepatitis. The
cycle is one of liver cell death (due to insult, either toxic,
viral, or immune mediated), followed by inflammation and
scarification. The end [[[[ requires all previously noted
techniques. No treatment is possible and ongoing palliative and
dietary care is the only treatment option..
Noninflammatory Liver Diseases
Portal vascular abnormalities Usually a portal-systemic shunt which
allows blood to pass from the digestive tract directly into the
general circulation without being detoxified by the liver first.
Usually a congenital defect restricted to young dogs and puppies,
but can be the result of hepatic cirrhosis. Symptoms are never
consistent, but many dogs are young, malnourished, chronically sick,
poorly tolerant of toxins, drugs, and anaesthetics, and tending to
eat strange items (pica). Diagnoses is based on physical exam,
history, laboratory tests, and specialized X rays showing blood flow
through the liver. Treatment is surgical correction of the
circulatory abnormality to force the blood into the liver prior to
it entering the general circulation.
Hepatic Lipidosis Most common form of severe liver disease in cats.
Most often seen in obese cats suddenly subjected to dietary
deprivation. May also be associated with diabetes mellitus, drug
injury and toxicity. Thedisease seems to result from the sudden
mobilisation of the bodies fat stores which quickly overwhelms the
liver's ability to process the raw fat into useful nutrients. The
fat accumulates in the liver rapidly and causes acute liver failure.
The end result is a swollen, greasy liver which is fragile and
yellow to see. The cats present with complete lack of appetite and
many signs of acute liver failure. Treatment is based on the
provision of a highly nutritious diet to provide the energy required
to run the body, stop the ongoing mobilisation of the fat stores,
and drive the liver to decrease the fatty accumulation in the liver.
Treatment is difficult and a long process.
Hepatic Cancer (Neoplasm) Falls into two categories: primary or
originally stemming from liver tissue or secondary; originating in
some other part of the body and spreading to the liver through the
circulation system.
Primary liver cancers can stem from exposure to toxins (oncogenic
compounds) which attack the liver full strength, since the liver is
the primary detoxification centre of
Secondary cancers may stem from any part of the body, but the liver
is a favourite destination for metastatic cancer because of it's
central function in the body and the micro- capillary network which
makes up the circulation passing through the liver.
Primary liver cancer is usually quite advanced prior to diagnoses
and tends to metastasize to the rest of the body very early in the
course of the disease.
Keep in mind the liver can function with less than one third of it's
volume still operating, therefore liver cancer can be very advanced
before any symptoms are noted.
Treatment is usually pointless, but would be based on diagnoses of
the specific cancer and the use of appropriate chemotherapy agents.
Basic Points for Treatment of Liver Disease
- Removal of toxic agents. Identify and remove any drug or toxin
which may potentially hurt the liver.
- Rest and confinement. This will help divert body resources to the
healing process at the liver and reduce discomfort caused by
inflammation of the liver such as painful belly, nausea, malaise.
- Dietary management: Extremely important. The goal is to provide
all the necessary nutrients which may be lost due to failure of
liver processing without overtaxing the liver with regards to
processing of dietary intake. High levels of top quality protein to
provide the essential amino acids in an easily digestible carrier
which will not produce high levels of ammonia during digestion.
Cottage cheese is good, meat tends to produce high levels of
ammonia. High level carbohydrates to drive the metabolism of the
body, essential fatty acids not less than 6% of the daily intake,
and a good mineral and vitamin supplement. Force feeding may be
necessary.
- Control of ascites and water retention. Reduce sodium intake.
Diuretics will help in resistant cases.
- Control concurrent infections with antibiotics.
- Deal with the concurrent medical problems as they crop up.
Remember that the dog may develop bleeding problems, malabsorption
problems, and neurological problems. Each separate problem has to be
dealt with both individually and as a part of the whole disease
entity. Neurological symptoms such as coma need to be addressed
aggressively with a combination of therapies.
I realise that this is a long, possibly boring paper that is far
from complete. I cannot emphasize too strongly how difficult this
topic is. I gleaned this information from a single source
Textbook of Veterinary Internal Medicine edited by Stephen
J.Ettinger 1989.
Liver Cleansing Diet
For a diet that is useful for dogs with liver disease, those on
extended medical treatment and dogs with epilepsy or seizures, the
following link will provide a healthy home cooked diet. Please
discuss this diet with your veterinarian before using it. It is a
balanced meal designed by Dr. Jean Dodds and has been used by
committee members for several years as a supplemental diet during
illness. It is approved by The Epilepsy Foundation and others.
http://www.canine-epilepsy-guardian-angels.com/liver_diet.htm
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