Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
 Special examination of the liver
When disease of the liver is suspected after a general clinical
examination, special techniques of palpation, biopsy and biochemical
tests of function can be used to determine further the status of the liver.
 Palpation and percussion
The liver lies beneath the costal arch and cannot normally be palpated. If
it is grossly enlarged or displaced posteriorly it may be palpated by
pushing the fingers behind the right costal arch. The liver may be
enlarged in chronic liver fluke infestation and congestive heart failure.
The exact location of the liver can be confirmed by percussion.
 BIOPSY
Biopsy of the liver has been used extensively as a diagnostic procedure in
infectious equine anemia, and other species of plants, and experimental
work on copper and vitamin A deficiency. The technique requires some
skill and anatomical knowledge. The most satisfactory instrument is
along, small-caliber trocar and cannula to which is screwed a syringe
capable of producing good negative pressure. The sharp point of the
instrument is introduced in an intercostal space on the righthand side (the
number depending on the species) and advanced across the pleural cavity
so that it will reach the diaphragm and diaphragmatic surface of the liver
at an approximately vertical position. The point of insertion is made high
up in the intercostal space so that the liver is punctured at the thickest part
of its edge. For example, in cattle the biopsy is made in the 11th
intercostal space at a point on an imaginary line between the right elbow
and tuber coxa. The instrument is rotated until the edge of the cannula
approximates the liver capsule; the trocar is then withdrawn, the syringe
is attached and strong suction is applied; the cannula is twisted vigorously
and advanced until it reaches the visceral surface of the liver. If its edge is
sufficiently sharp the cannula will now contain a core of liver
parenchyma and if the instrument is withdrawn with the suction still
applied a sample sufficient for histological examination and microassay
of vitamin A, glycogen or other nutrient is obtained.
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Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
 Medical Image of The Liver
 Ultrasonography:
Ultrasonography of the liver is used as an aid to diagnosis of diseases of
the liver of large animals. A complete ultrasonographic assessment of the
liver can provide detailed information about the size, position and
parenchymal pattern of the liver. In cattle, the liver, caudal vena cava,
portal vein and gallbladder can be visualized. Ultrasonography is the only
practical method for the diagnosis of thrombosis of the caudal vena cava.
Ultrasonographic technique Examination of the liver of cattle is done
with a 3.5 MHz linear transducer on the right side of the abdomen while
the cows are standing. The hair is clipped and the skin shaved between
the sixth intercostal space and a hand's breadth behind the last rib. After
application of transmission gel to the transducer the cows are examined,
beginning caudal to the last rib and ending at the sixth intercostal space.
Each intercostal space is examined dorsally to ventrally, with the
transducer held parallel to the ribs. The texture and the visceral and
diaphragmatic surface of the liver are scanned, and the hepatic and portal
veins, caudal vena cava and biliary system are examined. Breed and age
of cow does not influence the ultrasonographic appearance of the liver,
particularly position, size, and vasculature of the liver and gallbladder.
During pregnancy, the diameter of the caudal vena cava increases slightly
and that of the portal vein decreases. Ultrasonography has been used to
detect thrombosis of the caudal vena cava in a cow with ascites and
cholelithiasis in horses.
 Percutaneous ultrasound-guided cholecystocentesis in cows is
an excellent method of obtaining samples of bile for demonstration
of Fasciola hepatica and Dicrocoelium dendriticum eggs and
fordetermination of bile acids. The procedure is done on the right
side in the ninth, 10th or 11th intercostal space.
2
Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
 Percutaneous ultrasound-guided portocentesis in cows is an
excellent method for measuring the composition of hepatic portal
blood and comparing it with peripheral blood.
 Ultrasonography and digital analysis can be used for the
diagnosis of hydropic degeneration of the liver of cows instead of
biochemical analysis.Diffuse hepato-cellular disease such as fatty
liver in dairy cows can also be detected and evaluated.
Ultrasonography has been used to evaluate the liver-kidney
contrast in the diagnosis of fatty liver infiltration in dairy cattle.
 Radiography:
Lateral abdominal radiography can be used to determine the size and
location of the liver in foals. Fluoroscopy and contrast media injected into
the mesenteric vein have been used to detect the presence of
portosystemic shunts in foals and calves.
 Laboratory test for hepatic disease and function
Hepatic disease is difficult to diagnose based on clinical findings alone
and the use of laboratory tests is necessary. The results and interpretation
of such tests, however, depend on the nature of the lesion, the duration
and severity of the disease, and species variations. Specific tests that
identify the exact nature of the lesion are not available, and a combination
of tests is usually necessary to make a diagnosis. For example, it is
suggested that testing for serum bile acids, arginase and gamma-glutamyl
transferase (GGT) gives a sensitive indicator of cholestasis and/or hepatocellular necrosis, and a liver biopsy would form the minimum
combination of tests for the diagnosis and prognosis of hepatic disease in
the horse. Total serum bile acids, plasma glutamate dehydrogenase, GGT
and liver biopsy are useful in the horse with liver disease. Based on
experimentally induced liver disease in cattle, it is suggested that the
serum activities of sorbitol dehydrogenase (SDH), GGT and aspartate
aminotransferase (AST, formerly known as SGOT), and the BSP
clearance' test, provide sensitive indicators of hepatocellular injury in
cattle.
All laboratory tests are aids to diagnosis and must be carefully interpreted
in conjunction with clinical and other available data. This is particularly
3
Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
important in the laboratory investigation of liver disease in the horse. No
one test will provide sufficient information, and a combination of tests is
necessary. Depending on the time of sampling in relation to the
pathological processes developing and the presence of complicating or
secondary pathology there may be elevations in alkaline phosphatase
(ALP ) and GGT. A horse with chronic hepatic lesions may
aleukocytosis
and
neutrophilia,
hypoalbuminemia,
hyperbetaglobulinemia, increased ALP and GGT and, depending on other
factors, there may be increases in AST, SDH, total lactate dehydrogenase
and others. The laboratory tests for the diagnosis of hepatic disease and to
evaluate hepatic function in farm animals can be divided into those that
measure:
o Excretory rate of parenterally administered substances such as BSP
o Ability of the liver to remove substances from the serum and
detoxify them
o Serum levels of liver enzymes that increase following hepatic
injury Indirect assessment of hepatic function such as blood
glucose, serum proteins, clotting factors and urinalysis.
 Hepatic function:
The sulfobromophthalein sodium(BSP) clearance test has been used in
cattle, sheep and horses, and although little information is available the
test appears to have diagnostic value. This test uses an injected dye, BSP,
for diagnosis of liver disease. After the injection, several blood samples
are taken to determine the blood level of the dye. These levels will
indicate the liver's ability to excrete the dye and thus the general
functioning of the liver. This test is very diagnostic of inactive cirrhosis
of the liver. The time required by the normal liver to reduce the plasma
concentration of BSP to half the initial concentration is taken as the
standard BSP half-life and in cattle is 2.5-5.5 minutes, in sheep 2.0
minutes and in normal horses about 2.0 minutes All horses with
confirmed liver disease have a reduction in plasma BSP clearance
against time.The results are modified by the ability of the liver to excrete
BSP via the biliary system and to store it in hepatocytes. Factors other
than liver disease that increase the half-life significantly are starvation in
horses, competition with bilirubin for excretory capacity, and youth, foals
4
Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
less than 6 months of age having a Significantly slower clearance time.
Precise timing of samples is needed because of the rapid excretion rate .
In sheep, where severe hepatic dysfunction is accompanied by a steep rise
in blood ammonia levels, and where this is reflected in the development
of spongy degeneration in the brain, the level of glutamine in the
cerebrospinal fluid is also elevated. Glutamine is a byproduct of the
metabolism of ammonia in brain cells. Acute ammonia toxicity is
manifested by tetany, ataxia and pulmonary edema, and affected animals
are likely to die before the effects of subacute poisoning, hepatic
encephalopathy, are seen.
 Icteric index
Measurement of the icteric index of plasma, by comparing its color with a
standard solution of potassium dichromate, cannot be considered to be a
liver function test but it is used commonly as a measure of the degree of
jaundice present. The color of normal plasma varies widely between
species depending upon the concentration of carotene. Horse, and to a
less extent cattle, plasma is quite deeply colored, but sheep plasma is
normally very pale. The color index needs to be corrected for this factor
before the icteric index is computed. Hyperbilirubinemia occurs in many
diseases of cattle and in most cases is related to a failure of the liver to
remove unconjugated bilirubin from the serum rather than to a failure of
the liver to excrete conjugated bilirubin.The cause may be associated with
anorexia, which resembles the hyperbilirubinemia associated with fasting
in sick horses. Adult cattle with hepatic disease do not consistently have
high serum bilirubin concentrations and visible jaundice does not occur
frequently in cattle with hyperbilirubinemia. Total bilirubin
concentrations in adult cattle should be 0.4 mg/dL but young healthy
calves may have mean concentrations 0.57 mg/dL and even higher, up to
1.7 mg/dL.
5
Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
 Serum hepatic enzyme :
The determination of serum levels of hepatic enzymes is used commonly
for the detection and evaluation of hepatic disease. The interpretation of
elevated values of enzymes in plasma is dependent not only on the tissue
and site of origin but also on the half-time of clearance of the enzyme.
 Sorbitol dehydrogenase (also called L-iditol dehydrogenase
(ID) is almost completely selective as an indicator of liver damage
and is the preferred test for hepatic damage in sheep and cattle.
 Lactate dehydrogenase (LDH) is abundant in liver, kidney,
muscle and myocardium .
 Aspartate aminotransferase or L-alanine aminotransferase
(ALT, previously known as SGPT) are of some value as an
indicator of liver damage because of their high content in liver but
are generally considered to be too nonspecific to be of great
diagnostic value.
 Arginase is a specific indicator of hepatic disease because it is not
found in appreciable quantities in other organs. Arginase has a
short blood half-life, which makes it useful for the diagnosis of
acute hepatic disease but not for less severe forms.
 Gamma-glutamyl transferase is an enzyme widely distributed in
a variety of equine tissues. Specific activity of GGT in the horse is
highest in the kidney, pancreas and liver. Serum GGT activity is
used as a diagnostic criterion for hepatobiliary diseases in cattle,
sheep and horses. In the horse, increases in serum GGT may be
associated with hepatocellular damage and liver necrosis in_a
variety of natural and experimentally induced liver diseases. In
foals during the first month of life values were 1.5-3 times higher
than the upper physiological reference values for healthy adult
horses. In neonatal foals, the serum ALP, GGT and SDH activities
were increased during the first 2 weeks of life.
 Glutamate dehydrogenase (GD) occurs in high concentration in
the serum of ruminants and horses with liver disease .
 Ornithine carbamoyl-transferase (OCT) levels are also elevated
even in chronic diseases, but only when there is active liver
necrosis and not when the lesions are healing .
6
Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
 Alkaline phosphatase levels are used as a test of hepatic excretory
function in the horse and are of value in that species but variations
in normal cattle have such a wide range that results are difficult to
interpret. Of the tests available for testing of biliary obstruction the
serum ALP test is preferred. However, there is a similar response
to damage in other tissues.
 Serum bile acids
The concentration of total serum bile acids has been reported as a
sensitive and specific indicator of hepatobiliary disease in humans and
animals. Abnormalities of bile acid metabolism may be detectable in
animals with liver disease that have little evidence of hepatic dysfunction
as determined by other common liver function tests. Bile acids are the
end-products of the metabolism of cholesterol by the liver. They are
excreted in the bile and reabsorbed from the intestine either unchanged or
after further transformation by bacterial action. In experimental chronic
corper poisoning in sheep, the total bile acid concentration in the plasma
is a more sensitive indicator of hepatic damage than the concentration of
plasma bilirubin or the activity of transaminases. The rise in total serum
bile acid concentration usually correlates well with the severity of liver
disease. In cattle, there is extreme variability among all types and ages of
animals and the variation is even greater in beef cattle than in dairy
cattle.48Values for calves 6 weeks of age and for 6-month-old heifers are
significantly lower than values for lactating dairy cows.
 Blood ammonia levels
The microbial deamination of amino acids in the intestinal tract is the
major source of ammonia which is absorbed by the intestine into portal
venous blood and converted into urea by the liver. The concentration of
blood ammonia can be an indication of functional hepatic mass.
Generally, plasma ammonia concentration is a sensitive and specific
indicator of hepatic disease in the horse, although it may fluctuate widely
even on the same day and the concomitant low plasma urea concentration
anticipated because of the liver's reduced synthetic ability is often not
apparent. In cattle with hepatic disease, plasma ammonia levels are
significantly elevated compared to normal animals but not always
accompanied by a decline in plasma urea concentrations. In healthy
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Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
cattle, the plasma ammonia:urea concentration ratio is 9:1 and the plasma
ammonia:glucose concentration 11:1. In hepatic disease, a plasma
ammonia:glucose ratio 40:1 or plasma ammonia:urea ratio 30:1,
particularly with a rising total ketone body concentration and a declining
glucose concentration, represents a guarded prognosis.
 Principles of treatment in diseases of the liver
In diffuse diseases of the liver
No general treatment is satisfactory and the main aim should be to
remove the source of the damaging agent.
 In acute hepatitis is to tide the animal over the danger period of
acute hepatic insufficiency until the subsidence of the acute change
and the normal regeneration of the liver restores its function. Death
may occur during this stage because of hypoglycemia.
 Oral or intravenous injections of glucose to maintained the level of
blood glucose.
 Intake an adequate of calcium salts should be insured by oral or
parenteral administration. There is some doubt as to whether
protein intake should be maintained at a high level, as incomplete
metabolism of the protein may result in toxic effects, particularly in
the kidney.
 Amino acid mixtures, especially those containing methionine, are
used with apparently good results. The same general
recommendations apply in prevention as in the treatment of acute
diffuse liver disease.
 Diets high in carbohydrate, calcium and protein of high
biological value and a number of specific substances are known to
have a protective effect against hepatotoxic agents.
 In chronic, diffuse hepatic disease fibrous tissue replacement
causes compression of the sinusoids and is irreversible except in
the very early stages,
 Removal of fat from the liver by the administration of
lipotrophic factors including choline and maintenance on a
diet low in fat and protein may reduce the compressive effects
of fibrous tissue contraction.
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Diyala University
Stage : 4th Stage
Faculty of Veterinary Medicine
Subject: Internal Medicine
By: Dr. TAREQ RIFAAHT MINNAT (No.6)
 A high-protein diet at this stage causes stimulation of the
metabolic activity of the liver and an increased deposit of fat,
further retarding hepatic function.
 Local diseases of the liver require:
 surgical or medical treatment depending upon the cause, and
specific treatments.
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