How We Diagnose Liver Disease

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A thorough approach is needed for a correct diagnosis of any liver problem. An organ like the liver that is so intimately involved with other important organs will exhibit symptoms that mimic disease in these other organs. Also, what initially might appear as a diseased liver is in reality a disease elsewhere in the body that is involved with the liver secondarily. This is why it is crucial to follow a thorough and methodical approach called the diagnostic process.

1. Signalment

Liver disease can occur in pets of any age. If it occurs in young animals we tend to think more of toxicity, a liver shunt or a viral disease like adenovirus in dogs, or FIP in cats. In older pets we tend to think more of inflammation and cancer as the cause of the liver problem.

Several canine breeds are prone to getting liver disease:

Bedlington terrier’s, Skye terriers, Doberman pinschers, and West Highland White terriers get a problem with excessive copper accumulation that results from failure of normal biliary excretion of copper.

Cocker spaniels have an increased incidence of chronic hepatitis.

2. History

Early signs of liver disease are subtle, and might exhibit as some of the symptoms described above. It is important to remember that some pets do not show any symptoms early in the course of the disease. This is another reason for yearly exams, along with blood and urine samples in dogs and cats 8 years of age or more. Even though many cancers do not show up in a blood sample, we can sometimes get indirect evidence there is a problem, leading to additional diagnostic tests that might find cancer.

The recent use of pesticides, insecticides, and drugs might give us a clue. Some Labradors are sensitive to the use of the arthritis medicine Rimadyl. These dogs should have a blood panel analyzed prior to initiating Rimadyl therapy. Every 6 months this panel should be repeated.

A history of poorly controlled diabetes mellitus might also clue us in to liver problems. Pets with liver shunts might have stunted growth and become depressed right after eating. In cats with hepatic lipidosis the history usually involves a lack of appetite (anorexia), especially if the cat was previously obese.

3. Physical Exam

Routine physical exam findings might include:

Distended abdomen due to enlargement of the liver (hepatomegaly) might be found. This can be palpated in some situations, especially in the smaller animals. an enlarged liver from a disease other than liver disease can cause hepatomegaly. This includes heart disease and Cushing’s Disease.

Enlarged lymph nodes due to secondary bacterial infections or spread of a primary or metastatic liver tumor.

Bruising (hematoma) might be observed under the skin, or when a blood sample is obtained. This is due to the liver’s affects on the clotting mechanism.

Fever- a rectal temperature of greater than 103 degrees F could accompany liver disease when inflammation or infection is present.

Skin infections and wounds that do not heal, or recur after antibiotics are stopped.

Yellowish discoloration (icterus or jaundice) of the ears, gums, or hairless areas of the skin

Anemia might be observed by checking the mucous membranes for a normal pink color.

4. Diagnostic Tests

Several tests are used as an aid in making this diagnosis.

Blood Panel

A CBC (complete blood count) and BCP (biochemistry panel) should be run on every pet 8 years of age or more, especially if they have any of the symptoms of liver disease.

The CBC might show a decrease in the number of red blood cells (RBC’s). This decrease in RBC’s is called anemia. The white blood cell count (WBC) might be elevated (leukocytosis), normal, or decreased (leukopenia), mostly depending on the cause of the liver problem and how long it has been present. A change in the WBC’s does not necessarily indicate there is a liver problem.


This older dog with liver disease shows a normal Alk Phos, a significantly elevated ALT, a normal GGT and a normal albumin and Total Bilirubin.


This older dog has all the classic blood parameters of a dog with liver disease. The Alk Phos, ALT, GGT, and Total Bilirubin are significantly elevated. Even the cholesterol is high, which sometimes accompanies liver disease.


This older cat does not have liver disease, even though the enzyme levels are high. The lower arrow points to the real reason for the high liver enzymes. This very elevated thyroid level is a sign of Feline Hyperthyroidism.

 


After 2 weeks of treating for the thyroid problem the thyroid level and the liver enzymes started returning to normal.


Bile Acids

This is liver function test, not an enzyme test, and is not a routine part of the BCP. We will request this test when we suspect a liver problem, whether the enzyme tests are normal or not. This test is performed by taking a blood sample, giving a meal, then taking another blood sample 2 hours after the meal. Comparing the pre-meal and post-meal blood results gives us valuable information. The bile acids test is an accurate measure of liver function.


Urinalysis

A urine sample can give us important clues as to the existence of liver disease. The specific gravity might be below normal, an indication that PU/PD is present. Bilirubin might be present, a finding that is always abnormal in cats. There also might be ammonium biurate crystals, a sign of improper ammonia metabolism found in Hepatic Encephalopathy.

This urine sample from a dog shows a trace amount of bilirubin, which can be normal in a dog.


This bilirubin in a urine sample from a cat is a sign of liver disease or anemia.


Abdominocentesis

Analysis of the fluid obtained from a pet with ascites can give valuable clues as to its cause. There are numerous causes to ascites, some of the more common ones are heart disease, liver disease, and cancer.

Fluid is removed from the abdomen with a special needle and syringe.


Liver Biopsy

This is a very valuable test in the diagnosis of liver disease. A sample of the liver can be obtained during an exploratory surgery or during an ultrasound procedure. The pathologist can look at the hepatocytes microscopically and determine if disease is present and what the cause is.

This report is from a very ill cat.

It is helpful to run a coagulation panel prior to any liver biopsy. A diseased liver might not be able to clot properly, and a biopsy could cause hemorrhage into the abdomen.

Stool

A dog that excretes stool without normal pigmentation could indicate liver disease. It occurs when there is obstruction of the biliary system and normal bile pigments are not secreted to cause the normal dark color of stool.

Radiography

An enlarged liver on a radiograph is called hepatomegaly, an abnormally small one is called microhepatica. Either one can be a sign of a liver problem.

In addition to plain radiographs, contrast media can be put into the arterial or venous system to help outline the liver. These tests go by various names; cholecystography, portal venography, and hepatic arteriography.

The liver in this radiograph is enlarged because the edge of the liver is protruding far beyond the last rib. The edges of this liver are very sharp and clearly outline its borders.


This radiograph also shows hepatomegaly, but in this case the borders of the liver are not as sharp. This could be due to a swelling of one of the lobes or fluid in the abdomen. An enlarged spleen can look like this also.


Some radiographs of a liver with hepatomegaly don’t show the routine shape of the liver lobes. This case of a liver cancer has a very rounded appearance. A tumor of the stomach, spleen, or intestines can also have this appearance.


Sometimes we diagnose hepatomegaly or microhepatica indirectly by looking at the angle of the stomach This picture shows the angle of the stomach in a normal radiograph of the abdomen. Compare it to the radiograph below.


This abnormal liver is pushing the stomach (S) towards the rear, an indication of hepatomegaly, even though it is difficult to clearly see the liver.


Sometimes we can not say for sure whether an enlarged organ on a radiograph is the liver. This mass, located near the liver, could also be an enlarged spleen, small intestine, lymph node, stomach, or even pancreas.


Ultrasound

Ultrasound is highly beneficial in the diagnosis of liver disease. We recommend ultrasounding a liver when the liver enzymes tests are elevated over time, or the bile acids test is abnormal.

The internal structure (called parenchyma) can be analyzed, and post-hepatic liver disease can be differentiated from hepatic liver disease. This can be very important because disease in the liver can often be diagnosed with a biopsy during the ultrasound. Post-hepatic liver disease cannot easily be diagnosed in this matter. Instead it is diagnosed and treated with an exploratory surgery (called alaparotomy).

This liver ultrasound reveals a mass in the liver. Can you see its circular appearance at the arrow? It also shows abdominal effusion (this is the ascites described previously).

 


The final report summarized the problems this dog has with its liver and spleen:


The gall bladder can be seen with ultrasound also. This is a printout after an ultrasound has determined this dog indeed has a stone in its gall bladder.


This short Quicktime movie shows you how a stone in the gall bladder looks during the actual ultrasound. You will have to look fast, the stone is the whitish are in the center of the movie. Click on the link below for it to play. This movie gives you an idea of the skill that is needed by the ultrasonographer in making this diagnosis.

Ultrasound of the Gall Bladder


The liver can get cysts, which are also diagnosed with ultrasound


Our next page on Liver Disease shows graphic pictures of a surgery. You can skip this section and continue on to routine medical treatment of specific liver diseases by clicking here.