Ron Hines DVM PhD 4/285/06

Hepatitis means inflammation of the liver. The liver is a very complex organ that processes nutrients soon after they are absorbed from the intestine. This makes it the first organ to come in contact with toxins absorbed from your pet’s foods. It plays a major role in metabolism, detoxification, glycogen storage and plasma protein synthesis. It also produces bile, which aids in digestion. The liver has a very large reserve capacity so it will be severely damaged before any signs of illness become apparent in your pet. The following information relates to some of the more common causes of hepatitis in dogs and cats – there are many more, less frequent, causes that I do not discuss.

Infectious Canine Hepatitis Of Dogs:
This disease is caused by a virus. It is an adenovirus designated as type one or CAV-1. The disease is not infectious to people or animals other than dogs. Dogs acquire this disease by inhaling or ingesting the virus present in the urine, nasal and eye secretions of infected animals.
After entering the blood stream, the virus attacks the cells of the liver, eyes, kidneys and the inner linings of blood vessels throughout the body. Not every case of CAV-1 is serious. Many dogs have little or no symptoms after they are infected. In some dogs only a cough develops. In this mild form, dogs simply loose their appetite, are mopy and run low fevers for a few days. A few develop a bluish discoloration of the cornea of the eye called “blue eye” one or two weeks later. All these dogs are then immune to the disease for the rest of their lives. A few puppies, however, become severely ill. They develop liver disease, internal bleeding, tonsillitis, inflammation of the mouth and eye membranes, which can proceed to rapid shock and death. The virus can also attack these dog’s brain and spinal cord.

After the virus gaines entry to the dog, it localizes in the cervical lymph nodes and tonsils before traveling throughout the body. It takes approximately five days for infection to become apparent to the owners. By that time symptoms relate to virus in the liver, eyes, kidneys brain and lungs. Infected dogs shed the virus in their stool, saliva and urine. Over then next two weeks the dogs either succumb to the disease or go on to develop chronic hepatitis and cirrhosis of the liver. A few dogs develop chronic kidney disease (polynephritis), glaucoma or circulatory abnormalities (vasculitis, disseminated intravascular coagulation).

Once a dog has become infected with CAV-1 there is no treatment that will destroy the virus. The best I can do is to support the dog with good nursing care, intravenous fluids and medicines to lighten the workload on the liver. I give them antibiotics to prevent additional infections.

Luckily, a very good vaccine exists to prevent this disease. It is routinely given to puppies as part of their series of boosters and annual vaccinations. It has made cases of CAV-1 quite rare in the United States and Western Europe. The vaccine actually contains weakened canine adenovirus two (CAV-2), a close relative of CAV-1. When a dog becomes immune to CAV-2 it also becomes immune to CAV-1. We tend to over-vaccinate our pets - immunity after a single vaccine injection lasts seven years or more.

Chronic Active Hepatitis:
This disease is sometimes called chronic canine inflammatory hepatic disease. Chronic active hepatitis is more common in dogs than in cats. It can occur in any breed dog, male or female, and at any age, although most or the pets I see are middle aged or older. The fact that is chronic means that the disease has been going on for weeks or months as opposed to acute hepatitis that comes on abruptly and then ceases. Unfortunately full recovery is more likely after acute hepatitis than subsequent to a chronic condition. The term active means that liver cells are continually becoming inflamed and dying. Continuing inflammation and cell death eventually lead to the replacement of normal liver tissue with scar tissue. This is called cirrhosis. In most cases the exact cause will remain unknown. Certain breeds are predisposed to chronic active hepatitis, these include Bedlington Terriers, Doberman Pinschers, Skye Terriers, Standard Poodles, Cocker Spaniels and West Highland White Terriers. In many of these cases, copper is found in excessive quantities in the dog’s liver. Other diseases that can lead to chronic active hepatitis are infectious canine hepatitis, leptospirosis, autoimmune disease and drug and chemical toxicities. Aflotoxins found in moldy grain – especially corn – can cause this disease. High quality dog foods screen the grains they use for this toxin.

Symptoms of chronic active hepatitis are quite variable because the liver does so many things. The most common signs are increased lethargy, loss of appetite and diarrhea. Pets often drink and urinate more. As the disease progresses, many cases develop a swollen abdomen that is filled with fluid (ascites) and yellowish (icteric, jaundiced) gums, eyes and skin. In some cases the disease attacks the nervous system and the dogs become blind and obtuse. This can progress to seizures, coma and death.

My diagnosis relies on blood chemistry results that show an increase in the level of hepatic enzymes and on biopsies of the liver. Physical examination of the dog can suggest the disease when jaundice is present. Dogs with chronic active hepatitis have smaller than normal livers. This shows up on x-rays.

I find treatment of this disease quite difficult because no medicines I have encourage regeneration of the liver. Hospitalized dogs usually receive intravenous fluids and general supportive care. We often place them on antibiotics, anti-inflammatory agents and low protein diets.
I often administer in addition drugs that seem to help dogs with copper-associated chronic hepatitis. Patients should have liver enzyme levels monitored for the rest of their lives.

West Highland White Terriers and Bedlington Terriers sometimes inherit a defect in the metabolism of copper which causes a liver disease called copper-associated chronic hepatitis. We see two types of Bedlington Terriers with this condition. The first are young dogs less than six years of age that suddenly develop liver failure. Most of these dogs pass away quickly in spite of intensive treatment. A few do recover but are plagued with liver problems for the rest of their lives. This second group are older dogs that develop a slower, less severe form of the disease. They sicken very gradually and loose weight but the can live a long time. West Highland Terriers that develop the disease tend to have lower levels of copper in their livers and a less severe form of the disease. We estimate that twenty-five percent of Bedlington terriers suffer from this disorder and half the rest carry the genetic code for the defect but do not become ill. This is because two defective genes must be present for the disease to appear. These dogs can, however pass the disease on to their offspring. In these pets copper accumulates within the cells of the liver due to the presence of an abnormal binding protein. These dog’s failure to excrete toxic copper through their bile slowly leads to hepatitis or cirrhosis of the liver. It can first be detected when the dogs are about one year old. Clinical signs include enlarged liver, vomiting, depression, lack of appetite, jaundice, hemolytic anemia and hemoglobin in the urine. Treatment includes feeding diets low in copper and administering compounds that lower body copper stores. One of these compounds, D-penicillamine, binds with copper causing it to be voided in the urine. Another compound, trientine hydrochloride decreases the amount of copper absorbed through the intestine. Prednisone anti-inflammatory treatment is also often helpful. Ursodeoxycholic acid (ursodiol; Actigall or Urso) is another anti-inflammatory and bile facilitating drug that has been helpful. S-adenosylmethionine (SAMe) is an antioxidant compound that appears to help these dogs. Milk thistle herb is yet another compound used to treat liver disease. It’s active ingredients, which include antioxidants, protect liver cells and facilitate liver repair. Some veterinarians suggest these dogs receive vitamin E to protect against oxidative damage to liver cells. Dogs with this condition should not be bred, as they will pass on the disease through their genes.

Hepatitis of unknown origin or idiopathic or periportal hepatitis sometimes occurs in dogs. It most commonly affects dogs that are five or six years old. All breeds and both sexes are affected. Signs include vomiting, diarrhea, weight loss, jaundice, ascites, depression and weakness as well as increased thirst and urination. Lab work shows an increase in the enzymes ALT and AP as well as increases in bilirubin, bile acids and globulin and a decrease in blood albumin and red blood cells. I treat this disease with supportive care, antibiotics, low-protein diets and sometimes immunosuppressants. How the disease progresses or resolves depends on the degree of liver damage present when I first see the dog.

Chronic hepatitis of Doberman Pinschers is a perplexing disease. Some of these cases suggest copper storage disease similar to West Highland and Bedlington Terriers but we are uncertain if excessive copper causes the condition or if the disease simply causes excess copper to be stored in the liver. Female dogs are more commonly affected than males. This disease can occur at any age. Signs include weight loss, diarrhea, jaundice, vomiting and drinking and urinating excessively. Dogs may also be disoriented due to increased blood ammonia and they may bleed excessively due to blood clotting defects. Liver enzymes, bilirubin, blood ammonia and serum bile acids are usually elevated. Ultrasound studies will reveal a shrunken liver. Treatment for this disease includes supportive care, anti-inflammatory drugs and azathioprine and ursodeoxycholic acid. Chances for a long life after this disease has been diagnosed are quite poor.

Before all forms of liver disease become quite advanced the signs of the disease are rather vague and non-specific. The key to my diagnosis is measuring the level of liver enzymes that circulate in your pet’s blood. The most commonly elevated enzyme is ALT (Alanine Aminotranferase or SGPT). Elevated ALT tells me that your dog has hepatitis but they do not tell me what kind of hepatitis exists. To further characterize the disease I must do a biopsy of the pet’s liver. Using an ultrasound apparatus to assist me, I remove a small snippet of liver tissue called a biopsy with a specially designed needle. I send this sample to a veterinary pathologist who can tell the type of hepatitis present as well as the severity of the disease. Often even the pathologist’s report does not give me the cause of the hepatitis.

Hepatic Lipidosis in Cats:
This disease occurs in cats that will not eat for a variety of health reasons. Cats that are affected were often overweight. These cats may have stopped eating because of a change made in their diets or because of a stressful situation at home such as moving, kenneling or health problems in their owners. Secondary hepatic lipidosis also occurs in cats that suffer from diabetes, intestinal disease, pancreatitis or any other serious systemic disease. No mater what the cause, all cats develop an over-accumulation of triglycerides (fat) within their liver which blocks normal liver activity. Signs of this disease include weight loss, vomiting diarrhea, listlessness, drooling and jaundice. Laboratory tests reveal elevated liver enzymes and anemia. In treating this condition I try to address any underlying disease in order to get the cat to eat. Until this is done I tube-feed the cat an energy-rich gruel.

Inflammation Of The Biliary System In Cats:
This condition is common in cats but rare in dogs. Suppuration is the accumulation of white blood cells called nutrophils in an organ. In the suppurative form (called Suppurative Cholangitis or Cholangiohepatitis) bacterial, fungal or protozoal infection of the liver’s system of ducts that transport bile result in the diseases. In the nonsuppurative or lymphocytic form of the disease, blood cells called lymphocytes and plasmacytes accumulate around inflamed bile ducts. In biliary cirrhosis fibrous tissues surround and occlude the biliary system. A similar condition, lymphocytic portal hepatitis, is an inflammatory condition that is probably an underlying autoimmune disease.

Hepatitis Due to Feline Infectious Peritonitis Of Cats:
Feline infectious peritonitis or FIP is a deadly disease caused by a coronavirus that affects only cats. It causes inflammation of tissues throughout the body including the liver. Signs of this disease include weight loss, depression, abdominal fluid, jaundice, vomiting, diarrhea and fever. Mortality from this disease is a withering 100%. Affected cats are usually less than two years old or older than 10years. Many of these cats are also infected with the feline leukemia virus. Despite my intensive efforts and prayer, I have never succeeded in saving an animal with FIP.

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