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Many dog owners will know about the most obvious and dramatic symptoms of liver disease, such as the yellowing of the whites of the eye and an unnaturally swollen stomach. However, liver problems in dogs often develop gradually, and the prognosis can be poor by the time these symptoms appear.
One of the most common conditions of the liver in dogs is hepatitis. Being aware of the causes of canine hepatitis and spotting the subtle early signs increases the chance of your dog making a good recovery.
What Is Canine Hepatitis?
Hepatitis is the clinical term used to describe the inflammation of the liver. The inflammation results in various symptoms, and there are many causes. This is why canine hepatitis is classified as a syndrome, rather than a disease with specific origins.
Hepatitis affects how well your dog’s liver functions. It typically involves an accumulation of inflammatory cells, which can lead to the development of damaging excess fibrous tissue and scarring. Hepatitis in dogs can resolve by itself, but it usually needs treatment to prevent the damage from becoming life-threatening.
Acute and Chronic Canine Hepatitis
There are two types of hepatitis in dogs—acute and chronic. Dr. John Cullen, a world-renowned veterinary hepatopathologist, explains that acute hepatitis occurs within a short period (typically a few days to a week or two, at most). He prefers to refer to these sudden onset liver issues as acute hepatic injury, as they don’t always involve inflammation. Acute cases often relate to a viral infection or some sort of toxicity.
“Chronic hepatitis is usually something defined by a longer duration and, at a microscopic level, by the presence of fibrosis in the liver,” Dr. Cullen says. Fibrosis is only identifiable by doing a biopsy of the liver. This makes identifying chronic hepatitis, which may have been slowly developing for months, more challenging. Without treatment, chronic hepatitis can lead to cirrhosis (end-stage liver disease).
What Causes Hepatitis in Dogs?
Causes of hepatitis in dogs are wide-ranging and, particularly with chronic cases, sometimes idiopathic (the cause is unknown).
Causes of acute hepatitis include:
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Toxic chemicals
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Viral infections, such as Infectious Canine Hepatitis and herpes virus
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Bacterial diseases, such as leptospirosis
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Certain therapeutic drugs, such as the antibiotic nalidixic acid
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Mycotoxins found in fungi
Some known causes of chronic hepatitis include excess copper in the liver and bacterial infections. Immune-mediated chronic hepatitis is common in people, especially middle-aged women. Dr. Cullen says that while this isn’t yet well-characterized in veterinary medicine, there is general agreement that it also occurs in dogs.
Acute hepatitis can affect dogs of any age and breed. Chronic hepatitis more typically affects dogs from middle age onwards and is more common in females. Some breeds predisposed to hepatitis include Doberman Pinschers, Spaniels, Dalmatians, West Highland Terriers, and Skye Terriers.
Infectious Canine Hepatitis
Infectious Canine Hepatitis (ICH) is an acute disease caused by the adenovirus. Fortunately, most puppies receive protection from this infection through standard vaccinations, so it is relatively rare. However, outbreaks amongst unvaccinated dogs are possible as it spreads through feces, urine, and saliva.
Copper-Related Hepatitis in Dogs
Dr. Cullen says that one-third of chronic hepatitis cases in dogs relate to excess copper in the liver, and it’s of the greatest concern to veterinary experts. Also known as copper-associated hepatopathy (CAH), he says that the increase in liver damage from this disease is believed to be attributed to excess amounts of copper in commercial dog foods.
Dr. Cullen explains that while many dogs can cope with this copper excess, CAH can happen to any breed. However, there’s a subset of dogs that it poses more of a risk for. Bedlington Terriers, for example, are predisposed to having a specific genetic mutation that causes copper to accumulate. “If dogs with the mutation don’t receive treatment and change to a diet with lower copper levels, they will die from chronic hepatitis,” he says. Labrador Retrievers also have a genetic predisposition to CAH, although it’s a different genetic risk factor to Bedlington Terriers.
Experts expect the rise in CAH cases to continue while copper levels in commercial dog food remain high. Because of these findings, Dr. Cullen and many of his hepatopathologic colleagues now feed low copper diets.
Symptoms of Hepatitis in Dogs
“If you remove two-thirds of the liver of a healthy dog, it probably wouldn’t have any clinical signs because the organ has a dramatic capacity to compensate for injury,” Dr. Cullen says. He explains the problem with chronic hepatitis is that it is often subtle and goes undetected, especially in the early stages when there are no obvious clinical signs. You might not know your dog has a problem until the liver has severe damage. Typically, your veterinarian won’t diagnose chronic hepatitis until they take blood tests for another reason.
However, being vigilant and noting any changes in your dog’s behavior can be a good early indicator. “If you’re concerned your dog is not as bright, alert, interested in activity or food as normal, that’s when it’s time to get the blood test to see if it is a liver problem,” Dr. Cullen says.
The more advanced signs of chronic hepatitis can include:
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Accumulation of fluid in the abdomen
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Abdominal pain
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Jaundice, causing the whites of the eyes and gums to turn yellow
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Extreme weight loss
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Bleeding from the nose and mouth
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Bruising
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Increased thirst
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Depression
Acute hepatitis can lead to similar symptoms, but they happen suddenly and severely.
Diagnosis of Hepatitis in Dogs
Dr. Cullen explains that a liver biopsy is the most accurate method for diagnosing hepatitis. By checking for fibrosis, it’s also possible to evaluate the stage of the liver disease.
However, before a biopsy, your veterinarian will conduct a physical exam, take a detailed history, and draw blood to look for elevated liver values. Even if there are abnormalities in liver values, this won’t provide a definitive diagnosis of hepatitis or other liver problems. However, it’s the best place to start. Your veterinarian may also recommend a serum bile acids test to evaluate liver function. An ultrasound is another common diagnostic tool.
Treatment of Hepatitis in Dogs
If your dog receives a diagnosis of hepatitis, the goal will be to treat the underlying cause, reduce inflammation, and prevent the progression of cirrhosis. Supportive care is also necessary. “There is a grab bag of medications used as a form of liver support,” Dr. Cullen says. This includes, but is not limited to, antibiotics, anti-inflammatories, fluids, antioxidants, supplements, and diet changes. These can help boost liver function and protect against cell and tissue-damaging oxidative injury and irreversible necrosis, where cells in the liver die.
For CAH, “there are well-defined treatments for pulling the copper out of the liver, and then if the dog is on a low copper diet, their copper levels will return to the safe zone,” Dr. Cullen says. For immune-mediated hepatitis, he explains there are immunomodulatory drugs to reduce liver inflammation and control the problem.
Your veterinarian will want to see your dog regularly to evaluate the response to any treatment. In severe cases with irreversible and life-limiting necrosis, your dog may need palliative treatment to keep them comfortable during their final weeks or months.
Prognosis for a Dog with Hepatitis
The prognosis for hepatitis in dogs greatly depends on the underlying cause, how quickly the problem is detected, and the severity of any damage. Some dogs diagnosed with acute hepatitis recover independently; some progress to chronic hepatitis.
“There are certain histologic stages [detectable through the examination of the liver tissue under a microscope] that are regarded as end-stage liver disease,” Dr. Cullen says. “Once the liver has a lot of fibrosis and what are called regenerative nodules [cirrhotic lesions], at that point, it’s palliative care.”
The average survival time for dogs with chronic hepatitis is 18 months to three years. However, if your veterinarian diagnoses your dog with chronic hepatitis before it’s too advanced, the prognosis is often good, as, in many instances, they can control the condition. Dr. Cullen says early testing and early biopsy can save lives.
Prevention of Canine Hepatitis
Dr. Cullen explains that, fortunately, dogs can’t contract the chronic human viral infections Hepatitis A, B, or C, and they can’t transfer ICH to you and your family. However, keeping up with your dog’s regular vaccine schedule prevents the risk of them contracting acute ICH.
Because any breed or mixed breed can develop copper-related hepatitis, if you have concerns about your dog’s current diet, speaking with a board-certified veterinary nutritionist for further advice is a good idea.
It’s not always possible to prevent hepatitis in dogs, especially in idiopathic cases, although early detection can increase the chances of a positive prognosis.
The post Signs, Symptoms and Treatments of Canine Hepatitis appeared first on American Kennel Club.
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