Liver Disease in Dogs:Symptoms,Diagnosis & Treatment
Dr. Sanjeet Kumar,CEO-PET KINGDOM,NEW DELHI
Canine liver disease is among the top five leading causes of non-accidental death in dogs, and should be taken seriously. The liver is responsible for a number of essential bodily functions.
The liver is the second largest organ in the body and provides about 1500 critical biomechanical functions. The liver metabolizes medications, removes toxins from the body, and creates substances essential to life like the protein albumin and blood clotting factors.
The liver is responsible for several processes in a dog’s body. It creates bile to aid digestion and helps rid the body of waste. The liver also helps a dog metabolize fat, protein, carbohydrates, vitamins, and minerals. Additionally, the liver filters out the toxins and waste found in foods and medications.
The early signs of liver disease in dogs are nonspecific. They include loss of appetite, weight loss, and chronic intermittent vomiting and diarrhoea. Vomiting is more common than diarrhoea. Drinking and urinating more often than normal may be the first signs, and the principal reason for seeking medical attention.
In the early stages of liver problems in dogs, the liver swells and enlarges. As the disease progresses, the liver cells die and are replaced by scar tissue. The liver then becomes rubbery and firm. This condition is called cirrhosis. It is not reversible. Before the liver reaches this terminal stage, it can recover from damage and heal itself to the point where your dog has normal liver function. This is possible if proper treatment is instituted early on; the extent of recovery depends on the exact cause of the liver damage. Eighty percent of liver cells must die before the liver begins to fail. The signs of liver failure in dogs are jaundice, hepatic encephalopathy, ascites, spontaneous bleeding, and dependent edeoma-swollen lower limbs. Treatment of liver failure is directed toward treating the liver disease that is causing it.
Although the liver looks like a simple brown mass, it is a remarkable and complex organ that serves many essential functions. These include:
- Metabolizing proteins, fats, and carbohydrates
- Storing essential vitamins, minerals, and nutrients
- Producing enzymes that support digestion
- Breaking down toxins, including medications
- Eliminating waste from the body
The liver also has a large reserve capacity since all of its cells share the same abilities. If one part of the liver stops working properly, another portion can take over. In addition, the liver can regenerate tissue given time and the right circumstances.
Due to its central role in the body, the liver is susceptible to a wide variety of problems that can threaten the health of dogs, so it’s important for owners to be aware of the signs and causes of liver disease in order to keep your pet in optimum health!
Signs of Liver Disease in Dogs
The signs of liver disease can be very similar to those of other conditions. Symptoms to look out for include:
- Poor appetite or loss of appetite
- Weight loss
- Jaundice (yellowing of skin and whites of eyes)
- Increased thirst
- Vomiting or diarrhoea
- Changes in behaviour
- Excessive drooling
- Lack of energy or depression
Other possible signs of liver disease in dogs include dark-coloured urine, pale gums or a buildup of fluid in the abdomen that could be mistaken for sudden weight gain.
Common Disorders of the Canine Liver
Vessel Abnormalities: In young dogs, one of the most common liver disorders is a birth defect called congenital portosystemic shunt. In these cases, a blood vessel is present that bypasses the liver, causing a buildup of toxins that the liver would normally take care of. Congenital portosystemic shunts are suspected in young dogs who have stunted growth, develop seizures, or seem disoriented.
In older dogs, we more commonly see acquired shunts, which develop when there is a blood pressure backup in the liver due to hypertension or cirrhosis. In an effort to get around the “jammed” region, new vessels grow to bypass the blocked area, but they also bypass the liver cells themselves.
Treatment depends on the anatomy of the shunt. If it consists of one large vessel outside of the liver, as is more common with congenital shunts in small breed dogs, surgery can be very successful. Shunts inside the liver or those consisting of multiple vessels may not be surgically repairable, and in those cases the patient has to be managed with a low protein diet and medications to help reduce the amount of toxins in the blood. In these cases, the liver problem isn’t cured, but instead the emphasis is placed on controlling the symptoms.
Endocrine Diseases: Certain diseases that affect the endocrine glands can lead to liver problems. Diabetes mellitus, hyperadrenocorticism (Cushing’s disease), and hyperthyroidism can all cause impaired liver function because of their effects on the organ. In these cases, treating the underlying endocrine disease is the most important component of improving liver function.
Infectious diseases: Because the entire blood volume passes through the liver, it is especially susceptible to a variety of infectious diseases. The liver can be infected by bacteria, viruses, parasites, or fungi.
The most common viral disease associated with the canine liver is infectious canine hepatitis, which can cause inflammation and scarring. This is a vaccine-preventable disease.
Leptospirosis is a bacterial infection that can lead to liver disease, though many people associate it more with kidney disease. Dogs are infected with leptospirosis through contaminated water sources, and the disease can be spread to humans.
Leptospirosis is diagnosed by blood test or tissue biopsy. While it can be challenging to diagnose due to the wide variety of nonspecific clinical signs, the bacterial infection can be cleared with early treatment. Secondary liver and kidney damage may be permanent. Commercial vaccines for leptospirosis are available for at-risk dogs.
Coccidioidomycosis and histoplasmosis are the most common fungal causes of liver disease. Dogs are exposed through spores in the environment. These fungal infections can be difficult to clear and often require months of treatment with anti-fungal medications. Because of the difficulty in treating fungal disease of the liver, the long-term prognosis is guarded.
Liver masses: Dogs are susceptible to several types of liver masses. Liver cysts can be present from birth or acquired with age. Though often benign, large or growing cysts can cause symptoms of liver disease. Surgical excision is usually curative.
Liver cancer: Cancer of the liver comes in two main forms—primary tumors, which originate in the liver, and secondary or metastatic tumors, which means they spread from another area in the body. Primary tumors are less common than metastatic ones. Depending on the type of cancer, location, and number of masses, treatments may include surgery, chemotherapy, radiation, or a combination.
Breed Specific Liver Diseases in Dogs
Certain breeds of dogs are predisposed to specific liver conditions. Copper storage disease is a known problem in Bedlington terriers, Doberman pinschers, Skye terriers, and West Highland white terriers. In these dogs a metabolic defect causes copper to remain in the liver, leading to chronic hepatitis. Amyloidosis, caused by a malformed protein that accumulates in the cells, is a disease of Chinese Shar-peis.
Is Liver Disease Fatal for Dogs?
Depending on the severity of the disease and whether or not the underlying cause can be treated or eliminated, the prognosis for canine liver disease varies. If the cause is addressed before long-term damage occurs, the prognosis can be excellent. The liver is the only visceral organ known to regenerate, so in that respect it is truly remarkable.
Chronic or severe liver disease, however, has a poorer prognosis. In those cases, treatment is limited to managing the progression of disease and minimizing symptoms.
The most common medical management involves a higher carbohydrate/low protein diet to reduce the amount of circulating ammonia in the bloodstream, vitamin supplements, lactulose to bind toxins in the gut, antibiotics, and vitamin K if the patient has bleeding problems. It is essential that your veterinarian monitor your pet regularly if he or she has liver disease in order to control the symptoms.
Even with intensive management, many patients die of their disease, though good control extends the length and quality of their lives.
How Can Liver Disease in Dogs be Prevented?
Not all cases of liver disease can be prevented, but certain precautions can reduce the risk of specific diseases. Dogs should be vaccinated for infectious canine hepatitis and, for some dogs, leptospirosis. Keep your pet away from known toxins. And most importantly, know the signs of liver disease and see the vet sooner rather than later if you are concerned! Early intervention and treatment is one of the key factors in treating liver disease and preventing serious signs.
Types of Liver Disease
There are two types of liver conditions known as chronic and acute. Chronic liver disease occurs gradually and can be caused by an ongoing health condition like cancer or diabetes. Acute liver failure comes on suddenly and requires immediate medical attention. Poisoning is one of the most common reasons for acute liver failure.
Causes of Liver Failure (Acute) in Dogs
These are some of the most common causes of liver failure
Many types of poisoning
- Alcohol
- Drugs
- Antifreeze
- Herbicides, fungicides or insecticides
- Rat poison
- Some types of mold, amanita mushrooms or blue-green algae
Infectious diseases
- Infectious canine hepatitis
- Leptospirosis
- Fungal infections
- Toxoplasmosis
Chronic hepatitis
long-term inflammation of the liver, due to copper accumulation and other causes. This condition is more common among some breeds.
- Bedlington, Skye and West Highland White Terriers
- Cocker Spaniels
- Doberman Pinschers
- Standard Poodles
Endocrine disease
these may cause or contribute to liver failure.
- Diabetes
- Cushing’s Disease
- Hyperthyroidism
Liver cysts
more common in Cairn and West Highland White Terriers
Cancer
cancer that originates in or spreads to the liver can cause liver failure
Congenital abnormality
- Hepatic amyloidosis – an abnormal protein, more common among Chinese Shar-Peis
- Glycogen storage ; caused by a genetic enzyme deficiency
- Tendency to liver fibroses ; scar tissue replaces normal liver cells
- Vascular abnormality in the liver
Liver disease can also be due to congenital conditions. For instance, breeds including Yorkshire Terriers, Schnauzers, Golden Retrievers, Labrador Retrievers, Poodles, and German Shepherds are prone to copper storage disease where copper builds up in the liver and damages the organ. In addition, puppies can be born with liver shunt, which is a genetic condition that affects the circulation of blood in the liver.
Symptoms of Liver Disease in Dogs
The symptoms of early stage liver disease are non-specific, which means they are common to a number of ailments and do not directly point to a liver problem. This can make detecting liver issues difficult. Early stage symptoms can include:
- Vomiting and diarrhea
- An increase in thirst, which will cause the dog to pee more frequently
- Loss of appetite and weight loss
- Changes in behavior, such as irritability, lethargy, or depression
As the disease progresses, it can cause jaundice where the skin, eyes, and gums turn a yellowish color. This is one of the most telltale signs of liver disease. In addition to jaundice, later stage symptom include:
- Swelling of the abdomen due to enlargement of the liver or fluid build up
- Issues with blood clotting
- Blood in the urine or feces
- Blindness
- Seizures
- Coma
Neurological problems, such as disorientation, pacing, aimless wandering, or lack of coordination can also happen in the end stages. These are caused by an accumulation of toxins that normally would have been eliminated by the liver.
Diagnosis
Diagnosing liver disease requires a blood test to check the levels of enzymes, proteins, and other substances produced by the liver and a urinalysis to evaluate the overall health of the liver and kidneys. Both of these tests can also help diagnose or rule out underlying illnesses.
In addition, X-rays and an ultrasound can be done to see if the liver is enlarged and look for gallstones, cysts, or signs of cancer. In some cases, a liver biopsy might be needed for a more definitive diagnosis.
Treatment
Treatment of liver disease in dogs is focused on managing the symptoms and addressing the underlying cause if it has been diagnosed. It can include:
- Fluid therapy to treat or prevent dehydration
- Antibiotics to eliminate a viral infection
- Medications to control symptoms such as vomiting, gastrointestinal bleeding, or inflammation
- Surgery to remove cysts, gallstones, or cancerous portions of the liver
If your dog has liver cancer, chemotherapy or radiation could also be part of the treatment recommendations.
Prevention Tips
There are things you can do to help prevent both acute liver failure and chronic liver disease. For instance:
- Keep harmful substances including human medications, antifreeze, pesticides, and rodenticides out of paw’s reach.
- Know which foods could harm your dog and result in liver failure.
- Never give your dog over-the-counter medications such as Tylenol (acetaminophen) or Advil (ibuprofen) without consulting with your veterinarian first.
- If your veterinarian recommends medication for your dog, be sure to follow the instructions carefully to avoid overdosing.
- Don’t let your dog drink from stagnant or potentially unclean water sources because they can contain molds and blue-green algae, which can cause acute liver failure.
- Maintain your pet’s weight with a healthy diet and exercise routine. This can help avoid illnesses like diabetes that can lead to liver disease.
Treatment
If liver disease is suspected, a vet will order lab work to evaluate organ function.
Elevated liver enzymes found in the blood, like alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP), can indicate a problem. Additionally, the blood levels of bilirubin, a substance found in bile, and albumin, a protein made by the liver, provide information about overall liver health. Blood sugar levels, cholesterol, and levels of urea nitrogen—a byproduct of protein metabolism—can also give information on whether the level of liver disease constitutes liver failure. A complete blood count may indicate the presence of an infection or inflammation. Abdominal imaging, like radiographs (X-rays) or an ultrasound, may reveal scar tissue and tumors in or around the liver region.1 A liver biopsy may be recommended to check for the presence of bacteria, cancer cells, and more and is often the only way to get a definitive diagnosis for the cause of the liver disease.
The treatment options for acute liver disease depend on the type of disease and the degree of damage done to the liver. Fluids and electrolytes, and restricted activity are the recommended protocol for pets who have been acting sick. Medications and liver supplements are often used as well. Bile duct obstruction can sometimes be remedied with medications like ursodiol. However, for full duct obstruction, surgery is often necessary. Surgery has a high success rate for liver shunts and can be a cure for most dogs, however not all shunts can be repaired surgically and these cases will need lifelong medical management with diet and medication. Antibiotics and antiviral medications can be given in the presence of infection. Yet, chronic active hepatitis—not reversible or curable—is often managed with medications and a restricted diet. Treatment for liver tumors or cancer will depend on test results and may involve surgery, chemotherapy, and the administration of medications.
Medications and supplements, can help many dogs with liver disease or damage live for years with minimal symptoms. In some cases, dietary changes are also necessary. The response to treatment depends on the individual dog, but compliance from the owner is a major component to success. Be sure to adhere to your vet’s recommendations for medications, diet, and follow-up testing and exams.
How to Prevent Liver Disease
While keeping your dog healthy involves routine wellness exams, there are other ways to assure the health of its liver. Refrain from feeding your dog fatty foods as this may cause pancreatitis, which can secondarily affect the liver. Make sure your pet is fully vaccinated to prevent infectious causes of liver disease such as canine adenovirus and leptospirosis.
Reference-on request
