What is Liver Disease in Dogs?

Introduction

When Jack noticed that his normally playful and energetic Dalmatian, Spot, had become increasingly lethargic and was losing weight, he grew concerned. Spot had also developed a loss of appetite and a yellowish tint to his eyes and gums. Deciding it was time to consult their trusted veterinarian, Jack scheduled an appointment and brought Spot in for a thorough examination. After running a series of tests, the vet informed Jack that Spot was suffering from liver disease, a diagnosis that Jack had never expected.

Liver disease in dogs refers to various conditions that negatively affect the health and functioning of the dog’s liver. The liver is a vital organ responsible for many functions, including detoxifying harmful substances in the bloodstream, storing vitamins and iron, contributing to blood clotting factors, producing bile for digestion, and converting nutrients in the diet into substances the body can use.

When a dog suffers from liver disease, these functions may be impaired, leading to various health issues. The severity of liver disease can vary greatly, from mild conditions that only slightly affect liver function to severe, life-threatening diseases that cause significant liver damage. It’s important to note that some forms of liver disease can progress to liver failure if not properly addressed. In contrast, others might be managed effectively for extended periods with appropriate care.

The versatility and regenerative capacity of the liver can often compensate for disease-related damage in the early stages, making initial detection of liver disease challenging. Nonetheless, early identification and appropriate management are key to preserving the health and quality of life of a dog with liver disease.

Types of Liver Disease in Dogs

Dogs aged five years or older are susceptible to liver conditions, including cirrhosis, hepatitis, fatty liver disease, hepatic lipidosis, and hemochromatosis. It’s heartbreaking to note that as many as 10% of dogs within this age group may be affected by liver diseases. The manifestation of liver disease varies in dogs, depending on the type of liver damage. Some types of liver disease might not present noticeable symptoms, while others can cause severe health complications such as vomiting, diarrhea, lethargy, weight loss, jaundice, bleeding, and seizures. Here are some diseases of the liver that dogs may encounter:

Hepatitis

Hepatitis, an liver inflammation, can be acute or chronic in dogs. Viral or bacterial infections, toxins, or specific medications usually trigger acute hepatitis. It has a rapid onset and, if left untreated, can result in severe health implications, causing acute hepatic failure. Chronic hepatitis, alternatively, refers to long-lasting liver inflammation that slowly leads to the degeneration of liver cells. It can stem from various factors, such as autoimmune diseases, extended drug use, or idiopathic causes (unknown origin).

Cirrhosis

Cirrhosis is the final phase of prolonged liver illness, in which non-functional scars replace normal and healthy liver tissues. This gradual buildup of scar tissues hampers liver function. The root cause is unclear but typically arises from persistent alcohol intake, chronic hepatitis, or metabolic ailments. Dogs in the advanced stage of liver disease (cirrhosis) are susceptible to developing ascites and gastrointestinal bleeding compared to those without it. In addition, the administration of specific pharmaceuticals, such as acetaminophen, NSAIDs, phenobarbital, and valproate, may trigger a drop in liver size and lead to the development of cirrhosis. 

Liver Shunt (Portosystemic Shunt)

Liver shunts, alternatively known as portosystemic shunts, refer to abnormal blood vessels enabling blood to circumvent the liver. As a result, the liver cannot detoxify this blood, and the liver’s function is hampered. Liver shunts can be congenital (present from birth) or acquired due to severe liver disease, commonly seen in small-breed dogs.

Hepatic Lipidosis (Fatty Liver Disease)

Hepatic lipidosis, or fatty liver disease, involves the abnormal accumulation of fat within liver cells, impeding liver function. It’s typically seen in overweight dogs or those that have suddenly ceased eating, causing rapid body fat mobilization that the liver struggles to process.

Liver Tumors

Liver tumors can be benign (non-cancerous) or malignant (liver cancer). Benign tumors, such as hepatic adenomas, do not spread to other body parts and can often be surgically removed. Malignant tumors, such as hepatocellular carcinomas, are more serious as they can metastasize to other organs. They can either originate in the liver (primary) or spread to the liver from cancer elsewhere in the body (metastatic).

Liver Failure

Liver failure, the most severe form of liver disease, occurs when the liver cannot perform its normal functions, leading to acute liver failure. It can happen abruptly (acute liver failure) or progressively over time (chronic liver failure). It’s often the result of severe liver diseases or long-term, progressive liver damage. Without immediate and aggressive treatment, liver failure can be fatal.

Fatty Infiltration

Steatosis, called fatty infiltration, occurs when excess fat accumulates within liver cells and impairs their function. This condition is typically associated with underlying medical conditions such as obesity, diabetes mellitus, hypothyroidism, Hyperadrenocorticism, and malnutrition.  Steatosis, commonly called fatty infiltration, occurs when fat accumulates within the liver cells. This condition is typically caused by underlying factors such as obesity, diabetes, hypothyroidism, hyperadrenocorticism, and malnourishment.  Fatty infiltration, or steatosis, happens when excessive fat builds up in liver cells and affects their proper functioning. This condition is often linked to underlying medical conditions, including obesity, diabetes mellitus, hypothyroidism, hyperadrenocorticism, and malnourishment. 

Hemochromatosis

Pheochromocytoma is a tumor of the adrenal gland that produces too much adrenaline. Hemochromatosis is a hereditary disorder that causes iron overload in the body, and iron accumulates in the liver, causing fibrosis and cirrhosis. Pheochromocytoma is a growth within the adrenal gland that generates excessive adrenaline. Meanwhile, Hemochromatosis is a genetic condition resulting in excess iron in the body. The liver is the primary site where excess iron accumulates, leading to fibrosis and cirrhosis. 

Causes of Liver Disease in Dogs

Liver disease in dogs, which directly affects the function inside the liver, can originate from various sources:

1. Infectious Diseases: Diseases like canine hepatitis and leptospirosis are commonly associated with liver disorders in dogs, originating from viral, bacterial, or fungal infections.
2. Toxicity: The liver in dogs can be harmed by certain toxins or drugs, including specific medications, exposure to pesticides or certain plants, and ingesting harmful substances like xylitol. These toxins can result in liver damage when given to dogs.
3. Congenital Disorders: Some dogs are born with conditions like a portosystemic shunt that directly affect their liver by causing the blood to bypass the liver instead of flowing through it for detoxification.
4. Chronic Diseases: Chronic liver disease in dogs can be a secondary result of conditions like diabetes, pancreatitis, or Cushing’s disease, which have long-term impacts on the body. In some cases, liver problems might also accompany kidney disease, as both these organs are critical for waste filtration in the body.
5. Cancer: Tumors, whether they originate in the liver (primary) or spread from another location (secondary), can result in liver disease and significantly impact the severity of the disease.
6. Immune-Mediated Disease: In some animals with liver disease, the dog’s immune system may attack the liver, leading to inflammation and damage.
7. Age-Related Changes: Much like humans, a dog’s liver function can decrease, potentially leading to liver disease.
8. Breed Predisposition: Specific breeds, such as Bedlington Terriers, have a genetic predisposition to certain liver conditions like copper storage disease.
9. Nutrition: An improper diet can contribute to liver disease, particularly diets high in fats and low in essential nutrients.
10. Obesity: Overweight dogs and obesity can lead to fatty liver disease.

Noting the liver’s significant role in digestion, metabolism, detoxification, and immune function, seeking prompt veterinary care is crucial if your dog displays signs of liver disease. These signs can include jaundice (yellowing of the skin and eyes), loss of appetite, vomiting, diarrhea, increased thirst and urination, lethargy, or disorientation.

Symptoms of Liver Disease in Dogs

Here are some common signs and liver disease symptoms that can indicate liver problems in dogs:

• A decrease in appetite
• Unexplained weight loss
• Vomiting or diarrhea
• Elevated thirst levels Increased frequency of urination
• Yellowing of the gums or eyes, a condition known as jaundice
• Fluid accumulation leading to a distended abdomen

• Altered behavior, including confusion, seizures, or disorientation, indicative of potential infectious diseases of the liver
• Excessive drooling
• Generalized lethargy or weakness, hindering the ability to let your dog partake in regular activities
• Urine that appears unusually dark in color
• Stool that is pale or gray-colored
• Bleeding disorders, which may manifest as nosebleeds, bloody urine or feces, or prolonged bleeding even from minor wounds
• Ascites, a condition characterized by the buildup of fluid in the abdomen

It’s essential to note that these symptoms can also be associated with other health issues. Therefore, if your pet displays any of these clinical signs, particularly if you have a young dog, it’s crucial to consult a veterinarian promptly for a comprehensive examination and diagnosis.

Diagnosing Liver Disease in Dogs

Veterinarians use a variety of methods to diagnose liver disease in dogs. Here is an overview of the process:

Initial Clinical Assessment and History Review

The first step to diagnosing liver disease typically involves a thorough clinical examination and review of the dog’s medical history. Veterinarians look for signs indicating liver issues, such as weight loss, jaundice, fluid accumulation, or behavioral changes. Understanding the dog’s history – including age, breed, previous health conditions, and exposure to possible toxins or medications that could affect the liver – provides valuable insight. While these initial steps can’t conclusively diagnose liver disease, they help determine if further diagnostic tests are needed and guide the direction of these tests.

Blood Tests

Blood tests are critical in diagnosing liver disease, as they can indicate elevated liver enzymes and other potential liver damage. These tests measure levels of liver enzymes, along with substances such as bilirubin and albumin, which may increase when the liver is compromised. They also monitor blood clotting factors produced by the liver; a decrease in these factors may suggest liver disease. Nonetheless, abnormal levels can occur in many dogs for reasons unrelated to liver disease, so further testing, like imaging or a liver biopsy, might be necessary for a confirmed diagnosis.

Imaging Procedures

Non-invasive imaging techniques like X-rays and ultrasounds can be useful in visualizing a dog’s liver, helping to identify signs of potential disease. Abnormalities in liver shape, size, or position can indicate issues. For example, an enlarged liver may suggest inflammation, while irregular shapes or masses can point to tumors. Though these techniques don’t usually provide a definitive diagnosis, they can inform further diagnostic procedures such as a liver biopsy or additional blood tests.

Liver Biopsy

A liver biopsy is a pivotal diagnostic procedure in detecting liver disease in dogs. This procedure involves taking a small sample of liver tissue for microscopic examination, which allows veterinarians to assess the liver’s cellular health and structure directly. Findings may confirm the presence and type of liver disease, from inflammation and cancer to fatty changes. While this procedure is invasive, it offers the most definitive diagnosis and aids in formulating an effective treatment plan.

Urinalysis

Urinalysis serves as a valuable diagnostic tool in detecting liver disease. This test evaluates the presence of bilirubin in the urine, a product of red blood cell breakdown typically processed by the liver. An elevated bile acid level in the urine may suggest liver dysfunction. Additionally, urinalysis helps identify other urinary system issues that could indirectly impact liver function or reveal other health issues that mimic liver disease symptoms.

It’s essential to note that the sequence and necessity of these tests can vary based on the dog’s specific symptoms and the vet’s initial findings, aiming to avoid unnecessary procedures and manage potential complications of liver disease.

Treatment Options for Liver Disease in Dogs

Treatment for liver disease in dogs often varies based on the underlying cause and the individual dog’s condition.

Pharmaceutical Intervention

Pharmaceuticals are crucial in managing liver dysfunction in dogs, aiming to relieve symptoms, address the root cause, and support liver function. For instance, anti-inflammatory drugs may reduce liver inflammation, and antibiotics can help combat infectious hepatitis. In addition, other medications could be utilized to manage specific symptoms or related conditions. As such, pharmaceutical intervention can significantly enhance the dog’s overall health and quality of life, supporting the critical functions of the liver.

Prescribed Diet

Dogs with liver disease often require a specialized diet. Such diets usually have low protein content, but the included protein is of high quality, allowing easier digestion and minimizing metabolic waste, reducing the liver’s load. These diets also tend to be rich in soluble fiber, vitamins (especially B vitamins and vitamin K), and antioxidants, all of which support liver function and overall health. However, specific dietary needs can fluctuate depending on the dog’s condition, so it’s crucial to let a veterinarian guide any dietary changes.

Surgical Interventions

Sometimes, surgical procedures might be necessary to remove a tumor or blockage or correct a physical abnormality causing liver disease, such as a shunt (abnormal blood vessel bypassing the liver). Here are some prevalent procedures:

• Liver biopsy: This procedure can determine the type and extent of the liver disease.
• Liver lobectomy: In case of localized issues, like a tumor, one or more liver lobes might be removed.
• Shunt surgery: This procedure reroutes blood flow around the liver in cases of a portosystemic shunt.
• Gallbladder removal: Removal may become necessary in severe gallbladder disease.

Remember that the exact surgical intervention will rely on the type and severity of the liver disease and should always be determined by a veterinarian.

Hydration Management

Dogs with severe or end-stage liver disease might become dehydrated due to reduced appetite and increased fluid loss. In these situations, fluid therapy, either orally or intravenously, is beneficial to restore hydration and electrolyte balance.

Supplements for Liver Support

Certain supplements can be advantageous in managing liver disease in dogs. These include:

• S-Adenosylmethionine (SAMe): It promotes liver function through antioxidant properties and aids in the repair and regeneration of liver cells.
• Milk Thistle: Historically used for its liver-protective effects, this plant extract fosters liver health and function.
• Vitamins E and B: These antioxidants help minimize oxidative stress in the liver.
• Amino acids: Some amino acids, such as L-arginine and L-carnitine, are thought to assist in detoxification and liver metabolism.

The dog’s treatment will depend on a customized plan that meets its specific needs. When determining the best course of action, the veterinarian will consider the dog’s overall health, the liver disease’s stage and cause, and other factors like liver values and alkaline phosphatase levels. The owner must stick to the treatment plan and closely observe the dog’s response, especially when treating acute liver failure. Regular check-ups with the vet are necessary to track progress and tweak the treatment as needed. Don’t let your dog drink excessively, which could further exacerbate the condition.

Prevention of Liver Disease in Dogs

Preventing liver disease in dogs primarily revolves around maintaining general health and frequent veterinarian consultations. Here are some crucial strategies:

• Balanced Diet – To prevent common liver disorders in dogs, providing a balanced, nutritious diet suitable for their age, size, and breed is crucial. In addition, this practice supports a robust immune system and proper liver function.
• Consistent Exercise – Regular physical activity helps manage your dog’s weight, mitigating obesity risks that could lead to liver issues.
• Controlled Toxin Exposure – It’s vital to protect the liver by minimizing your dog’s exposure to toxins, such as specific plants, chemicals, and medications, as these can cause potential liver damage.
• Routine Veterinary Care – Regular vet check-ups can identify potential health issues early, including chronic liver failure. Blood tests and other diagnostics can detect abnormalities in liver function before symptoms even emerge.
• Vaccinations and Parasite Management: Ensure your dog’s vaccinations are current and deworming is done regularly. Certain diseases and parasites can contribute to liver disease, a condition in dogs that can lead to severe health problems.
• Hydration – Supply your dog with fresh, clean water consistently. Adequate hydration supports kidney function and aids liver processes.
• Alcohol and Certain Medications Avoidance – Refrain from giving your dog alcohol, and be cautious about medications. When overused or used over an extended period, some drugs can cause liver damage. Always consult your vet when giving any medication to your dog to prevent scenarios where the liver begins to scar, a sign of severe damage.

While these steps can diminish the risk of liver disease, especially in dogs with acute liver conditions, they can’t completely avert it. Hence, maintaining a steady line of communication with your veterinarian is always recommended to ensure the best care for your dog’s health.

Frequently Asked Questions