What is Liver Disease in Dogs: Types, Causes, Symptoms and Treatment

The liver is an important organ that serves numerous functions in the body of a dog. It metabolises proteins, carbohydrates, and fats. It also produces enzymes that aid digestion and helps to discard waste from the body. However, the liver is susceptible to wounds and diseases, affecting the overall functioning of a canine’s body.  

The article highlights the symptoms of liver disease in dogs and related causes and treatment, helping one to give instant and necessary medical attention. 

Liver disease in dogs is a state in which the liver swells and enlarges, eventually leading to cell damage. In this adverse case, it is replaced by scar tissue where the liver becomes rubbery. This condition is known as cirrhosis and can be treated before it reaches its terminal stage.

Liver diseases are apparent in dogs when they start ageing. In many scenarios, it results due to genetics. 

A dog can contract liver diseases due to different reasons:

• Cysts that obstruct bile ducts result in liver ailments.
• Liver cancer i.e. hepatocellular carcinoma
• Certain types of mushrooms, amanita, blue-green algae, etc., also lead to liver problems. 
• Due to leptospirosis, a bacterial disease that dogs contract when they come in direct contact with the urine of other animals.
• Endocrine diseases like diabetes, Hyperthyroidism, hyperadrenocorticism (Cushing's disease), etc., also contribute to liver failure.
• Congenital abnormalities like Hepatic amyloidosis, resulting from the over-accumulation of protein; glycogen storage disease which has resulted from the deficiency of genetic enzymes. 

Another very common cause for liver disease in dogs is consumption of a poor diet. Though it cannot be directly linked with liver disease, an unbalanced diet triggers genetics and puts stress on the liver. 

Liver disease in dogs arises from genetic conditions. For instance, young dogs, in some scenarios, have a liver shunt or congenital portosystemic shunt from the time of their birth. However, acquired shunts are apparent in older dogs which surface due to blood pressure back up in scenarios of hypertension or cirrhosis. The treatment procedure for a shunt depends on its anatomy.

Coccidioidomycosis and histoplasmosis are other fungal causes that are attributed to liver diseases. 

It is hard for a dog's liver to dissociate toxins. Hence the organ is prone to damage when exposed to excessive toxins. Here are the toxins that damage a dog's liver:

• Vaccines and medications
• Environmental toxins
• Pesticides and herbicides
• Chemical cleaners
• Processed foods
• Food additives
• Heartworm drugs
• Virus and autoimmune diseases

Signs and symptoms of liver disease in dogs will vary. In the early stage, the liver of the dog swells. With time, the disease kills the liver cells, which are later replaced by scar tissue, making the liver firm and rubbery. This condition is referred to as cirrhosis. 

The initial symptoms of liver disease in dogs are:

• Weight loss and loss of appetite 
• Vomiting and diarrhoea
• Behaviour changes 
• Lethargy and fatigue
• Increased drinking and urination
• Shaking resulting from discomfort or nausea

Other major symptoms are:

• Yellowish eyes, gums, or tongue (resulting in jaundice)
• Blood in stool and toilet 
• Unstable walk and body movement
• Increased thirst
• Seizures
• Digestive disorders
• Issues in ligament or tendon
• Dull eyes or retinal disorders
• Painful, bloated belly
• Hepatic encephalopathy (a nervous system disorder)
• Irritability and aggression
• Spontaneous bleeding
• Frequent urination
• Excessive drooling
• Gastrointestinal bleeding

There are two types of liver disease in dogs: chronic and acute. Let us understand these two types one by one: 

• Chronic Liver Disease: This situation arises with time and due to the presence of ongoing medical conditions like diabetes or hepatitis. 
• Acute Liver Disease: Acute liver disease or failure is a state that mostly arises due to toxins like pesticides and herbicides, chemical cleaners, and even the effects of vaccines and medications. It even results from a ruptured flow of fluids to the liver and tissues surrounding it, excess exposure to heat, when necrosis sets, leading to liver failure which is why immediate medical attention is required.  

Even metabolic disorders in the synthesis of proteins, absorption of glucose, and abnormalities cropping up metabolic detoxification process result in acute liver failure.

The liver regulates a plethora of body mechanisms. It helps to release blood clotting problems and eliminate toxins from the body.

Hence, when the liver stops working, the entire body gets affected, which might result in the following complications:

• Hepatic Encephalopathy

Hepatic encephalopathy is considered to be a syndrome that circles around neurological problems. When the liver stops functioning, it can no longer eliminate toxins from the bloodstream. The symptoms of Hepatic Encephalopathy include the dog's inability to react and respond to commands, aimless strolling, dullness, poor coordination, dementia, seizures, etc. 

• Clotting Defects

One of the significant problems that emerge with poor liver function is clotting defects. The liver releases proteins that aid the clotting process. However, liver diseases jeopardise the clotting process. Transfusions of plasma or blood are an effective way to improve clotting. In addition, administering heparin and vitamin K proves helpful in increasing and decreasing clotting potential.

• Bacterial Infections

Dogs suffering from long-standing liver ailments are highly prone to bacterial infections. Antibiotics prove helpful in treating this type of infection. 

In addition, fibrosis is a major complication that crops up from severe liver disease in dogs. Prolonged liver disease leads to the formation of scar tissue over the actual liver cells.

Liver diseases in dogs occur in four different stages:

• First Stage: This stage is marked by abnormal inflammation. Such conditions can be easily treated with proper medications and a healthy diet plan. 
• Second Stage: The disease progresses if not treated on time, scars and hardens the liver resulting in fibrosis. Even at this stage, the disease can be reversed, bringing the dog out of danger.
• Third Stage: Liver cirrhosis is the third stage that leads to permanent liver scarring. 
• Fourth Stage: The final stage is marked by liver failure when the liver of the dog cannot function any longer.

The symptoms exhibited by dogs with liver disease will determine the diagnosis procedure. Generally, a veterinarian collects blood samples and urine, enabling them to understand the dysfunctional level and root cause behind the problem. 

Veterinarians will examine the hormone or enzyme imbalance caused inside the dog, signs of poisoning, etc. Some of the recommended diagnosis procedure to determine the severity of liver diseases in dogs are as follows:  

• Blood Chemistry Test: In this test, a veterinarian will observe if there is any abnormality in enzymes present in the liver of a dog, like alkaline phosphatase, alanine aminotransferase, etc., which regulates albumin, glucose, blood urea nitrogen, creatinine, cholesterol, etc. 
• Urinalysis: In this veterinarian will analyse the protein, crystals, blood, and pH level through the dog’s urine.
• Computed Tomography: Computed Tomography (CT) scan is used to detect the presence of mass lesions. It also enables vets to understand whether there is any abnormality in veins or arteries that connect to the liver.
• Complete Blood Count: Complete Blood Count (CBC) helps to compute the red blood cell, white blood cells, and platelets. For instance, in case vets find out lower RBC counts, which is indicative of anaemia and anaemia is a major sign of chronic liver disease. 
• Coagulation Profile: Coagulation profile reflects Prothrombin time and activated partial thromboplastin time. This helps in identifying the bleeding risk of dogs along with showing their ability to form blood clots. 
• Stimulation Test of Bile Acid: Vets conduct this test to determine liver function. In this test, vets take a blood sample of the dog to evaluate the amount of bile acids that are present before and after the dog eats food. 
• Biopsy: The liver biopsy includes the collection of cells and tissue present in the liver, which is then examined under a microscope. A biopsy helps the vets to understand whether there is any cellular abnormality or disease that is surfacing in the body of a dog.  There are different methods relying on which veterinarians take out the biopsy sample.
• Ultrasound-Guided Needle Biopsy: In this, an ultrasound probe is used to detect the liver, and then a small part of liver tissue is taken out with a syringe and needle. The entire process is carried out under sedation or anaesthesia, where dogs do not have to undergo surgical incisions. 
• Wedge Biopsy: In this process, a small wedge is aspirated from the liver during the laparoscopic or abdominal surgery. Even this is performed under the effect of anaesthesia.

Treatment for liver disease in dogs depends on the severity of the symptoms and causes. For instance, if the liver has resulted from having a specific toxin, a specific treatment will be effective. Before the liver disease progresses to the terminal stage, it can be treated. However, the recovery rate depends on the cause which damages the liver.

The veterinarian performs several treatment procedures:

• Changing the Diet Plan

Vets generally recommend to start with a normal protein diet and encompass supplemental vitamins E and K. For instance, low sodium and protein diet is recommended for dogs with chronic liver problems. Even an individual must shift to giving special foods for dogs that are high in minerals and vitamins, helping heal the liver to recover. 

• Giving Antibiotics

Antibiotics help in preventing and treating infections as the immune system becomes fragile after contracting liver disease. 

Even antiemetics are used to treat liver diseases in dogs. These drugs are meant for hepatic encephalopathy, coagulopathy drugs, hepatoprotectives, etc.

• Surgery

In case liver diseases escalate to tumours or cysts; dogs have to undergo surgeries. In addition, abdominal surgery is used to treat Extrahepatic Portosystemic Shunts (PSS), thereby preventing future contraction of any liver disease. 

• Supplements

Besides a healthy diet plan, supplements like SAM-E and milk thistle extract containing vitamin E, zinc, etc., also help in treating liver diseases.

• Restricting Activity

Dogs have to undergo restricted activity for some time when their livers will be able to regenerate. In case of acute liver failure, veterinarians will comatose the dog and will keep them on intravenous fluids and electrolytes. This will help in reducing blood toxicity. On the other side, in case there is excess fluid in the abdomen, a long needle is used to take out the fluid. It helps the dog to fight respiratory difficulty.

Livers are regenerative; hence liver diseases can be treated if detected in the initial stage. Here are the following post-treatment recovery measures one must adopt for their dog: 

• Post-recovery, dogs must be kept under special care. After surgery, vets will provide every dog owner with discharge instructions, which must be followed to ensure a faster recovery.
• Dogs must be provided with food that is calorie-dense and highly digestible after treatment. Nutrition plays a major part to help dogs come out of the surgical procedure. It is equally important to provide the utmost rest and comfort to the dog. 
• In multiple instances, physical therapy proves helpful, assisting dogs to move and get back to their previous momentum gradually.