What is liver disease/chronic liver failure?
Liver disease is caused by damage to the liver. Chronic liver failure is due to long term damage to the liver, causing the liver no longer to work properly. Liver disease is far more common than liver failure, as the liver has the ability to regenerate, even if the initial damage was severe. Liver failure only occurs when more than 70-75% of the liver is irreparably damaged (cirrhosis) and the liver begins to fail as it is no longer able to repair itself.
Damage to the liver can be caused by bacterial or viral infections, congenital defects of the liver, exposure to toxins, trauma or injury to the liver, malnutrition or anorexia (cats that don’t eat for a few days or longer can get a disease called hepatic lipidosis). Other diseases can also result in damage to the liver, these include (but are not limited to) diabetes, hyperthyroidism, and cancer. There are some canine breeds that are more susceptible to liver disease, including Terriers and Cocker Spaniels. Cats are also susceptible to liver disease, as they have some altered metabolic pathways that are unable to process waste in the body in the same way dogs or humans can.
Symptoms of liver disease
The symptoms of liver disease are usually vague and non-specific, usually manifesting as gastrointestinal problems.
You may see symptoms such as:
- Reduced appetite
- Reduced energy
- Weight loss
- Bloated abdomen
- Yellow skin and mucus membranes (jaundice)
Diagnosing and monitoring liver disease
Liver disease is diagnosed by laboratory diagnostics that test the function of the liver. Diagnostic imaging may also be recommended. After of your pet is diagnosed with liver disease, ongoing monitoring of blood work will be required to monitor for improvement (liver regeneration) or progression of liver disease to liver failure.
Complete Blood Count (CBC): this test is done on whole blood. It checks the white and red blood cells for signs of anemia and of infection.
Alkaline Phosphatase (ALKP): is an enzyme produced by many tissues in the body, but it is largely produced by the liver. An elevated ALKP level is not specific for liver disease, but along with other blood results it helps in diagnosing liver disease.
Alanine Aminotransferase (ALT): is a liver specific enzyme. An elevated ALT level indicates damaged liver cells, and therefore liver disease.
Aspartate Aminotransferase (AST): is an enzyme produced by the liver, heart, kidney and bones. So it is not a liver specific enzyme, but like ALKP, it is helpful for diagnosing and monitoring liver disease.
Bilirubin: when old red blood cells are broken down by the body, bilirubin is produced. The liver is responsible for removing the bilirubin waste from the body. Elevated levels of bilirubin in the blood can indicate problems with the liver (i.e. the liver is unable to remove the bilirubin) or concerns relating to red blood cells (i.e. an increased break down of blood cells in the body).
Gamma-glutamyltransferase (GGT): this enzyme is more so associated with the bile ducts, pancreas and kidneys, and less associated with the actual liver. However elevated levels of GGT can be found in pets that have liver conditions associated with impaired bile flow from the bile ducts.
Bile acids: After eating, the gall bladder releases bile into the system to aid in digestion. Afterwards the liver is responsible for removing the bile acids from the system. If the post feeding blood sample comes back with elevated bile acid levels compared to the fasted sample it can indicate the liver is not working properly, as it was unable to remove the bile acids from the body.
Urine Specific Gravity (USG): this test is part of a complete urinalysis. It checks your pet’s ability to concentrate urine. Low USG may indicate health issues with the kidneys, which can influence the health of the liver.
Urine Stick: this is also a part of the complete urinalysis. The urine stick test tests many parameters in the urine. In the case of liver disease, bilirubin and urobilinogen are what we are interested in. Elevated urine bilirubin and urobilinogen levels can indicate the presence of liver disease.
Sediment: The final part of the complete urinalysis is the sediment evaluation. This can check for signs of a urinary tract infection, as well as bilirubin crystals. The presence of bilirubin crystals, along with a low USG may indicate the presence of liver disease.
Imaging: diagnostic imaging such as X-rays or ultrasound may be recommended to determine liver size. Imaging will also help rule out cancer of the liver or stones in the gall bladder.
Physical exam: pets with liver disease will show varying degrees of jaundice (yellowing of the skin or mucous membranes) which may be noted by the veterinarian.
Treatment of liver disease
Treatment for liver disease will vary from pet to pet. Treatment will also need to be adjusted as the disease hopefully improves or unfortunately progresses to failure. The goal of treatment is to support the liver and its regeneration or if failure is occurring to manage and monitor your pet to keep them comfortable as long as possible. Management of liver disease involves a proper diet, medications, supplements and possibly surgery.
If your pet has been diagnosed with liver disease, it’s a good idea to change them over to a liver diet. These diets are specially formulated to help support your pet’s liver. The are formulated with:
- High quality and highly digestible protein sources- reduces the workload on the liver and promotes healing and regeneration of liver tissue.
- Low sodium levels- to help control symptoms associated with edema, ascites and high blood pressure.
- Added carnitine- helps to improve fat metabolism in the liver.
- Added vitamin K and zinc- to help manage deficiencies of these nutrients commonly seen in pets with liver issues.
- Low copper levels- to help minimize the accumulation of copper in the liver cells.
- High energy/ dense calories- to ensure energy requirements are met in animals that may not be eating well.
- Added antioxidants- to promote a healthy immune system and to defend the body from free radical damage.
Liver support diets are available commercially at veterinary clinics as prescription diets. They come as both canned and kibble formulations. You may also choose to cook for your pet. If you go the home cooked route, please make sure your recipes are properly balanced for your pet and their liver condition by consulting a pet nutritionist. Veterinary nutritionist Hillary Watson recipes specifically formulated for supporting the liver.
When your pet is diagnosed with liver disease, all medications your pet is on should be reviewed as the liver plays a large role in processing many medications in the body. Changes may need to be made to your pet’s prescriptions.
Treatment of liver disease with medications are usually given to help with inflammation, support liver regeneration, or to deal with secondary health concerns.
- Steroids- can be beneficial to pets with liver disease due to their anti-inflammatory and immunosupressive properties. This can increase survival time of pets in liver failure and help them feel more comfortable.
- Ursodiol- can help pets with chronic liver disease by increasing the flow of bile acids, preventing the build-up of toxic bile acids.
- Azathioprine- is an immnosuppressant sometimes used to help treat chronic liver disease.
- Antibiotics- will be prescribed if there is a bacterial infection present, such as hepatic abscesses.
Supplements that promote liver cell regeneration are always recommended for pets suffering from liver disease. One or more supplement may be prescribed.
- S-Adenosylmethionine (SAMe)- is usually produced by the body from the amino acid methionine. SAMe is a substance that supports the function of the liver. By giving an animal with liver disease already made SAMe, the liver can protect itself from further damage.
- Milk thistle- is a herbal supplement that specifically protects the liver against toxins. It also activates protein synthesis and stimulates regeneration on liver cells. Milk thistle is also a strong antioxidant and anti-inflammatory.
- Carnitine- may be helpful in supporting cats recovering from hepatic lipidosis (fatty liver disease), as it helps improve fat metabolism in the liver.
- Mass removal surgery may be recommended when there is an identifiable liver or gall bladder mass. These surgeries are referred out to a specialist centre.
- Feeding tube placement is usually recommended for cats suffering from hepatic lipidosis. It is very important to get food into these cats to stimulate recovery.