What Causes Sudden Liver Failure In Cats?


Sudden liver failure in cats, also known as acute liver failure, refers to a rapid loss of liver function that occurs over days or weeks. It is a serious condition that can be fatal if not treated promptly. Liver failure happens when large parts of the liver become damaged beyond repair. Causes include toxins, infections, cancer, and inherited disorders. Without the liver performing its critical functions of protein synthesis, detoxification, and bile production, toxins accumulate and impact other organs.

Acute liver failure progresses quickly and can lead to death within a few days. According to one study, liver disease was diagnosed clinically in 1 out of every 100 cats visiting veterinary teaching hospitals. Treatment involves managing complications and addressing the underlying cause if possible. With aggressive therapy, up to 70% of cats can recover from liver failure. However, the prognosis is generally guarded for this condition. Preventing liver failure through prompt treatment of predisposing illnesses gives a cat the best chance of survival.


There are several potential causes of sudden liver failure in cats:


Exposure to toxins is a common cause of acute liver failure in cats. Toxins that can damage the liver include acetaminophen, antifreeze, lead, and toxic plants like lilies (Source 1). Cats are especially sensitive to acetaminophen toxicity. Even small doses can overwhelm the liver’s ability to process the toxin. Antifreeze, which contains ethylene glycol, is highly toxic to cats if ingested.


Certain viral, bacterial, and fungal infections can infect the liver and lead to inflammation, cell death, and acute liver failure. Feline infectious peritonitis (FIP), an aggressive viral disease, often causes liver impairment. Bacterial infections like salmonellosis can also trigger liver failure. Fungal diseases such as histoplasmosis sometimes spread to the liver from the respiratory or intestinal tracts (Source 2).


Cancer arising in the liver or spreading to the liver from elsewhere can disrupt normal liver function. Lymphoma, hemangiosarcoma, mast cell tumors, and adenocarcinoma are cancers that may affect the liver. As tumor growth accelerates, it can lead to sudden liver failure (Source 3).

Hepatic Lipidosis

Hepatic lipidosis, also known as fatty liver disease, is characterized by excessive fat accumulation in liver cells. It is often triggered by anorexia or rapid weight loss. The liver becomes overloaded with fat and unable to function normally. Hepatic lipidosis is the most common liver disorder in cats.

Inherited Disorders

Some breeds are prone to inheriting genetic mutations that impair liver function. For example, Siamese cats may develop an inherited enzyme deficiency leading to liver failure. Portosystemic shunts, abnormal blood vessels that bypass liver filtration, are another congenital abnormality that can eventually cause liver failure.


Common toxins that can cause sudden liver failure in cats include:

  • Lilies – All parts of the lily plant are toxic to cats and ingestion of even small amounts can lead to kidney and liver failure. Lilies are found in many bouquets and floral arrangements.
  • Antibiotics – Certain antibiotics like amoxicillin-clavulanate and tetracycline are associated with liver toxicity in felines. They can cause inflammation and damage liver cells.
  • NSAIDs – Non-steroidal anti-inflammatory drugs like ibuprofen and naproxen are toxic to cats’ livers even in small doses. They inhibit liver enzymes and cause liver cell death.
  • Acetaminophen – Extremely toxic to cats and damages their red blood cells leading to liver failure. Even quarter of a regular strength tablet can be fatal.
  • Antifreeze – Ethylene glycol found in antifreeze tastes sweet but is highly toxic. It crystallizes in the kidneys and causes liver damage.
  • Rodenticides – Rodent poisons contain chemicals that prevent blood clotting and cause internal bleeding, liver failure, and death.
  • Plants – Many common houseplants like azaleas, sago palms, and rhododendrons contain toxins that can damage cats’ livers.

Exposure to any of these toxins requires immediate veterinary care to try to prevent liver failure and death. Prevent access to toxins and be vigilant of any exposure.


Certain viral infections can cause sudden liver failure in cats. Two of the most common are feline infectious peritonitis (FIP) and feline leukemia virus (FeLV). FIP is caused by a mutated form of a common feline coronavirus. It leads to severe inflammation in organs like the liver, eventually causing organ failure. According to this source, up to 12% of sudden liver failure cases in cats are caused by FIP. FeLV is another viral infection spread through saliva and body fluids of infected cats. It can damage the liver, lowering immune defenses and making cats susceptible to secondary infections. FeLV is responsible for over 15% of feline liver disease cases, and may directly or indirectly cause liver failure.


Cancer, especially lymphoma and hepatic carcinoma, is a common cause of sudden liver failure in cats. Lymphoma is a cancer that originates in the lymph nodes but can spread to other organs including the liver. Hepatic carcinoma is a primary liver cancer that arises from liver cells. Both types of cancer can cause rapid deterioration of liver function leading to sudden liver failure (Source 1).

Cats with lymphoma may show nonspecific signs like weight loss, reduced appetite, and lethargy before acute liver failure occurs. There may be enlargement of the lymph nodes or presence of a abdominal mass on exam. Diagnosis is made by biopsy. Chemotherapy can be used to treat lymphoma in cats, but prognosis is poor once liver failure develops (Source 2).

Hepatic carcinoma also causes nonspecific symptoms initially like weight loss and lethargy. Some cats may show signs of jaundice. Diagnosis is made by ultrasound and biopsy. Surgery is the main treatment option for cats with hepatic carcinoma, but once acute liver failure occurs, prognosis is very poor (Source 3).

Hepatic Lipidosis

Hepatic lipidosis, also known as fatty liver disease, is a common cause of liver failure in cats. It is caused by an accumulation of fats and triglycerides in the liver cells, which impairs liver function. According to the Cornell Feline Health Center, hepatic lipidosis is the most common liver disease in cats, accounting for approximately 50% of liver disease cases [1].

Hepatic lipidosis is often caused by anorexia or decreased appetite leading to rapid weight loss and fat mobilization. Obese and overweight cats are at a higher risk. During starvation, fat stores are broken down and mobilized to the liver at a rate that exceeds the liver’s ability to process fats. This results in a buildup of triglycerides in hepatocytes, impairing their normal metabolic functions. Cats can develop hepatic lipidosis after just 2-3 days of decreased eating.

Additional factors like obesity, concurrent illnesses, and stress can also contribute to the development of hepatic lipidosis. The underlying cause leading to anorexia, such as cancer, infections, toxins, or other diseases, needs to be addressed as well.

Inherited Disorders

Two inherited disorders that can cause sudden liver failure in cats are portosystemic shunts and amyloidosis.

Portosystemic shunts are abnormal connections between the portal vein (which brings blood from the digestive tract to the liver) and the systemic circulation (which carries blood to the rest of the body). This allows blood to bypass the liver, preventing proper detoxification and filtering. Signs include behavioral changes, lack of appetite, vomiting, and possible sudden onset of severe neurological symptoms. It is most common in purebred cats like Persians, Himalayans, and Siamese. Diagnosis involves bloodwork, imaging tests, and sometimes exploratory surgery. Treatment depends on the type of shunt and may involve surgery, medications, or dietary changes (Merck Manual).

Amyloidosis is an inherited disease seen primarily in Abyssinian, Siamese, and Oriental shorthair cats where abnormal protein deposits accumulate in organs like the liver. Many cats show no outward signs, but it can lead to liver failure. Diagnosis is through biopsy. Treatment focuses on managing symptoms and may include dietary changes, medications, and intravenous fluids. Prognosis depends on the extent of organ involvement (iCatCare).


The most common symptoms of sudden liver failure in cats include:

  • Jaundice – Yellowing of the skin, gums, and whites of the eyes caused by a buildup of bilirubin. This is one of the most telling signs of liver dysfunction.
  • Vomiting – Cats may vomit repeatedly as the liver loses its ability to remove toxins from the blood. Vomit may contain blood and have a yellow tinge.
  • Diarrhea – Diarrhea containing blood or abnormally loose stool can occur as the liver loses its ability to digest food and remove waste products.
  • Loss of appetite – Sick cats often lose interest in food as toxins build up in the bloodstream. Sudden anorexia is a common symptom.
  • Lethargy – Liver failure leads to fatigue and weakness as the body struggles to function without this vital organ. Cats may move little and sleep excessively.

Other symptoms include weight loss, increased thirst and urination, head pressing, and bleeding disorders. Owners may also notice behavioral changes in their cat as toxins affect the brain. Any sudden onset of these symptoms in a previously healthy cat warrants an urgent vet visit to test liver function.


Diagnosis of sudden liver failure in cats begins with a complete medical history and physical exam. The veterinarian will look for symptoms like jaundice, weight loss, vomiting, diarrhea, increased thirst and urination that point to liver disease. They will also feel the abdomen to check for an enlarged liver that could indicate inflammation or scarring.

From there, the vet will likely run a panel of blood tests. Elevated liver enzymes like ALT, AST and ALP indicate liver injury. Low albumin and blood glucose levels are also seen with liver disorders. Bilirubin levels help assess bile flow [1]. A complete blood count checks for anemia and infection. The blood is also tested for clotting function since the liver makes proteins needed for proper clotting.

Imaging like x-rays or ultrasound allow the vet to visualize the size, shape and texture of the liver. An enlarged, irregular liver could indicate cancer. Ultrasound can also detect gallstones blocking the bile ducts.

Finally, a biopsy of liver tissue may be needed for a definitive diagnosis. Microscopic examination can determine if cancer, inflammation or infection is destroying liver cells [2].


Treatment for sudden liver failure in cats focuses on hospitalization and supportive care to help stabilize the cat while the liver hopefully can regenerate and heal. According to WagWalking, hospitalization is vital for treating acute liver failure in cats.

Some key components of treatment include:

  • Hospitalization for close monitoring and care
  • Intravenous (IV) fluids to prevent dehydration and support circulation, as noted by PetMD
  • Medications like antibiotics, vitamin supplements, and liver drugs as stated by the Merck Veterinary Manual
  • Potential surgery such as a liver biopsy to determine the underlying cause

The main goals are to stabilize the cat, address any underlying issues or infections, provide nutritional support, and give the liver time to potentially regenerate. However, the prognosis depends on the severity and cause of the liver failure.

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