The liver performs numerous functions. It has a large storage capacity and functional reserve and is capable of regenerating. These properties provide some protection against permanent damage. However, the liver is also susceptible to injury because of its role in metabolizing, detoxifying, and storing various toxic compounds.
Signs that a cat has liver disease can vary and include loss of appetite, vomiting, stomach ulceration, diarrhea, fever, blood clotting problems, jaundice, abdominal swelling, excessive urination and thirst, changes in liver size, weight loss, and occasionally gastrointestinal bleeding.
Hepatic encephalopathy is a neurologic syndrome seen in a number of liver diseases. Signs suggestive of hepatic encephalopathy include circling, head pressing, aimless wandering, weakness, poor coordination, blindness, excessive drooling, aggression, dementia, seizures, and coma.
Ascites is a condition in which fluid collects in the abdomen. In patients with liver disease, ascites is caused by a combination of high blood pressure in the liver and an imbalance in salt and water metabolism. The swelling may be controlled by prescribing a diuretic (a medication to increase the amount of water excreted into the urine), by extracting the excess fluid with a needle, or a combination of steps.
Hepatic lipidosis is the most common cause of liver disease in cats. Excessive accumulation of fat (triglycerides) within the liver leads to liver failure. The cause is unknown but the disease is associated with a period of poor appetite (a few days to several weeks), especially in obese cats. Factors that may trigger loss of appetite include a change of diet to initiate weight loss or other stressful events such as moving, boarding, or death of other pets or owners. Hepatic lipidosis can also be associated with a metabolic disease (such as diabetes mellitus) or digestive system disease that causes loss of appetite.
Signs of hepatic lipidosis vary but can include dramatic weight loss (up to 30 to 40% of body weight) due to loss of appetite, vomiting, lethargy, and diarrhea. Signs of hepatic encephalopathy and bleeding are unusual, but can be seen in advanced disease. Jaundice or pale mucous membranes, excessive drooling, enlarged liver, and decreased body condition with retention of abdominal fat are commonly seen.
Treatment is primarily supportive unless the underlying cause can be found. Fluid treatment is used to correct dehydration. Feeding as soon as possible is essential. Occasionally, the veterinarian will prescribe an appetite stimulant. However, placement of a feeding tube is usually necessary. Once the cat is able to eat, a high-protein, calorie-dense, balanced diet is usually recommended unless the cat shows signs of hepatic encephalopathy, in which case a low-protein diet should be used. Initially, feedings are small and given frequently. The outlook is good if the diagnosis is made early, treatment is started promptly, and the underlying disease, if any, can be treated.
Inflammatory Liver Disease
Inflammatory liver disease is the second most common liver disease reported in cats. The 2 types of inflammatory liver disease in cats are cholangiohepatitis (both short- and longterm) and lymphocytic portal hepatitis.
Cholangiohepatitis is an inflammation of the biliary tract (ducts that connect to the gallbladder) that extends into the liver. Cats with cholangiohepatitis may have other digestive disorders as well, such as inflammatory bowel disease and pancreatitis.
Short-term (acute) cholangiohepatitis is often associated with bacterial, fungal, or protozoal infections, or less frequently, liver fluke infection. Signs are usually of short duration and include fever, enlarged liver, abdominal pain, jaundice, lethargy, vomiting, poor appetite, and weight loss. Treatment consists of fluids to correct dehydration and longterm (3 to 6 months) antibiotics to treat the infection. If there is an obstruction between the liver and the gallbladder, surgery is required to restore normal function.
Longterm (chronic) cholangiohepatitis may be a variant of short-term cholangiohepatitis, an immune-mediated disease, or a condition caused by any of several infections including feline infectious peritonitis, feline leukemia, toxoplasmosis, or liver flukes. It may occur more often in Persian cats than other breeds. Abdominal swelling and jaundice are the most frequently reported signs, and the lymph nodes may be inflamed. Other signs are similar to those seen with short-term cholangiohepatitis. Progression to cirrhosis (end-stage liver disease) is possible. Supportive fluid treatment, antibiotics, and other appropriate drugs may be prescribed. Treatment with a corticosteroid is often recommended because of the suspected immune-mediated aspect of this disease. Some cats respond well to initial treatment, others relapse repeatedly, and some do not recover and die from the disease.
Lymphocytic Portal Hepatitis
Lymphocytic portal hepatitis is an inflammatory disease of the liver that does not appear to be related to cholangiohepatitis. The cause is uncertain, but it may be related to immune function. It is more common in hyperthyroid cats. Signs include loss of appetite, weight loss, and less frequently vomiting, diarrhea, lethargy, and fever. An enlarged liver is noted in about half of cats with lymphocytic portal hepatitis. A combination of antibiotics and immunosuppressive drugs has been tried with variable results. Your veterinarian will be able to provide a treatment program based on the most current information.
Poisons Affecting the Liver
Because of the liver's function in metabolizing drugs, some drugs have been associated with liver dysfunction in cats. The specific signs and effects depend on the the drug and dosage. In many cases your veterinarian will be aware of the potential for liver disease when prescribing these drugs and will monitor your cat for any signs of decreased or altered function. Other substances that are toxic to the liver include heavy metals, certain herbicides, fungicides, insecticides, rodent poisons, aflatoxins (produced by mold), amanita mushrooms, and blue-green algae.
If your pet has had an accidental overdose of a medication, has had an adverse reaction to a medication (even at the prescribed dosage), or has eaten a poison, a veterinarian should be consulted immediately. If necessary, the veterinarian can take steps to minimize absorption of the drug or poison. Depending on the situation, the veterinarian may induce vomiting, administer activated charcoal, pump the animal's stomach, or administer an appropriate antitoxin. Any information you can provide regarding the toxin can help your veterinarian provide more rapid treatment. see Poisoning: Introduction to Poisoning
Portosystemic shunts have already been described as a congenital (inborn) defect (see Digestive Disorders of Cats: Liver). However, in some cases they can develop as a part of illness. In these instances they are called acquired shunts. Signs include excessive thirst, vomiting, and diarrhea. Fluid accumulation in the abdomen (ascites) is common. Medical treatment of the underlying disease, along with placing a band around the caudal vena cava (to slightly raise the blood pressure outside the liver and reduce shunting), can lead to a favorable response in some cats.
Infectious Diseases of the Liver
Several types of infections may cause liver disease, including viral, bacterial, fungal, and parasitic disease.
Feline infectious peritonitis is caused by a virus. Infection leads to widespread inflammation in the abdomen, including the liver, and inflammation of the blood vessels (vasculitis). Jaundice, abdominal effusion, vomiting, diarrhea, and fever are common signs (see Disorders Affecting Multiple Body Systems of Cats: Feline Infectious Peritonitis).
The most common fungal infections associated with liver dysfunction are coccidioidomycosis and histoplasmosis (see Disorders Affecting Multiple Body Systems of Cats: Fungal Infections in Cats). If the liver is involved, signs may include abdominal swelling, jaundice, and liver enlargement. Coccidioidomycosis can be treated with longterm (6 to 12 months) use of antifungal medications. However, relapses sometimes occur. Histoplasmosis is often treated using prescription antifungal medications. Depending on the level of illness, the outlook for recovery may be poor.
Toxoplasmosis is a parasitic disease that can cause acute liver failure due to liver cell death. The parasite is a protozoan, Toxoplasma gondii, that is found worldwide. Infection is more common in cats positive for feline immunodeficiency virus. Jaundice, fever, lethargy, vomiting, and diarrhea are seen, in addition to signs of central nervous system or eye involvement. The outlook depends on the severity of the illness (see Disorders Affecting Multiple Body Systems of Cats: Toxoplasmosis in Cats).
Endocrine Diseases Affecting the Liver
Several diseases involving endocrine glands can cause liver problems in cats. These diseases include diabetes mellitus (see Hormonal Disorders of Cats: Diabetes Mellitus) and hyperthyroidism (see Hormonal Disorders of Cats: Hyperthyroidism).
Cats with diabetes mellitus have an increased risk of developing hepatic lipidosis because diabetes mellitus increases the metabolism and mobilization of lipids. Lipids include any of a group of water-soluble fats and fatlike chemical substances that are sources of fuel for the body. However, when too many lipids are deposited in the liver, the function of the organ is impaired. Insulin replacement may or may not correct this storage problem.
Cats with hyperthyroidism have increased levels of certain chemicals (enzymes) in the liver and, in some cases, an excessive amount of bilirubin (a yellow bile pigment). Cats with excess bilirubin may have jaundice. The liver enzyme levels almost always return to normal when the underlying causes are treated.
Hepatocutaneous syndrome is rare, longterm, progressive, and usually fatal. Diabetes mellitus is often present at the same time. Crusting and abnormalities on the footpads, ears, skin around the eyes, and pressure points are typical skin changes. Poor appetite, weight loss, and lethargy are also reported. Treatment may include antifungal and antibiotics for skin infections, zinc and vitamin supplementation, high-protein diets, control of diabetes mellitus with insulin, and topical cleansing of affected skin. Unfortunately, treatment has little effect on the course of the disease, and the outlook is guarded to poor.
Liver cysts can be acquired (usually single nodules) or present at birth (usually multiple nodes). Congenital polycystic disease of the liver has been reported in Persian cats. The cysts often go undiagnosed but occasionally they enlarge and cause abdominal swelling and other signs such as lethargy, vomiting, and excessive thirst. Your veterinarian may be able to feel nonpainful masses in the abdomen. Cysts may be identified with x-rays or ultrasonography, but a biopsy is needed for a definite diagnosis. Surgical removal of the cysts usually cures the condition.
Cancers of the Liver
Tumors that originate in the liver (called primary tumors) are less common than those caused by spread from another part in the body. Primary tumors are most often seen in cats more than 10 years old, and can be either malignant or benign. Metastatic (spreading) tumors of the liver are less common in cats than in dogs. Cancers that can spread to the liver include pancreatic, intestinal, and renal cell carcinomas. Metastatic tumors usually occur at multiple sites.
Cats with liver tumors are usually uninterested in food and lethargic. Seizures may develop because of hepatic encephalopathy, low blood sugar, or spread of cancer to the brain. An enlarged liver or an abdominal mass may be found during a physical examination. Animals may be pale (due to bleeding or anemia caused by longterm liver disease) or jaundiced. A biopsy is needed for a definitive diagnosis. If a single liver lobe is involved, surgical removal of the lobe is recommended. Chemotherapy may be effective for some other cancer types. The outlook is poor for primary liver tumors that involve multiple lobes because an effective treatment is not yet available.
Amyloid is a protein that is not folded into the correct shape. The misfolded protein causes damage by displacing normal cells. Amyloidosis is an inherited disease of Abyssinian, Siamese, and oriental cats. Although some cats may show no signs, others may have loss of appetite, excessive thirst and urination, vomiting, jaundice, and an enlarged liver. Affected cats may collapse and have pale mucous membranes due to rupture of the liver and subsequent bleeding. Diagnosis is made by identifying amyloid deposits in liver biopsy samples. Amyloidosis is progressive and the outlook for recovery is poor, especially if the diagnosis is made late in the disease.
Diseases of the Gallbladder and Bile Duct
The liver secretes bile, a substance that assists with digestion and absorption of fats and with elimination of certain waste products from the body. Bile is stored in the gallbladder and is released into the duodenum through the bile duct.
Jaundice (a yellow tinge noticeable in the skin, mucous membranes, and eyes) is often the main sign of diseases of the gallbladder and bile duct. An exception is cancer of the gallbladder, which may not cause jaundice.
Obstruction of the Bile Duct
Obstruction of the bile duct is most often caused by pancreatic disease. Pancreatic swelling, inflammation, or fibrosis can cause compression of the bile duct. Diagnosis is based on laboratory tests, x-rays, and ultrasonographic evidence of pancreatic disease. Treatment of pancreatitis will often relieve the obstruction. If this is not successful, surgery may be necessary to rejoin the gallbladder and intestine. Gallstones rarely cause obstruction, but when this does occur, removal of the gallbladder is the preferred treatment in most cases. Cancer of the pancreas, bile ducts, liver, intestines, and lymph nodes can also cause obstruction. A biopsy is needed to confirm the diagnosis. When cancer is present, surgery can provide temporary relief but is not a cure.
Inflammation of the Gallbladder (Cholecystitis)
Inflammation of the gallbladder (cholecystitis) is usually caused by bacterial infections that start in the intestines and either travel up the bile duct or are spread through the blood. Loss of appetite, abdominal pain, jaundice, fever, and vomiting are common signs. The cat may be in a state of shock due to abdominal inflammation.
The inflammation can also spread to the surrounding branches of the bile duct and the liver. Diagnosis can be confirmed by biopsy for bacterial cultures and tissue analysis. Treatment usually consists of removal of the gallbladder and appropriate antibiotic medication to treat infection. The outlook is good if appropriate antibiotics are started early but is less favorable if diagnosis and treatment are delayed.
Gallstones rarely cause disease. In cats, gallstones are generally associated with bile duct inflammation. Signs include vomiting, jaundice, abdominal pain, and fever. Treatment consists of removal of the stones and appropriate antibiotics.
The liver fluke Platynosomum concinnum is an uncommon cause of bile duct disease in cats. It occurs in Malaysia, Hawaii, southeastern US, the Caribbean, South America, and western Africa. The fluke's life cycle includes lizards and toads as intermediate hosts. Cats are infected when they catch and eat these animals. The flukes may not cause any signs in some cats, but in others they obstruct the bile duct, which causes severe liver dysfunction. Signs vary depending on the number of flukes involved, but may include vomiting, diarrhea, jaundice, depression, poor appetite, and an enlarged liver. The flukes can also damage the pancreas. Antiparasitic drugs can be used to treat the infection. The outlook is favorable for mild forms of the disease.
Rupture of the Gallbladder or Bile Duct
Rupture of the gallbladder or bile duct is most often due to gallstones, inflammation of the gallbladder, or blunt trauma. Rupture of the bile duct may also occur as a result of cancer or certain parasites. Rupture leads to leakage of bile into the abdomen, causing a serious condition called bile peritonitis, which may be fatal if the rupture is not repaired. Treatment includes surgery, which consists of tying off the bile duct, removing the gallbladder, or connecting the gallbladder with the small intestine.
Last full review/revision July 2011 by Dana G. Allen, DVM, MSc, DACVIM; Sharon Campbell, DVM, MS, DACVIM; Ben H. Colmery, DVM, DAVDC; James G. Fox, DVM, MS, DACLAM; Carlton L. Gyles, DVM, PhD, FCAHS; Walter Ingwersen, DVM, DVSc, DACVIM; Lisa E. Moore, DVM, DACVIM; Sofie Muylle, DVM, PhD; Sharon Patton, MS, PhD; Andrew S. Peregrine, BVMS, PhD, DVM, DEVPC; Stanley I. Rubin, DVM, MS, DACVIM; H. Carolien Rutgers, DVM, MS, DACVIM, DECVIM-CA, DSAM, MRCVS; Jörg M. Steiner, DrMedVet, PhD, DACVIM, DECVIM-CA; Thomas W. Swerczek, DVM, PhD