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HEPATIC DISEASE (LIVER DISEASE)
The liver is a large organ situated just behind the diaphragm and next to the stomach in the abdominal cavity. It consists of several sections, called lobes and includes the gall bladder where bile is stored. The liver performs hundreds of essential metabolic functions including the detoxification and excretion of poisons and drugs, the production and elimination of bile, important metabolism and synthesis of proteins, fats and carbohydrates.
Most of the blood from the intestinal tract and a portion from other parts of the body, flows though the liver as it returns to the heart so that the liver can perform these actions, especially the removal of toxins. Bile that is formed by the liver cells, called hepatocytes, travels along tiny bile ducts to larger channels and finally into the gall bladder where is it stored and excreted to help digest fatty foods. When blood cells die or are destroyed, the liver also recycles the iron and hemoglobin for future blood production.
Because the liver is exposed to blood flowing from the intestines during digestion, it stands as the true first defense against outside infections and toxins entering and damaging other parts of the body. This, however, makes the liver itself susceptible to damage from these insults. The liver can if not too severely damaged, heal and regenerate its tissues following injury.
ACUTE HEPATITIS/ACUTE HEPATIC FAILURE
Sudden insult to the liver tissue by various agents can cause acute hepatitis; if more than 70% of the liver tissue is compromised (destroyed) then acute hepatic failure will occur. Initial symptoms include poor appetite, lethargy, diarrhea and vomiting, but may include jaundice, increased thirst and urination, bleeding and behavioral changes in more advanced cases. These signs will not be specific for the cause of the disease but will simply reflect dysfunctions caused by damage to the liver and its inability to perform essential metabolic functions.
Chemicals, drugs, anesthetics, biologic poisons, feline leukemia virus, feline infectious peritonitis, bacteria, systemic fungi, internal parasites and protozoa including toxoplasmosis, can all lead to primary liver disease. Acute pancreatitis, heat stroke, colitis, enteritis, hemolytic anemia, diabetes mellitus, hyperthyroidism, lymphosarcoma and infections in other body areas can also cause liver damage.
Diagnosis of liver disease is based on the history and physical findings, a complete blood count, serum enzyme analysis, urinalysis, special liver function tests, analysis of how the blood clots, X-rays, ultrasound studies and possibly a biopsy of the liver. Tests for internal parasites or heartworm disease, serology for fungi, chemical or drug detection tests may also be needed to help confirm the precipitating cause of the disease. ((Jaundice))
TREATMENT OF ACUTE HEPATITIS/ACUTE LIVER FAILURE
While there is not a "one pill" cure for liver disease, there are certain general guidelines for treatment that needs to be followed in most cases. 1. Identify and remove any specific cause of the disease. 2. Treat the complications of liver failure. 3. Maintain the patient until the liver heals and regeneration has occurred so that normal function has resumed. After (or while) your veterinarian performs the necessary diagnostic tests, supportive care is undertaken as follows:
1. Provide IV fluids, electrolytes and dextrose.
2. Provide high quality modified diets and vitamin supplementation.
3. Control Hepatic Encephalopathy with diets, antibiotics and other medications.
4. Avoid drugs that will worsen the condition.
5. Control seizures (if present).
6. Treat clotting disorders and intestinal symptoms.
7. Treat specific infections or poisoning.
8. Institute long-term treatment, which usually involves special diets to reduce the "work load" of the liver and specific medications for specific conditions as, noted:
Bacterial Infection: antibiotics based on culture and sensitivities.
Chemicals and certain Drugs: specific antidotes if available.
Fungal Infections: antifungal drugs.
Hepatic Abscesses: surgical removal or drainage.
Protozoa: antibiotic therapy.
Chronic hepatitis indicates an on-going inflammation of the liver which causes progressive damage to the organ and may lead to cirrhosis and death of the cat. Cats with biliary tract disease are at greatest risk for developing chronic disease. The signs of chronic hepatitis are similar to those of acute hepatitis but generally will include poor appetite, weight loss, increased thirst and urination, abdominal swelling, jaundice and vomiting. Most cats affected are over 5 years of age.
Diagnosis of chronic hepatitis is based on the history and physical findings, a complete blood count, serum enzyme analysis, urinalysis, special liver function tests, analysis of how the blood clots, X-rays, ultrasound studies and often a biopsy of the liver. Tests for internal parasites, serology for fungi, chemical or drug detection tests may also be needed to help confirm the cause of the illness.
TREATMENT OF CHRONIC HEPATITIS
Chronic hepatitis is treated initially like an acute hepatic failure, then with corticosteroids, often prednisolone, to control the ongoing inflammation. Other drugs used include azathioprine and ursodeoxycholic acid. Long term use of prednisolone and a low protein, low fat, high fiber diet is advised. Some cats do well, others will not and it is difficult to determine beforehand how any specific patient will respond.
Cirrhosis occurs after an acute or chronic disease of the liver causes irreversible damage to most of the liver tissue, which then becomes replaced with non-functional fibrous and nodular tissue. Most commonly, biliary tract disease is the cause. Most cats, unlike dogs, will die of the primary disease before the liver actually becomes cirrhotic. This process can become self-perpetuating and ultimately, the liver completely fails to function. ((Cirrhosis))
Clinical signs are similar to that of chronic hepatitis with most cats appearing thin, weak, having fluid in the abdomen and jaundiced membranes. Behavioral changes (hepatic encephalopathy) will also be suggestive of this disease. Diagnosis is based on history, physical examination, blood counts, serum chemistry including bile acids, liver function tests, X-rays, ultrasonography and liver biopsy. ((Ascites))
TREATMENT OF CIRRHOSIS OF THE LIVER
Treatment is symptomatic and usually for the comfort of the patient only. Careful use of fluids or plasma can be given. Fluid in the abdomen should not be removed in large amounts, but certain diuretics may be tried. Antibiotics may be helpful to control endotoxemia (a type of infection). Medications to reduce gastrointestinal upset and control bleeding are also administered. Sometimes, the use of D-penicillamine, colchcine or prednisolone to slow the build-up of fibrous tissue has been used with some success. A low sodium, low protein diet has also proven somewhat useful and Enlaparil is also being studied as to its usefulness in these cases.
CHOLANGITIS/CHOLANGIOHEPATITIS/CHOLECYSTITIS
These are the terms associated with inflammatory diseases of the bile ducts, the bile ducts and liver tissues and/or the gall bladder. Cirrhosis may represent a terminal stage of this/these conditions. These diseases are somewhat common in the cat and may represent the majority of liver problems encountered in this species. Some cases occur when an infection by bacteria or protozoa ascend (climbs up) the biliary tract from the intestines. Infections of the liver can also spread and cause damage to the biliary system.
Another form of these diseases not associated with infection has been seen in cases of pancreatitis and secondary to liver fluke infestation. Other than the difference in cause there is no difference in the manifestation of the disease.
Symptoms of biliary tract diseases include poor appetite, depression, fever, vomiting, jaundice, weight loss and dehydration. More advanced cases my exhibit abdominal swelling due to fluid accumulation, behavioral changes (hepatic encephalopathy) and bleeding, but these are uncommon. Diagnosis is based on the history and physical findings, a complete blood count, serum enzyme analysis, analysis if how the blood clots, x-rays and ultrasound studies and liver biopsy. ((Ascites))
TREATMENT OF BILIARY TRACT DISEASE
Treatment is supportive and similar to that of other acute liver diseases; identify and remove any specific cause of the disease and provide IV fluids, a high quality modified diet and antibiotics or other specific therapy as warranted. Prednisolone is used in most cases. Surgery may be required in a few cases to clear the biliary tract. Diets high in soluble and insoluble fiber may also be beneficial and some doctors have used choline or dehydrocholic acid in supplement form to improve bile flow. The prognosis for these conditions varies greatly; some cats do quite well, others die despite proper treatment.
CHOLELITHIASIS/CHOLEDOCHOLITHIASIS
These terms refer to stones of the gall bladder or common bile duct and are extremely rare and usually insignificant; the causes of such are poorly understood. Poor or improperly balanced diets may cause this disease. Often, if present, these stones do not cause any symptoms. Clinical signs in symptomatic patients would include vomiting, diarrhea, depression, dehydration, poor appetite, jaundice and abdominal pain. Diagnosis would be similar to other liver problems with x-rays and ultrasound studies being most important.
TREATMENT OF CHOLELITHIASIS/CHOLEDOCHOLITHIASIS
Treatment is only required if there are clinical signs and would involve surgery to remove the stones.
Hepatic lipidosis defines a condition where fats accumulate in the liver and lead to poor bile flow and liver failure. It is common in cats and may have some relation to feline obesity. It can occur also in relation to or secondary to diabetes mellitus, hyperthyroidism, cardiomyopathy, pancreatitis, chronic renal disease, chronic respiratory disease and certain tumors. Some veterinarians may refer to this as "Fatty Liver Syndrome" denoting alterations in liver function due to intrahepatic fat accumulation.
Clinical signs include a poor appetite, lethargy, diarrhea and vomiting, but may include jaundice, increased thirst and urination, bleeding and behavioral changes in more advanced cases. A period of appetite loss in an obese cat appears to be the trigger to start this disease process.
Diagnosis of hepatic lipidosis is based on the history and physical findings, a complete blood count, serum enzyme analysis, urinalysis, special liver function tests, analysis of how the blood clots, X-rays, ultrasound studies and possibly a biopsy of the liver. Animals too ill for a biopsy may be diagnosed with a hepatic aspirate. ((Fatty Liver))
TREATMENT OF HEPATIC LIPIDOSIS
After (or while) your veterinarian performs the necessary diagnostic tests, supportive care is undertaken as follows:
1. Provide IV fluids, electrolytes and dextrose.
2. Place some type of feeding tube so that heavy, liquid nutritional support can be given.
This is the most important aspect of treatment.
3. Control Hepatic Encephalopathy with diets, antibiotics and other medications.
4. Avoid drugs that will worsen the condition.
5. Control seizures (if present).
6. Institute long-term treatment that usually involves special diets to reduce the "work load" of the liver and specific medications for specific conditions as noted.
Treatment including tube feeding may need to continue for a month or more. Cats have been treated for upto 20 weeks before the liver healed and they were normal again.
PORTOSYSTEMIC SHUNTS & HEPATIC ENCEPHALOPATHY
Some kittens can have an abnormal communication between blood vessels that should flow into the liver and those that flow more directly to the heart. This means that blood that should filter through the liver passes directly into the general circulation and thusly, toxins absorbed from the intestine are not detoxified in the liver. Once in the general circulation, these metabolic toxins often alter function of the brain, intestines and urinary system. Cats with cirrhosis of the liver or chronic hepatitis can develop these shunts, but more commonly, congenital shunts are seen in young kittens.
Signs of these toxins causing central nervous system (brain) problems is called Hepatic Encephalopathy and includes episodes of weakness, salivation, staggering, head pressing, circling, behavioral changes and seizures. Gastrointestinal signs include poor appetite, vomiting and diarrhea. Abnormal urate metabolism can lead to urolithiasis and symptoms associated with that disease. Symptoms of hepatic encephalopathy are often worse after meals. Hepatic encephalopathy also occurs in cases where severe liver damage is present and the liver cannot adequately metabolize chemicals in the blood.
Diagnosis is based on the historical findings, physical examination, blood counts and serum chemistries, urinalysis, ultrasound or special X-rays where dye is injected into the blood vessels which go through the liver. Blood ammonia tests are also useful to make this diagnosis. ((Shunt))
TREATMENT OF PORTOSYTEMIC SHUNTS
If at all possible, surgery can result in a cure for this condition. Medical and dietary management can help some patients for a few years, but without surgery, the liver will atrophy and be completely non-functional after a time. A low protein food, antibiotics and the use of lactulose can benefit some affected cats.
