Hepatic Failure in Cats
A complete blood count (CBC) may be within normal limits, or may reveal a mild anemia and/or an elevation in white blood cell count.
Certain diagnostic tests must be performed to diagnose liver failure and, as importantly, exclude other disease processes that may cause similar symptoms. Obtaining a complete history, description of clinical signs, and thorough physical examination are all an important part of obtaining a diagnosis. Ultimately, a liver biopsy is necessary to obtain a definitive diagnosis. Your veterinarian may recommend the following tests to rule out other disorders and to confirm a diagnosis of liver failure.
A biochemical profile usually reveals elevations in liver enzymes, and may reveal electrolyte abnormalities, an elevated bilirubin, low albumin (a protein), elevated globulin (a protein), low blood sugar, low blood urea nitrogen and low cholesterol. It also may help rule out other disease processes.
A urinalysis helps assess the kidneys and level of hydration of the patient and may reveal bilirubin in some cases.
A coagulogram (clotting profile) should be assessed, as clotting disorders are not uncommon with liver disease.
Serum bile acids are paired blood tests obtained before and after a meal that evaluate liver function. The test is very safe and can be performed at your local veterinary hospital. It may be performed in patients who have normal bilirubin levels.
Ammonia levels are blood tests that when abnormal often correlate with liver disease. Test inaccuracy is a concern, as many factors affect test results, and special handling is necessary.
Abdominal radiographs (X-rays) may be within normal limits, although may reveal ascities (fluid in the abdomen), enlarged liver or small liver.
Abdominal ultrasound is recommended in most cases to evaluate all of the abdominal organs, including the liver. It is equally important to rule out other disorders or diseases that may initially be difficult to differentiate from liver failure. With the guidance of ultrasound, it is often possible to obtain a sample of the liver via aspirate or biopsy for evaluation and culture/sensitivity. A clotting profile should be performed first, and tissue should only obtained if the clotting parameters are within normal limits. Ultrasound is often considered the diagnostic tool of choice. The ultrasound itself is a noninvasive procedure, although sampling of the tumor tissue will often necessitate sedation or general anesthesia and is associated with some minor risks. These procedures generally necessitate the expertise of a specialist and/or referral hospital.
Your veterinarian may recommend additional tests to exclude or diagnose other conditions or to diagnose liver failure more definitively. These tests are not necessary in every case, but they may be of benefit in certain individuals and are selected on a case by case basis. These include;
Laparoscopy. This procedure allows visualization and sampling of abdominal structures by an instrument introduced through a tiny incision. It is more invasive than ultrasound-guided biopsies, but it allows direct visualization of the liver and associated structures and generally facilitates a larger biopsy. However, it necessitates general anesthesia and should be performed by an individual who has both the experience and the appropriate instruments for the procedure.
Laparotomy. This is an abdominal exploratory surgery that allows close inspection of the entire liver and other abdominal structures. It allows large biopsy samples to be obtained, and may be indicated in cases where an biliary obstruction needs to be relieved and diverted. This procedure should be left to an individual who has experience and expertise, and performed in a facility where close postoperative monitoring is available.
There are several goals in the treatment of liver failure. They include eliminating any underlying cause, providing an environment for hepatic recovery and controlling complications. Patients with liver failure often require hospitalization and aggressive therapy. Although the prognosis for survival is generally guarded initially, these animals have the potential for complete recovery if they survive the first few days. It is extremely important to have a diagnosis confirming liver failure, as treatment protocols rely on the definitive diagnosis.
Eliminating any underlying disorders or factors such as leptospirosis or removal of toxic drugs is an important aspect of treatment.
Providing an environment for hepatic rest and regeneration is one of the most important parts of therapy.
Hospitalization and support to include fluid and electrolyte therapy as well as intravenous dextrose (sugar) should be instituted as needed for dehydration, electrolyte disturbances and hypoglycemia (low blood sugar).
Providing nutritional support through intravenous routes may need to be instituted in some cases.
Dietary recommendations for animals with liver disease include protein modification. A major dilemma in formulating diets for animals with liver disease is the fact that these animals are often malnourished, and it is vitally important to maintain body weight and muscle mass while minimizing the signs of liver failure. Several prescription diets are designed to provide reduced levels of high quality protein, including a new diet from the Hill's company specifically designed for animals with liver disease (Hill's Prescription Diet L/D®), as well as ways to formulate homemade diets to provide similar benefits.
Ascities may be treated with diuretics (drugs that facilitate removal of fluid) such as spironolactone (Aldactone®).
Treatment for hepatic encephalopathy (a disorder affecting the central nervous system secondary to advanced liver disease) is indicated when present. Lactulose (Chronulac®), a substance that slows absorption of ammonia from the intestinal tract into the body should be administered orally. It can also be used rectally as an enema when diluted with warm water. Neomycin enemas may be of value as well. Antibiotics, such as oral neomycin or metronidazole, may be recommended.
Treatment for cerebral edema (brain swelling) is extremely important. Combinations of mannitol, furosemide (Lasix®), and hyperventilation (over oxygenation) should be considered and instituted early in the disease process.
Gastrointestinal ulceration may be treated with drugs that decrease acid production by the stomach. Cimetidine (Tagamet®), famotidine (Pepcid®), ranitidine (Zantac®), misoprostol (Cytotec®) and omeprazole (Prilosec®) may expedite the resolution of GI ulceration associated with liver disease.
Antiemetics to reduce vomiting should be considered in some patients. Metoclopramide (Reglan®) or chlorpromazine (Thorazine®) are excellent choices.
Coagulopathies (clotting disorders) associated with liver disease need to be treated with injectable vitamin K and/or fresh frozen plasma.
Optimal treatment for your pet requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your pet does not rapidly improve.
Administer all prescribed medication and diet as directed. Alert your veterinarian if you are experiencing problems treating your pet.
Monitoring blood every day or two initially, and then weekly to monthly depending on the underlying cause.