Liver failure in dogs: causes, symptoms and treatment

Liver failure occurs when the liver loses more than 75% of its functionality, resulting in a massive and severe liver necrosis. It is a syndrome more commonly observed in dogs than in cats, although both may be affected. There are no age, race or gender preferences.

General causes

drugs

• Antimicrobials (antibiotics)

• Anthelmintics (antiparasitic drug)

• Analgesics (painkillers)

Biological toxins

• Amanita phalloides mushrooms

• Aflatoxins (toxin produced by a mold or fungus)

Infectious agents

Other causes

• Disseminated intravascular coagulation (CID)

• Acute circulatory failure

Liver failure is a condition that arises when the liver presents or experiences: poor blood supply, reduced oxygen supply, hepatotoxicity from drugs or chemicals, excessive heat or infectious agents. This condition can affect several organs and systems, including the liver and gallbladder (hepatobiliary tract), nervous system, gastrointestinal tract and hematological system (blood). Affected dogs can exhibit several signs, including anorexia, lethargy, depression, vomiting, diarrhea, seizures, ascites, hemorrhage and jaundice.

There are several diseases / disorders that present similar symptoms and / or are capable of causing liver failure, including:

• Hepatotoxins. These are agents or drugs that are harmful to the liver and include heavy metals, anti-inflammatory agents, some antibiotics, anticonvulsants and some sprays and chemicals.

• Infectious agents. Leptospirosis (a bacterial infection) or canine infectious hepatitis (a viral infection) can be associated with liver failure.

• Even massive multisystem events (such as heatstroke, thromboembolic disease, shock and disseminated intravascular hemolysis) can be associated with liver failure.

• Liver cancer (most commonly lymphosarcoma). It can cause alterations and clinical signs similar to those of liver failure.

• Bile duct obstruction. It can be due to tumors, inflammation or infection. This obstruction can cause signs similar to those of liver failure.

• Pancreatitis (inflammation of the pancreas). It often manifests as vomiting, lethargy and loss of appetite and can be associated with liver failure or initially mistaken for liver failure.

• Pancreatic cancer. It can obstruct the biliary tract causing symptoms similar to those of liver failure.

• Intestinal inflammation, tumors or foreign bodies must be considered.

Ascites

Ailments associated with collecting fluid in the abdominal cavity can also be mistaken for liver failure. Some of them are associated with protein loss, others are caused by functional abnormalities in the organs.

• Protein-dispersant enteropathies. These intestinal disorders cause profound protein loss and include inflammatory bowel disease, lymphangiectasia and intestinal cancer. Protein loss can promote the accumulation of liquid.

• Protein-dispersing nephropathies. These are kidney disorders that promote protein loss. The most common are glomerulonephritis (inflammation of a portion of the kidney) or amyloidosis (deposition or collection of protein material in organs and tissues, which compromises the normal functionality of the latter).

• Right heart failure. It can cause fluid buildup in the chest and / or abdominal cavity.

• Carcinomatosis. It is a cancer spread to the entire abdominal cavity.

Jaundice

The disorders associated with jaundice are varied, including liver failure.

• Autoimmune hemolytic anemia, in which the immune system destroys red blood cells.

• Infectious diseases, such as babesiosis, leishmaniasis and liver flukes.

Other causes

• Inflammatory liver diseases (chronic active hepatitis, cholangiohepatitis) and other disorders, including cirrhosis (severe end-stage liver disease), copper hepatotoxicity and portosystemic shunt.

• Primary pathologies of the gallbladder (stones, cancer, inflammation, infection). They need a differential diagnosis.

• coagulopathies (clotting disorders), including thrombocytopenia (reduced platelet count), ingestion of warfarin and disseminated vascular coagulation (CID).

• Disorders that cause brain edema should be ruled out.

• It is also necessary to consider the pathologies associated withhypoglycemia (low blood sugar levels), such as insulinoma, hepatomas, sepsis and others.

Symptoms

• Jaundice (yellowing of skin and mucous membranes)

• Stupor (dulling condition)

• Ascites (collecting fluid in the abdominal cavity)

Diagnosis

To diagnose liver failure and exclude other pathological processes that can cause similar symptoms, certain diagnostic tests must be performed. The collection of the anamnesis, the description of the clinical signs and a thorough physical examination are important for diagnostic purposes. Ultimately, a liver biopsy is required to reach a definitive diagnosis. The veterinarian can recommend the tests that we are going to list below to rule out other disorders and confirm the diagnosis of liver failure.

• Complete blood count test. The values ​​may fall within normal limits or reveal a mild anemia and / or an increase in the white blood cell count.

• Biochemical profile. Typically it reveals elevations of liver enzymes. It can also reveal electrolyte disturbances, elevated bilirubin, low albumin levels, elevated globulin, low blood sugar levels, low blood urea nitrogen levels and low cholesterol levels. The biochemical profile can contribute to excluding other pathological processes.

• Urine analysis. It is useful for evaluating the patient’s kidney and hydration level. In some cases, it can reveal the presence of bilirubin.

• Coagulogramma. It should be taken into consideration, since coagulation disorders are not uncommon in case of liver disease.

• Bile acid analysis. These are blood tests done before and after a meal to evaluate liver function. Bile acid analysis can be performed in patients who have normal bilirubin levels.

• Measurement of serum ammonia levels. It’s about blood tests. Abnormal outcomes are often related to liver disease.

• Abdominal radiographs. The results can be within normal limits, although they can reveal the presence of ascites, enlarged liver or small liver.

• Abdominal ultrasound. It is recommended in most cases for the evaluation of all abdominal organs, including the liver. It is equally important to rule out other ailments or pathologies that may initially be difficult to differentiate from liver failure. Using the ultrasound-guided mode, it is often possible to take a sample of liver tissue (by aspirate or biopsy) for a subsequent evaluation. A coagulation profile should be performed before taking the liver sample. The tissue should only be removed if the coagulation parameters are within normal limits. Ultrasound is often considered the diagnostic tool of choice. Ultrasound itself is not an invasive procedure, although the collection of samples from any tumor tissue often requires the use of sedation or general anesthesia and is associated with some minor risks.

To exclude or diagnose other conditions or to diagnose liver failure more definitively, the veterinarian may recommend further tests. These are not always necessary and are selected according to each specific case. They include:

• Laparoscopy. This procedure allows the visualization and collection of samples of the abdominal structures with the aid of an instrument (laparoscope), which is introduced through a small incision. It is more invasive than ultrasound-guided biopsies, but allows direct visualization of the liver and associated structures. This procedure requires general anesthesia.

• Laparotomy. It is exploratory abdominal surgery. Allows close inspection of the entire liver and other abdominal structures. It also allows the collection of large biopsy specimens and can be indicated in cases where it is necessary to relieve and deflect a biliary obstruction. This procedure should be performed at a facility that includes careful post-operative monitoring.

Treatment

In the event of liver failure, the objectives of the treatment are manifold: resolution of a possible underlying cause, promoting liver recovery and keeping complications under control. Dogs with liver failure often need aggressive therapy and hospitalization. It is vitally important that a diagnosis is made that confirms the presence of liver failure, since therapeutic protocols are based on definitive diagnosis.

• An important aspect of treatment is the resolution of any underlying disorders or factors (such as leptospirosis) or the elimination of toxic drugs.

• One of the most important parts of the therapy consists in guaranteeing the patient the conditions suitable for promoting rest and liver regeneration.

• Hospitalization and supportive therapy (fluid therapy, electrolytic therapy and intravenous administration of dextrose) should be instituted as necessary in the event of dehydration, electrolyte disturbances and hypoglycaemia.

• In some cases, it may be necessary to establish adequate intravenous nutritional support.

• Dietary recommendations for dogs with liver disease include protein variation. One of the most important dilemmas about the formulation of diets for animals suffering from liver disease, is the frequent presence of malnutrition and it is vitally important to maintain the animal’s body weight and muscle mass, while minimizing the signs of liver failure. There are several dietary lines specially formulated to bring reduced levels of high quality proteins (for example Hill’s Prescription Diet L / D). It is also possible to formulate home diets that can bring similar benefits. In both cases, however, it is always advisable to consult the veterinarian.

Control of complications

• Ascites can be treated through the use of diuretics, such as spironolactone.

• Treatment for hepatic encephalopathy (a disease affecting the central nervous system secondary to advanced liver disease) is indicated when present. Lactulose, a substance that slows the absorption of ammonia from the intestinal tract into the body, should be administered orally. If diluted with lukewarm water, the administration can also be carried out rectally by means of enteroclism. Neomycin enteroclisms may also be of use. Antibiotics, such as neomycin or oral metronidazole, may be recommended.

• Brain edema treatment is extremely important. In the early stages of the pathological process, combinations of mannitol, furosemide and hyperventilation (hyperoxygenation) should be considered and established.

• The gastrointestinal ulcers they can be treated with drugs that reduce the production of gastric acid. Cimetidine, famotidine, ranitidine, misoprostol and omeprazole can accelerate the resolution of gastrointestinal ulcerations associated with liver disease.

• In some patients, the use of antiemetics to reduce vomiting episodes should be considered. Metoclopramide or chlorpromazine are excellent choices.

• Coagulopathies associated with liver disease need to be treated with injectable vitamin K and / or fresh frozen plasma.

What to do at home

It is recommended to administer to the dog all the medications and the recommended diet according to the modalities suggested by the veterinarian. If you experience difficulty following therapy, promptly notify your veterinarian.

It will be necessary to carry out biochemical tests and evaluations to monitor the progress of the animal, initially every day or every two days and then on a weekly / monthly basis depending on the underlying cause.

The prognosis for liver failure depends on the amount of liver mass destroyed and the ability to control the underlying disorder and complicating factors.

Preventing liver failure can be difficult, if not impossible. To reduce the risk, it is advisable to vaccinate the dog against canine infectious hepatitis and leptospirosis and try to avoid the drugs and toxins associated with hepatotoxicity.