Liver failure in dogs: symptoms, tests and treatment

Overview

The liver processes dietary fats, carbohydrates and proteins. It also helps store, metabolise and activate vitamins. It produces bile acids needed for digestion. It changes medicines into forms easier to eliminate. The liver makes proteins needed for blood clotting. It removes harmful metabolic products such as ammonia. Failure can therefore affect digestion, circulation and the nervous system simultaneously.

The liver has substantial functional reserve and regenerative capacity. Acute failure can develop when around 70–80% of functioning tissue is damaged. This reserve allows chronic liver disease to progress with few signs for a long time.

A raised liver enzyme result alone does not mean liver failure. Enzymes are released from damaged cells, but assessing function requires other information too.

Causes

Acute injury and deterioration of chronic disease are different starting points

A previously healthy liver can be damaged by a toxin, severe systemic infection or sudden circulatory disturbance. Harmful exposures include medicines, chemicals, plants and some herbal remedies or supplements. After removal of a large liver tumour, less than 20% of functioning tissue may remain. Some dogs then need temporary support until the remaining tissue compensates for lost function. Severe copper accumulation in liver tissue is another possible cause.

An already diseased liver may rapidly lose function following a new stress or injury. This is called acute-on-chronic liver failure. Previous medical records help distinguish it from injury to a previously healthy liver.

Longstanding inflammation can alter liver structure

In chronic hepatitis, inflammation gradually destroys liver cells. Fibrous tissue, or fibrosis, may replace functioning tissue. Early fibrosis can sometimes decrease with appropriate treatment. Advanced structural change leads to cirrhosis, which impairs liver function. Liver disease can also involve abnormal blood flow and formation of vessels bypassing the liver.

A diseased liver may resist blood flow sufficiently for bypassing vascular connections to open. These acquired shunts can cause fluctuating encephalopathy signs and abdominal fluid accumulation.

Leptospirosis can damage both kidneys and liver tissue. However, the cause of failure cannot always be identified.

Risk factors

Risk factors depend on whether failure results from poisoning or slowly progressive liver disease. Chronic hepatitis occurs in every breed. Predisposed breeds include Bedlington Terriers, Labrador Retrievers, Dobermanns and English Springer Spaniels. This predisposition concerns the underlying liver disease rather than a shared breed risk for every form of failure.

Previous liver damage may make a new medicine or toxin exposure more serious. A medicine can also cause an individual, unexpected liver reaction called an idiosyncratic reaction. New medicines and herbal products therefore belong in the history alongside possible access to toxins. Travel and leptospirosis exposure are also considered when investigating the cause.

Typical symptoms

Early signs may be vague, such as reduced appetite and tiredness. More obvious changes can appear as function declines:

• Your dog eats poorly, loses weight or vomits.
• Drinking and urination increase.
• The skin, gums or whites of the eyes turn yellow.
• The abdomen enlarges because fluid accumulates.
• Your dog seems vacant, wanders or fails to respond to familiar commands.
• Walking becomes unsteady, drooling increases unusually or seizures occur.
• Bleeding appears in the skin or gastrointestinal tract.

Brain signs associated with impaired liver function are called hepatic encephalopathy. Signs can also include head pressing, circling or sudden behavioural changes. Low blood glucose can cause similar neurological signs and worsen encephalopathy.

Complications and consequences

Failure can involve life-threatening infection, brain swelling or a clotting disorder. Kidney and other organ function may also decline. Abdominal fluid accumulation is called ascites. In liver disease, contributing factors include raised portal venous pressure, low blood protein, and salt and water retention.

Albumin is a blood protein produced in the liver.

Chronic hepatitis can also predispose dogs to a blood clot, or thrombus, in the portal vein. Clotting problems in liver disease therefore extend beyond bleeding alone.

The outlook depends on the cause and whether functioning liver tissue can regenerate. Among 39 dogs with biopsy-confirmed cirrhosis, average survival was 23 days, with a standard deviation of 23 days. This concerns advanced cirrhosis and does not apply to every liver injury or raised enzyme result. In acute injury, supportive care can give the liver time to regain function.

Diagnosis at the vet

Liver enzymes and functional markers are interpreted together

Your vet reviews previous blood tests, medicines, supplements, foods and possible toxic exposures. Examination assesses jaundice, liver size, abdominal fluid and bleeding signs. Behaviour, consciousness and blood glucose are also considered when interpreting neurological signs.

ALT and ALP help detect cell injury or impaired bile flow. Albumin, bilirubin, glucose and other blood constituents provide information about different impaired functions. Low albumin can also result from protein loss in urine or through the intestine. Bilirubin can rise because of impaired bile flow or red blood cell destruction. Distinguishing these possibilities requires a blood count and assessment of other findings, among other tests. Clotting tests investigate how liver disease affects the requirements for coagulation. Bile acids and ammonia can be measured in appropriately selected situations. Encephalopathy can occur without increased blood ammonia.

Imaging and biopsies investigate the underlying disease

Ultrasound examines liver structure, blood vessels, bile ducts and possible abdominal fluid. Confirming chronic hepatitis requires a liver tissue biopsy. Liver copper can also be measured from the biopsy.

Biopsy safety is assessed separately, particularly in an unwell dog or one prone to bleeding. Blood products may be prepared when needed, and a sampling method allowing bleeding control selected. Vital functions in an acutely ill dog are supported before all underlying disease investigations are complete.

Treatment

Hospital care supports circulation, glucose and the nervous system

Acute failure often needs intravenous fluids and close monitoring of vital functions. Fluids are tailored to circulation, electrolytes and any ascites. Low blood glucose is corrected under supervision because it can cause or intensify brain signs.

Hepatic encephalopathy treatment aims to reduce harmful substances absorbed from the intestine, particularly ammonia. It may include lactulose, dietary changes and, according to the situation, medication affecting intestinal bacteria. Triggers such as constipation, dehydration, infection or gastrointestinal bleeding are also treated. Do not force-feed a dog with reduced consciousness, because safe nutrition requires assessment. Your vet selects all medication.

The underlying cause determines targeted treatment

A medicine responsible for liver injury is reviewed and stopped when necessary under veterinary guidance. Poisoning may require substance-specific decontamination or an antidote if one exists. Chronic inflammatory disease may need treatment to suppress inflammation. Copper accumulation requires treatment directed at reducing it and restricting copper intake.

A copper-binding, or chelating, medicine helps remove copper in urine. N-acetylcysteine may support production of the body's own antioxidant, glutathione.

Ascites may need reduced dietary salt and a diuretic. If fluid impairs breathing or eating, it can be removed by abdominal drainage. Bleeding problems may require plasma or another blood product. Infections associated with severe failure are treated with antibiotics when needed.

Nutrition maintains weight and muscle

The diet must provide enough energy to maintain weight. Smaller, more frequent meals may suit feeding a liver patient. A dog that will not eat may need a feeding tube once safe to use. Protein restriction is not automatically recommended for every liver patient. Restriction may be needed with clear hepatic encephalopathy. Inadequate protein intake can worsen low blood albumin. Chronic hepatitis alone does not require dietary fat restriction. Vitamins and other support products are selected individually because excessive use can also be harmful.

Prevention

Not every disease leading to liver failure is preventable, but recognised exposures can be reduced. Keep medicines, herbal remedies, chemicals and toxic plants out of reach. Regular liver disease monitoring helps identify progression before severe failure signs.

Combination vaccination protects against infectious canine hepatitis. Some national recommendations particularly advise leptospirosis vaccination for dogs travelling to areas where infection is common. Leptospirosis vaccination protects against clinical disease, but a vaccinated dog can still shed Leptospira bacteria. The prescribed diet for diagnosed copper disease is followed long term.

Important for dog owners

Record appetite, weight progress, drinking, urination and any behavioural changes daily. Tell your vet about constipation, black stools and new medicines or supplements. At discharge, agree what to monitor and when to call immediately. Keep an up-to-date medication list for visits to other vets too.

Monitoring considers condition, bilirubin, substances produced by the liver and possible fluid or ammonia problems. Enzyme changes alone therefore do not replace overall assessment of function and signs. Follow-up frequency depends on the cause and response. Do not change protein intake or start liver support products yourself. Seizures, clearly reduced consciousness, bleeding or breathing difficulty need urgent care.

Frequently asked questions

Do high liver enzymes always mean liver failure?

No. Raised liver enzymes and loss of liver function are different things. Other diseases or medicines can also raise these results. Your vet interprets enzymes alongside signs, functional blood tests and imaging.

Can a dog recover from acute liver failure?

The liver can regenerate, and early supportive care aims to give it time to do so. Recovery depends on the injury's cause and complications. Severe brain swelling, infection or clotting disorders can be life-threatening. The outlook for advanced cirrhosis should not be applied to every acute liver injury.

Why does a dog with liver disease behave strangely or drool?

Hepatic encephalopathy causes brain signs when liver disease disrupts processing of harmful substances. It can involve drooling, wandering, failure to respond to commands or seizures. Low blood glucose can look similar. A clear new behavioural change or reduced consciousness needs urgent assessment.

Should all protein be removed from a liver patient's food?

Protein is not automatically removed because of liver disease. With clear encephalopathy, however, its quantity may be adjusted as part of treatment. Inadequate intake can worsen low albumin. The diet must also provide enough energy and support weight maintenance.

Can vaccination prevent liver failure?

Combination vaccines include protection against infectious canine hepatitis. Some national recommendations particularly advise leptospirosis vaccination for dogs travelling to infection-risk areas. However, liver failure can also result from toxins, copper accumulation and other causes vaccines do not prevent. Vaccination needs and other prevention are assessed individually.