Hepatic Encelphalopathy

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By Innovet Pet Team

• Updated on July 20, 2026

If your dog suddenly seems confused, unsteady, or starts having seizures, the issue might actually start in the liver.

Hepatic encephalopathy in dogs is a neurological disorder caused by liver problems that let toxins like ammonia reach the brain.

Knowing the causes, warning signs, and treatment options is key to helping dogs get the care they need.

What Is Hepatic Encephalopathy in Dogs?

Hepatic encephalopathy is a brain condition that happens when the liver is not working properly. The liver usually filters out ammonia and other toxins from the blood. If it cannot do this, these toxins build up and affect the brain.

The name explains the connection: “hepatic” refers to the liver, and “encephalopathy” means brain problems that result from another health issue.

Hepatic encephalopathy can affect dogs of any age, breed, or sex. It can show up suddenly or develop slowly, depending on the underlying cause.

What Are The Symptoms of Hepatic Encephalopathy in Dogs?

Since hepatic encephalopathy happens when the liver cannot filter toxins well, its signs often mimic other liver disease symptoms. Ammonia buildup affects the brain, so the most obvious symptoms are usually neurological.

Dogs with hepatic encephalopathy might walk in a confused or “drunken” way, look dizzy or unsteady, or even pass out without warning. Seizures are the most obvious sign and are most likely to indicate this condition, since the other symptoms could be caused by different issues.

Liver problems can also cause other signs like low energy, poor appetite, dark urine, eye discharge, brittle nails, stomach upset, weight loss, jaundice, or blood in the stool. If you notice any of these symptoms, especially seizures or confusion, contact your vet right away. Go to an emergency clinic if needed.

What Causes Hepatic Encephalopathy?

Hepatic encephalopathy happens when ammonia and other toxins skip the liver’s filter and reach the brain. This can be due to something a dog is born with or something that develops later.

It’s is a serious neurological condition that develops when the liver can no longer remove toxins from the bloodstream. As these toxins, especially ammonia, build up, they travel to the brain and affect the nervous system, leading to changes in behavior, coordination, and mental function.

The condition is most often seen in dogs with advanced liver disease or a portosystemic shunt, a birth defect or acquired condition that allows blood to bypass the liver instead of being filtered. Because hepatic encephalopathy can become life-threatening if left untreated, early diagnosis and veterinary care are essential.

1. Congenital Portosystemic Shunts

Some dogs are born with a portosystemic shunt, which is an unusual blood vessel that lets blood skip the liver instead of being filtered.

Signs from a shunt like this usually show up in the first year of life.

2. Acquired Causes

A shunt or liver problems can also develop later, sometimes after a bad reaction to medicine or anesthesia. If your dog has had a negative reaction to a drug or toxin, watch for signs of encephalopathy over time.

3. Liver Disease as an Underlying Cause

Hepatic encephalopathy starts with the liver. The liver’s job is to clear ammonia and other toxins from the blood. If it is damaged by a shunt, disease, or long-term problems, it cannot filter well and toxins reach the brain.

Since both problems start with the liver, their signs are very similar.

Many of the symptoms mentioned earlier, like poor appetite, jaundice, behaviour changes, and seizures, can be signs of liver disease as well as hepatic encephalopathy.

How Is Hepatic Encephalopathy Diagnosed in Dogs?

To diagnose hepatic encephalopathy, your veterinarian will start with a complete checkup. They will ask about your dog’s symptoms and medical history, then do a physical exam to look for signs of liver disease and neurological issues.

Blood tests are often the first thing your vet will do. A complete blood count and a biochemistry profile help check your dog’s liver and general health. Dogs with liver problems might have high liver enzymes, more bilirubin, low blood sugar, anemia, or other changes.

If your vet thinks your dog might have a bleeding problem, they may also suggest tests to see how well your dog’s blood clots.

To confirm the diagnosis, your vet might do bile acid tests and check the amount of ammonia in your dog’s blood. The liver usually removes ammonia, so high levels can mean the liver is not working well and point to hepatic encephalopathy.

Sometimes, these tests do not show what is causing the liver disease. In that case, he may suggest more tests like an abdominal ultrasound or X-rays. These can help find liver problems, abnormal blood vessels, tumors, or other issues affecting the liver.

Often, your vet will start treatment as soon as they suspect hepatic encephalopathy, instead of waiting for all the test results. Finding and treating the problem early is important to stop it from getting worse and to help your dog recover.

How Is Hepatic Encephalopathy Treated?

Treatment depends on the cause and how bad the symptoms are, since hepatic encephalopathy can come from a shunt a dog is born with, one that develops later, or general liver problems.

If your pet is experiencing liver disease, it is vital for the vet to instantly know about his condition and unique symptoms he is suffering. She or he might need to alter your dog’s medications or diet as to not interfere with the present diagnosis.

Depending upon how serious the symptoms are, the vet might opt to take a biopsy or blood sample to further assess the scenario and offer a more accurate prognosis and diagnosis.

Dogs that have frequent seizures or pass out often are usually hospitalized first. This lets the vet stabilize them and watch them closely.

Once a dog is stable enough to go home, most are put on a special diet to lower the toxin load on the liver.

For dogs with a portosystemic shunt, surgery can help reduce or even get rid of symptoms, but it is not always a complete cure.

The earlier you have the ability to detect liver disease signs, the better the opportunities of treatment are going to be with the clinical condition. Besides your routinely scheduled vet visits, keep a close eye out for any changes, small or big, in your dog’s behavior and appearance.

How to Prevent Liver Disease in Dogs

Not every case of liver disease can be prevented, especially when genetics or congenital conditions are involved. However, you can take steps to protect your dog’s liver and reduce avoidable risks.

Regular veterinary checkups are important in order to catch changes in liver function before obvious symptoms appear. Make sure your vet knows about every medication and supplement your dog takes, as some substances can affect the liver.

A balanced diet and proper food storage also matter.

Spoiled or moldy food can contain toxins such as aflatoxins, which can cause serious liver damage.

You should also avoid exposing your dog to potentially harmful household cleaners, pesticides, lawn chemicals, and other toxins.

Before changing your dog’s diet, supplements, or medications, speak with your veterinarian. Early detection and appropriate care can make a significant difference when liver problems develop.

Look Out for Your Dog’s Liver Health

Hepatic encephalopathy is serious, but it can often be managed if caught early. Seizures, confusion, and sudden collapse are the main warning signs and mean you should get veterinary help right away.

Since this condition is linked to liver disease, the best way to prevent it long-term is to support your dog’s liver health with a good diet, limit toxin exposure, and keep up with regular checkups.