Overview

Hepatic encephalopathy (huh-PAT-ik en-sef-uh-LOP-uh-thee) is a serious condition that occurs when the liver is unable to filter toxins from the blood, including ammonia from the intestines. A buildup of toxins affects the brain's ability to function. If left untreated or not treated successfully, hepatic encephalopathy can lead to unresponsiveness, coma or death.

Hepatic encephalopathy may be caused by injury to the liver, cancer or a chronic liver disease that results in liver failure, such as cirrhosis. Hepatic encephalopathy occurs in 30% to 40% of people who have cirrhosis. Alcohol use, infections, use of some medicines and blood clots in the veins also may cause hepatic encephalopathy.

Prompt treatment is needed for hepatic encephalopathy to prevent death. Call 911 or emergency medical help if you think you or a loved one might have hepatic encephalopathy.

Types

There are three types of hepatic encephalopathy:

  • Type A. Type A hepatic encephalopathy results from acute liver failure, which is loss of liver function that happens quickly — in days or weeks.
  • Type B. Type B hepatic encephalopathy happens when blood that should go to the liver through the portosystemic shunt instead goes into the bloodstream. The shunt is an opening between the portal vein and the hepatic vein, which carries blood from the liver to the heart.
  • Type C. Type C hepatic encephalopathy occurs in people who have cirrhosis, which is advanced scarring of the liver. People with acute-on-chronic liver failure, which is rapid decline in people with chronic liver failure, also may have type C.

Acute hepatic encephalopathy comes on suddenly. Chronic hepatic encephalopathy is long-lasting. People who have hepatic encephalopathy may have a wide range of cognitive or mental changes, which range from barely noticeable to coma. When symptoms are noticeable, the condition is called overt hepatic encephalopathy. When symptoms are not noticeable, the condition is called covert encephalopathy.

Symptoms

Common symptoms of hepatic encephalopathy include:

  • Trouble focusing or paying attention.
  • Not knowing where you are.
  • Sleepiness during the day or trouble sleeping at night.
  • Memory loss or confusion.
  • Flapping tremor in the limbs.
  • Personality or mood changes.
  • Slurred speech or movement.
  • Falling into a coma.

Over time, the symptoms of hepatic encephalopathy can lead to a lower quality of life and ability to function. Having other chronic conditions besides hepatic encephalopathy may make daily life even harder.

When to see a doctor

If you or someone with liver disease has sudden confusion, cannot wake up or displays unusual behavior, call your healthcare professional or go to a hospital emergency room right away.

Causes

Hepatic encephalopathy is caused by a buildup of toxins, especially ammonia, when the liver can't filter waste from the blood. This buildup may result from:

  • Alcohol use and conditions that arise from it, such as cirrhosis.
  • Imbalances of electrolytes in the body, such as a low potassium or low sodium level.
  • Infections.
  • Bleeding in the digestive tract.
  • Complications from a liver transplant.
  • Surgery placing shunts in the liver to improve blood flow.

Other factors that may cause hepatic encephalopathy include:

  • Certain medicines, such as diuretics, opioids and sedatives.
  • Dehydration arising from vomiting, diarrhea or other causes.
  • Constipation.
  • Older age.

Risk factors

You're more likely to develop hepatic encephalopathy if you have:

  • Diabetes.
  • Advanced liver disease, such as cirrhosis.
  • Kidney disease.
  • Epilepsy.
  • Low muscle mass, sometimes called sarcopenia.
  • Large portosystemic shunts in your liver.
  • Low sodium or high ammonia levels in your blood.
  • Certain genetic risk factors.

You're also at higher risk of hepatic encephalopathy if you:

  • Are an older adult.
  • Drink alcohol.
  • Have poor eating habits.
  • Take diuretics, proton-pump inhibitors, opioids or benzodiazepine medicines.
  • Have a history of hepatic encephalopathy.

Your healthcare professional may tell you about other risk factors based on your health or lifestyle.

Complications

Some complications from hepatic encephalopathy may be very serious. Common complications include:

  • Trouble with daily life or work.
  • Falls and injuries.
  • Lasting memory and attention problems.
  • Trouble driving a car.
  • Sleep disturbances.
  • Hospitalizations.
  • Coma.
  • Death.

Prevention

It's possible to reduce your chances of getting hepatic encephalopathy by taking care of your health. Some ways to prevent hepatic encephalopathy include:

  • Take prescription medicines as prescribed.
  • Eat protein from plants and dairy.
  • Avoid alcohol and sedating medicines.
  • Avoid opioids.
  • Stay hydrated.
  • Prevent constipation.
  • Treat infections as soon as they appear.
  • Get regular checkups for liver disease.

May 31, 2025
  1. Abraldes JG, et al. Update in the treatment of the complications of cirrhosis. Clinical Gastroenterology and Hepatology. 2023; doi:10.1016/j.cgh.2023.03.019.
  2. Nardelli S, et al. Hepatic encephalopathy — Recent advances in treatment and diagnosis. Expert Review of Gastroenterology & Hepatology. 2023; doi:10.1080/17474124.2023.2183386.
  3. Glasgow Coma Scale. Royal College of Physicians and Surgeons of Glasgow. https://www.glasgowcomascale.org. Accessed May 2, 2025.
  4. European Association for the Study of the Liver. EASL clinical practice guidelines on the management of hepatic encephalopathy. Journal of Hepatology. 2022; doi:10.1016/j.jhep.2022.06.001.
  5. Amin A, et al. Acute-on-chronic liver failure: Definition, prognosis and management. Frontline Gastroenterology. 2020; doi:10.1136/flgastro-2018-101103.
  6. Häussinger D, et al. Hepatic encephalopathy. Nature Reviews Disease Primers. 2022; doi.org/10.1038/s41572-022-00366-6.
  7. Chen A, et al. Pathophysiology of hepatic encephalopathy: A framework for clinicians. Clinics in Liver Disease. 2023; doi:10.1016/j.cld.2024.01.002.
  8. Sahney A, et al. Encephalopathy in cirrhosis: Prevention and management. Journal of Clinical and Experimental Hepatology. 2022; doi:10.1016/j.jceh.2021.12.007.
  9. Medical review (expert opinion). Mayo Clinic. May 4, 2025.

Related

Associated Procedures