Hepatic encephalopathy (HE) is a major neurological complication of advanced liver disease that can affect thinking, behavior, consciousness, and everyday functioning. As liver function deteriorates, harmful substances such as ammonia can accumulate in the bloodstream and reach the brain, contributing to cognitive impairment and neurological symptoms.
The condition is expected to remain a substantial health concern in the United States, with an estimated 697,000 adults with cirrhosis projected to experience HE by 2030.
HE is generally divided into three types based on its underlying cause. Type A occurs with acute liver failure, Type B is associated with portosystemic bypass in the absence of significant intrinsic liver disease, and Type C develops in people with cirrhosis. Symptoms can range from subtle cognitive changes, known as covert HE, to severe or overt hepatic encephalopathy (OHE).
People with overt HE may experience confusion, unusual sleepiness, changes in behavior, impaired coordination, and a characteristic hand-flapping movement called asterixis. In severe cases, the condition can progress to unconsciousness or coma. Because no single test definitively establishes HE, diagnosis generally relies on clinical evaluation while excluding other possible causes of neurological symptoms.
A Major Impact on Patients and Families
Hepatic encephalopathy can substantially reduce a person's independence and quality of life. Recurrent episodes may interfere with sleep, relationships, and the ability to work or perform routine activities. Employment among people with HE has been reported at just 13%, compared with 81% in cohorts of patients with liver disease without HE.
The condition can also place a considerable emotional burden on family members and caregivers. As patients may require ongoing supervision and assistance, caregivers can experience significant psychological stress, with studies reporting clinically important anxiety or depression in approximately 28% to 39% of caregivers.
HE also contributes heavily to healthcare utilization. About 43.6% of patients may require rehospitalization within a year, while HE accounts for a substantial proportion of 90-day readmissions among people with cirrhosis. Individual hospital admissions can be extremely costly, contributing to an estimated annual inpatient economic burden of more than $11 billion in the United States.
Why Does Hepatic Encephalopathy Develop?
Several biological processes appear to contribute to HE. When the liver can no longer adequately remove toxins from the blood, ammonia and other potentially harmful compounds can accumulate. Changes in the gut microbiome, oxidative stress, and inflammation in the nervous system may further contribute to brain dysfunction.
Portosystemic shunting can allow these substances to bypass the liver and enter the circulation. Once they reach the brain, ammonia can contribute to swelling and dysfunction of astrocytes, specialized cells that support normal brain activity.
Loss of muscle mass can make the problem worse. Skeletal muscle helps remove ammonia from the circulation, so sarcopenia may reduce the body's ability to compensate for impaired liver detoxification.
Common Triggers Can Push Patients Into Overt HE
A variety of medical problems and lifestyle factors can precipitate an episode or increase the likelihood of recurrence. Important triggers include:
- Infections, which can increase inflammation and metabolic stress.
- Gastrointestinal bleeding, which can increase the amount of nitrogen available for ammonia production.
- Dehydration and electrolyte abnormalities, particularly when associated with excessive diuretic use or gastrointestinal losses.
- Constipation, which may increase intestinal ammonia absorption.
- Poorly controlled diabetes and metabolic disturbances.
- Loss of muscle mass, which reduces ammonia clearance.
- Certain medications, particularly opioids and sedating drugs, which can worsen neurological impairment.
- TIPS procedures, which alter blood flow around the liver and may increase the risk of HE.
- Poor adherence to treatment, often because of unpleasant taste or gastrointestinal side effects.
Treatment adherence is especially important because inconsistent use of preventive therapy can increase the risk of another overt episode.
Treatment Focuses on Preventing Recurrence
Management generally begins with identifying and correcting the trigger responsible for an episode. Infection, bleeding, dehydration, constipation, and electrolyte disturbances should be addressed promptly.
Lactulose remains a cornerstone of HE treatment and prevention. The medication is generally adjusted to produce about two to three soft bowel movements each day. Proper dosing is important because both undertreatment and excessive diarrhea can create problems.
For patients who experience recurrent episodes despite lactulose, rifaximin may be added. A commonly used regimen is 550 mg twice daily. Clinical evidence has shown that adding rifaximin can substantially reduce the risk of recurrent HE and HE-related hospitalization.
Other approaches may be considered in selected circumstances. Polyethylene glycol (PEG) can help promote rapid bowel clearance during certain acute episodes, while L-ornithine L-aspartate (LOLA) may have a role in reducing ammonia levels and preventing recurrence in specific patients.
Nutrition Is Part of Treatment
Older approaches sometimes emphasized restricting dietary protein, but prolonged protein restriction can worsen muscle loss and ultimately reduce the body's ability to clear ammonia.
Current management generally emphasizes adequate calories and protein while maintaining nutritional status. Depending on the individual's condition and medical guidance, patients with cirrhosis may require approximately 35–40 kcal/kg of energy and 1.2–1.5 g/kg of protein daily. Branched-chain amino acids and zinc supplementation may be useful for selected patients with nutritional deficiencies or persistent symptoms.
Regular meals and appropriate nutritional support can also help preserve muscle mass, which is an important part of ammonia metabolism.
Education and Advanced Treatment Options
Patient and caregiver education can play an important role in preventing recurrent episodes. Recognizing early changes in behavior, sleep patterns, concentration, or alertness may allow medical attention before symptoms become severe.
Sleep management and supportive approaches such as mindfulness may also help overall well-being, while medications that cause excessive sedation should generally be avoided or carefully reviewed by the treating clinician.
For patients whose HE remains difficult to control, specialists may investigate structural causes such as large spontaneous portosystemic shunts. In selected cases, embolization of these abnormal vessels or reduction of a TIPS may be considered. For advanced or refractory liver disease, liver transplantation may ultimately provide the most definitive treatment.
Looking Ahead
Hepatic encephalopathy is more than a temporary episode of confusion. It can affect independence, employment, family well-being, and healthcare costs while signaling significant underlying liver dysfunction. Early recognition of triggers, consistent preventive treatment, adequate nutrition, and close follow-up can help reduce recurrent episodes and hospitalizations.
Because HE can rapidly become severe, new confusion, extreme drowsiness, unusual behavior, difficulty staying awake, or loss of consciousness in someone with advanced liver disease should be treated as a medical emergency.
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