Hepatic encephalopathy – Diagnostics – Overview of Information and Clinical Research

Diagnosing hepatic encephalopathy involves recognizing the signs of brain dysfunction in people with liver disease, ruling out other causes of confusion or altered behavior, and identifying what might have triggered the symptoms. Because there is no single test that confirms the condition, doctors rely on a combination of clinical observation, blood work, imaging studies, and specialized tests to understand what is happening and how to help.

Introduction: Who Should Undergo Diagnostics

If you have liver disease, especially advanced scarring known as cirrhosis, you should be aware of the possibility of developing hepatic encephalopathy. This condition occurs when the liver can no longer filter toxins from the blood effectively, allowing harmful substances to reach the brain and affect how it works. Up to 8 out of 10 people with cirrhosis will experience some symptoms of hepatic encephalopathy at some point in their lives, making it one of the most common complications of advanced liver disease.^[5]

It is important to seek diagnostic evaluation as soon as you or someone close to you notices changes in behavior, mood, thinking, or coordination. Often, it is a family member or friend who first recognizes the signs, especially in the early stages when symptoms can be subtle. You might notice forgetfulness, mood swings, difficulty concentrating, or changes in sleep patterns. These early signs can easily be mistaken for other conditions such as dementia or depression, which is why proper diagnosis is crucial.^[5]

Anyone with cirrhosis should remain alert to the possibility of hepatic encephalopathy, particularly after certain events. For example, if you have an infection, gastrointestinal bleeding, dehydration, or if you have undergone a procedure like TIPS (transjugular intrahepatic portosystemic shunt), you are at higher risk. These situations can trigger episodes of brain dysfunction, and recognizing them early allows for faster treatment and better outcomes.^[8]

If you are experiencing more obvious symptoms such as severe confusion, disorientation, slurred speech, or difficulty staying awake, this is a medical emergency. Grade 3 symptoms, which include drowsiness, severe confusion, inability to recognize where you are, or involuntary shaking movements, require urgent medical attention. Without prompt treatment, hepatic encephalopathy can progress to coma or even death.^[1]

⚠️ Important

Hepatic encephalopathy often appears with very mild changes at first, and these can go unnoticed by the person experiencing them. Family members and caregivers play a critical role in recognizing early signs such as personality changes, forgetfulness, or inappropriate behavior. If you care for someone with liver disease, stay alert to these changes and encourage them to see a doctor promptly.

Diagnostic Methods

Diagnosing hepatic encephalopathy is not straightforward because there is no single test that can confirm it. Instead, doctors use a process of clinical evaluation, which means they look at your medical history, observe your symptoms, and rule out other possible causes of confusion or altered mental state. This approach is called a diagnosis of exclusion, meaning doctors first eliminate other conditions that might explain your symptoms before confirming hepatic encephalopathy.^[3]

Medical History and Clinical Observation

The first step in diagnosis is a detailed review of your medical history. Your doctor will ask about your liver disease, any previous episodes of confusion or behavioral changes, recent infections, hospitalizations, and medications you are taking. They will also want to know if you have had gastrointestinal bleeding, recent changes in fluid balance, or if you have been taking your prescribed medications regularly, especially lactulose or rifaximin, which are commonly used to prevent hepatic encephalopathy.^[11]

Next, the doctor will perform a physical examination to assess your mental state, speech, coordination, and muscle tone. They may look for signs such as asterixis, which is a flapping tremor of the hands that occurs when you hold your arms outstretched with wrists bent back. Asterixis is a common sign of hepatic encephalopathy but can also occur in other conditions like kidney failure or severe respiratory problems.^[8]

Your doctor will also grade the severity of your symptoms using a scale called the West Haven Criteria. This scale ranges from Grade 0, where symptoms are barely noticeable and only detected by special tests, to Grade 4, which represents coma. Understanding the grade helps guide treatment decisions and gives a sense of how urgent the situation is.^[1]

Psychological and Neuropsychological Tests

When symptoms are mild or not easily noticeable, doctors may use psychological or neuropsychological tests to detect subtle changes in thinking, memory, or motor skills. These tests help identify what is sometimes called minimal hepatic encephalopathy or covert hepatic encephalopathy, which affects daily function but may not be obvious to others.^[11]

One simple test involves asking you to name as many animals as you can within a short period of time. Another test, called the Psychometric Hepatic Encephalopathy Score, uses pencil-and-paper tasks to assess thinking skills, motor coordination, speed, and hand-eye coordination. There are also tests that measure your reaction time to sounds, such as the continuous reaction time test. These assessments help doctors understand how much your cognitive function has been affected.^[11]

Blood Tests

Blood tests are an essential part of diagnosing hepatic encephalopathy, not because they confirm the condition directly, but because they help rule out other causes and identify triggers. Your doctor will order blood tests to check for ammonia levels, electrolytes like sodium and potassium, glucose levels, and markers of infection such as C-reactive protein. These tests help ensure that your symptoms are not caused by conditions like diabetes, stroke, or severe infection.^[11]

Ammonia is a toxin that builds up in the blood when the liver is not working properly, and it is strongly linked to hepatic encephalopathy. However, ammonia levels alone are not enough to diagnose the condition because they do not always match the severity of symptoms. Some people with high ammonia levels have no symptoms, while others with normal or only slightly elevated levels may have significant brain dysfunction.^[8]

Blood tests also help identify potential triggers such as infections, kidney problems, or dehydration, all of which can worsen hepatic encephalopathy. For example, if you have an infection, your doctor may start antibiotics even before culture results are available because infections are the most common cause of hepatic encephalopathy episodes.^[8]

Imaging Studies

Imaging tests such as CT scans or MRI scans are often used to rule out other causes of confusion or altered consciousness, such as stroke, bleeding in the brain, seizures, or tumors. A CT scan or MRI of the brain can also show whether there are structural changes related to chronic liver disease. In some cases, scans of the abdomen may reveal problems with blood flow to the liver or other complications of cirrhosis.^[11]

MRI scans can sometimes show deposits of manganese in a part of the brain called the globus pallidus. Manganese is another toxin that can accumulate when the liver is not working properly, and its presence in the brain is associated with some of the structural changes seen in hepatic encephalopathy.^[9]

Electroencephalogram (EEG)

An electroencephalogram, or EEG, measures the electrical activity in your brain. This test can help healthcare professionals understand the severity of hepatic encephalopathy and distinguish it from other causes of altered mental state. In hepatic encephalopathy, the EEG typically shows slowing of brain waves, which reflects the overall dysfunction of the brain. This is a supportive finding but not specific to hepatic encephalopathy alone.^[11]

Additional Tests to Identify Triggers

Because hepatic encephalopathy is often triggered by other medical problems, doctors will perform additional tests to find and treat these triggers. For example, if you have fluid in your abdomen, known as ascites, your doctor may perform a procedure called diagnostic paracentesis to check for infection called spontaneous bacterial peritonitis. This is a common and serious infection in people with cirrhosis and can trigger hepatic encephalopathy.^[8]

Your doctor will also evaluate you for other infections such as pneumonia, urinary tract infection, or gastroenteritis. A chest X-ray, urinalysis, and sometimes blood cultures are part of this evaluation. If bleeding in the gastrointestinal tract is suspected, procedures like endoscopy may be needed to identify and treat the source of bleeding.^[8]

Dehydration is another important trigger, often related to overuse of diuretics or large-volume fluid removal during paracentesis. Blood tests to check kidney function and electrolyte balance help identify dehydration and guide treatment.^[8]

⚠️ Important

Hepatic encephalopathy is a diagnosis of exclusion, meaning other causes of confusion or altered behavior must be ruled out first. Conditions like infections, strokes, brain bleeding, medication side effects, and metabolic imbalances can all mimic hepatic encephalopathy. A thorough evaluation is essential to ensure the correct diagnosis and treatment.

Diagnostics for Clinical Trial Qualification

When people with hepatic encephalopathy are considered for participation in clinical trials, specific diagnostic tests and criteria are used to ensure that participants meet the requirements for the study. These criteria help researchers select the right patients and ensure that the results of the trial are reliable and meaningful.

Clinical trials typically require a confirmed diagnosis of hepatic encephalopathy based on clinical evaluation using the West Haven Criteria. Participants are often required to be at a specific grade or stage of the condition, such as having experienced at least one episode of overt hepatic encephalopathy, which means obvious symptoms that others can recognize.^[3]

Blood tests are commonly used to confirm liver dysfunction and measure markers such as liver function tests, ammonia levels, and kidney function. These tests help ensure that participants have the underlying liver disease that causes hepatic encephalopathy and rule out other conditions that might affect the trial results.

Neuropsychological tests may be required to assess the degree of cognitive impairment and establish a baseline level of function before the trial begins. This allows researchers to measure whether the treatment being tested improves cognitive function over time. Tests such as the Psychometric Hepatic Encephalopathy Score or reaction time tests are commonly used for this purpose.^[11]

Imaging studies such as CT or MRI scans may be required to rule out other causes of brain dysfunction and to assess the overall condition of the liver and blood vessels. For example, some trials may exclude participants who have large portosystemic shunts or other complications that could interfere with the treatment being studied.

Participants may also need to undergo tests to identify and document any triggers of their hepatic encephalopathy, such as infections or gastrointestinal bleeding. This helps researchers understand the context of each person’s condition and ensures that the trial includes patients with similar characteristics.

In addition to diagnostic tests, clinical trials often have specific inclusion and exclusion criteria related to the severity of liver disease, the presence of other medical conditions, and the use of certain medications. For example, participants may need to have a certain level of liver function, measured by scores like the Child-Pugh score or MELD score, to be eligible. They may also need to be taking standard medications such as lactulose or rifaximin, or they may be required to stop certain medications before the trial begins.

Overall, the diagnostic process for clinical trial qualification is more rigorous and standardized than routine clinical diagnosis, ensuring that the trial results are accurate and applicable to the broader population of people with hepatic encephalopathy.

Prognosis and Survival Rate

Prognosis

The outlook for people with hepatic encephalopathy depends on several factors, including the severity of liver disease, the frequency and severity of encephalopathy episodes, and how well triggers are managed. Hepatic encephalopathy is a serious complication of cirrhosis, and its development signals that liver function has declined significantly. The condition can improve with treatment, but it often recurs, especially if the underlying liver disease continues to worsen or if triggers are not well controlled.

People with overt hepatic encephalopathy, meaning symptoms that are obvious and noticeable to others, generally have a worse prognosis than those with minimal or covert symptoms. Once overt hepatic encephalopathy develops, it marks a critical point in the natural history of cirrhosis. Up to 40 percent of people with cirrhosis will develop overt hepatic encephalopathy during their lifetime, and the condition is associated with increased use of healthcare resources, frequent hospital readmissions, and a higher burden on patients and caregivers.^[8]

The ability to manage and prevent recurrent episodes depends on identifying and treating triggers such as infections, gastrointestinal bleeding, dehydration, and medication non-adherence. People who experience frequent or severe episodes may have refractory hepatic encephalopathy, which is difficult to control even with standard treatments. In such cases, liver transplantation may be considered as a definitive treatment option.

Survival Rate

The survival rate for people with hepatic encephalopathy is significantly lower than for those with cirrhosis who do not develop this complication. The occurrence of an episode of encephalopathy severe enough to require hospitalization is associated with a survival probability of about 42 percent at one year and 23 percent at three years.^[7]

Approximately 30 percent of patients dying of end-stage liver disease experience significant encephalopathy, with some progressing to coma. The median survival after the first diagnosis of overt hepatic encephalopathy is around two years, highlighting the serious nature of this condition.^[8]

Liver transplantation can significantly improve survival and quality of life for people with hepatic encephalopathy who are otherwise suitable candidates. After successful transplantation, most patients experience resolution of encephalopathy symptoms and a return to normal cognitive function, assuming there has been no permanent brain damage.

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