AI Summary Hepatic encephalopathy (HE) is a decline in brain function that can happen with advanced liver disease. Doctors diagnose overt HE mainly from your history, mental state, and exam. Ammonia levels, thinking tests, blood tests, and scans add detail, but no single test confirms it. Results help grade severity and find triggers such as infection, bleeding, constipation, or sedating medicines. Treating the trigger often clears an episode, and lactulose is the usual first treatment.
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Hepatic encephalopathy (HE) is a decline in brain function that can happen when advanced liver disease lets toxins build up in the blood. It is also called portosystemic encephalopathy. Evaluation is how your care team finds HE, grades it, and looks for what set it off.
No single test diagnoses HE. Doctors start with your history and a check of your thinking and movement. Ammonia levels, neurocognitive tests, blood tests, and imaging add detail.
This page explains each step, what results can and cannot tell you, and how to prepare for a visit with a liver specialist.
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Overview
Hepatic encephalopathy (HE) is a brain dysfunction caused by the liver's inability to remove toxins from the blood. It can look like brain fog, memory loss, irritability, disorientation, sleep changes, or muscle twitches. Hepatic encephalopathy evaluation is the set of steps doctors use to confirm HE, rate how severe it is, and find what triggered it.
For overt HE, the diagnosis is mainly clinical. That means your doctor relies on your history, your mental state, and a physical exam. EASL guidance says other causes of confusion must be ruled out before HE is confirmed. Lab tests, scans, and thinking tests support that judgment.
Two pages cover the main tests in detail:
HE is treatable and often reversible, especially when it is caught early. If you or someone you know is suddenly and severely confused, get medical help right away.
Tests in This Group
Your doctor chooses the tests that fit your symptoms and liver condition.
This score estimates your risk of HE. It combines a blood ammonia level, liver and kidney blood markers, and a short thinking test. A score under 10 means low risk. A score from 10 to 20 means intermediate risk, and a score over 20 means high risk and needs urgent evaluation. Doctors can repeat it over time to track your risk.
This bedside grading system rates how severe overt HE is, based on your mental state and movement. A flapping hand tremor called asterixis is a hallmark of grade II. Grades III and IV are called brain failure, according to AASLD guidance, and need hospital care.
How the Tests Compare
Doctors combine these steps. No one step tells the whole story.
| Step | What It Checks | What It Can Show | Main Limit |
|---|---|---|---|
| History and exam | Mental state, sleep, movement, and signs such as asterixis | Overt HE and its severity | Cannot find subtle, covert HE |
| Ammonia level | Ammonia in the blood | A normal level makes HE unlikely | A high level alone cannot confirm HE |
| Neurocognitive tests | Attention, speed, and planning | Covert HE, including PHES and EEG | Do not replace the clinical exam |
| Blood tests | Liver function, kidney function, and electrolytes | Clues to triggers and overall liver health | Do not diagnose HE by themselves |
| CT or MRI | The brain and other organs | Other possible causes of confusion | Not a test for HE itself |
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Understanding Your Results
Doctors grade overt HE by how much your thinking and movement are affected. Asterixis is a hallmark of West Haven grade II. Later grades bring severe drowsiness or coma. Our [Hepatic Encephalopathy Scores](/liver-tests/medical-scores/hepatic-encephalopathy-scores) page explains the grading tools.
A normal ammonia level helps rule out HE. A high level does not prove it. Your doctor reads the number together with your symptoms.
If thinking tests show problems but you have no obvious symptoms, that may be covert HE. EASL guidance notes that covert HE predicts overt HE, more hospital stays, and shorter survival. That is why early detection matters.
Most HE episodes have a trigger. Common ones are bacterial infection, bleeding in the digestive tract, constipation, and sedating medicines or diuretics. Treating the trigger often clears the episode.
Next Steps
Preparing helps your team see patterns that a single visit can miss.
Lactulose is the usual first treatment for an overt HE episode, according to AASLD and EASL guidance. Your care team decides on treatment.
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Common Question
Doctors mainly diagnose overt HE from your history, your mental state, and a physical exam. Overt HE means the signs are easy to see, such as confusion, slurred speech, drowsiness, or a flapping hand tremor called asterixis. Your doctor must also rule out other causes of confusion before confirming HE. Blood tests, ammonia levels, CT or MRI scans, and thinking tests add detail, but they support the exam rather than replace it. Brain scans do not diagnose or grade HE. They are often used the first time HE appears, because bleeding in the brain can look the same.
No. A high ammonia level alone cannot confirm HE. Ammonia is one of the toxins linked to HE, and levels are often high in people who have it. But a high number is not specific enough to make the diagnosis without symptoms. A normal level is more useful. EASL guidance says a normal ammonia level makes HE unlikely, and AASLD guidance says a normal level in someone with obvious symptoms calls for a second look at the diagnosis. AASLD also says a high level alone adds no diagnostic, staging, or outlook value in chronic liver disease. Your doctor reads the number together with your symptoms and exam.
Covert HE is a form of HE with subtle changes in attention, thinking speed, and planning. You may feel fine, and family members may notice little. A routine exam cannot find it. Doctors look for it with special tests. Pencil-and-paper tests such as the Psychometric Hepatic Encephalopathy Score (PHES) measure thinking skills. Brain-wave testing called EEG measures brain activity. Finding covert HE matters because, according to EASL guidance, it predicts overt HE, more hospital stays, and shorter survival. Early detection gives your team time to act.
Tell your care team if you notice brain fog, memory loss, irritability, disorientation, apathy or fatigue, sleep changes, or muscle twitches. Slurred speech, problems with movement, and a flapping hand tremor can also occur. A short daily note on your sleep, clarity, and mood can help you and your caregiver spot a slow drift early. HE is often reversible when it is caught early. If you or someone you know is suddenly and severely confused, get medical help right away.
Yes. Most HE episodes have a trigger. According to EASL guidance, common triggers are bacterial infections, bleeding in the digestive tract, constipation, and sedating medicines or diuretics. Finding the trigger is a key part of the evaluation, because treating it often clears the episode. That is why your team may ask about fever, bleeding, bowel habits, and every medicine you take, including sleep aids and pain pills. Call your liver team quickly if you get sick, notice bleeding, or start a new medicine.
Medical disclaimer: LiverDirectory provides educational information and a directory of providers. It does not provide medical advice, diagnosis, or treatment. Always consult a licensed physician regarding any medical condition.
