Hepatic encephalopathy (HE)

What is HE?

HE is a complication of decompensated cirrhosis

Up to 8 in 10 people with cirrhosis will have some symptoms of HE at some point. Around half of these will develop serious HE. It can happen as a sudden emergency or start with very small changes. Often it is a family member or friend who will spot the first signs of HE. It can often be mistaken for dementia or depression.

Make sure that you and those closest to you know what to look out for and what to do if HE becomes an emergency.  

 HE happens when your liver is no longer able to remove toxins from your blood. This causes the toxins to build up and then get into your brain.

HE causes problems with short term memory and in some cases alters your personality. In some people HE can be very serious. If you have been diagnosed with HE it will not be safe for you to drive

HE can get better and worse and can be quite unpredictable. But there are treatments that can help.

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What causes HE?

One of your liver’s main jobs is to help remove harmful toxins from the body. But it cannot do this properly when it is very damaged.

During the normal digestion process, toxins such as ammonia are produced. Your blood carries these toxins from your gut to your liver.

If your liver is healthy, it can change the toxins into a safer form. Your kidneys can filter the toxins out of your body when you pee.

If you have severe (decompensated) cirrhosis, this process doesn’t work properly. Instead the toxins build up in your blood. Eventually they start to get into your brain. This can:

• cause brain cells to swell and push on other parts of your brain
• stop the signals between your brain cells working properly

These changes in your brain can affect your mental and physical health.

HE episodes and triggers

HE can come and go in “episodes”. These episodes can be triggered by things like:

• losing too much water (dehydration) for example due to diarrhoea
• not being able to poo enough (constipation)
• infections
• certain medicines including diuretics and some pain killers and sleeping medicines
• bleeding in the bowel, stomach or gullet (oesophagus) also known as varices
• kidney problems
• surgery

HE usually stops if it is treated and the trigger is taken away. But a new episode can be triggered in the future. Some people with advanced liver disease have episodes of HE that keep coming back.

It is a good idea to be aware of the triggers. And speak to your clinical team if you think you are likely to be affected by any of them.

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Symptoms

There are lots of possible symptoms of HE. You may have just a few or lots all at once. The symptoms can be physical, mental or a combination of the two. Over time you might notice different symptoms.

To begin with, the symptoms of HE can be quite subtle and easy to miss. You may find that other people notice your symptoms before you do.

Mild or moderate HE symptoms

What to look out for:

• changes to when you sleep for example staying awake at night and sleeping in the day
• not being able to concentrate on things like watching a favourite TV programme
• feeling confused or forgetful
• changes in your personality or behaviour, mood changes, or poor judgment
• difficulty making small hand movements such as handwriting
• sweet smelling or stale breath

What to do:

Get in touch with your medical team straight away if you or those close to you notice these symptoms. Do not drive yourself to any appointments  as this might not be safe.

More severe HE symptoms

Over time, the symptoms will happen in more defined episodes. These episodes can be mild at the start and get worse bit by bit, or they can happen suddenly, as an emergency.

What to look out for:

• feeling very confused or not knowing where you are
• obvious personality changes, including inappropriate behaviour
• tiredness or sleepiness
• anxiety or worry
• slurred speech
• poor coordination, being more clumsy than usual
• shaking or flapping movements with your hands
• moving slowly
• seizures

What to do:

Go to a hospital emergency department. Do not drive yourself there. Tell them you have or may have HE and ask them to let your liver medical team know.

Very severe HE symptoms

What to look out for:

• very odd and unusual behaviour
• generally not responding to people or surroundings
• finding it hard to remain conscious
• feeling extremely confused and not knowing where you are
• eventually, going into a coma

What to do:

Call 999 or go to a hospital emergency department straight away. Do not drive yourself there. Tell them you have or may have HE and ask them to let your liver medical team know.

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Diagnosis

Your doctor should ask you about your liver condition and your symptoms. They should do tests to check for HE and to rule out anything else that could be causing your symptoms.

If your HE symptoms are quite mild doctors will do simple tests to check on:

• memory
• reaction time
• problem solving
• coordination

There are several different ways to do this.

• The Trail test is a bit like a join the dots puzzle. You will be given a pencil and a sheet of paper with numbers on it, then asked to connect the numbers in order.
• For the animal naming test you will be asked to name as many animals as you can in 1 minute.
• The critical Flicker test or CFF measures your reaction to a flickering light that you view in a special eye mask.

Brain scans

You might also have a scan, usually a CT or MRI scan. These look for changes in your brain.

An EEG test (electroencephalography) might be used to look at brain activity.

If you have symptoms of severe HE you should be seen by a specialist. They will do a physical examination. This will focus on physical symptoms like flapping hands or poor coordination.

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Treatment

Treatment for HE will depend on:

• Your symptoms
• How severe your HE is
• What might have triggered the episode

Emergency treatment

If you are very unwell, the first step will be emergency treatment to deal with the possible trigger. For example:

• Stopping the bleeding from varices
• Treating an infection
• Treating kidney failure
• Getting levels of salt and minerals in the blood back to normal
• Life support if you are in a coma

Making sure people know you have HE in an emergency

Carry an alert card or medical bracelet to make sure that doctors will know about your HE in an emergency. Some smart phones also have an ICE (In Case of Emergency) app where you can put this information.

You could also give a copy of the card to a family member or carer so that they can give it to the medical team if you are not able to.

You can use our patient passport to keep a record of your condition and your medicines. You can show it to healthcare workers so they can quickly understand your needs.

Download the patient passport here

Or email: publications@britishlivertrust.org.uk and we will post you a copy

Not all hospitals are used to looking after people with HE. You could keep a copy of our HE factsheet handy to give your emergency medical team. Or show them this webpage on your phone.

Stopping another HE episode

Each episode of HE can add damage to your brain. So it is important to try and reduce the number of episodes you have.

To do this, doctors will use medicine to try to improve the health of your gut.

Your gut contains lots of bacteria that help you to digest your food. Some of these produce toxins like ammonia. Normally, some of these toxin producing bacteria come out in your poo and your liver helps to get rid of the toxins. But if you have cirrhosis this does not work properly. So you need medicine to help.

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Living with HE

Diet

If you have cirrhosis it is important that you eat well and get enough of the energy and nutrients that you need.

What you eat could also have an impact on HE.

The best diet for you will depend on a lot of different things. Ask your liver team to refer you to a registered NHS dietician. They will be able to help you work out what to eat and when.

In the past, people with HE were advised to have a low protein diet. It is now known that this is wrong.  People with HE should follow a high protein diet. Protein is mostly found in foods such as beans and pulses, dairy foods, fish, poultry, and meat, as well as some vegetarian meat alternatives such as tofu and Quorn.

There is some evidence that fermented milk products containing “friendly” bacteria might also be helpful. These include live yogurt and kefir.

You can also find out more about diet and cirrhosis here.

 Driving

If you have been diagnosed with HE, do not drive. You must also tell the DVLA. You can find out more about this on the gov.uk website here.

Research has shown that people with HE have reduced driving ability. They also tend to think that they can drive better than they actually can.

It is recommended that you do not drive for 3 months after an HE episode.

Even if your condition has improved, you should not drive if there are any concerns about:

• Memory
• Judgment
• Attention
• Reaction time
• Disorientation

Not being able to drive for yourself can be difficult. But driving when you have HE can put you and those around you at serious risk. If you are unsure if you should be driving, talk to your medical team.

You can find out about benefits here. Including benefits related to mobility and transport.

  Financial and legal considerations

HE can affect your memory and how clearly you can think. If it becomes very severe it could make it hard for you to make important decisions. It could also mean you are more at risk from things like financial scams.

It is a good idea to talk to those closest to you about these possibilities before they happen. You can make sure that someone you trust understands what you want. And can make decisions for you if that becomes necessary.

You could share our Information for family, friends and carers with them. This includes information on:

• Keeping money safe
• Lasting power of attorney for health and care and for property and financial affairs

 Support

If HE becomes more severe, you may need support from a caregiver. This could be somebody you know or a healthcare professional.

You may need a lot of emotional support too. From family, friends or other people going through the same experience. Ask your doctor about local groups you could join or places to get specialist support and advice.

The British Liver Trust also offers a variety of support. Including our nurse led helpline, online forum, and support groups.

Find out more about how we can support you here.

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Find out about other cirrhosis complications

Special thanks

We would like to thank all of the medical specialists, and people with personal experience of cirrhosis who helped us to plan, develop, and review this information.

Including members of our patient advisory group, Jennifer Voller, Michael Kennedy, Dr Victoria Kronsten, Senior Clinical Research Fellow in Hepatology, King’s College Hospital, Katharine Caddick, Consultant Nurse, North Bristol Trust.

Published: February 2025