Hepatic encephalopathy (HE) is a decline in brain function that results from a build-up of toxins in the blood.
The condition occurs when a person's liver cannot remove sufficient toxins from the bloodstream. People with acute liver damage or advanced liver disease are at risk of developing HE.
Keep reading for more information about the symptoms, causes, and treatments of HE.
HE refers to a decline in brain function due to a build-up of toxins in the blood. It is a secondary condition that results from liver damage.
Ordinarily, the liver removes toxins, such as ammonia, from the blood. A liver that is damaged or diseased is less able to remove these toxins, which collect in the bloodstream and travel to other organs.
HE develops when toxins enter the brain and damage brain cells. This can cause physical and psychological symptoms.
People with HE experience at least some decline in brain function. In severe cases, a person may lose consciousness and go into a coma.
The symptoms of HE differ, depending on the cause of the liver damage and the severity of HE.
People with mild-to-moderate HE may experience:
- difficulty with small hand movements, which may affect handwriting, for example
- sweet- or musty-smelling breath
- difficulty thinking and concentrating
- poor judgment
- changes in personality
People with severe HE may experience additional symptoms, such as:
- extreme sleepiness
- slowed movements
- severe anxiety
- more significant personality changes
- confused or slurred speech
- an inability to perform mental tasks
- shaking of the hands or arms
A person who experiences any symptoms of severe HE should receive emergency medical attention.
There are three types of HE, and each progress in the same five stages.
Types of HE
Doctors have identified the following three types of HE:
Type A HE results from acute liver failure (ALF), which occurs when someone with no preexisting liver disease experiences a rapid decline in liver function. This decline usually takes place over days or weeks.
The most common cause of ALF is acetaminophen overdose. Some other causes include:
- excessive alcohol consumption
- hepatitis infection
- Wilson's disease, a hereditary condition that involves an accumulation of copper in the body
Type B HE results from a portal-systemic bypass. This involves blood flowing around the liver when it would ordinarily flow to the liver. The redirection prevents the liver from effectively filtering toxins from the blood.
Two potential causes are congenital abnormality and trauma.
Type C HE results from severe scarring — cirrhosis — of the liver. Cirrhosis develops during late stage liver disease.
Over time, as scar tissue increasingly replaces healthy tissue, the liver is less able to remove toxins from the blood and perform its other functions.
According to the American Liver Foundation, the most common causes of cirrhosis are:
Stages of HE
According to the American Liver Foundation, there are five stages of HE. The severity of a person's symptoms determines the stage of HE.
The five stages are:
- Stage 0: minimal symptoms, which may involve coordination and concentration
- Stage 1: mild symptoms, such as loss of sleep and shortened attention span
- Stage 2: moderate symptoms, such as memory loss and slurred speech
- Stage 3: severe symptoms, including personality changes, confusion, and extreme lethargy
- Stage 4: a loss of consciousness and coma
Below are some causes of liver damage that can result in HE:
- electrolyte imbalances
- consuming too much protein
- prescription medications
- herbal supplements
- liver infection
- kidney problems
The following tips can help people protect their livers from disease and infection, thereby helping reduce the risk of developing HE:
- avoiding excessive alcohol consumption
- avoiding high fat foods
- maintaining a healthy weight
- washing the hands effectively and consistently after using the bathroom
- refraining from sharing needles
- getting vaccinated against hepatitis A and hepatitis B
The diagnostic procedure for HE begins with a physical examination and a discussion of the person's symptoms and medical history. In some cases, a doctor may be able to diagnose HE using these methods alone.
In other cases, a doctor may order one or more tests to help determine whether a person's symptoms are the result of HE. Examples of such tests include:
- Blood tests: These can help identify conditions associated with HE, including infection, bleeding, and liver or kidney dysfunction. They can also identify an increase of toxins in the blood.
- Imaging tests: An MRI or CT scan of the brain can help a doctor identify abnormalities.
- Electroencephalogram: Also known as an EEG, this test measures electrical activity in the brain to identify changes associated with HE.
The best treatment for HE will depend on the following factors:
- the severity of HE
- the types of symptoms
- the severity of the underlying liver damage
- the person's age
- their overall health
Some treatments will target the underlying cause of HE. Depending on the cause, these treatments may involve:
- medications to treat infection
- medicines or procedures to control bleeding
- stopping the use of medication that could be triggering HE
- treating any underlying kidney problems
The doctor may also prescribe medication to help reduce levels of ammonia and other toxins in the blood. Because these toxins are often produced in the intestines, this type of treatment targets the gut.
For example, the doctor may prescribe lactulose, a synthetic sugar, to speed up digestion and prevent the intestines from absorbing toxins. Lactulose also reduces the amount of ammonia-producing bacteria in the intestines.
In terms of other treatments, people who experience breathing difficulty as a result of HE may require oxygen or a ventilator.
When severe liver damage or disease has caused severe HE, a person may require a liver transplant.
A person with HE has the best chance of recovery if they and their doctor identify the symptoms quickly and begin treatment as soon as possible. This will entail treating HE and its underlying cause.
Appropriate treatment can often reverse HE. However, people with chronic liver disease or cirrhosis may experience recurring episodes of HE symptoms.
The best way to prevent these episodes is to manage the condition with treatment.