(Hepatic Encephalopathy, Portal-systemic Encephalopathy, Hepatic Coma)
Metabolic encephalopathy describes temporary or permanent damage to the brain that happens when the body’s metabolic processes are seriously impaired. Most cases occur when the liver cannot act normally to remove toxins from the bloodstream.
Metabolic encephalopathy occurs during significant metabolic derangements, after some types of poisoning, and during diseases such as cirrhosis or hepatitis that slow or stop liver function.
It can also happen during medical conditions that cause blood circulation to bypass the liver. These problems keep the liver from removing toxins like ammonia, which build up in the blood as part of normal metabolism. High levels of these toxins can temporarily or permanently damage the brain, causing metabolic encephalopathy.
A risk factor is something that increases one’s chance of getting a disease or condition.
- In people who already have liver problems, the risk of metabolic encephalopathy increases by:
- Low oxygen levels in the blood
- Major surgery
- Any serious illness that causes changes in the body’s chemical make-up or metabolism
- Use of certain medicines, such as sedatives and narcotics
- Bleeding within the intestines
- Persistent vomiting or diarrhea that lowers blood potassium levels
- Metabolic encephalopathy also happens to people without liver problems who suffer sudden liver failure due to poisoning, develop severe electrolyte imbalances, or for other reasons.
The symptoms of metabolic encephalopathy include:
- Confusion or agitation
- Changes in behavior and personality
- Muscle stiffness or rigidity
- Tremor (particularly a flapping tremor of the hands)
- Difficulty speaking
- Uncontrollable movements, or, rarely, seizures
- Stupor or coma
These problems can develop quickly, and may all resolve when the metabolic encephalopathy is reversed. However, prompt treatment is required to save a patient that has lapsed into a coma.
Metabolic encephalopathy is a very serious problem that can quickly become a medical emergency. Hospitalization is always required. Doctors will perform a detailed physical examination to assess the patient’s neurologic condition.
Blood tests usually show high blood ammonia levels and other significant abnormalities related to the failing liver and possible causes for the ensuing encephalopathy. An electroencephalogram (EEG; a reading of electrical activity in the brain) may be useful to determine how seriously the brain is affected.
During hospitalization the doctor and hospital staff will work to treat the problems that caused the metabolic encephalopathy, in an effort to remove or neutralize toxins that have built up in the bloodstream. Reversing the underlying problem is necessary to treat the encephalopathy, but it does not guarantee that there will not be residual brain injury if the condition was severe enough or persisted long enough to cause permanent damage.
A low-protein diet is usually prescribed to help lower blood ammonia levels (the body creates ammonia when it metabolizes and uses protein). Special tube feedings may be needed and life support machines may be required, especially in the case of coma.
In cases of metabolic encephalopathy due to chronic liver failure (eg, cirrhosis patients), strong consideration is often given for liver transplantation.
Appropriate early treatment of liver problems may prevent metabolic encephalopathy in some people. If you have longstanding liver problems you should see your healthcare provider immediately if you develop confusion or any type of behavior change.