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The liver is critical to maintain body function. Unfortunately, millions of Americans suffer from liver disease. When the liver suffers prolonged damage, scarring can form. This scarring, called cirrhosis, is debilitating and reduces liver function. Cirrhosis is sometimes called end stage liver disease, and is irreversible. On its own, cirrhosis can be painful and cause suffering, but is frequently made worse through complications. One of these is encephalopathy.

Encephalopathy is a broad term used to describe several diseases and disorders. The unifying concept is that these diseases change the brain’s structure or function. When the cause of this change is through cirrhosis, the condition is called hepatic encephalopathy. This is the condition caused by cirrhosis of the liver, and can be horrible. It comes with a high mortality rate, over 25%, and affects over 30% of people with cirrhosis.

The full mechanism of how hepatic encephalopathy works isn’t fully known. The most likely candidate for hepatic encephalopathy is a buildup of ammonia in the bloodstream. Ammonia is a common waste product for many cells. A damaged liver has trouble filtering ammonia from the blood. The ammonia accumulates in the blood where it can travel to the brain and cause confusion and disorientation at first. Additionally, liver damage can result in reduced muscle mass and immunosuppression. Muscles can remove excess ammonia from the blood, but may become damaged without a functional liver and be unable to help. A reduced immune system can lead to a buildup of harmful bacteria that produce excess ammonia. These combine to create excess toxic levels of ammonia in the bloodstream that make their way to the brain.

The brain is normally protected from toxins in the blood through the blood brain barrier. Astrocytes are special cells in the brain that surround blood vessels and help filter the blood, letting only specific nutrients and particles through. Excess ammonia in the blood appears to damage astrocytes, with wide ranging effects on the brain. When the blood-brain barrier is reduced, toxins can enter the brain. This can lead to damage in neurotransmission, meaning the brain cannot function effectively. There is also an increased chance of infection in the brain and alterations to brain metabolism.

This is a devastating compilation which can drastically reduce quality of life. In the early stages of hepatic encephalopathy, people may experience a general slowing of the brain. This is noticeable in attention, some motor response, and other vague areas. As the encephalopathy progresses, people experience more severe symptoms. Changes in personality have been reported, such as irritability and impulsivity. They may angrily buy m&ms in the checkout line. It also slows the brain and reduces its ability to function. People may become disoriented, experience distortions of time and space, become excessively sleepy, and descend into a coma. Clearly this condition needs medical attention!

Luckily, hepatic encephalopathy can be reversible in many patients! The most important short-term treatment is to get rid of excess blood ammonia. The current standard of care is lactulose, a chemical that binds to ammonia and expels it rectally. This helps in the short term, and can also be recommended to help reduce recurrence. Though effective, lactulose is a laxative and can cause bloating, cramping, and other undesirable side effects. Because of this, many patients don’t like using this drug long term. Since the immune system is suppressed with cirrhosis, antibiotics may help as well. In fact, antibiotics may be helpful in preventing hepatic encephalopathy in the first place by eliminating harmful, ammonia producing bacteria before they can produce too much ammonia. Used with or without probiotics and drugs that help restore normal brain chemistry, we may be able to lower the burden of hepatic encephalopathy for those who suffer.

Written by Benton Lowey-Ball, BS Behavioral Neuroscience

Sources:

Bustamante, J., Rimola, A., Ventura, P. J., Navasa, M., Cirera, I., Reggiardo, V., & Rodés, J. (1999). Prognostic significance of hepatic encephalopathy in patients with cirrhosis. Journal of hepatology, 30(5), 890-895. https://doi.org/10.1016/s0168-8278(99)80144-5

Ferenci, P. (2017). Hepatic encephalopathy. Gastroenterology report, 5(2), 138-147. https://doi.org/10.1093/gastro/gox013