Why does hepatic encephalopathy happen in liver cirrhosis?

The liver is responsible for breaking down toxic substances in the blood. One of these toxic substances is ammonia, which is formed by bacteria in the intestine. If a liver is severely damaged, as in cirrhosis, it cannot filter out these harmful substances as it would normally. The toxins then continue to flow through the blood into the brain, where they accumulate. The toxins can impair the ability to think clearly or even move normally. Everyday things like writing or walking may suddenly become difficult. Symptoms of HE can be physical, mental or a combination of both.1

HE may affect as many as one third of liver cirrhosis patients. If everyone was rigorously tested, up to two thirds of patients may have some degree of mild HE.2 Hepatic encephalopathy can be difficult to recognize in the early stages, and can share symptoms with other diseases.3 It is therefore important to identify symptoms early, and to deal with them quickly and effectively, to help prevent them from getting worse.1

HE grades indicate its severity

HE is classified according to the West Haven criteria. Changes in consciousness, mental abilities and behavior are assessed. Depending on their features, they are divided into four main grades of severity:2

Grade 1: shortened attention span, lack of concentration, slowed thinking, increased need for sleep and reduced fine motor skills (e.g. changes in handwriting)

Grade 2: severe fatigue, lethargy, slurred speech and impaired awareness of time, rough trembling of the hands when the arm is stretched out

Grade 3: drowsiness, impaired awareness of time and place, incoherent speech, forgetfulness

Grade 4: coma, loss of tendon reflexes2

If you experience these symptoms, you should consult your doctor to find out the exact cause. If you are diagnosed with HE, you can help prevent the condition from getting worse by starting the appropriate treatment early. The sooner HE is recognized, the more likely treatment will be successful!1

It is worth noting that you may not be allowed to drive while you have HE. While this may be frustrating, it is for your safety and for the safety of others.4

It is important to recognize the symptoms early, and to deal with them effectively.


  1. Canadian Liver Foundation team. Canadian Liver Foundation. Hepatic Encephalopathy. Available at: https://www.liver.ca/patients-caregivers/liver-diseases/hepatic-encephalopathy/. Last accessed: October 2020
  2. Shaker, M and Carey, W. Cleveland Clinic. Hepatic Encephalopathy. Available at: https://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/hepatology/hepatic-encephalopathy/. Last accessed: October 2020
  3. Jones EA, Weissenborn K.Neurology and the liver. Journal of Neurology, Neurosurgery & Psychiatry 1997;63:279-293.
  4. Wein C, Koch H, Popp B, Oehler G, Schauder P. Minimal hepatic encephalopathy impairs fitness to drive. Hepatology. 2004 Mar;39(3):739-45.

May 2021. GL-HEP-XIF-2000184

Other articles you might also be interested in...