Introduction
Occasionally one is faced with a situation wherein someone in the family is diagnosed with acute liver failure with no history of any pre-existing liver disease and is advised liver transplant as a life saving measure. Many questions come to mind in such situations:
1) How does a liver fail suddenly?
2) Why is liver transplant advised for acute liver failure?
3) Are there any alternatives to liver transplant?
What is acute liver failure?
Acute liver failure is a condition wherein a patient presents with signs of liver failure and altered sensorium in an acute setting, usually without any history of pre-existing liver disease. The most widely accepted definition of ALF includes evidence of coagulation abnormality, usually an International Normalized Ratio (INR) ≥ 1.5 and any degree of mental alteration (encephalopathy due to increased blood ammonia levels) in a patient without pre-existing liver cirrhosis and with an illness of <26 weeks.
What causes acute liver failure?
Common causes of ALF are paracetamol poisoning, drug induced liver injury (e.g., Anti-tuberculosis treatment), viral hepatitis – commonly Acute hepatitis A, B or E, alcoholic liver disease, Wilson disease, acute autoimmune hepatitis, and others. Some poisons like Ratol (yellow phosphorus) can also cause acute liver failure. Acute ischemia due to shock and acute fatty liver of pregnancy can also lead to ALF. Some other diseases like Dengue and Leptospirosis are also known to cause ALF.
How is ALF managed?
Which patients require liver transplantation?
Etiology (cause) of ALF is a major prognostic factor. Transplant free survival is estimated to be >50% in ALF due to paracetamol poisoning, Acute Hepatitis A, shock liver and pregnancy related disease. Conversely, in ALF due to other causes, only <25% patients survive without a liver transplant. Multiple prognostic models have been devised to predict the likelihood of spontaneous survival without liver transplant. One of the most used models is King’s College criteria. This model is based on acidosis, arterial lactate, grade of hepatic encephalopathy, International Normalized Ratio (INR), serum creatinine level, age, duration of jaundice before encephalopathy, serum bilirubin level and etiology of ALF. These prognostic models do not predict the need for liver transplantation accurately and clinical judgement must be exercised to take a decision on transplant. The window provided to save the life by liver transplant is generally very short. Cerebral edema is a major cause of mortality in early period of ALF. Sepsis is a major cause of death in later period.
Conclusion
A liver can fail acutely due to multiple causes. Acute liver failure is a life-threatening condition. A patient with ALF must be transferred to a unit where liver transplant facility is available. Liver transplant may be required in more than half of the cases of ALF as life saving modality.
