I. Definition and etiology of liver failure
(A) Definition
Liver failure is a group of clinical syndromes caused by severe liver damage caused by various factors, resulting in serious impairment or loss of compensation of its synthesis, detoxification, excretion and biotransformation functions, with the main manifestations of impaired coagulation mechanism and jaundice, hepatic encephalopathy and ascites.
(B) Etiology
The main cause of liver failure in China is hepatitis virus (mainly hepatitis B virus), followed by drugs and hepatotoxic substances (such as alcohol, chemical agents, etc.). In Europe and the United States, drugs are the main cause of acute and subacute liver failure; alcoholic liver damage often leads to chronic liver failure, and liver failure in children can also be seen in genetic metabolic diseases.
Second, the diagnosis and staging of liver failure
1. Clinical diagnosis
The clinical diagnosis of liver failure needs to be determined based on a comprehensive analysis of medical history, clinical manifestations and auxiliary examinations.
(1) Acute liver failure
Acute onset, hepatic encephalopathy of degree II or higher (classified according to degree IV classification) within 2 weeks with the following manifestations.
(1) Extreme weakness with severe gastrointestinal symptoms such as marked anorexia, abdominal distension, nausea and vomiting.
(2) Progressive deepening of jaundice over a short period of time.
(3) Significant bleeding tendency with INR ≥ 1.5 (or PTA ≤ 40%), and other causes are excluded.
(4) Progressive shrinkage of the liver.
(2) Subacute liver failure
Those with a more acute onset and the following manifestations between 15 and 26 weeks.
(1) extreme malaise with marked gastrointestinal symptoms
(2) Rapidly deepening jaundice, total serum bilirubin greater than 10 times the upper limit of normal or rising ≥ 17.1 μmol/L daily, or hepatic encephalopathy.
(3) Significantly prolonged prothrombin time, INR ≥ 1.5 (or PTA ≤ 40%) and exclusion of other causes.
(3) Slow plus acute (subacute) liver failure
On the basis of chronic liver disease, the clinical syndrome of acute liver failure occurs within a short period of time, manifested as
(1) extreme weakness with marked gastrointestinal symptoms.
(2) Rapid deepening of jaundice with total serum bilirubin greater than 10 times the upper limit of normal or a daily rise of ≥ 17.1 μmol/L.
(3) bleeding tendency with markedly prolonged prothrombin time, (INR ≥ 1.5 prothrombin activity ≤ 40% ) (or)
(4) Progressive shrinkage of the liver.
(5) Hepatic encephalopathy.
(4) Chronic liver failure
Progressive decompensation and loss of liver function on the basis of cirrhosis. It is manifested by.
(1) With ascites or other manifestations of portal hypertension.
(2) May have hepatic encephalopathy.
(3) Elevated total serum bilirubin and markedly decreased albumin.
(4) coagulation dysfunction, INR ≥ 1.5 (or PTA ≤ 40%).
2.Histopathological manifestations
Histopathological examination is of great value in the diagnosis, classification and prognosis determination of liver failure, but due to the severely reduced coagulation function of patients with liver failure, performing liver puncture has certain risks, which should be paid special attention in clinical work.
In liver failure (except for chronic liver failure), extensive hepatocellular necrosis can be observed on liver histology, with the site and extent of necrosis varying depending on the etiology and course of the disease. According to the extent of necrosis, it can be classified as massive necrosis (necrosis exceeding 2/3 of the liver parenchyma), submassive necrosis (approximately 1/2 to 2/3 of the liver parenchyma), fusion necrosis (necrosis of adjacent patches of hepatocytes) and bridging necrosis (more extensive fusion necrosis with destruction of liver parenchyma). In the liver tissue of different stages of liver failure, one-time or multiple lesions of old and new hepatocyte necrosis can be observed. Currently, there is no consensus on the association of the etiology, classification and staging of liver failure with hepatic histological changes. Since liver failure due to hepatitis B virus infection is the most common in China, this guideline introduces the typical pathological manifestations of various types of liver failure, taking hepatitis B virus infection-induced liver failure as an example.
(1) Acute liver failure
The hepatocytes are necrotic at once, with necrosis covering ≥2/3 of the liver parenchyma; or submassive necrosis, or bridging necrosis, with severe degeneration of surviving hepatocytes and non-collapse or incomplete collapse of the reticular scaffold of the liver sinusoids.
(2) Subacute liver failure
The hepatic tissue shows sub-massive necrosis or bridging necrosis of varying age; collapse of the reticular fibers in the older necrotic areas or collagen fiber deposition; regeneration of residual hepatocytes of varying degrees, and hyperplasia of fine and small bile ducts and cholestasis are seen.
(3) Slow plus acute (subacute) liver failure
On the basis of the pathological damage of chronic liver disease, new necrotic lesions of hepatocytes of varying degrees occur.
(4) Chronic liver failure
Mainly diffuse liver fibrosis and abnormal nodule formation, which may be accompanied by unevenly distributed hepatocellular necrosis.
(iii) Staging
According to the severity of clinical manifestations, subacute liver failure and slow plus acute (subacute) liver failure can be divided into early, intermediate and late stages.
1.Early stage
(1) Extreme weakness with severe gastrointestinal symptoms such as obvious anorexia, vomiting and abdominal distention.
(2) Progressive deepening of jaundice (total serum bilirubin ≥ 171 μmol/L or a daily rise of ≥ 17.1 μmol/L).
(3) Bleeding tendency with 1.5 < INR ≤ 2.0.
(4) No hepatic encephalopathy or significant ascites.
2.Intermediate stage
On the basis of the early manifestations of liver failure, the disease further progresses and one of the following two items appears.
(1) The appearance of hepatic encephalopathy below grade II and/or significant ascites.
(2) Significant bleeding tendency (bleeding spots or petechiae), 2 < INR ≤ 2.5.
3. Advanced stage
On the basis of mid-stage manifestations of liver failure, the condition is further aggravated with severe bleeding tendency (petechiae at the injection site, etc.), INR ≥ 2.5, and one of the following four items: hepatorenal syndrome, upper gastrointestinal hemorrhage, severe infection, hepatic encephalopathy of degree II or higher.