Liver Failure - acute / chronic - causes, symptoms and treatment

Liver Failure - acute / chronic - causes, symptoms and treatment

Liver Failure - the inability of the LIVER to function. Liver failure may be acute (comes on suddenly) or chronic (develops over time). Because the liver has the unique ability to regenerate, the damage it takes to cause liver failure is substantial. Liver failure generally occurs when more than 75 percent of the liver’s hepatocytes, the cells that carry out most of the liver’s functions, die, a circumstance called hepatocellular necrosis. LIVER TRANSPLANTATION is the only curative treatment for permanent liver failure.

Causes of Liver Failure

The most common causes of hepatocellular necrosis leading to liver failure are

  • ALCOHOL
  • acetaminophen and especially acetaminophen OVERDOSE
  • Amanita mushroom ingestion
  • the illicit DRUG ecstasy (MDMA)
  • isoniazid and rifampin in combination to treat TUBERCULOSIS
  • industrial chemicals such as arsenic, phosphorus, carbon tetrachloride, and vinyl chloride
  • disease processes

Hepatocellular necrosis is a SIDE EFFECT possible with numerous prescription medications, notably certain ANTIBIOTIC MEDICATIONS, “statin” lipid-lowering medications, and tricyclic ANTIDEPRESSANT MEDICATIONS. In some circumstances prompt medical intervention, such as with known overdose of drugs, can slow or halt hepatocellular necrosis and prevent liver failure, though liver damage may still occur. Such interventions might include aggressive medical efforts to remove or neutralize the responsible drug, administration of acetylcysteine for acetaminophen overdose, and liver hemodialysis (though this is of limited availability). In many circumstances, however, the destructive action of the toxin or the inflammatory process overwhelms the liver and attempted medical interventions have little effect.

Conditions that can Cause Liver Failure
BILIARY ATRESIA chronic HEPATITIS
CIRRHOSIS HEAT STROKE
HEMATOCHROMATOSIS HEMORRHAGIC FEVER
LIVER CANCER LIVER DISEASE OF ALCOHOLISM
PORTAL HYPERTENSION PRIMARY BILIARY CIRRHOSIS
PRIMARY SCLEROSING CHOLANGITIS REYE’S SYNDROME
secondary AMYLOIDOSIS WILSON’S DISEASE

Acute liver failure

Acute liver failure, also called fulminant HEPATITIS, develops in days to weeks. It nearly always follows a significant assault to the liver, such as drug overdose or severe trauma (such as gunshot wound) that destroys liver tissue. Hepatitis A INFECTION also can cause acute liver failure. Recovery without liver transplantation is uncommon and is most likely to occur with hepatitis A infection (about 50 percent recovery rate) and promptly treated acetaminophen toxicity.

 

Chronic liver failure

Chronic liver failure, also called nonfulminant hepatitis, develops over months. Repeated attacks of INFLAMMATION progressively kill hepatocytes until the level of hepatocytic function falls below 25 percent. In many situations a culminating event, such as a flare of hepatitis or an episode of acute alcohol INTOXICATION, pushes the liver across the boundary. CIRRHOSIS is the leading cause of chronic liver failure. Chronic liver failure without liver transplantation is fatal.

Symptoms of Liver Failure and Diagnostic Path

People who are in liver failure are very ill. The most prominent symptoms are severe JAUNDICE (yellowish discoloration of the SKIN) and disturbances of cognitive and BRAIN functions, ranging from CONFUSION and HALLUCINATION to COMA, known collectively as hepatic ENCEPHALOPATHY. Neurologic signs that accompany these symptoms include disturbances of reflexes, tremors, and myotonus (MUSCLE spasms and rigidity). Evidence of clotting dysfunction, such as bruising and frank bleeding (internal or external), is also often present as the liver synthesizes many of the proteins and CLOTTING FACTORS necessary for COAGULATION. The diagnostic path includes LIVER FUNCTION TESTS that measure the levels of liver enzymes in the blood, toxicology screens to detect the presence of chemicals in the blood, and imaging procedures of the liver and the brain such as ULTRASOUND, COMPUTED TOMOGRAPHY (CT) SCAN, and MAGNETIC RESONANCE IMAGING (MRI).

ALCOHOL AND ACETAMINOPHEN: A DANGEROUS COMBINATION

Regular ALCOHOL consumption, even as little as one drink a day, depletes the LIVER’s supply of glutathione, an amino acid compound essential for metabolizing toxins. Insufficient glutathione exposes the liver to rapid hepatocellular necrosis, with resulting acute liver failure. People who drink regularly can experience acetaminophen OVERDOSE with as little as 4 grams of acetaminophen a day for three or four consecutive days, an amount that is well within the therapeutic dosage range.

Liver Failure Treatment Options and Outlook

Treatment options for liver failure are primarily supportive. Some people benefit from novel approaches such as liver hemodialysis, which filters the blood similarly to renal dialysis (renal dialysis cannot remove the same substances from the blood), though such methods remain limited to major medical centers. Liver transplantation remains the only viable treatment for permanent liver failure, and the need for donor livers far outpaces the availability of donor organs. In some situations living donor liver segment transplantation, in which a living person donates a segment of his or her liver, is an alternative to cadaver donor liver transplantation.

Risk Factors and Preventive Measures

Chronic hepatitis infection and cirrhosis due to alcoholism are the leading risks for liver failure. Vaccination can prevent much, though not all, hepatitis. Drinking cessation can end the progression of cirrhosis, though damage already done is permanent.

See also ANALGESIC MEDICATIONS; COGNITIVE FUNCTION AND DYSFUNCTION; HEPATOTOXINS; ORGAN TRANSPLANTATION; REFLEX.

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The Gastrointestinal System

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