months. Repeated attacks of INFLAMMATION pro-
gressively kill hepatocytes until the level of hepa-
tocytic function falls below 25 percent. In many
situations a culminating event, such as a flare of
hepatitis or an episode of acute alcohol INTOXICA-
TION, pushes the liver across the boundary. CIRRHO-
SISis the leading cause of chronic liver failure.
Chronic liver failure without liver transplantation
is fatal.
Symptoms and Diagnostic Path
People who are in liver failure are very ill. The most
prominent symptoms are severe JAUNDICE(yellow-
ish discoloration of the SKIN) and disturbances of
cognitive and BRAINfunctions, ranging from CONFU-
SIONand HALLUCINATIONto COMA, known collectively
as hepatic ENCEPHALOPATHY. Neurologic signs that
accompany these symptoms include disturbances
of reflexes, tremors, and myotonus (MUSCLEspasms
and rigidity). Evidence of clotting dysfunction, such
as bruising and frank bleeding (internal or exter-
nal), is also often present as the liver synthesizes
many of the proteins and CLOTTING FACTORSneces-
sary for COAGULATION. The diagnostic path includes
LIVER FUNCTION TESTSthat 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 ULTRA-
SOUND, COMPUTED TOMOGRAPHY(CT) SCAN, and MAG-
NETIC RESONANCE IMAGING(MRI).
ALCOHOL AND ACETAMINOPHEN:
A DANGEROUS COMBINATION
Regular ALCOHOLconsumption, 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 necro-
sis, with resulting acute liver failure. People who
drink regularly can experience acetaminophen
OVERDOSEwith as little as 4 grams of acetamino-
phen a day for three or four consecutive days, an
amount that is well within the therapeutic
dosage range.Treatment Options and Outlook
Treatment options for liver failure are primarily
supportive. Some people benefit from novel
approaches such as liver hemodialysis, which fil-
ters 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 out-
paces the availability of donor organs. In some sit-
uations 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 progres-
sion of cirrhosis, though damage already done is
permanent.
See also ANALGESIC MEDICATIONS; COGNITIVE FUNC-
TION AND DYSFUNCTION; HEPATOTOXINS; ORGAN TRANS-
PLANTATION; REFLEX.liver function tests A panel of BLOODtests that
measures the levels of ALBUMIN, BILIRUBIN, and cer-
tain LIVERenzymes in the blood. More specifically
targeted tests further identify the reasons for
abnormal results, as the findings may also indicate
dysfunctions of other organs.Reasons for Doing This Test
Liver function tests provide a general assessment
of how effectively the liver is performing its meta-
bolic tasks. They also allow the doctor to monitor
the progression of liver disease and the effective-
ness of treatment.
Albumin The liver synthesizes (produces) the
key amino acids that make up albumin, the pri-
mary protein in blood PLASMA. Albumin transports
numerous substances—including other proteins,
NUTRIENTS, and hormones—through the blood.
When albumin levels are low the blood cannot
carry these substances, which has a variety of con-
sequences throughout the body. Many liver condi-
tions cause ASCITES(abdominal edema), in which a
deficiency of albumin in the plasma allows plasma
to seep across cell membranes to accumulate in
the abdominal cavity. Decreased blood albuminliver function tests 73