COMPUTED TOMOGRAPHY(CT) SCAN, and PERCUTANEOUS
LIVER BIOPSY. Treatment targets the underlying
cause or condition.
Longstanding cholestasis can result in deficien-
cies of fat-soluble vitamins, notably vitamin D and
VITAMIN K, as the SMALL INTESTINE needs bile to
digest fats.
See also ALCOHOLISM; LIVER FAILURE; XANTHOMA.
cholesterol, endogenous A sterol ALCOHOLmole-
cule essential for many functions of cellular
METABOLISM and the synthesis (production) of
numerous hormones. The LIVER synthesizes the
cholesterol that circulates within the body
(endogenous) from dietary fats, particularly satu-
rated fats, and the components of dietary choles-
terol that enter the bloodstream from the
gastrointestinal tract. The liver can continue to
synthesize cholesterol as long as it receives the
ingredients to do so, under genetically mediated
regulation.
Because cholesterol is fat soluble it does not
dissolve in the blood, so lipoproteins bind with
cholesterol to transport it through the blood-
stream. Excessive amounts of cholesterol in the
bloodstream contribute to cardiovascular condi-
tions such as ATHEROSCLEROSISand CORONARY ARTERY
DISEASE(CAD). Inadequate amounts of cholesterol
in the body are uncommon though occur with
conditions such as myelogenous LEUKEMIA and
AIDS. Low cholesterol prevents cells from repair-
ing themselves and also the body unable to pro-
duce “stress” hormones, such as CORTISOLthat are
essential for IMMUNE RESPONSE. The liver also uses
cholesterol to synthesize BILE, which carries cho-
lesterol into the gastrointestinal tract for reabsorp-
tion and recycling or elimination. Various
endocrine glands use cholesterol to synthesize
STEROIDhormones, such as the ADRENAL GLANDS,
which produce cortisol, and the gonads (sex
glands), which produce TESTOSTERONEand ESTRO-
GENS. Cells throughout the body use cholesterol
for cell membrane repair.
See also CHOLESTEROL BLOOD LEVELS; CHOLESTEROL,
DIETARY; HIV/AIDS; HYPERLIPIDEMIA; LIFESTYLE AND
HEALTH; STRESS RESPONSE HORMONAL CASCADE.
cirrhosis A progressive condition in which
fibrous tissue replaces damaged LIVERtissue, usu-
ally over an extended time and as a result of con-
tinued injury to the liver. The scarring is perma-
nent and interferes with the liver’s ability to
function, eventually resulting in LIVER FAILURE.
Numerous circumstances and health conditions
can result in cirrhosis. The most common causes
of cirrhosis are HEPATITIS, LIVER DISEASE OF ALCO-
HOLISM, chronic dysfunction of the BILE system,
STEATOHEPATITIS, and HEPATOTOXINS. Cirrhosis is the
leading reason for LIVER TRANSPLANTATION, the only
treatment for end-stage cirrhosis and resulting
liver failure.Symptoms and Diagnostic Path
In its mild to moderate stages, cirrhosis often does
not show symptoms or generates vague symptoms
that suggest a variety of causes. Until cirrhosis
becomes fairly advanced, even BLOODtests that
measure liver enzymes (a hallmark of liver func-
tion) and diagnostic imaging procedures such as
COMPUTED TOMOGRAPHY(CT) SCANoften show nor-
mal findings. When symptoms become apparent,
the cirrhosis has significantly compromised liver
function, and numerous changes occur through-
out the body. Indications of these changes often
include- edema (swelling of the limbs) and ASCITES(fluid
accumulation in the abdominal cavity) result-
ing from PORTAL HYPERTENSION(increased resist-
ance to blood flow through the liver) and RENAL
FAILURE(kidney dysfunction) - JAUNDICE(yellow discoloration of the SKIN) and
PRURITIS(extreme itching of the skin) resulting
from the liver’s inability to metabolize HEMO-
GLOBINand synthesize bile, which allows BILIRU-
BINconcentrations in the blood to rise - easy bruising and prolonged bleeding due to
the liver’s inability to synthesize CLOTTING FAC-
TORSand produce enough bile to metabolize the
dietary fats necessary for absorbing VITAMIN K - lack of APPETITE, resulting from diminished bile
production, and corresponding unintended
weight loss - INSULIN RESISTANCEor type 2 DIABETESresulting
from the liver’s inability to properly metabolize
cholesterol and manage GLUCOSE(sugar) storage
and retrieval
24 The Gastrointestinal System