Encyclopedia of Health and Medicine

24 The Gastrointestinal System
COMPUTED TOMOGRAPHY (CT) SCAN, and PERCUTANEOUS
LIVER BIOPSY. Treatment targets the underlying
cause or condition.
Longstanding cholestasis can result in deficiencies
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 ALCOHOL molecule
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 saturated
fats, and the components of dietary cholesterol
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 bloodstream.
Excessive amounts of cholesterol in the
bloodstream contribute to cardiovascular conditions
such as ATHEROSCLEROSIS and 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 repairing
themselves and also the body unable to produce
“stress” hormones, such as CORTISOL that are
essential for IMMUNE RESPONSE. The liver also uses
cholesterol to synthesize BILE, which carries cholesterol
into the gastrointestinal tract for reabsorption
and recycling or elimination. Various
endocrine glands use cholesterol to synthesize
STEROID hormones, such as the ADRENAL GLANDS,
which produce cortisol, and the gonads (sex
glands), which produce TESTOSTERONE and ESTRO-
GENS. Cells throughout the body use cholesterol
for cell membrane repair.
See also CHOLESTEROL BLOOD LEVELS; CHOLESTEROL,
DIETARY; HIV/AIDS; HYPERLIPIDEMIA; LIFESTYLE
HEALTH; STRESS RESPONSE HORMONAL CASCADE.
AND
cirrhosis A progressive condition in which
fibrous tissue replaces damaged LIVER tissue, usually
over an extended time and as a result of continued
injury to the liver. The scarring is permanent
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 BLOOD tests that
measure liver enzymes (a hallmark of liver function)
and diagnostic imaging procedures such as
COMPUTED TOMOGRAPHY (CT) SCAN often show normal
findings. When symptoms become apparent,
the cirrhosis has significantly compromised liver
function, and numerous changes occur throughout
the body. Indications of these changes often
include
• edema (swelling of the limbs) and ASCITES (fluid
accumulation in the abdominal cavity) resulting
from PORTAL HYPERTENSION (increased resistance
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-
GLOBIN and synthesize bile, which allows BILIRU-
BIN concentrations in the blood to rise
• easy bruising and prolonged bleeding due to
the liver’s inability to synthesize CLOTTING FAC-
TORS and 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 RESISTANCE or type 2 DIABETES resulting
from the liver’s inability to properly metabolize
cholesterol and manage GLUCOSE (sugar) storage
and retrieval