4. FATTY LIVER (HEPATIC STEATOSIS)
The liver normally contains about 5% lipids of which 20%
is triacylglycerol. In fatty infiltration of the liver from any
cause, large amounts of triacylglycerol are deposited in
hepatocytes and their lipid content may increase to 30%.
Many agents and a variety of nutritional conditions cause
fatty livers. These include the following.
5. Increased
mobilization of fat from
the fat depots to the liver.
Increased synthesis of fat in the
liver.
Decreased removal of fat from the
liver.
Decreased oxidation of fat in the
liver.
6. CAUSES OF FATTY LIVER
Nutritional factors
High fat diet – An increased supply of fat to
the liver result in fatty liver.
High carbohydrate diet – Excess of
carbohydrate is converted to fats, a part of
which accumulates in liver also.
Low protein diet – This results in methionine
deficiency leading to fatty liver: kwashiorkor,
a disease affecting children with low protein
intake, is associated with fatty liver.
7.
Deficiency of vitamins – These include
vitamin E, pyridoxine, pantothenic
acid, folic acid and vitamin B12.
Starvation – This results in an excessive
mobilization of depot fat because
glucose supply is cut off.
8. Deficiency of lipotropic factors
Lipotropic factors are substances which
tend to prevent the deposition of
excessive fat in the liver. Choline is the
most important lipotropic factor. The
other lipotropic factors are betaine and
methionine which provide methyl groups
in the body.
9.
Inositol also exerts a lipotropic effect
because it also forms complex with
lipids, e.g. phosphatidylinositol that is
a glycerophospholipid. The amino acid
methionine is an important lipotropic
factor because it takes part in the
synthesis of choline.
10. Obesity. It is also a predisposing factor
for fatty liver. A special type of fatty
liver associated with obesity is nonalcoholic fatty liver disease
(NAFLD)/non-alcoholic-steato-hepatitis
(NASH)
Ethyl alcohol – It has a direct
hepatotoxic effect and causes a
decreased oxidation of fat in the liver.
11. Insulin deficiency – This is seen in
diabetes mellitus. There is an increased
FFA mobilization from the adipose.
Excessive amounts of certain hormones
– These include the hormones of the
thyroid, catecholamines, ACTH, glucocor
titoids and the female sex hormones.
Severe acute fatty liver is seen sometime
in third trimester of pregnancy when
female sex hormone production is very
high.
12.
i.
ii.
iii.
Toxic factors – These include the following:Chemical poisons –
CCl4, chloroform, phosphorus, lead, arsenic,
DDT, orotic acid, petrochemicals, etc
Bacterial toxins –
Drugs – Excessive aspirin intake in children
causes Reye’s syndrome in which fatty liver is
accompanied by encephalopathy; however
this syndrome may be seen in the absence of
aspirin intake.
13.
Other drugs which can produce fatty liver
include tetracyclines, valproic
acid, methotrexate, , vatimin
A, glucocorticoids, calcium channel
blockers, etc.
Disorders of lipid metabolism. These include
certain lipid storage disease, certain
hyperlipoproteinemias and
abetalipoproteinemia.
14.
Also known as Hepatic Steatosis or fatty liver refers
to a reversible condition in which there are
acummulation
of
trygliceride
fat
into
intracitoplasmic vacuoles.
15.
It is commonly associated
with alcohol or metabolic
syndrome (diabetes, hyperte
nsion, obesity and dyslipide
mia) but can also be due to
any one of many causes
it is difficult to distinguish alcoholic FLD
from non alcoholic FLD and both show
micro-vesicular and macrovesicular
fatty changes at different stages
24. The treatment of fatty liver is related
to the cause. It is important to
remember that simple fatty liver may
not require treatment. The benefit of
weight loss, dietary fat restriction, and
exercise
in
obese
patients
is
inconsistent.
Reducing or eliminating alcohol use
can improve fatty liver due to alcohol
toxicity. Controlling blood sugar may
reduce the severity of fatty liver in
patients
with
diabetes.
Ursodeoxycholic acid may improve
liver function test results, but its effect
on improving the underlying liver
abnormality is unclear.
