FATTY LIVER

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    04-Dec-2014
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  • 1. 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.

2. Increasedmobilization 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. 3. CAUSES OF FATTY LIVER Nutritional factorsHigh 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. 4. 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. 5. 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. 6. 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. 7. 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. 8. 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. 9. 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 Reyes syndrome in which fatty liver is accompanied by encephalopathy; however this syndrome may be seen in the absence of aspirin intake. 10. 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. 11. Also known as Hepatic Steatosis or fatty liver refers to a reversible condition in which there are acummulation of trygliceride fat into intracitoplasmic vacuoles. 12. 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 causesit is difficult to distinguish alcoholic FLD from non alcoholic FLD and both show micro-vesicular and macrovesicular fatty changes at different stages 13. Macroscopic changesMicroscopic changes 14. Cirrhosis 15. 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.