Hepatic steatosis

Introduction Lipid droplets appearing in the cytoplasm exceed the physiological range, or fat droplets appear in cells that do not normally have lipid droplets, which is called steatosis. The liver is the main organ of fatty acid metabolism, and liver fat is more common. In severe cases, almost all liver cells undergo fatty changes, liver enlargement, mild tenderness and abnormal liver function, called fatty liver.

Cause

The mechanism of hepatic steatosis has the following aspects:

1 lipoprotein synthesis disorder, can not transport fat out, so it causes fat to accumulate in liver cells. Often due to the lack of synthetic lipoprotein raw materials (such as phospholipids or choline-constituting phospholipids), or chemical poisons (such as alcohol, carbon tetrachloride, etc.), other toxins (such as true toxins) damage the structure of the endoplasmic reticulum, or It inhibits the activity of certain enzymes and causes the synthesis of lipoproteins and phospholipids, proteins, etc., which constitute lipoproteins.

2 too much neutral fat synthesis, mostly due to hunger or certain diseases (such as digestive tract diseases) caused by hunger and state, or diabetes patients use sugar barriers, mobilize a large amount of fat from the fat pool, most of which are fatty acids Forms enter the liver, causing increased liver synthesis fat, exceeding the liver's ability to oxidize and transport its synthetic lipoproteins, thus causing fat to accumulate in the liver.

3 The oxidative barrier of fatty acids reduces the use of cells for fat. For example, diphtheria exotoxin can regulate the oxidation process of fatty acids, and hypoxia affects both the synthesis of lipoproteins and the oxidation of fatty acids. In short, the steatosis of hepatocytes is the result of a combination of one or more of these factors.

an examination

Related inspection

Liver function test liver upper and lower boundary percussion liver ultrasound examination hepatitis B virological index serum lipid peroxide

When the liver is fat, the liver is evenly swollen, and the yellow is yellow, the capsule is tight, the edges are blunt, and the texture is slightly soft. The cut surface is light yellow and slightly bulged, and the envelope is everted, which makes it feel greasy. Microscopically, there are many small fat vacuoles that appear in light liver cells, which are mostly distributed around the nucleus. The heavy vacuoles are large and large, scattered throughout the cytoplasm, and even merge into large vacuoles, squeezing the nucleus to one side, similar to fat cells. The fat is mostly distributed in the center of the hepatic lobules, and may be in the periphery or the entire hepatic lobules.

Differential diagnosis

Identification:

1. Alcoholic fatty liver: In morphology, alcoholic fatty liver is characterized by large lipid droplets in the liver cells. The cells are distributed in a focal shape, and the central area of the hepatic lobules is most obvious. Individual hyperlipidated hepatocytes undergo lytic necrosis and are replaced by fatty granuloma, which consists of lipid droplets surrounding lymphocytes, histiocytes and eosinophils. If this fatty granuloma is brought together into a multinodular structure, it will be accompanied by extravagant fibrosis. Non-specific reactive hepatitis can be seen in the portal area.

2, toxic fatty liver: morphological changes in toxic fatty liver can be small lipid drops or fat droplets of liver cells, fatty liver cells can occur first in the center of the hepatic lobules (such as carbon tetrachloride, chloroform poisoning Caused by it, can also occur around the hepatic lobules (such as those caused by phosphorus poisoning).

3, malnutrition fatty liver: Although the body can adapt to nutritional deficiencies, but if the lack of serious or long time, will produce a series of obvious pathological changes. Fatty liver is one of its pathological changes. First, there is a small lipid droplet in the liver cells around the liver. Later, the lipid droplets increase and extend to the center of the hepatic lobules. In severe cases, all liver cells are filled with large lipid droplets, the nucleus is pushed to one side, and there is very little cytoplasm. However, liver function remained normal and severe liver failure rarely occurred.

4, pregnancy fatty liver: usually seen in patients with pregnancy-induced hypertension or primipara at the end of pregnancy. The latter has a low incidence rate, accounting for about one in ten thousand of pregnant women. In general, the liver is pale yellow and the volume is small. Under light microscopy, a large number of small fat vacuoles can be seen in the liver cells, which can be distributed in the whole lobules, or involve the regional distribution of the middle zone and the peripheral zone. Sometimes, obvious macrobubble steatosis and hepatocyte ballooning can be seen.

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