Nonalcoholic fatty liver disease

Introduction to nonalcoholic fatty liver disease Non-alcoholic fatty liver disease (NAFLD) refers to a land-based pathological syndrome, including simple fatty liver, caused by alcohol and other well-defined liver-damaging factors, with diffuse hepatic macrobubble fat becoming a major feature. And the evolution of steatohepatitis (NASH) and cirrhosis. basic knowledge The proportion of sickness: 0.01% Susceptible people: no special people Mode of infection: non-infectious Complications: hyperlipidemia

The cause of nonalcoholic fatty liver disease

NAFLD is divided into two major categories, primary and secondary, the former is related to insulin resistance and genetic susceptibility, while the latter is caused by some special reasons. Overweight, weight gain and overweight, obesity, diabetes, hyperlipidemia and other metabolic syndrome-related fatty liver, and cryptogenic fatty liver belong to the primary NAFLD category; and malnutrition, total gastrointestinal Fatty liver caused by external nutrition, weight loss after weight loss surgery, drug/environmental and industrial poisoning, etc. belongs to the category of secondary NAFLD.

Nonalcoholic fatty liver disease prevention

Losing weight, lowering blood sugar, scientific diet, and moderate exercise are the key to prevention.

Nonalcoholic fatty liver disease complications Complications

1. Hyperlipidemia.

2. Hyperviscosity.

3. Liver fibrosis and cirrhosis.

4. Metabolic syndrome.

5. Atherosclerosis.

Symptoms of nonalcoholic fatty liver disease Common symptoms Fat infiltration, hypertensive cirrhosis, excessive accumulation of fat in liver cells, indigestion, visceral obesity

There are no symptoms at all, and it is found during routine physical examination that there may be mild liver function abnormalities.

Non-alcoholic fatty liver disease check

Serum enzymatic examination

(1) ALT, AST: generally mildly elevated, reaching 2 to 3 times the upper limit of normal. In non-alcoholic fatty liver, ALT/AST>1. ALT>130U, suggesting that liver lobular fat infiltration is obvious, and persistently elevated ALT suggests fatty granuloma.

(2) -GT, ALP: -GT can be elevated in patients with nonalcoholic fatty liver disease.

(3) GST: It can reflect stress-induced liver injury and is more sensitive than ALT.

(4) Glutamate dehydrogenase (GDH) and ornithine carbamoyltransferase (DCT). GDH is a mitochondrial enzyme, which is mainly active in the hepatic acinar III zone, and DCT is a urea synthase, which is involved in the transmethylation reaction. Both enzymes are elevated in fatty liver.

(5) Cholinesterase (CHE), lecithin cholesterol acyltransferase (LCAT): 80% fatty liver serum CHE.

And LCAH is elevated. CHE has a certain significance in the identification of obese fatty liver.

2. Plasma protein changes

(1) -globulin, 1, 2, -lipoprotein increased.

(2) Albumin is normal.

(3) In obese fatty liver, LDL-C increased, HDL-C decreased significantly, and Apo B, Apo E, Apo CII and III increased.

3. Plasma lipids TG, FA, cholesterol, and phospholipids are often elevated, and cholesterol is significantly elevated, often >13mmol/L.

4. Pigment excretion test BSP, ICG excretion decreased. In obese fatty liver, because fat accumulation is mostly in the liver acinar III zone, and pigment treatment is also in this area. Liver fat storage affects the function of hepatocytes to excrete pigments. The extent of excretion is related to the extent of liver fat infiltration.

5. Bilirubin may have elevated blood bilirubin in severe fatty liver, and mild to moderate fatty liver bilirubin is normal.

6. Prothrombin time (PT).

7. The blood insulin level showed a high response delay type, and the glucose tolerance curve peaked and the decline was delayed.

8. Blood urea nitrogen and uric acid occasionally increase.

Diagnosis and identification of nonalcoholic fatty liver disease

Clinical diagnostic criteria

Any of the following items 1 through 5 and 6 or 7 can be diagnosed as NAFLD.

1. No alcohol history or alcohol consumption is equivalent to ethanol in men <140g per week, women <70g per week.

2. Excluding viral hepatitis, drug-induced liver disease, total parenteral nutrition, hepatolenticular degeneration and other specific diseases that can lead to fatty liver.

3. In addition to the clinical manifestations of the primary disease, there may be non-specific symptoms and signs such as fatigue, indigestion, pain in the liver area, hepatosplenomegaly.

4. There may be components related to metabolic syndrome such as overweight and/or visceral obesity, increased fasting blood glucose, dyslipidemia, and hypertension.

5. Serum transaminase and Y-glutamine transpeptase levels may have a mild to moderate increase (less than 5 times the upper limit of normal), usually with alanine aminotransferase (ALT) increased.

6. Liver imaging findings are consistent with imaging diagnostic criteria for diffuse fatty liver.

7. Liver biopsy Histopathological changes meet the pathological diagnostic criteria for fatty liver disease.

Imaging diagnosis

Imaging examination used Ding to reflect the distribution of liver fat infiltration, roughly judge the degree of diffuse fatty liver, suggesting the presence of dominant cirrhosis, but it can not distinguish between simple fatty liver and NASH, and it is difficult to detect <33% of liver Slightly saturated fat. It should be noted that diffuse liver echo enhancement and density reduction can also be seen in chronic liver diseases such as cirrhosis.

(1) B-ultrasound diagnosis

1. The near field echo of the liver area is diffusely enhanced (stronger than the kidney and spleen), and the far field echo is gradually attenuated.

2. The structure of the intrahepatic duct is unclear.

3. The liver is mild to moderately swollen and the edges are rounded.

4. Color Doppler flow imaging can reduce the color flow signal in the liver or reduce it, but the blood vessels in the liver go normal.

5. The right hepatic envelope and transverse echo are unclear or incomplete.

Those who have one of the above items 1 and 2 to 4 are mild fatty liver; those with the above items 1 and 2 to 4 are moderate fatty liver; Two of the second and fourth items and the fifth item are severe fatty liver.

(two) CT diagnosis

Diffuse liver density is reduced, and the ratio of CT values of liver to spleen is less than or equal to 1. Diffuse liver density decreased, liver/spleen CT ratio 1.0 but greater than 0.7 was mild; liver/spleen CT ratio 0.7 but large dry 0.5 was moderate; liver/spleen CT ratio 0.5 was severe.

Histopathological diagnosis

According to whether the diseased liver tissue is accompanied by inflammatory reaction and fibrosis, NAFLD can be divided into: simple fatty liver, NASH, HASH-related cirrhosis.

(1) Simple fatty liver

According to the range of liver cell steatosis occupied by liver cell steatosis, it is divided into 4 degrees (F _{0 ~ 4} ): F _O < 5% hepatocyte steatosis; F ₁ 5% ~ 30% hepatocyte steatosis; F ₂ 31% to 50% hepatocyte steatosis; F ₃ 51% to 75% hepatocyte steatosis; F ₄ 75% or more hepatocyte steatosis.

(2) NASH

The degree of fatty liver in NASH is consistent with that of simple fatty liver, which is divided into 4 degrees (F0~4). According to the degree of inflammation, NASH is divided into 3 grades (G0~3): G0 has no inflammation; G1 acinar 3 band presents a few balloon-like Hepatocytes, follicular necrosis scattered in individual follicles; G2 acinar 3 with balloon-like hepatocytes, focal necrosis in the acinus increased, mild to moderate inflammation in the portal area; G3 acinus 3 with a wide balloon-like Liver cells, focal follicular necrosis in the acinus, mild to moderate inflammation in the portal area with or around the portal area inflammation.

According to the extent and morphology of fibrosis, NASH liver fibrosis is divided into 4 stages (S0~4): S0 is not fibrotic; S1 acinar 3 is focal or extensive sinus per pericellular fibrosis; S2 fibrosis Expanded into the portal area, focal or extensive portal area of astral fibrosis; S3 fibrosis extends around the portal area, focal or extensive bridging fibrosis; S4 cirrhosis.

NASH histopathological diagnosis report: NASA-F (0 ~ 4) G (0 ~ 3) S (0 ~ 4). F: fatty liver index; G: inflammation grade; S: fibrosis stage.

The histological features of NASH in children have mild inflammation in the lobular area. The inflammation in the portal area is heavier than that in the lobular area. There is little balloon-like change. The fibrosis in the lobes is not obvious. The fibrosis in the portal area and its surrounding area is obvious. It may be cryptogenic liver. An important cause of hardening.

Hepatocyte ribosylation is a histological feature of "static NASH."

Differential diagnosis

Identification of fatty liver caused by alcoholic fatty liver and other well-defined liver damage factors.

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