What is fatty liver?
It is a pathological change of the liver
But it is a reversible disease!
Fatty liver refers to lesions with excessive accumulation of fat in liver cells due to various reasons, and is a common liver pathological change rather than an independent disease.
Fatty liver disease is seriously threatening the health of the Chinese people, becoming the second largest liver disease after viral hepatitis, with an increasing incidence and a younger age of onset.
Normal human liver tissue contains a small amount of fat, such as triglycerides, phospholipids, glycolipids and cholesterol, etc., its weight is about 3% to 5% of the liver weight, if the fat accumulation in the liver is too much, more than 5% of the liver weight or histology more than 50% of the liver cells have steatosis, it can be called fatty liver. Its clinical manifestations are mild and asymptomatic, and in severe cases, the disease is fierce.
In general, fatty liver is a reversible disease, and early diagnosis and timely treatment often return to normal.
Formation of fatty liver
Two factors: triglyceride accumulation, inflammation
Three sources: new intake, new synthesis, and storage
1. New intake: The fat we ingest in three meals can be directly transported to the liver, abdomen, or subcutaneous storage after digestion and absorption. Therefore, fat intake encourages liver cells to store fat.
2, new and into: when the body's caloric intake is greater than expenditure, excess carbohydrates are first converted into glycogen in the liver. After the glycogen reservoir is filled, the liver begins to use glucose to synthesize fat, which is stored. Another way to synthesize fat is through alcohol. Heavy alcohol consumption causes the liver to produce acetaldehyde, which provides the best ingredient for synthetic fat – NADH.
3, storage: when hungry, the fat reserves of the body's fat tissue are mobilized and enter the liver through blood circulation. Its purpose is to be oxidized here to provide fuel.
But fat in the liver is also a dynamic system of in-balance. Fats need protein carrier VLDL (very low-density lipoprotein) to leave the liver. In a state of extreme hunger, once the synthesis of protein is affected, VLDL will also run out of stock, so the fat cannot effectively leave the liver, and the balance in and out of the liver is broken. Fat is also stored in the liver.
The inflammatory response has a strong effect on the accumulation of triglycerides in liver cells. Factors contributing to the inflammatory response include leaky gut caused by animal and high-fat diets, iron excess, hepatitis virus, and psychological stress.
All in all, high-fat, high-calorie, animal-based diets and alcohol are the main reasons for the formation of fatty liver disease.
Examination of fatty liver
Physical examination, laboratory tests, ultrasound
CT and magnetic resonance imaging, pathological examination of liver tissue
1. Physical examination: most patients with fatty liver are obese, mild liver enlargement can have tenderness, slightly tough texture, blunt edges, smooth surface, and a small number of patients may have splenomegaly and liver palms. When cirrhosis progresses, patients may present with jaundice, edema, fluttering awphyloid tremor, and signs of portal hypertension.
2. Laboratory examination: mild fatty liver, liver function is basically normal. Moderate and severe fatty liver, manifested by alanine aminotransferase (ALT) and aspartate aminotransferase (AST) mild to moderate increase, up to 2 to 5 times the normal upper line. In general, obese fatty liver ALT is higher than AST, conversely, alcoholic fatty liver AST is higher than ALT. Alkaline phosphatase (ALP) and γ-glutamyl transpeptidase (GGT) are elevated by 2 to 3 times in half of patients. Serum cholinease is elevated in more than 80% of patients. Serum bilirubin may be abnormal.
3.B ultrasound: B ultrasound is sensitive to the detection of fatty liver, mainly based on the clarity of liver vessels, the degree of ultrasound attenuation, etc. for graded diagnosis of fatty liver, has been used as the preferred diagnostic method for fatty liver, and is widely used in the epidemiological investigation of the incidence of fatty liver in the population. However, the accuracy of ultrasound detection of liver steatosis is low, and the extent of liver function impairment cannot be determined, and it is difficult to detect early cirrhosis.
4. CT and magnetic resonance: CT scan can show a general decrease in liver density (CT value), lower than the spleen, kidney and intrahepatic blood vessels, severe fatty liver CT value can become negative, liver / spleen CT value ratio can be used to measure the degree of fatty liver. CT is less sensitive than B ultrasound in diagnosing fatty liver, but specifically superior to B ultrasound. Magnetic resonance imaging is mainly used in ultrasound and CT examination to diagnose difficulties, especially when focal fatty liver disease is difficult to distinguish from liver tumors.
5. Liver histopathological examination: can carry out clinical pathological classification of non-alcoholic fatty liver disease. Hepatic puncture under the guidance of ultrasound B is advocated to improve the accuracy of puncture and minimize liver damage. Hepatocyte fat infiltration can be seen microscopically, the nucleus can be pushed aside in large fat spheres, and the entire hepatocyte cleft can form a fat cyst. Hepatocyte necrosis and inflammatory response are mild or absent. Liver tissue biopsy is currently the "gold standard" for diagnosing NAFLD and staging, but its clinical application is limited due to its invasiveness and inaccuracies caused by sampling errors.
How to eat fatty liver back?
Mild and moderate fatty liver combined with a healthy lifestyle
Abnormal liver function requires drug-assisted coordination
Fatty liver disease is not light, not heavy. If you pay attention to your thinking and change your behavior, then it is completely reversible after the early investigation. However, if you indulge yourself and let your liver be in a harsh environment, it may gradually strike out and eventually evolve into cirrhosis or even liver cancer, which can also lead to type II diabetes.
Simple mild and moderate fatty liver disease generally does not need to be treated with drugs, and can be restored with a healthy lifestyle. Lifestyle medicine includes: plant-based diet, regular exercise, adequate sleep, good relationships, stress regulation, and avoidance of drug dependence.
If the patient has metabolic syndrome or abnormal liver function (such as a double increase in transaminases), it is necessary to assist with some antihypertensive, lipid-lowering or liver protection drugs, but the premise must be to change the lifestyle, and the effect of simply taking drugs and adhering to the previous lifestyle may not be satisfactory.
Edited by / Huang Qianwen
Source/ Renji Hospital affiliated to Jiaotong University