Fatty liver disease is a secondary or independent pathological syndrome characterized by the accumulation of fat in the liver tissue. The cause of the development of this condition is alcohol consumption; diseases accompanied by metabolic disorders (diabetes mellitus, thyroid pathology, malabsorption, and others), as well as taking certain medications. Fatty liver disease has no specific clinical picture and is asymptomatic for a long time. Diagnosis consists in liver biopsy, as well as imaging studies (MRI of the liver, scintigraphy, ultrasound). The treatment is conservative, the prognosis is favorable.
Fatty liver disease is a pathological process consisting in the degeneration of liver tissue with fatty degeneration of hepatocytes. Morphological changes are characterized by intracellular and/or intercellular accumulation of fat droplets. This pathology occurs in a third of patients with non-alcoholic fatty liver disease and in the majority of patients with alcoholic lesions.
Fatty liver disease is the initial stage of alcoholic liver disease and can lead to irreversible cirrhotic changes and death. Currently, fatty liver disease is considered a global problem not only in gastroenterology, but also in integral medicine, since this disease is associated with an increased risk of liver cirrhosis, cardiovascular pathology, endocrine and metabolic disorders, allergic diseases, varicose veins and other severe changes.
Causes of fatty liver disease
The etiological factors of fatty liver disease are diverse and diverse. Dystrophic changes in hepatocytes can develop due to toxic effects, nutritional characteristics, disorders of carbohydrate and fat metabolism. Eating disorders, alcohol intake, the use of medications are factors that occur in almost every patient. Among the main reasons are considered:
- Alcohol consumption. The most important factor in the development of fatty liver dystrophy is alcohol damage to hepatocytes. The severity of morphological changes and the risk of transition to cirrhosis directly depend on the amount and duration of alcohol consumption.
- Taking medications. Corticosteroids, synthetic estrogens, nonsteroidal anti-inflammatory drugs, methotrexate, antibiotics (tetracycline) have a toxic effect on the liver.
- Diabetes mellitus. Hyperglycemia with insulin resistance leads to an increase in the concentration of free fatty acids in the blood, resulting in increased synthesis of triglycerides in the liver. If the rate of their formation exceeds the metabolic reactions with the formation of VLDL-TG complexes, fat deposition occurs in the liver.
- Fatness. The main role is played not by the percentage of adipose tissue in the body, but by the insulin resistance that occurs with metabolic syndrome. In the conducted studies, the amount of fat in the liver, determined by proton spectroscopy, directly depended on the fasting insulin level.
- Other metabolic disorders. The causes of fatty liver disease may be other diseases accompanied by metabolic disorders: myxedema, Cushing syndrome, thyrotoxicosis, chronic diseases of the gastrointestinal tract with malabsorption (including chronic pancreatitis), Wilson-Konovalov disease, pathology of the cardiovascular system (hypertension, coronary heart disease), other chronic diseases that lead to exhaustion of the patient (oncopathology, pulmonary and heart failure).
- Features of nutrition. The so–called “Western” diet – a diet with a high content of hydrogenated fats, simple carbohydrates, as well as a lifestyle with a low level of physical activity – leads to a violation of the metabolism of fats, carbohydrates and fatty degeneration of hepatocytes.
- Hereditary enzymopathies. A separate group of factors contributing to the accumulation of fat in the liver is a hereditary deficiency of enzymes involved in lipid metabolism. It is often impossible to identify an etiological factor, since there is no pure liver damage of one or another genesis.
Regardless of the primary cause of the disease, with fatty liver disease (especially non-alcoholic etiology), insulin resistance occurs, in turn, dystrophic changes in the liver are one of the pathogenetic links of the metabolic syndrome. The accumulation of fat in and between hepatocytes is caused by an excessive intake of fats due to hyperlipidemia or alcohol damage, a violation of their utilization during peroxidation, as well as a reduced excretion of fat molecules from cells due to impaired synthesis of apoprotein, which forms the transport forms of fats (this explains the alipotropic obesity of the liver).
There are two forms of fatty liver disease, which are independent nosological units: alcoholic fatty liver dystrophy and non-alcoholic steatohepatitis. Among all patients undergoing liver biopsy, non-alcoholic steatosis is registered in 7-8% of cases. Alcohol damage is more common – it occurs 10 times more often.
Depending on the type of fat deposition in the liver lobule, the following morphological forms are distinguished: focal disseminated (often has no clinical manifestations), pronounced disseminated, zonal (fat accumulates in different parts of the hepatic lobule) and diffuse (microvesicular steatosis).
Fatty liver disease is classified into:
- Primary. It is caused by endogenous metabolic disorders (obesity, diabetes mellitus, hyperlipidemia).
- Secondary. Its cause is external influences, against which metabolic disorders develop. Secondary hepatosis includes liver damage when taking certain medications, malabsorption syndrome during surgical interventions on the gastrointestinal tract (ileoejunal anastomosis, gastroplasty as a method of treating obesity, intestinal resection); with prolonged parenteral nutrition, fasting, etc.
Fatty liver disease symptoms
The complexity of this pathology lies in the fact that, despite significant morphological changes, most patients lack specific clinical signs. 65-70% of patients are women, and most of them are overweight. Many patients have insulin-independent diabetes mellitus. The vast majority of patients have no symptoms characteristic of liver damage.
There may be an indefinite feeling of discomfort in the abdominal cavity, mild aching pains in the right hypochondrium, asthenization. The liver is enlarged, with palpation it may be slightly painful. Sometimes the disease is accompanied by dyspeptic syndrome: nausea, vomiting, stool disorders. Some jaundice of the skin is possible. With diffuse liver damage, episodes of hemorrhages, hypotension, fainting states may occur, which is explained by the release of a tumoronecrotizing factor as a result of the inflammatory process.
Clinical symptoms are nonspecific, consultation with a hepatologist suggests fatty liver disease and determine diagnostic tactics. Biochemical liver tests also do not reveal significant changes, serum transaminases can be increased by 2-3 times, while their normal values do not exclude the presence of fatty liver disease. The main diagnostic methods are aimed at excluding other liver diseases:
- Blood test. It is mandatory to conduct a blood test for the presence of specific antibodies to the pathogens of viral hepatitis, cytomegalovirus, Epstein-Barr virus, rubella; determination of markers of autoimmune liver damage. The level of thyroid hormones in the blood is being investigated, since hypothyroidism can be the cause of fatty liver disease.
- Abdominal ultrasound. Allows you to identify signs of fatty steatosis if the lesion covers more than a third of the liver tissue.
- Liver biopsy. An important role is assigned to liver biopsy with morphological examination of the biopsy. Histological signs of fatty liver disease include the phenomena of fatty degeneration, intra-lobular inflammation, fibrosis, steatonecrosis. Most often, the presence of large-drop dystrophy is detected.
- Methods of visualization and evaluation of the function. A highly informative diagnostic method that allows detecting changes in parenchyma is liver MRI. To detect focal steatosis, radionuclide scanning of the liver, CT is used.
The diagnostic program necessarily includes methods for assessing concomitant diseases that affect the progression of liver damage and the prognosis for the patient. In order to assess the detoxification function of the liver, a C13-metacetin respiratory test is performed. The results of this study allow us to judge the number of functioning hepatocytes.
Fatty liver disease treatment
Patients are treated on an outpatient basis or in the gastroenterology department. The treatment is conservative, carried out in several directions. The alimentary status is necessarily assessed and diet therapy is prescribed. In order to reduce the effect of the main pathogenetic factor (insulin resistance), correction of excess body weight is mandatory. The loss of even 5-10% of body weight leads to a significant improvement in carbohydrate and fat metabolism. However, the rate of weight loss should be 400-700 g per week, faster weight loss can lead to the progression of fatty liver disease and the development of liver failure, as well as the formation of concretions in the gallbladder. Main directions:
- Diet therapy. In some cases, it is the diet that is the key and only method of treating fatty liver disease. Therapeutic nutrition provides for the restriction of animal fats, the consumption of protein in the amount of 100-110 g per day, sufficient intake of vitamins and trace elements.
- Hypolipidemic therapy. Lipotropic drugs are used that eliminate fatty infiltration of the liver: folic acid, vitamin B6, B12, lipoic acid, essential phospholipids. However, it has not been definitively established whether statins are safe for fatty liver disease, since these drugs themselves have the ability to damage hepatocytes.
- Hepatoprotection. Hepatoprotectors are prescribed to normalize liver functions. Vitamin E, ursodeoxycholic acid, betaine, taurine are used. Studies are being conducted on the effectiveness of pentoxifylline and angiotensin receptor blockers in this pathology.
- Reduction of insulin resistance. To increase the activity of oxidative phosphorylation processes in muscles, and, consequently, the utilization of fatty acids, physical activity is shown, which also improves the sensitivity of receptors to insulin. Pharmacotherapy of insulin resistance is carried out using thiazolidinediones and biguanides.
Thus, the key points of the treatment of fatty liver disease are the elimination of the etiological factor (including alcohol consumption), normalization of weight and nutrition. Drug therapy has an auxiliary value. For patients suffering from alcoholism, treatment with a narcologist is a priority.
Prognosis and prevention
Fatty liver disease has a relatively favorable prognosis. In most cases, eliminating the cause of the disease is enough to restore the liver. The ability to work of patients is preserved. Be sure to follow the recommendations of a gastroenterologist on the diet, physical activity, exclude alcohol consumption. In the case of the continued action of hepatotropic factors, inflammatory and dystrophic changes in the liver progress, the transition of the disease to cirrhosis is possible.
Prevention consists in eliminating the effects of toxic damaging factors, including acetaldehyde, timely detection of endocrine and other diseases and their effective treatment, maintaining a normal weight and a sufficient level of activity.