Metabolic liver disease

What is metabolic liver disease?

Metabolic liver diseases encompass a group of inherited or acquired conditions that disrupt normal liver function, resulting in metabolic abnormalities. Examples include Wilson’s disease, hemochromatosis, and fatty liver disease. Nonalcoholic fatty liver disease is a most common form of metabolic liver disease, that is why this article will be dedicated mainly to this form. Fatty liver disease is a pathology of a non-infectious nature, characterized by clinical and morphological changes in its structure, such as excessive accumulation of fat molecules (triglycerides) in hepatocytes, steatohepatitis, fibrosis, and cirrhosis. 

Fatty liver disease is characterized by a relatively benign course, but its close association with several metabolic diseases increases the risk of complications from the heart and blood vessels, worsening the patient’s prognosis and reducing the quality and length of life.

About the disease

Accumulation of fat molecules in hepatocytes leads to disruption of the structure of the membranes of these cells, changing the processes of oxidation and metabolism within them. As a result, the affected cells are destroyed, fibrous (scar tissue) is formed in their place, and liver function is disturbed, which in turn causes changes in the biochemical composition of the blood, increases the risk of metabolic syndrome, leads to the formation of cirrhotic changes in the organ.

Fatty liver disease can develop in any person aged 30 years and older, not abusing but regularly consuming small doses of alcohol, preferring fatty caloric food, and leading a sedentary lifestyle. Although, in most cases, this pathology is wholly or practically asymptomatic, structural changes in the organ are progressing, and metabolic disorders are increasing, which is reflected in the results of additional methods of examination. The prevalence of the disease in the world averages about 20%.

Types

According to the number of fatty inclusions in hepatocytes, 4 degrees (stages) of nonalcoholic fatty liver disease are distinguished:

• 0 – tiny lipid droplets are determined on the surface of individual hepatocytes;
• I – medium and large fat droplets are localized superficially on small foci of functional cells of the organ;
• II – triglycerides impregnate hepatocytes and accumulate within them;
• III – fats affect the structural tissue of the organ diffusely over the entire surface, accumulate in the intercellular space, and form cysts.

Based on the causes of the development of fatty liver disease are primary (caused by metabolic syndrome) or secondary (resulting from the impact on the body of hepatotoxic external factors – taking aggressive drugs, surgery on the digestive system, prolonged starvation).

Symptoms

There are no external signs of the disease in the initial stage of the pathological process. The patient may learn about its presence accidentally in connection with a preventive examination or visiting a doctor for another disease. Hepatocytes are characterized by active regeneration, so the functional abilities of the organ are preserved for an extended period from the onset of fatty liver disease.

But over time, the function of damaged cells does decline – symptoms of fatty liver disease occur:

• feeling of heaviness, some discomfort in the right subcostal region, epigastrium;
• nausea;
• belching;
• a bitter taste in your mouth;
• general weakness, fatigue, decreased efficiency;
• weight gain;
• seemingly unexplained subfebrile fever;
• the appearance of vascular asterisks on the skin.

In the case of advanced forms of the disease, the development of complications may be yellowing of the skin, sclerae, mucous membranes, skin itching, and ascites.

Reasons

This pathology results from an improper lifestyle, a consequence of a violation of the lipid metabolism processes in the body. The provoking factors are:

• abdominal obesity (waist circumference of more than 80 cm in women, 94 cm in males);
• diseases of the endocrine system (hyperthyroidism, Icenko-Cushing’s syndrome);
• impaired glucose tolerance, insulin-independent diabetes mellitus;
• unbalanced diet;
• fully parenteral nutrition (by intravenous infusion of nutrient solutions);
• acute and chronic infectious liver diseases;
• congenital anomalies of the liver structure, hereditary deficiency of enzymes that are involved in fat metabolism;
• sedentary lifestyle;
• arterial hypertension;
• taking certain medicines (amiodarone, corticosteroids).

Diagnosis

An essential role in the diagnosis of fatty liver disease is played by the collection of patient complaints, anamnesis, and assessment of possible risk factors of the disease. Before making this diagnosis, other liver diseases, especially of viral etiology, should be excluded. To examine a patient with possible fatty liver disease, laboratory and instrumental diagnostic methods are used:

• blood work, urinalysis;
• fibrosis test;
• coagulogram;
• blood biochemical study (ALT, AST, cholesterol, total and fractional bilirubin, alkaline phosphatase, sugar, protein fractions);
• blood tests for infections (determination of viral hepatitis markers);
• puncture biopsy with subsequent histologic examination of the taken parenchyma sample;
• ultrasound of abdominal and retroperitoneal organs;
• CT, MRI of the liver;
• elastometry.

Treatment

The most critical component of the treatment of nonalcoholic fatty liver disease – is lifestyle correction: physical activity at least 150 minutes per week, normalization of body weight, refusal of alcoholic beverages and several medications, balanced diet, compliance with work, and rest.

The patient should exclude fatty meat, fish, canned food, smoked meat, easily digestible carbohydrates, cooking fats, chocolate and ice cream, cocoa, black coffee, and alcohol. Preference in the diet to give low-fat varieties of meat, fish, fruit and vegetable dishes, and complex carbohydrates (cereals, pasta).

The optimal rate of weight loss in fatty hepatosis is 1 kg per 7 days. Abrupt weight loss will lead to steatosis, steatohepatitis, and acceleration of fibrosis of liver tissue. Reduction of body weight in obese individuals with nonalcoholic fatty liver disease by 10% will significantly improve the values of AST, ALT, and other liver enzymes, as well as histologic parameters.

Medication treatment for this pathology includes:

• medications to overcome insulin resistance;
• omega-3-fatty acids, statins, and fibrates to reduce the risk of cardiovascular complications;
• hepatoprotectors.

If other weight loss methods are ineffective, bariatric surgery – gastric bypass and banding – can be utilized.

Progression of liver failure may be an indication for orthotopic liver transplantation.

All these treatment options are available in more than 150 hospitals worldwide (https://doctor.global/results/diseases/metabolic-liver-diseases). For example, liver transplantation can be performed in 14 clinics across Germany (https://doctor.global/results/europe/germany/all-cities/all-specializations/procedures/liver-transplantation). 

Prevention

To reduce the risk of developing nonalcoholic fatty liver disease, you should:

• lead an active lifestyle, avoid hypodynamia;
• control body weight, keep it within normal limits, avoid obesity;
• eat a healthy diet (the Mediterranean diet is the best option);
• undergo regular preventive examinations for timely diagnosis of diseases of the cardiovascular and endocrine systems.

Rehabilitation

Patients suffering from fatty hepatosis should monitor the course of the disease, timely detect its complications and correct therapy. Patients should periodically (once every 1-6 months, depending on the condition) visit the attending physician to conduct a minimum of examinations.