Fatty liver (steatosis hepatis) is a disease of the liver in which the cells (hepatocytes) are filled with fat.
It is a reversible liver disease, the liver is not yet severely diseased, but something should be done about it.
Steatosis hepatis is divided into:
- Alcoholic fatty liver disease
- Non-alcoholic fatty liver disease
The only difference is practically the alcohol.
A threshold of < 20 g of alcohol per day for women and < 30 g for men is usually used to diagnose hepatis steatosis.
If inflammation is present, the disease becomes non-alcoholic fatty liver hepatitis (steatohepatitis), which over time can progress to cirrhosis and hepatocellular carcinoma.
Steatosis hepatis is associated with obesity, diabetes and lipid metabolism disorders (dyslipidemia).
It has been described as a hepatic manifestation of metabolic syndrome.
Classification of fatty liver
Microvesicular (small droplet) steatosis is characterized by many small blisters filled with fat inside the cells.
This disease can go into fatty liver hepatitis and cirrhosis.
It is a severe form of hepatic steatosis that usually occurs during pregnancy or secondarily in Reye’s syndrome.
Macrovesicular (large droplet) steatosis is so called because it has a large bubble with lipids inside the cell. It has a better prognosis than microvesicular steatosis and is reversible under therapy.
As a rule, alcohol, obesity or diabetes is the cause.
Stages of hepatic steatosis
Steatosis hepatis closely resembles alcohol-induced liver affection, but is caused by factors other than alcohol. The four phases are described below.
Phase 1: simple fatty liver (steatosis)
Hepatic steatosis is the 1st phase of the disease. It occurs when excess fat accumulates in the liver cells, but is considered harmless. In most cases, there are no symptoms and you do not know that you are ill until a blood test shows deviations from the reference values.
Phase 2: non-alcoholic fatty liver hepatitis (steatohepatitis)
Few people with simple fatty liver develop a 2nd phase of the disease called non-alcoholic steatohepatitis.
This is a more aggressive form of the disease, in which the liver becomes inflamed.
Inflammation is a reaction of the body to damage or lesions, in this case it is a sign that liver cells are damaged.
Phase 3: Fibrosis Some people with hepatic steatosis develop fibrosis
over time. In the process, fibrous connective tissue forms around the cells and blood vessels of the liver.
This fibrous tissue replaces some of the healthy liver tissue, but there is still enough healthy liver tissue to allow normal functioning.
Phase 4: Cirrhosis
In this serious phase, scar marks and liver cell nodules develop. The liver shrinks and becomes fibrotic.
This phenomenon is known as cirrhosis.
Cirrhosis occurs after 50-60 years of life, after many years of inflammation of the liver.
People with cirrhosis of the liver caused by steatosis hepatis often also have type 2 diabetes. The damage caused by cirrhosis persists and cannot be repaired.
The slowly progressing cirrhosis causes an obstruction of liver function over the course of many years. This phenomenon is called hepatic insufficiency.
Acute gestational fatty liver is a rare and dangerous complication of pregnancy that usually occurs in the last trimester of pregnancy.
It is believed that the cause is a disorder of the metabolism of fatty acids in the mitochondria of the mother, which is caused by an enzyme deficiency.
This condition used to be fatal, but today the prognosis is better when aggressive therapy is given to stabilize the mother through infusions and blood products before birth.
Causes of steatosis hepatis
The consumption of alcohol causes liver disease.
Two-thirds of chronic alcohol users have fatty liver and alcohol-induced hepatitis.
Alcoholics can suffer from diseases such as chronic pancreatitis or dilated cardiomyopathy, which lead to heart failure with a poor prognosis.
Daily consumption of 60-80 g of alcohol in men and 40-50 g in women is considered a toxic dose.
Women are more sensitive than men.
The behavioral patterns associated with alcohol appear to be hereditary.
Infections with the hepatitis B or C virus and an unbalanced diet make the disease more serious.
Chemotherapy can cause steatosis hepatis or steatohepatitis in the patient.
In the case of a tumor, this disease is even more dangerous, because it can hide some small liver metastases.
Signs and symptoms of hepatic steatosis
Most people with hepatic steatosis have no symptoms, and liver disease is often discovered by accident when blood tests show elevated levels of liver enzymes.
This is the most common cause of unexplained and persistently elevated liver enzymes after hepatitis and other chronic diseases of the liver.
The most common symptoms caused by fatty liver are:
- Fatigue and weakness
Complications of fatty liver
Fatty liver hepatitis, like other liver diseases, can progress to cirrhosis and hepatic insufficiency.
The progression to cirrhosis is faster if there is alcoholic liver disease or a concomitant liver disease (for example, chronic viral hepatitis).
Lack of controls for hyperlipidemia or diabetes also accelerates the progression of fibrosis.
Hepatocellular carcinoma can occur with the same probability as other liver diseases.
If cirrhosis begins, the patient falls ill and there are other consequences for the liver, for example:
- Cobweb angiomas
- Hardened liver margin
- Palmarerythema (redness of the palm of the hand)
- Varicose veins of the esophagus (esophageal varices)
- Jaundice (jaundice)
- Mental confusion (hepatic encephalopathy)
- Right-sided flank pain in the upper part or diffuse discomfort
Most patients also have the characteristics of metabolic syndrome: obesity (47% – 90%), diabetes mellitus (28% – 55%) and, in varying percentages, hypertension and hyperlipidemia (4% – 92%).
Infantile steatosis hepatis has as a complication an early change in heart function.
Diagnosis of fatty liver
Liver enlargement is often noticed during a clinical examination or ultrasound.
A definitive diagnosis can only be made by a liver biopsy and histopathological examination.
Researchers are trying to find non-invasive markers for hepatic steatosis. However, there is currently no generally accepted method besides liver biopsy.
Blood test for fatty liver
In a patient with suspected steatosis hepatis, a blood test is useful to determine the level of AST, ALT, total bilirubin and direct bilirubin, fasting blood glucose and lipidemia.
Slightly elevated levels of aminotransferases (ALT or GPT) in the blood are often found.
In general, the ratio of AST to ALT is less than 1, but this ratio increases slowly as fibrosis progresses.
Liver enzyme levels are normal in most patients with non-alcoholic steatosis hepatis.
Normal values of transaminases (ALT or GPT) do not exclude the presence of the disease in advanced phase.
Alkaline phosphatase in the blood and g-glutamine transpeptidase (GGT) may be slightly abnormal. Since more than 80% of patients with nonalcoholic fatty liver disease have some components of metabolic syndrome, it is necessary to measure cholesterol and triglycerol levels in addition to blood sugar in a fasting state.
The values of platelets, bilirubin and albumin are usually normal if the disease has not yet developed into cirrhosis. Some patients with non-alcohol-induced fatty liver have low autoimmune antibodies (for example, antinuclear antibodies) and elevated ferritin levels. The significance of these markers is still unclear.
Diagnostic imaging techniques can be used to define the extent and course of the disease. Steatohepatitis is usually diffuse, while steatosis can be focal or diffuse.
This examination shows a clear and hyperechogenic picture.
Echography gives an accurate diagnosis of fatty liver in advanced phase, but is not helpful in the initial phase of fatty liver.
A CT scan can be useful to show the course of the disease.
Magnetic resonance imaging can be used to assess fat infiltration, the stage and extent of liver disease or other liver diseases (with the use of contrast media).