How Does Liver Fibrosis Occur?
Liver fibrosis is the excessive scarring of liver tissue, which is due to progressive liver inflammation and liver cell death in chronic liver diseases. Liver fibrosis occurs when liver tries to repair its damaged cells through deposition of new collagen fibers. This deposition of repaired tissue results in scarred tissue or fibrous tissue formation. This exaggerated wound healing response interferes with normal liver function.
How Does Liver Fibrosis Occur?
Liver fibrosis occurs due to repeated damage caused either by various drugs or by disorders. The hepatocytes/the functional liver cells are injured due to trauma, excess alcohol consumption, toxins, or virus such as hepatitis B or hepatitis C, biliary obstruction, autoimmune hepatitis, non-alcoholic fatty liver disease (NAFL), and alcoholic liver disease (ALD). However, very rarely is liver fibrosis the primary problem, mostly it is secondary to some other liver disease such as liver cirrhosis. The people who are at risk of developing liver fibrosis are people above the age of 50 years, immunocompromised patients, fatty liver(steatosis), resistance to insulin and who are infected with hepatitis B or C virus. Fibrosis is also believed to occur more rapidly in men than women.
Hepatitis C virus is known to result in 60-70% of cases and almost 75% of the cases of acute hepatitis turn into chronic hepatitis. Hepatitis B mostly occurs as a co-infection with hepatitis D and contributes to 5-10% of the cases. A 90% of the newborn suffering with acute hepatitis progress to chronic hepatitis and 25-50% also progress to chronic cases in young children.
Fatty liver mostly occurs in people who are obese, diabetic with abnormal levels of cholesterol and fats in the blood. These conditions will lead to synthesis of more fat and ultimately accumulation inside the liver cells causing fatty liver. This fatty liver causes chronic inflammation and liver cirrhosis.
Alcoholic hepatitis occurs in people who have been drinking heavily for many years. This leads to widespread inflammation and destruction of liver cells.
Drugs leading to chronic hepatitis are isoniazid, methyldopa, and nitrofurantoin when they are taken for a long period of time.
Other causes of chronic hepatitis include alpha-1 antitrypsin deficiency (a hereditary disorder, celiac disease and hemochromatosis. They all in turn lead to liver fibrosis and if not treated liver cirrhosis.
Stages of Liver Fibrosis
The stages determine the degree of damage afflicted to the liver. The activity or the prediction of how the fibrosis is progressing is done based on a popular scoring system called the METAVIR scoring system. The activity grade ranges from A0 to A3 with A0 having no activity, A1 showing mild activity, A2 showing moderate activity and A3 showing severe activity.
The Fibrosis Stages Range From F0 To F4:
F0: shows no evidence of fibrosis.
F1: shows portal fibrosis without septa formation.
F2: shows portal fibrosis with few septa formation.
F3: shows various septa without any cirrhosis.
F4: shows liver fibrosis.
The most severe form includes F3 and F4.
Symptoms of Liver Fibrosis
Generally liver fibrosis is not diagnosed in mild to moderate stages, as the symptoms do not usually occur until severe liver damage has occurred. The symptoms include loss of appetite, fatigue, lethargy, jaundice, nausea, vomiting, weight loss, accumulation of fluid in the legs and stomach, mental confusion, excessive sleepiness and coma. Mostly the symptoms are those of liver cirrhosis. The brain function deteriorates due to inability of the damaged liver cells to filter toxic substances from the blood, which in turn build up in the blood and reach the brain.
Management of Liver Fibrosis
Diagnosis is made based on physical examination, symptoms, blood tests, liver function tests (measuring level of liver enzymes and determining the liver function and presence of damage to the liver). Other tests used are ultrasound elastography, CT scan, magnetic resonance elastography and liver biopsy.
Treatment aims at curing the underlying cause and palliative treatment such as abstinence from alcohol in cases of alcohol abuse, weight reduction in cases of fatty liver and anti-viral drugs and interferon therapy in cases of hepatitis B and hepatitis C.