Fatty liver disease is also referred to as Nonalcoholic Fatty Liver Disease (NAFLD) or Nonalcoholic Steatohepatitis (NASH). This is a group of conditions where there is accumulation of excess fat deposits over the liver seen among individuals who take little or no alcohol. Fatty liver disease is most common among obese and overweight individuals.
The condition is similar to alcoholic liver disease but the risk factors are different. There are essentially four stages of Nonalcoholic Fatty Liver Disease or fatty liver.
Stage 1 is simple fatty liver and is also called steatosis. In this stage excess fat builds up in the liver cells. This is abnormal but does not cause harm. Usually there are no symptoms at this stage.
Fatty changes of the liver cells mean accumulation of neutral fats or triglycerides within the liver cells.
Initially the cytoplasm of the liver cells show small fat filled vacuoles or sacs around the nucleus. This is called microvesicular fatty change. Here the vacuoles containing fat are multiple but do not displace the centrally located nucleus.
As the condition progresses the vacuoles increase in size and push the nucleus to the sides of the cell. This is called a signet ring appearance and is due to macrovesicular fatty change. Many of the cells with large vacuoles join together, to form fatty cysts.
Stage 2 is termed non-alcoholic steatohepatitis (NASH). This is a more severe condition than simple fatty liver and there is cellular level inflammation at this stage.
The patients with non-alcoholic steatohepatitis may have some symptoms including a dull pain at the right upper side of the abdomen and may feel tired or fatigued easily.
Stage 3 is also termed stage of fibrosis. With non-alcoholic steatohepatitis and its inflammatory processes, there is scarring of the liver tissues. These fibrous scar tissues around the liver cells and the blood vessels lead to formations of fibrosis.
This fibrous tissue eventually replaces the healthy liver tissues to a great extent but the liver still continues to function.
Stage 4 is termed as stage of cirrhosis where there is extensive scarring of the liver tissues severely affecting liver functions. The liver shrinks and becomes deformed.
Cirrhosis usually occurs years after development of inflammation of the liver.
With time the liver damage caused by cirrhosis may lead to liver failure.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)