Fatty Liver

Fatty Liver - What is Fatty Liver?

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. This fat deposit is also seen among alcoholics.

Non alcoholic fatty liver disease is seen in patients who drink little or no alcohol. The commonest form of Non alcoholic fatty liver disease is termed fatty liver.

Statistics

Fatty liver is a very common disorder and up to 20 percent of adults and approximately 5 percent of children are affected.

One of the common risk factors for this condition is obesity. Nearly two thirds of obese adults and half of obese children are found to have fatty liver.

Nonalcoholic Steatohepatitis – the more severe form of fatty liver – is seen in is around 20% of the obese individuals.

With the rise of obesity over the last couple of decades, there has been a rise in number of individuals with fatty liver.

Pathology

Having some amount of fats over the liver cells is normal and seldom causes damage to the liver. As the disease progresses to Nonalcoholic Steatohepatitis (NASH) there is presence of liver cell inflammation followed by formation scars within the liver tissues.

NASH may eventually lead to liver scarring and cirrhosis that leads to substantial damage to the liver and liver failure.

Causes and risk factors

Some of the risk factors for fatty liver disease include:-

  • Obesity
  • Diabetes
  • Metabolic syndromes that include diabetes, pre-diabetes or insulin resistance, being overweight or obese, having raised blood cholesterol and triglycerides and high blood pressure

Symptoms of fatty liver

Commonly there are no symptoms. There may, however, be some amount of abdominal pain that may be concentrated in the central or right upper part of the abdomen.

There may be fatigue and tiredness in addition.

The liver may be enlarged in some children.

Some patients experience dark discoloration of the skin called acanthosis nigricans that occurs in the neck or in the underarm region.

Diagnosis

Diagnosis is suspected in an obese individual. On blood tests there are mild elevations of the liver enzymes – Aspartate transaminase (AST) and Alanine transaminase (ALT). However, blood tests may also be normal in many cases.

An ultrasound of the abdomen, however, can show the fatty deposits over the liver and confirm the diagnosis.

A more confirmatory test is by taking a small sample of liver tissue from the affected liver. This is called a liver biopsy. The sample is stained appropriately and looked under the microscope. The abnormal fat deposits in the liver cells can be seen under the microscope.

Treatment

Patients are advised to take a healthy balanced diet and regular exercise in order to lose weight and maintain a normal body weight.

They are advised to avoid alcohol and unnecessary medications.

Diabetics and those with other associated conditions like high blood cholesterol, high blood pressure etc. need to be treated individually for the same.

Stages of liver damage. Image Credit: National Institute of Diabetes and Digestive and Kidney Diseases.

Fatty Liver Pathology

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

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

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

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

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.

Fatty Liver Diagnosis

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 patients who consume little or no alcohol.

Symptoms of fatty liver disease

Around 50 to 100% patients with fatty liver disease have no symptoms of the condition. Detection of the disease is more often than not an incidental finding on routine blood tests.

Some of the other symptoms that may be present include:-

  • Obesity
  • Enlarged liver
  • Fatigue and weakness
  • Vague pain over the right upper side of the abdomen
  • Rarely there may be intense itching
  • Anorexia or loss of appetite
  • Nausea and sometimes vomiting
  • Severe cases may lead to jaundice and development of fluid within the abdomen in a condition called ascitis
  • Bleeding in the gastrointestinal tract
  • Muscle wasting in advanced cases
  • Presence of surface blood vessel prominences called spider naevi and palmar erythema
  • Liver failure leading to hepatic coma or loss of consciousness or confusion due to advanced liver disease

Diagnosis

  • Routine blood tests show mild to moderate elevation of serum aminotransferases including Aspartate transaminase (AST) and Alanine transaminase (ALT).
  • Some patients have no raised liver enzymes in routine blood tests and thus these are not always indicative of fatty liver disease. Further there is no direct association between rise of serum aminotransferases and severity of inflammation of the hepatic cells.
  • Patients with fatty liver usually have an AST/ALT ratio less than 1. The AST/ALT ratio rises with the development of cirrhosis.
  • Other tests show mild rise in Serum alkaline phosphatases, bilirubin levels etc. The level of blood protein albumin is lowered. Blood coagulation or clotting profile shows lengthened prothrombin time. This however is seen only in very advanced cases.
  • In patients with metabolic syndrome there are additional rises in blood glucose, cholesterol, triglycerides etc.
  • Ultrasonography of the abdomen is one of the commonest imaging studies for diagnosis of fatty liver. This involves creation of images of organs within the abdomen using high frequency sound waves. Ultrasound images show fat deposits over the liver.
  • Other imaging studies include computed tomography (CT), and magnetic resonance imaging (MRI).
  • Magnetic resonance spectroscopy is one of the newer imaging techniques that gives a better picture of the fatty infiltration of the liver.
  • To confirm the diagnosis a small sample of liver tissue may be taken using a long thin hollow needle under the guidance of an imaging technique commonly ultrasound. The tissue sample or the biopsy sample is stained with appropriate dyes and is examined under the microscope for infiltration of liver cells with fat.