Non-Alcoholic Fatty Liver Disease (NAFLD)
Non-Alcoholic Fatty Liver Disease (NAFLD)
McKenzie Pediatrics 2018
Non-alcoholic fatty liver disease (NAFLD) refers to a group of conditions where there is accumulation of excess fat in the liver of people who drink little or no alcohol. The most common form of NAFLD is a non-serious condition called fatty liver. In fatty liver, fat accumulates in the liver cells. Although having fat in the liver is not normal, by itself it probably does not damage the liver.
However, a small group of people with NAFLD may have a more serious condition named non-alcoholic steatohepatitis (NASH). In NASH, fat accumulation is associated with liver cell inflammation and different degrees of scarring. NASH is a potentially serious condition that may lead to severe liver scarring and cirrhosis.
Cirrhosis occurs when the liver sustains substantial damage, and the liver cells are gradually replaced by scar tissue, which results in the inability of the liver to work properly. Some patients who develop cirrhosis may eventually require a liver transplant (surgery to remove the damaged liver and replace it with a "new" liver). The development of cirrhosis at a young age will likely result in a shortening of a person's eventual lifespan.
The majority of individuals with NAFLD have no symptoms and a normal examination. Children may exhibit symptoms such as abdominal pain, which may be in the center or the right upper part of the abdomen, and sometimes fatigue. However, other causes of abdominal pain and fatigue should be considered. On physical examination, the liver might be slightly enlarged and some children may have patchy, dark discoloration of the skin present (acanthuses nigricans) most commonly over the neck and the under arm area.
Causes of NAFLD/NASH
NAFLD is part of the Metabolic Syndrome characterized by diabetes, or pre-diabetes (insulin resistance), being overweight or obese, elevated blood lipids such as cholesterol and triglycerides, as well as high blood pressure. Not all patients have all the manifestations of the metabolic syndrome.
Less is known about what causes NASH to develop. Researchers are focusing on several factors that may contribute to the development of NASH. These include:
- Oxidative stress (imbalance between pro-oxidant and anti-oxidant chemicals that lead to liver cell damage)
- Production and releases of toxic inflammatory proteins (cytokines) by the patient's own inflammatory cells, liver cells, or fat cells
- Liver cell necrosis or death, called apoptosis
- Adipose tissue (fat tissue) inflammation and infiltration by which blood cells
NAFLD is a very common disorder affecting and may affect as many as one in three adults and around one in four adolescents in the United States. Obesity is thought to be the most common cause of fatty infiltration of the liver. Some experts estimate that about two thirds of obese adults and half of obese children may have faty liver. Up to 25 percent of adults who are obese may suffer from the more severe condition NASH! The number of children who have NASH is not known, but it it known that the numbers are climbing rapidly. The presence of type 2 diabetes and other conditions associated with insulin resistance, such as polycystic ovarian syndrome, are also known risk factors for the development of fatty liver and NASH.
The diagnosis of NAFLD is usually first suspected in an overweight or obese person who is found to have mild elevation in their liver tests during a routine blood testing or incidentally detected on radiologic investigations such as abdominal ultrasound or CT scan. Some experts are now recommending that every obese child or adolescent should have these liver enzymes checked.
The diagnosis of NAFLD is confirmed by imaging studies, most commonly liver ultrasound, showing accumulation of fat in the liver. But the only reliable way of telling whether a person has NASH o just simple fatty liver is by a liver biopsy. A liver biopsy is not routinely done just because there is fatty liver...usually it is worsening liver disease as evidenced by worsening labs or clinical signs or symptoms that necessitate a biopsy.
In this procedure, a small needle is inserted through the skin after local anesthesia is given to obtain a small piece of the liver for microscopic evaluation. NASH is diagnosed when examination of this piece of liver under the microscope shows fatty infiltration of the liver in addition to inflammation and different degrees of scarring. If only fat is present, then the diagnosis of simple fatty liver is made. The liver biopsy provides essential information regarding the degree of scarring within the liver, which would not be apparent on a blood test, ultrasound, or an x-ray alone. Liver biopsy rarely can be associated with serious risks including bleeding and patients should discuss the risks and benefits of the procedure with their physician.
Treatment of NAFLD/NASH
A few studies have suggested that weight loss may be associated with regression of fat within the liver. Therefore, the most important recommendations for people with fatty liver are to lose weight if they are overweight or obese, increase their physical activity, follow a balanced diet and avoid alcohol and unnecessary mediations. New evidence suggests that Mediterranean diet (rash in monounsaturated fatty acids) may be more beneficial than low fat diet.
What is most important is to significantly reduce your child's consumption of processed grains and also high-fructose corn syrup (HFCS). Todays' kids and teens are consuming up to ¾ th of their daily calories from foods made from wheat flour (pancakes, waffles, most breakfast cereals, bagels, breads, pizza, pasta, snack crackers, buns, and more). Parents should limit their child's intake of such foods to one serving daily, and should avoid purchasing foods and beverages sweetened by HFCS. Parents control what foods are brought into the home; the family diet should emphasize proteins, good fats, fruits, and vegetables day in and day out.
If your child or teen has been diagnosed with NAFLD (by labs or ultrasound), except a repeat of lab testing every 6-12 months to follow the liver disease. If your child is also obese, such testing will include measurements to screen for the development of type 2 diabetes. In America today, one out of four new cases of type 2 diabetes is being diagnosed in children under the age of 19!