What is the Difference Between NASH and NAFLD

The main difference between NASH and NAFLD is that NASH or non-alcoholic steatohepatitis has the accumulation of fat, inflammation, and damage to the liver cells. But, NAFLD or non-alcoholic fatty liver disease is a pathological condition with excessive build-up of fat in the liver. Furthermore, NASH is a type of NAFLD, while the two types of NAFLD are NASH and NAFL or the non-alcoholic fatty liver. Moreover, NAFL only shows the accumulation of fat in the liver. 

NASH and NAFLD are two pathological conditions, which shows an excessive buildup of fat in the liver along with the insulin resistance. Generally, these conditions arise due to causes other than alcohol use.  

Key Areas Covered 

1. What is NASH
     – Definition, Features, Significance
2. What is NAFLD
     – Definition, Features, Significance
3. What are the Similarities Between NASH and NAFLD
     – Outline of Common Features
4. What is the Difference Between NASH and NAFLD
     – Comparison of Key Differences

Key Terms 

Accumulation of Fat, Inflammation, NAFL, NAFLD, NASH

What is NASH 

NASH (non-alcoholic steatohepatitis) is the most serious form of NAFLD, the non-alcoholic fatty liver disease. Generally, NAFLD can progress into NASH, and eventually leading to serious complications such as cirrhosis, liver cancer, liver failure, or cardiovascular disease. Of these, cirrhosis is a more severe form of liver damage or advanced liver scarring, which may impair liver function. Also, patients with cirrhosis have a higher risk of developing liver cancer and may need a liver transplant. Besides, there is about a 20% chance to develop NASH in people with NAFLD.

Figure 1: Stages of Liver Damage

Furthermore, the above scarring or fibrosis develops due to the accumulation of fat, inflammation, and liver cell damage. Concerning the symptoms of NASH, it includes fatigue, swelling of the abdomen (ascites), enlarged blood vessels just below the skin, enlarged spleen, red palm, and jaundice (yellowing of the skin and eyes). 

What is NAFLD 

NAFLD (non-alcoholic fatty liver disease) is one of the leading causes of liver disease characterized by the development of excessive fat in the liver due to causes other than alcoholic consumption. Also, it occurs along with the resistance to insulin, which in turn builds up the three risk factors of NAFLD; obesity, type 2 diabetes, and metabolic syndrome in combining with a large waistline, high blood pressure, low HDL cholesterol, high triglycerides, and diabetes. Consequently, they cause over-weight. On that account, the treatment of NAFLD is the weight-loss by dietary changes and exercises. 

Figure 2: NAFLD Prevalence

Moreover, the other health issues that can develop into NAFLD include high cholesterol, high triglycerides, sleep apnea, hyperthyroidism, hyperpituitarism, POS, etc. Also, the common symptoms of NAFLD include fatigue, enlarged liver, and the pain in the upper right abdomen. Besides, there are two types of NAFLD; NASH and NAFL. Here, NAFL (non-alcoholic fatty liver) is characterized only by the accumulation of fat in the liver. Therefore, there is no inflammation, and hence, it is less serious than NASH. Also, it does not progress into NASH. Furthermore, although it is a leading cause of liver disease in the USA, NAFLD is less common in African Americans. Hence, the likeliness of the development of NAFLD depends on ethnicity.  

Similarities Between NASH and NAFLD  

• NASH and NAFLD are two pathological conditions, which show an excessive buildup of fat in the liver.  
• Also, along with NAFL, they are the three leading causes of liver disease.  
• Basically, both occur along with insulin resistance, which arises due to causes other than alcohol use.    
• Mainly, they occur in individuals with over-weight.  
• Generally, both cause fewer or no symptoms until liver damage is significant. However, certain health conditions may develop, such as obesity, metabolic syndrome,  and type 2 diabetes.  
• Apart from that, the possible symptoms include fatigue, enlarged liver, pain in the upper right abdomen, etc.    
• Usually, diagnosis is done through the physical exam, medical history, and tests including blood tests,  imaging tests, liver biopsy, etc.  
• Moreover, weight loss is the treatment for these diseases as it reduces the fat, inflammation,  and fibrosis in the liver. Also, a healthy diet is important as well. 

Difference Between NASH and NAFLD 

Definition 

NAFLD (non-alcoholic fatty liver disease) refers to pathological conditions of accumulation of excess, non-alcoholic fat in the liver. But, NASH (non-alcoholic steatohepatitis) refers to the liver inflammation and damage caused by a buildup of fat in the liver. 

Correspondence 

NASH is a type of NAFLD, while the two types of NAFLD are NASH and NAFL or the non-alcoholic fatty liver.  

Significance 

NASH has the accumulation of fat, inflammation, and damage to the liver cells. In contrast, NAFLD is a pathological condition with excessive build-up of fat in the liver, while NAFL only has the accumulation of fat in the liver. 

Symptoms 

The symptoms of NASH include fatigue, swelling of the abdomen (ascites), enlarged blood vessels just below the skin, enlarged spleen, red palm, and jaundice. Meanwhile, the symptoms of NAFLD include fatigue, enlarged liver, and the pain in the upper right abdomen.  

Severity 

NASH is more severe as it leads to cirrhosis, but NAFLD is less severe. 

Conclusion 

NAFLD is a pathological condition, characterized by the accumulation of fat due to causes other than alcohol use. While NASH is one type of it, the second type of NAFL or the non-alcoholic fatty liver. That is; NASH or non-alcoholic steatohepatitis is the severe form of NAFLD. Generally, the main characteristic features of NASH include the accumulation of fat along with inflammation and liver cell damage. And, it can lead to cirrhosis. But, NAFL is less severe as its only characteristic feature is the development of fat in the liver with no inflammation. Hence, the main difference between NASH and NAFLD is the characteristic features and severity. 

References:

1. “Definition & Facts of NAFLD & NASH.” National Institute of Diabetes and Digestive and Kidney Diseases, U.S. Department of Health and Human Services, 1 Nov. 2016, Available Here.

Image Courtesy:

1. “Stage of liver damage high” By NIDDK (Public Domain) via Commons Wikimedia   
2. “NAFLD-prevalence-2019” By Signimu – Own work (CC0) via Commons Wikimedia