Evaluation of Hepatic Fibrosis Staging in Non-Alcholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis Using Transient Elastography

Abstract

SUMMARY N on alcoholic fatty liver disease (NAFLD) is recognized as a clinical and pathological entity evolving from simple steatosis towards steatohepatitis, advanced fibrosis, liver failure and, in some cases, hepatocellular carcinoma. The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing in the context of the general epidemics of obesity and diabetes mellitus, which has become a public health issue. The clinical importance of this condition is not only due to its high prevalence in the general population, but also to the wide spectrum of risk factors, the indisputable link to the metabolic syndrome, and, of utmost importance, the potential evolution towards cirrhosis and hepatocellular carcinoma. The diagnosis of NAFLD was traditionally based on the histopathological changes of the liver, evaluated by needle liver biopsy (LB). Unfortunately, this is an invasive method, with potential adverse effects. Therefore, rapid, noninvasive assessment methods are being currently researched for non alcoholic fatty liver (NAFLD) patients. Several clinical studies have attempted to identify serum markers that might be correlated with the severity of histopathological findings in these patients. Many clinical variables have been proposed until now as predictors of severity in patients with NAFLD, including old age, underlying type 2 diabetes mellitus, obesity, serum transaminase levels, platelet count, etc. Transient elastography (Fibroscan) is a noninvasive method for the diagnosis of liver fibrosis. It has high degree of accuracy and reproducibility in predicting bridging fibrosis and cirrhosis in patients with viral hepatitis. Nevertheless, NAFLD patients are underrepresented in previous validation studies. Whether factors other than fibrosis, such as degree of hepatic steatosis and prehepatic fat, may affect liver stiffness is uncertain. The present study assessed the value of fibroscan as non invasive tool in the assessment of the degree of hepatic steatosis in patients with NAFLD in comparison to patients with non-alcoholic steatohepatitis NASH. This study was conducted on 44 patients suffering from dyspeptic symptoms, fatigue and unexplained elevation of aminotranseferases which were traced till the possibility of fatty liver disease was diagnosed by clinical, biochemical and imaging techniqyes. This study included two groups with fatty liver disease and were classified into two groups NAFLD group (n=22) and NASH group (n=22): The diagnosis of NAFLD was based on: 1. A history of no or limited daily alcohol intake (<20 g for women and <30 g for men), 2. Presence of ultrasonographic features of fatty liver, which include increased liver echogenicity. The diagnosis of NASH was based on: 1. A history of no or limited daily alcohol intake (<20 g for women and <30 g for men), 2. Increase aminotranseferases levels. 3. Ultrasound examination (moderate or severe liver steatosis with posterior attenuation) The studied patients were subjected to full history taking and clinical examination, routine laboratory investigations, lipid profile, fasting and two hours post prandial blood sugar, serological markers to exclude other causes of chronic liver diseases, abdominal ultrasonographic examination and fibroscan evaluation. This study revealed that there was a significant increase in the rate of diabetes mellitus, obesity and hyperlipidemia with higher grades of steatosis in the NASH group and also most of patients had elevated liver enzymes and other liver profiles were not affected.