Non Alcoholic Fatty Liver Disease- Is It Always Benign?

Abstract

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease observed in the clinical practice of hepatology affecting approximately 20% of the general population. It is increasingly apparent that non alcoholic steatohepatits (NASH) and NAFLD are not Western disease. There is evolution of Western-style life among the Asian population and NASH has increasingly been diagnosed in several regions in Asia. NASH is considered as a type of a larger spectrum of NAFLD that is a consequence of insulin resistance and other underlying factors with histological findings ranging from fatty change alone to fat plus inflammation, to fat plus ballooning degeneration, and to fat plus alcoholic hepatitis-like lesions including Mallory body and fibrosis, the latter two categories being considered as NASH. Although liver biopsy is currently the gold standard for diagnosis, there is a need for less invasive methods. Imaging by ultrasound, computerized tomography and magnetic resonance are all able to demonstrate fat. Ultrasound, although probably not the most reliable imaging method, has many advantages and, when positive, gives a high degree of certainty of the diagnosis depending on the prevalence of fatty liver in the population being studied. Unlike liver biopsy, none of these techniques is able to differentiate simple steatosis from non- alcoholic steatohepatitis. The ultimate goal of treating the patient with NASH is to prolong life by avoiding the end-organ diseases associated with insulin resistance and the metabolic syndrome. Treatment of patients with nonalcoholic fatty liver has typically been focused on the management of associated conditions as well as discontinuation of potentially hepatotoxic drugs. Weight loss and exercise improve insulin sensitivity. Bariatric surgery may improve liver histology in patients with morbid obesity. Insulin sensitising drugs showed promise in pilot trials as have a number of hepatoprotective agents. Further randomised, well controlled trials are required to determine the efficacy of these drugs. In this article, we will review (1) various processes that are involved in the pathogenesis of NASH (2) the existing medical therapy for patients with nonalcoholic fatty liver, (2) the emerging and potentially useful medications. (J Bangladesh Coll Phys Surg 2007; 25 : 144-152)