('''NAFLD''') is fatty of the liver.Clark JM, Diehl AM. Nonalcoholic fatty liver disease: an underrecognized cause of cryptogenic cirrhosis. ''JAMA'' 2003;289:3000-4. PMID 12799409.
Most patients with NAFLD have no or few symptoms. Infrequently patients may complain of fatigue,
Malaise and dull right upper quadrant
Abdominal Discomfort . Mild
Jaundice can rarely be noticed. More commonly it is diagnosed as a result of abnormal
Liver Function Tests during routine blood tests. By definition, alcohol consumption of over 20 g/day excludes the condition.
NAFLD is associated with
Insulin Resistance and the
Metabolic Syndrome (
Obesity ,
Combined Hyperlipidemia ,
Diabetes Mellitus (type II) and
High Blood Pressure ).
NAFLD can also be caused by the following medications (termed ''secondary'' NAFLD):
Disturbed
Liver Enzyme s are common, and liver
Ultrasound may show
Steatosis ; it may also be used to exclude
Gallstone problems (
Cholelithiasis ). A
Biopsy (tissue examination) of the
Liver is the only widely accepted test which can distinguish NASH from other forms of liver disease, and can be used to assess the severity of the inflammation and resultant fibrosis.
Other tests generally performed are other blood tests (
Erythrocyte Sedimentation Rate ,
Glucose ,
Albumin ,
Renal Function etc.) As the liver is important in
Coagulation , some coagulation studies will generally be done, especially the INR (international normalized ratio). To distinguish this disease from viral
Hepatitis , blood tests (
Serology ) are generally done (hepatitis A, B, C,
EBV ,
CMV and
Herpes viruses, as well as
Rubella ) to ensure these are not playing a role. Additionally, autoimmune causes are ruled out with serology.
TSH is warranted, as
Hypothyroidism is more prevalent in NASH patients.Liangpunsakul S, Chalasani N. Is hypothyroidism a risk factor for non-alcoholic steatohepatitis? ''J Clin Gastroenterol'' 2003;37:340-3. PMID 14506393
NAFLD is considered a spectrum of disease activity. This spectrum begins as fatty accumulation in the liver (hepatic
Steatosis ). A fatty liver can remain without disturbing the function of the liver, but by varying mechanisms and possible insults to the liver, may progress to outright
Inflammation of the liver. When inflammation occurs in this setting, the condition is then called NASH. Over time, up to 20 percent of patients with NASH may develop
Cirrhosis .
The exact cause is still ''unknown''. However both
Obesity and
Insulin Resistance likely play a strong role in this disease process. The exact reasons and mechanisms by which this disease progresses from one entity to the next is a subject of much research and debate.
One such debated mechanisim proposes a "second hit", or further injury, enough to cause change that leads from hepatic steatosis to
Hepatic inflammation.
Oxidative Stress , hormonal imbalances and
Mitochondrial abnormalities may be potential causes for this "second hit"
Phenomenon .
Trials are presently being conducted to optimise treatment of NASH. No standard treatment has yet emerged as the "gold standard". General recommendations include improving metabolic risk factors and reducing alcohol intake.
A large number of treatments have been studied for NAFLD. While many may improve biochemical markers, such as
Alanine Transaminase levels, most have not been shown to reverse the histological abnormalities or reduce clinical endpoints:
NASH was described in 1980 in a series of patients of the
Mayo Clinic Ludwig J, Viggiano TR, McGill DB, Oh BJ. Nonalcoholic steatohepatitis: Mayo Clinic experiences with a hitherto unnamed disease. Mayo Clin Proc. 1980;55:434-438. PMID 7382552.. Its relevance and high prevalence were recognized mainly in the 1990s.
