Non-alcoholic steatohepatitis
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As its name signifies, Non-alcoholic steatohepatitis (NASH) or Nonalcoholic Fatty Liver Disease (NAFLD) is fatty inflammation of the liver when this is not due to excessive alcohol use. It is a major cause of cryptogenic cirrhosis of the liver.
It differs from the simple accumulation of fat in the liver (fatty liver, or hepatic steatosis) in that the inflammation of NASH causes damage to the liver cells while simple fatty liver probably does not.
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Signs and symptoms
Sometimes dull right upper quadrant pain is felt, occasionally radiating to the right shoulder. Mild icterus (jaundice) can sometimes be noticed.
NASH is associated with metabolic syndrome X, diabetes mellitus (type II) and insulin resistance.
Laboratory, imaging and diagnosis
Disturbed liver enzymes are common. 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.
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. TSH is warranted, as hypothyroidism is more prevalent in NASH patients [1] (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14506393&dopt=Abstract).
Liver ultrasound is often done to distinguish the disease from gallstone problems (cholelithiasis).
Usually, a liver biopsy will have to be done to distinguish NASH from other causes of hepatitis.
Causes
The main cause is insulin resistance, which explains co-occurrence of NASH and syndrome X.
NASH can also be caused by the following medications:
- Amiodarone
- Antiviral drugs (nucleoside analogues)
- Aspirin / NSAIDS
- Corticosteroids
- Methotrexate
- Nifedipine
- Perhexiline maleate
- Tamoxifen
- Tetracycline
- Valproic acid
Treatment
Trials are presently being conducted to optimise treatment of NASH. Generally, treatment of underlying diabetes mellitus will be undertaken, including weight loss and insulin sensitising drugs (metformin, pioglitazone or rosiglitazone).
History
Although NASH was described in 1980 in a series of patients of the Mayo Clinic, it has only recently become a major interest of clinicians.
References
- 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.
External links
- Medscape (http://www.medscape.com/viewarticle/458509_1) article on NASH.
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