Non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is fatty inflammation of the liver when this is not due to excessive alcohol use. It is thought to be the major cause of cryptogenic cirrhosis of the liver.

Classification

NASH fits into a spectrum of disease processes. The term non-alcoholic fatty liver disease (NAFLD), is in fact a spectrum of disease of which NASH is an extreme. 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 inflamation of the liver (i.e. NASH). Over time this may lead to cirrhosis. The exact reasons and mechanisims by which this disease progresses from one entity to the next is a subject of much research and debate.

Signs and symptoms

Most patients with NASH 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.

NASH is associated with obesity, hyperlipidemia, metabolic syndrome X, diabetes mellitus (type II) and insulin resistance.

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.Liangpunsakul S, Chalasani N. Is hypothyroidism a risk factor for non-alcoholic steatohepatitis? J Clin Gastroenterol 2003;37:340-3. PMID 14506393

Liver ultrasound is often done to distinguish the disease from gallstone problems (cholelithiasis).

A biopsy (tissue examination) of the liver is the only test which can distinguish NASH from other forms of liver disease.

Causes

The main cause is still unknown. However both obesity and insulin resistance likely play a strong role in this disease process.

NASH can also be caused by the following medications (termed secondary NASH):

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 ClinicLudwig 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., it has only recently become a major interest of clinicians.

References

External links

Medscape article on NASH.
MEDICINENET article on Steatosis.

Gastroenterology | Hepatitis

Esteatohepatitis no alcohólica

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