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.
The main cause is insulin resistance, which explains co-occurrence of NASH and syndrome X.
NASH can also be caused by the following medications:
- Antiviral drugs (nucleoside analogues)
- Aspirin / NSAIDS
- Perhexiline maleate
- Valproic acid
Signs and symptoms
Although most patients with NASH are asymptommatic, but others present with fatigue and abdominal discomfort. 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.
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.
Trials are presently being conducted to optimize treatment of NASH. Generally, treatment of underlying diabetes mellitus will be undertaken, including weight loss and insulin sensitizing drugs (metformin, pioglitazone or rosiglitazone).