Nonalcoholic fatty liver disease

Dr Henry Knipe and Dr Matt A. Morgan et al.

Nonalcoholic fatty liver disease (NAFLD) occurs when fat is deposited into hepatocytes without a known cause (such as with alcoholic fatty liver disease). The deposition of fat may lead to hepatic inflammation (hepatitis) and may eventually lead to cirrhosis.

"Nonalcoholic fatty liver disease" (NAFLD) is differentiated by some into:

  • nonalcoholic fatty liver (NAFL)
    • signs of hepatic inflammation are absent
  • nonalcoholic steatohepatitis (NASH)
    • signs of hepatic inflammation are present

NAFLD has a prevalence of ~30% (range 10-46%) in the U.S. 2 and a prevalence worldwide of 6-35% 3. NASH has a prevalence of 3-5% 3.

It is more commonly seen at ages 40-60. No gender predominance has been noted.

Often asymptomatic, although vague abdominal pain has been reported. Hepatomegaly has been reported in a minority of patients. Elevated liver enzymes (such as AST/ALT) may be present, especially with NASH. 

NAFLD has been associated with dysmetabolic conditions:

The pathogenesis of NAFLD is not well understood.

The role of imaging is to demonstrate fat deposition in the liver, determine if cirrhotic changes are present, and to exclude other possible diagnoses. For general features of fatty deposition in the liver, see: diffuse hepatic steatosis.

Ultrasound
CT
  • diffuse hypoattenuation of the liver relative to the spleen
    • noncontrast liver attenuation of <40 is specific, but not sensitive for diffuse hepatic steatosis
MRI
  • IP/OP: drop in signal intensity in liver on the out-of-phase sequence, compatible with intracellular lipid deposition

Liver biopsy may be needed in indeterminate situations to establish the diagnosis.

No definitive treatment has been established for NAFLD, but weight loss is thought to eliminate one of the factors contributing to the condition.

Patients who develop cirrhosis from NASH are treated similarly to other patients with cirrhosis.

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Article information

rID: 34751
Section: Pathology
Synonyms or Alternate Spellings:
  • Fatty liver hepatitis
  • Diabetic hepatitis
  • Nonalcoholic steatohepatitis
  • NASH
  • NAFLD
  • NAFL
  • Nonalcoholic fatty liver disease (NAFLD)
  • Non-alcoholic fatty liver disease (NAFLD)

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