What is the workup for a liver ultrasound showing hepatic (fatty liver disease) steatosis?

Workup for Hepatic Steatosis on Ultrasound

The workup for hepatic steatosis found on ultrasound should include comprehensive laboratory testing for liver function, metabolic parameters, and evaluation for both non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD), followed by fibrosis assessment using non-invasive methods such as FibroScan and FIB-4 score. 1

Initial Laboratory Evaluation

• Liver Function Tests:

  • Complete liver chemistry panel including ALT, AST, GGT, alkaline phosphatase, bilirubin (total and direct)
  • AST/ALT ratio assessment (>1 suggests alcoholic etiology, <1 suggests metabolic etiology) 1
  • Albumin, prothrombin time/INR to assess synthetic function

• Metabolic Workup:

  • Fasting glucose, HbA1c
  • Lipid profile (total cholesterol, LDL, HDL, triglycerides)
  • Assessment for metabolic syndrome components (hypertension, central obesity, dyslipidemia, insulin resistance) 1

• Exclusion of Other Liver Diseases:

  • Viral hepatitis serology (HBV, HCV)
  • Autoimmune markers (ANA, ASMA, immunoglobulins)
  • Iron studies (ferritin, transferrin saturation) for hemochromatosis
  • Ceruloplasmin (Wilson's disease)
  • Alpha-1 antitrypsin levels 1

• Alcohol Consumption Assessment:

  • Detailed alcohol history
  • Consider biomarkers for alcohol use: GGT, MCV, %CDT (carbohydrate-deficient transferrin) 1
  • Consider EtG (ethyl glucuronide) testing in urine or hair for objective alcohol assessment in suspected cases 1

Fibrosis Assessment

• Non-invasive Fibrosis Evaluation:
  • FibroScan (transient elastography) for liver stiffness measurement 2
    • <8 kPa: low risk of advanced fibrosis
    • 8-12 kPa: intermediate risk

    • 12 kPa: high risk, suggesting advanced fibrosis/cirrhosis

  • FIB-4 score calculation (using age, AST, ALT, and platelet count) 2
  • Consider Controlled Attenuation Parameter (CAP) measurement during FibroScan to quantify steatosis 1, 2

Additional Imaging

• Consider Advanced Imaging Based on Initial Findings:
  • If simple steatosis is suspected with normal fibrosis markers: no additional imaging required
  • If advanced fibrosis is suspected: consider MRI or MR elastography 1
  • If focal lesions are present: multiphasic contrast-enhanced CT, MRI, or contrast-enhanced ultrasound 2
  • If portal hypertension is suspected: Doppler ultrasound of portal system 2

Grading Steatosis Severity

Ultrasound findings can be graded as 1, 2:

• Mild steatosis: Mild diffuse increase in liver echogenicity, clear visualization of diaphragm and intrahepatic vessel walls
• Moderate steatosis: Moderate diffuse increase in liver echogenicity, obscuration of diaphragm and intrahepatic vessel walls
• Severe steatosis: Marked increase in liver echogenicity, non-visualization of diaphragm and intrahepatic vessel walls, significant posterior beam attenuation

Follow-up Recommendations

• Low-risk patients (normal liver enzymes, no fibrosis):

  • Lifestyle modifications (weight loss, exercise, dietary changes)
  • Annual liver function tests
  • Repeat FibroScan every 2-3 years 2

• High-risk patients (abnormal liver enzymes, evidence of fibrosis):

  • Referral to hepatologist
  • Liver function tests every 6 months
  • Annual FibroScan to monitor disease progression 2
  • Consider liver biopsy if discordant non-invasive test results or suspected advanced disease 1

Important Caveats

• Ultrasound has excellent sensitivity (84.8%) and specificity (93.6%) for moderate to severe steatosis but is less reliable for mild steatosis (sensitivity drops to 53-65%) 1, 3
• Ultrasound cannot reliably distinguish between NAFLD and NASH (non-alcoholic steatohepatitis) 1
• Obesity can limit the diagnostic accuracy of ultrasound 1
• The presence of inflammation or fibrosis can affect the ultrasound appearance and interpretation 1
• Consider referral to hepatology for patients with evidence of advanced fibrosis or cirrhosis, regardless of etiology 2