What are the liver ultrasound findings in hepatitis B and D co-infection?

Ultrasound Findings in Hepatitis B and D Co-infection

Patients with hepatitis B and D co-infection typically show more advanced liver damage on ultrasound compared to HBV mono-infection, with higher rates of cirrhosis and signs of portal hypertension evident at diagnosis.

Characteristic Ultrasound Findings

Early to Moderate Disease

• Heterogeneous liver parenchyma with increased echogenicity
• Coarse echotexture of the liver parenchyma
• Nodular liver surface (more prominent than in HBV mono-infection)
• Irregular liver margins
• Thickened gallbladder wall

Advanced Disease (Common at Diagnosis)

• Volume redistribution (enlarged caudate lobe with atrophy of right lobe)
• Prominent nodularity of the liver surface
• Significantly coarse parenchymal echotexture
• Regenerative nodules
• Signs of portal hypertension:
  • Splenomegaly
  • Portosystemic collaterals
  • Ascites
  • Dilated portal vein or reduced portal vein velocity

Clinical Context

HDV co-infection significantly accelerates liver disease progression compared to HBV mono-infection 1. Approximately 30-70% of patients with chronic hepatitis D already have cirrhosis at the time of diagnosis 2, making advanced ultrasound findings common at initial presentation.

Diagnostic Performance of Ultrasound

Ultrasound has varying diagnostic accuracy for detecting cirrhosis in viral hepatitis:

• Sensitivity: 77.8-82.4%
• Specificity: 70.7-92.5%
• Accuracy: 74.8-86.6% 3

The diagnostic accuracy is generally higher in HBV-related cirrhosis than in HCV-related cirrhosis 3, though specific data for HBV/HDV co-infection is limited.

Ultrasound Scoring Systems

Several ultrasound scoring systems have been developed to assess the severity of liver disease in viral hepatitis. These typically evaluate:

• Liver surface nodularity
• Parenchymal echotexture
• Vascular structure changes
• Splenic size 3, 4

Higher ultrasound scores correlate with more advanced fibrosis stages. A score of 7 or higher has been shown to be predictive of cirrhosis in HBV infection 3.

Limitations of Ultrasound

• Operator-dependent technique
• Limited sensitivity for early fibrosis
• May miss early cirrhotic changes
• Cannot reliably distinguish between different causes of cirrhosis 5
• Cannot definitively differentiate between HBV mono-infection and HBV/HDV co-infection based solely on ultrasound appearance

Recommended Imaging Approach

1. Baseline ultrasound at diagnosis of HBV/HDV co-infection
2. Regular ultrasound surveillance every 6 months for HCC in patients with advanced fibrosis or cirrhosis 1
3. Consider supplementing with transient elastography (FibroScan) for more accurate fibrosis assessment 1
4. Liver biopsy may still be necessary when clinical signs or imaging evidence of cirrhosis are absent 1

Practical Considerations

• Due to the high prevalence of cirrhosis at diagnosis in HBV/HDV co-infection, clinicians should have a low threshold for suspecting advanced liver disease even with subtle ultrasound findings
• Ultrasound findings should be interpreted in conjunction with clinical parameters, laboratory tests, and when available, elastography results
• The presence of advanced ultrasound findings in a patient with HBV should raise suspicion for possible HDV co-infection

In summary, ultrasound findings in HBV/HDV co-infection often reveal more advanced liver damage than would be expected in HBV mono-infection of similar duration, reflecting the more aggressive disease course associated with dual infection.