Can decompensated hepatitis B (HBV) cause pleural effusion?

Decompensated Hepatitis B Can Cause Pleural Effusion

Yes, decompensated hepatitis B can cause pleural effusion, specifically in the form of hepatic hydrothorax, which is a well-recognized complication of decompensated cirrhosis regardless of etiology. 1

Pathophysiology of Hepatic Hydrothorax in Decompensated HBV

• Hepatic hydrothorax is defined as the accumulation of transudate (>500 mL) in the pleural space of patients with decompensated cirrhosis in the absence of cardiac, pulmonary, or pleural disease 1
• The primary mechanism involves the movement of ascitic fluid from the peritoneal cavity into the pleural space through small diaphragmatic defects 1, 2
• These diaphragmatic defects are more commonly located on the right side (73% of cases), though they can also occur on the left side (17%) or bilaterally (10%) 2
• During inspiration, negative intrathoracic pressure "pulls" ascitic fluid through these diaphragmatic defects, creating continuous flow from abdomen to thorax 2
• Portal hypertension, which is present in decompensated HBV cirrhosis, is the primary driver of ascites formation that subsequently migrates to the pleural space 2

Clinical Characteristics and Diagnosis

• Hepatic hydrothorax occurs in approximately 4-6% of all cirrhotic patients and up to 10% in patients with decompensated cirrhosis 3
• The pleural fluid in hepatic hydrothorax is a transudate with:
  • Low protein content
  • Serum-to-pleural fluid albumin gradient greater than 1.1 g/dL 1
  • May have higher protein content than concurrent ascites due to hydrostatic pressure gradients 2
• Diagnostic thoracentesis is essential, especially when infection of the pleural effusion is suspected 1
• Cardiopulmonary and primary pleural diseases must be ruled out before diagnosing hepatic hydrothorax 1
• Importantly, hepatic hydrothorax can occasionally occur even in the absence of clinically detectable ascites 4

Prognostic Implications

• Hepatic hydrothorax is associated with poor prognosis, with:
  • Median survival ranging from 8-12 months 1
  • Mortality rates at 90 days of up to 74% despite moderate MELD scores 2
• The presence of hepatic hydrothorax indicates advanced liver disease with significant portal hypertension 3

Management Approach

• First-line treatment relies on management of the underlying decompensated liver disease:
  • Diuretics and salt restriction 1, 2
  • For decompensated HBV specifically, antiviral therapy with nucleos(t)ide analogues should be initiated immediately if HBV DNA is detectable 1
  • Entecavir (1 mg daily) or tenofovir are preferred for patients with decompensated HBV cirrhosis 1
• Therapeutic thoracentesis is indicated for dyspneic patients but provides only temporary relief as fluid rapidly reaccumulates 1, 2
• Transjugular intrahepatic portosystemic shunt (TIPS) should be considered for recurrent symptomatic hepatic hydrothorax in selected patients 1
• Liver transplantation represents the definitive treatment for patients with refractory hepatic hydrothorax when indicated and possible 1

Potential Complications

• Spontaneous bacterial empyema (infected pleural fluid) 2, 5
• Progressive respiratory failure 2
• Trapped lung syndrome 2
• Complications from thoracentesis (pneumothorax, bleeding) 2
• Protein depletion and malnutrition with prolonged pleural drainage 2

Important Caveats

• Chronic chest tube drainage is not recommended due to high risk of complications 2
• Chemical pleurodesis may be considered in patients who are not candidates for TIPS or transplantation, but has a high complication rate (82%) 2
• Close monitoring for drug tolerability and rare side effects like lactic acidosis or kidney dysfunction is necessary when using antivirals in decompensated HBV cirrhosis 1
• Spontaneous bacterial empyema can be the first sign of decompensation in cirrhotic patients 5