Can decompensated hepatitis B (HBV) infection cause pleural effusion?

Hepatic Hydrothorax in Decompensated Hepatitis B Infection

Yes, decompensated hepatitis B infection can cause pleural effusion, specifically a condition known as hepatic hydrothorax, which occurs in patients with cirrhosis and portal hypertension.

Pathophysiology of Hepatic Hydrothorax in Decompensated HBV

• Hepatic hydrothorax is defined as the accumulation of transudate 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, which are more often located on the right side 1.
• The negative intrathoracic pressure during inspiration "pulls" ascitic fluid through these diaphragmatic defects, creating a continuous flow from the abdomen to the thorax 2.
• Hepatic hydrothorax can occur in up to 4-6% of all cirrhotic patients and up to 10% in patients with decompensated cirrhosis 3.
• Notably, hepatic hydrothorax can sometimes develop even in the absence of clinically detectable ascites 4.

Clinical Characteristics

• Hepatic hydrothorax is more commonly located on the right side (73% of cases), though it can occur on the left side (17%) or bilaterally (10%) 2.
• The pleural fluid in hepatic hydrothorax is a transudate with low protein content and a serum-to-pleural fluid albumin gradient greater than 1.1 g/dl 1.
• The appearance of hepatic hydrothorax is associated with poor prognosis, with median survival ranging from 8-12 months 1.
• Hepatic hydrothorax can lead to respiratory failure and may be complicated by spontaneous bacterial infections (empyema) 1, 5.

Diagnosis

• Cardiopulmonary and primary pleural diseases must be ruled out before diagnosing hepatic hydrothorax 1.
• Diagnostic thoracentesis is essential, especially when infection of the pleural effusion is suspected 1.
• The protein content of pleural effusion in uncomplicated hepatic hydrothorax is low, and the serum-to-pleural fluid albumin gradient is greater than 1.1 g/dl 1.
• Diaphragmatic defects can be assessed using radioisotope techniques, magnetic resonance imaging, or color-Doppler ultrasonography 1.

Management Approach

First-line Management

• The first-line treatment relies on the management of ascites with diuretics and salt restriction 1.
• Therapeutic thoracentesis is indicated in patients with dyspnea but provides only transient relief 1.
• Chronic pleural drainage should be avoided due to the high risk of complications including pneumothorax, pleural infection, bleeding, and renal dysfunction from fluid loss 1.

Advanced Management Options

• Transjugular intrahepatic portosystemic shunt (TIPS) is recommended for recurrent symptomatic hepatic hydrothorax in selected patients 1.
• Pleurodesis can be considered for patients with refractory hepatic hydrothorax who are not candidates for TIPS or liver transplantation, though it has a high rate of complications (82%) 1.
• Thoracoscopic repair with mersilene mesh may be effective in selected patients with well-defined diaphragmatic defects 1.

Definitive Treatment

• Liver transplantation represents the best option for patients with refractory hepatic hydrothorax when indicated and possible 1.
• For patients with decompensated hepatitis B cirrhosis specifically, antiviral therapy with nucleos(t)ide analogues (NAs) should be initiated immediately if HBV DNA is detectable, regardless of the level of replication 1.
• Antiviral therapy can significantly modify the natural history of decompensated cirrhosis, improving liver function and increasing survival 1.

Complications and Prognosis

• Bacterial infections, including spontaneous bacterial empyema, can complicate hepatic hydrothorax and further worsen prognosis 5.
• Bacterial infections significantly increase the risk of decompensation in patients with HBV-related cirrhosis 6.
• Even with effective nucleos(t)ide analogue therapy, the risk of developing hepatocellular carcinoma remains high in patients with decompensated HBV cirrhosis 1.

Key Considerations in Management

• PegIFNα is contraindicated in patients with decompensated cirrhosis due to the risk of serious side effects including liver failure 1.
• Entecavir (1 mg daily) or tenofovir are the preferred treatment options for patients with decompensated HBV cirrhosis 1.
• Patients should be closely monitored for drug tolerability and rare side effects like lactic acidosis or kidney dysfunction 1.
• All patients with decompensated HBV cirrhosis and hepatic hydrothorax should be evaluated for liver transplantation 1.