Direct proof of hepatic hydrothorax by intracavitary contrast-enhanced ultrasound
[Mar 2022]

A 71years old male patient was diagnosed with non-alcoholic fatty liver cirrhosis and portal hypertension in 2019. He suffered from arterial hypertension and diabetes mellitus since 2013 and was first hospitalized with an episode of ascitic decompensation in August 2019. Now he was re-admitted to the hospital with dyspnea.

On ultrasound, a right-sided pleural effusion was diagnosed (Fig. 1). Diagnostic thoracocentesis and pleural drainage were performed. Only a small amount of perihepatic ascites was found (Fig. 2). Laboratory analysis of the pleural effusion revealed a transudate. A hepatic hydrothorax was suspected. To prove this diagnosis, after antiseptic preparation, ultrasound-guided injection of 10 ml saline with a drop of SonoVue ultrasound contrast agent was performed directly below the right diaphragm into the ascites (Video 1 and 2). In CEUS mode, intense enhancement of ascites was observed. With a slight time delay, isolated microbubbles were first visible in the pleural effusion, followed by a moderate enhancement of the entire pleural effusion as well (Video 2, Fig. 3).

Hepatic hydrothorax as a complication of NASH-cirrhosis with portal hypertension

BACKGROUND
There are many causes of unilateral pleural effusions. Diagnostic puncture with biochemical analysis, supplemented, if necessary, by cytological and microbiological analyses, allows differentiation into transudate or exudate and can also provide specific clues to the etiology. In this case, a transudate was detected. In most cases, this will be caused by cardiac insufficiency or hypervolemia. Hepatic hydrothorax should be considered in patients with liver cirrhosis and portal hypertension.

CLINICAL PERSPECTIVE
Hepatic hydrothorax is a rare clinical manifestation of portal hypertension and was described to occur in up to 15% of patients hospitalized due to decompensated liver cirrhosis and ascites. Hepatic hydrothorax virtually always presents with ascites, but often the amount of ascites is relatively small. Typically, hepatic hydrothorax presents as unliteral right-sided pleural effusion. Pathophysiology is related to direct passage of ascitic fluid from the peritoneal cavity to the pleural cavity through small diaphragmatic defects due to an increased abdominal pressure. These small diaphragmatic defects are not detectable with ultrasound or other imaging modalities (1-3).

THERAPY PLANNING
Pleural interventions (therapeutic thoracocentesis, indwelling pleural catheters, pleurodesis) have limited efficacy and are associated with a relatively high risk of infection and mortality (4, 5). Hepatic hydrothorax is treated like ascites aiming at the elimination of the fluid in both peritoneal and pleural cavities by maintaining a negative sodium balance, through dietary sodium intake and diuretics (aldosterone antagonists and loop diuretics). In refractory cases, transjugular intrahepatic stent shunt (TIPPS) and liver transplantation are useful treatment options (1-3). br/>br/> OUTCOME
Hepatic hydrothorax may be complicated by spontaneous bacterial pleuritis and is associated with a poor outcome (6). Risk factors for hepatic hydrothorax are recurrent need for paracentesis, a high bilirubin level, diabetes, and non-use of non-selective beta-blockers (7).

In most cases, diagnosis of hepatic hydrothorax is indirectly established as a diagnosis of exclusion when patients with liver cirrhosis and portal hypertension have a mostly unilateral-right pleural branch fluid and cardiac, renal, or primary pulmonary etiologies of pleural effusion have been ruled out (1-3). Intracavitary contrast-enhanced ultrasound allows for a fast, and direct diagnosis of hepatic hydrothorax by proof of communication between fluids in the peritoneal and pleural cavities (8-9).

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