Prepared by Robert L. Emery, MD of the Department of General Surgery and Justin Q. Ly, MD of the Department of Radiology and Nuclear Medicine, Wilford Hall Medical Center, Lackland Air Force Base, San Antonio, TX.

CASE SUMMARY

A 56-year-old man with a history of cirrhosis and recurrent ascites acutely developed a right pleural effusion (Figure 1). A thoracentesis revealed the effusion to be transudative. The patient had no known history of pulmonary or cardiac disease.

IMAGING FINDINGS

This patient's clinical history, radiographic findings (Figure 1), and thoracentesis results raised the possibility of a hepatic hydrothorax. After consulting with nuclear medicine staff, scintigraphic evaluation with technetium-99m sulfur colloid by intraperitoneal injection through an indwelling catheter was performed. A scintigraphic image obtained immediately following injection of the radiotracer showed prompt uptake in an expected distribution within the peritoneum (Figure 2A). Ten minutes later, a right lateral decubitis image revealed a large amount of radiotracer uptake layering in a dependent fashion within the right hemithorax (Figure 2B). At 25 minutes postinjection, an upright view showed radiotracer uptake involving nearly one-half of the hemithorax (Figure 2C). These findings were indicative of an abnormal communication between the peritoneum and the right hemithorax, resulting in a hepatic hydrothorax in this patient with known cirrhosis complicated by ascites. The patient underwent transjugular intrahepatic portosystemic shunt (TIPS) placement, which provided temporarily relief of the hepatic hydrothorax.

DIAGNOSIS

Hepatic hydrothorax

DISCUSSION

A pleural effusion noted in cirrhotic patients in the absence of primary cardiac or pulmonary disease is most likely a hepatic hydrothorax. This complication is noted in approximately 6% of cirrhotic patients and is also an infrequent complication of continuous ambulatory peritoneal dialysis. ^1,2 Although the effusion may be bilateral or left-sided, the majority (67%) are right-sided. ^1,3 Unidirectional transdiaphragmatic defects allowing peritoneopleural communication are believed to play a role in the transit of the transudative ascites into the thorax, and there is debate as to whether these communications are congenital or acquired. ^1,3,4 Along with the identified diaphragmatic defects, other proposed etiologies are transdiaphragmatic lymphatics and hypoalbuminemia. ^1,3

The goal of treating hepatic hydrothorax is the removal of the thoracic effusion and prevention of its reaccumulation by minimizing ascitic fluid accumulation within the abdomen. Treatment options include therapeutic thoracentesis, salt and water restriction, and diuretics. A possible complication of this regimen is volume depletion and impaired renal function. ³ Another treatment option is chemical pleurodesis. Prior to performing this procedure, it must be proven that the peritoneopleural shunt is unidirectional by injecting radiotracer into the pleural space and observing the abdomen for uptake. Ensuring that the radiotracer does not pass into the peritoneal cavity will prevent accidental sclerosing of the abdominal organs. ³ Aside from a liver transplant, a TIPS procedure may be the most effective therapeutic intervention, working to decrease portal hypertension and thereby decrease ascitic fluid accumulation. Other more invasive treatment options include surgical repair of the diaphragmatic defect and the creation of a peritoneovenous shunt. ⁴

CONCLUSION

Hepatic hydrothorax is not an uncommon condition in cirrhotic patients. When suspected clinically, the diagnosis can be confirmed using intraperitoneal injection of a radiotracer, such as technetium-99m sulfur colloid, which will demonstrate transit of the radiotracer into the pleural space.