Radioisotope scintigraphy in the diagnosis of hepatic hydrothorax.

Background: Pleural effusion in cirrhotic patients (hepatic hydrothorax) may result from migration of ascitic fluid across defects in the diaphragm. Biochemical analysis of ascitic and pleural fluid provides only indirect information about the nature and origin of the effusion. The present study was performed in order to demonstrate the presence/absence of peritoneo-pleural communication by radioisotope imaging.

Methods: Ten patients with cirrhotic ascites and pleural effusion were studied with 99mTc sulfur colloid scintigraphy to look for movement of the radiotracer from the peritoneal to the pleural cavity. Serum-ascitic albumin gradient (SAAG) and serum-pleural fluid albumin gradient (SPAG) values were determined in eight patients to examine the nature of the ascitic and pleural fluids.

Results: Transdiaphragmatic movement of ascitic fluid into the pleural space was demonstrated (generally within 2 h of intraperitoneal injection of the radiotracer) in eight of 10 patients; six on the right side, one on the left and one bilaterally. Two patients in whom pleural fluid was transudative on SPAG values were negative for peritoneo-pleural communications.

Conclusions: Radionuclide scintigraphy is a simple, safe and relatively non-invasive method to confirm passage of ascitic fluid across the diaphragm.