Pleural fluid analysis and radiographic, sonographic, and echocardiographic characteristics of hepatic hydrothorax.

BACKGROUND: There are limited published data defining complete pleural fluid analysis, echocardiographic characteristics, or the presence or absence of ascites on sonographic or CT imaging in patients with hepatic hydrothorax.

METHODS: We reviewed pleural fluid analysis and radiographic, sonographic, and echocardiographic findings in 41 consecutive patients with hepatic hydrothorax referred to the Pleural Procedure Service for thoracentesis.

RESULTS: Ascites was detected on sonographic or CT imaging in 38 of 39 patients (97%). Diastolic dysfunction was found in 11 of 21 patients (52%). Contrast echocardiography with agitated saline demonstrated an intrapulmonary shunt in 18 of 23 cases (78%). Solitary hepatic hydrothorax had a median pleural fluid pH of 7.49 (fifth to 95th percentile, 7.40-7.57), total protein level of 1.5 g/dL (0.58-2.34), and lactate dehydrogenase (LDH) level of 65 IU/L (36-138). The median pleural fluid/serum protein ratio and pleural LDH/upper limit of normal serum LDH ratio were 0.25 (0.10-0.43) and 0.27 (0.14-0.57), respectively. The median absolute neutrophil count (ANC) was 26 cells/μL (1-230). Only a single patient had a protein discordant exudate despite 83% of patients receiving diuretics. When comparing solitary hepatic hydrothorax and spontaneous bacterial pleuritis, there was no statistically significant difference among pleural fluid total protein (P = .99), LDH (P = .33), and serum albumin (P = .47). ANC was higher in patients with spontaneous bacterial pleuritis (P < .0001).

CONCLUSIONS: Hepatic hydrothorax virtually always presents with ascites that is detectable on sonographic or CT imaging. The development of an "exudate" from diuretic therapy is a rare phenomenon in hepatic hydrothorax. In contrast, diastolic dysfunction and intrapulmonary shunting are common in patients with hepatic hydrothorax. There was no statistically significant change in pleural fluid parameters with spontaneous bacterial pleuritis, except an increased ANC.