Spontaneous bacterial empyema in cirrhotic patients: complements 3 and 4, opsonic power and C-reactive protein as pathogenic mechanisms and diagnostic tools

ABSTRACT

Hepatic hydrothorax occurs in approximately 5-12% of patients with cirrhosis and portal hypertension and may be complicated by spontaneous bacterial empyema [SBE]. Pathogenic mechanisms of SBE still need to be investigated. The present work assesses the role of complement components [C3, C4], opsonizing power and C-reactive protein in the pathogenesis of SBE in cirrhotic patients. Twenty five cirrhotic patients with hepatic hydrothorax were randomly selected and 10 patients with hydrothorax secondary to heart failure were included as controls in the study. Pleural fluid [PF] and serum samples were analyzed for total protein [TP], albumin, lactic dehydrogenase [LDH], glucose, polymorph nuclear leukocytic count [PMNL], complement components [C3, C4], opsonic activity [on the basis of log-kill] and high sensitive C-reactive protein [CRP]. SBE was diagnosed when pleural fluid PMNL was > 250 cells/mm[3] with a positive culture or >500 cells/ mm[3] with a negative culture after exclusion of pulmonary infections. Thirteen patients [52%] [Group I] were diagnosed as SBE and 12 patients [48%] had no SBE [Group II]. There was no significant difference between patients and controls [GIII] as regards age, gender, serum proteins, serum C3, serum WBC and effusion CRP. Levels of serum albumin, total pleural effusion proteins, PT% and opsonic activity of groups I and II were significantly lower than in GIII with no significant difference between groups I and II. Levels of serum bilirubin and C4 of groups I and II were significantly higher than group III with no significant difference between groups I and II. Level of pleural effusion C3 in group I was significantly lower than in groups II and III and level of C3 in group II was significantly lower than in group III. Level of pleural effusion C4 in group I was significantly lower than group III, but there was no significant difference between groups I and II. In hepatic patients, 7 patients [28%] belonged to Child's class B and 18 [72%] to class C. Spontaneous bacterial empyema was detected in 56% of hepatic patients with Child's class C and in 43% of Child's class B. There was no significant difference between hepatic patients with and without SBE with regard to Child-Pugh's score. In patients with SBE, levels of C3 and C4 were significantly less in pleural fluid than in serum but there was no significant difference with regard to opsonic activity. Local complement defects [especially C3] and opsonic activity in cirrhotic patients predispose to SBE. Serum CRP increases, but effusion CRP level should be reassessed as a cheap diagnostic tool