1309 The Etiological Value of Lactate Dehydrogenase in Respiratory Tract Viral Infections

Abstract

Background: Many tissues in the body containlactate-dehydrogenase (LDH) including lungs, liverand muscles. Among five isozymes described, LDH-3 was discovered in the lungs. Interleukin6(IL-6) is a pro-inflammatory cytokine secreted by Tcells and macrophages and high serum values aresuggestive for bacterial infections. Aims: To evaluate LDH prognostic value as a markerfor etiology of lower respiratory tract infections(LRTI); to monitorise LDH values variations duringviral LRTI; to establish the correlations between “C”reactive protein (CRP) and LDH in viral LRTI. Methods: Authors have analyzed all childrenadmitted for acute LRTI (pneumonia, bronchiolitis, bronchitis) during 1 week period. The childrenwere investigated at Day 0(D0) and Day 4(D4) ofhospitalization: LDH, CRP, ASAT, ALAT, IL-6. Inclusion criteria: Children less than 7 yearsof age, no liver disease (ALAT normal range), no muscle involvement (ASAT normal value), IL-6normal range. Exclusion criteria: subjects agedmore than 7 years diagnosed with bacterial LRTI. Results: Among 88 included children, 68 subjectshad viral etiology and 20 children had bacterialcause (based on IL-6 low level). The LDH meanvalue in viral LRTI was higher than bacterial LDHmean values, not only for D0, but also for D4, without statistical correlation. There is no significantcorrelation between LDH mean value in D0 and D4in viral LRTI (p value 0,150). The authors didn't findcorrelations between LDH and CRP mean values orbetween IL-6 and CRP. Conclusions: LDH isn't a sensitive marker foretiological diagnosis of LRTI.