Congenital chylothorax: lymphopenia and high risk of neonatal infections

AIM: To describe the clinical course of patients with congenital chylothorax focusing on infectious complications. Congenital chylothorax is a common manifestation of non-immune hydrops fetalis (NIHF). The drainage of chyle leads to loss of cellular and plasmatic factors that influence the patient's immune response and increase the risk of infections. METHODS: In a retrospective analysis of 24 preterm infants with NIHF treated between 1998 and 2002, congenital chylothorax was diagnosed in 7 patients. RESULTS: All 7 patients were treated conservatively with pleural drainage over a median period of 22 d (range 10-36 d). Lymphopenia was found in all patients (median of minimal lymphocyte counts 285/microl, range 80-770). The nadir was on day 5 (2-6 d). Lymphopenia lasted for 12 d median (range 4-39 d) and was significantly correlated with the duration of lymph drainage (p = 0.001). Cell-surface analysis of peripheral blood lymphocytes was performed in two patients. Both patients had a decreased number of total T cells. Four out of seven (57%) patients developed nosocomial infections. This incidence of nosocomial infections in patients with congenital chylothorax is about three times higher than that in other neonatal patients. None of the children suffered from fungal or viral infection. Although there was a very high incidence of infections, no correlation between lymphopenia and the occurrence of infections could be shown. CONCLUSION: Drainage of congenital chylothorax results in the loss of lymphocytes and bears a high risk of infections.