Nosocomial sepsis-induced late onset thrombocytopenia in a neonatal tertiary care unit: a prospective study

Late onset sepsis (LOS)( onset of sepsis >72 hours of age or nosocomial sepsis) is an important cause of morbidity and mortality in the neonatal intensive care unit (NICU). Thrombocytopenia is an important complication of sepsis. We investigated the incidence of thrombocytopenia in LOS patients and studied the influence of various parameters on platelet response.

Infants born in the level 3 neonatal intensive care unit between January 2002 and December 2006 with documented LOS were included in this prospective study. Multiple hemograms with platelet counts, bacterial blood culture and fungal blood culture were obtained in all patients. Demographic and clinical data were compared between patients without thrombocytopenia and with mild, moderate and severe thrombocytopenia. Duration of thrombocytopenia in relation to type of organism and mortality with respect to degree of thrombocytopenia were also studied.

Of 200 patients with culture-proven nosocomial sepsis, 119 (59.5%) patients developed thrombocytopenia (platelet count <150 X 109/L). In our series Klebsiella pneumoniae was the most frequently isolated organism (125/200, 62.5%) and the incidence of thrombocytopenia was 60.0% (75/125). However, the incidence of thrombo- cytopenia was highest among patients who had concurrent bacterial and fungal sepsis (28/31, 90.3%). Coagulase- negative staphylococcal (CoNS) sepsis was present in 21 (10.5%) patients and the incidence of thrombocytopenia was 33.3%. Isolated fungal sepsis was present only in 6 (3%) patients and the incidence of thrombocytopenia was 66.0%. The incidence of thrombocytopenia was highest among preterm babies and low-birth weight (LBW) babies. Twenty-seven percent (54/200) of babies presented with mild thrombocytopenia, 20% (40/200) presented with moderate thrombocytopenia, and 12.5%(25/200) developed severe thrombocytopenia. Severity of thrombocytopenia was also directly related to the presence of necrotizing enterocolitis (NEC) and disseminated intravascular coagulation (DIC). The mortality rate was significantly associated with the degree of thrombocytopenia.

LOS sepsis is an important risk factor for thrombocytopenia in the NICU. Fungal and gram- negative sepsis are frequently associated with a decreased platelet count. Sepsis-induced thrombocytopenia is more common among LBW babies and preterm babies. The mortality rate is significantly related to degree of thrombocytopenia.