Prevalence and course of Thrombocytopenia in culture positive and culture negative Neonatal Sepsis

Introduction: Neonatal Sepsis is commonly associated with thrombocytopenia. Objective: To assess the prevalence and course of thrombocytopenia in culture positive and culture negative neonatal sepsis in comparison to normal newborns. Methods: This is a retrospective case analysis of 533 neonates between January-2012 to December-2014. The parameters examined were Baseline Platelet Count, Change In Platelet Count, (Baseline Platelet Count- Change In Platelet Count)/ Baseline Platelet Count, Platelet Nadir, Incidence, Duration & Severity of Thrombocytopenia. Statistical Analysis: All data were collected in validated preformatted proforma sheet & analysed using appropriate statistical methods. Results : Among 533 neonates, 21.2% had Culture negative sepsis, 9.75% had culture positive sepsis & 69.04% had no sepsis. The prevalence of early onset sepsis was 17.44% & late onset sepsis was 13.50%. About 24.76% babies had thrombocytopenia; 9.56% had mild thrombocytopenia, 10.13% had moderate & 5.06% had severe thrombocytopenia. Late onset sepsis was associated with significant thrombocytopenia. Culture positive sepsis had significant drop in platelets with lower platelet nadir, higher incidence, more severe & prolonged thrombocytopenia compared to culture negative sepsis & normal neonates. Conclusion: There are quantitative differences in the platelet response to neonatal sepsis, particularly to culture positive sepsis. Hematological changes in platelet count induced by culture proven and culture negative neonatal sepsis can be used to make an early diagnosis and prompt management of neonatal sepsis. Summary: We noted significant drop in platelet count among late onset sepsis .Significant variations of all platelet indices were noted among lower gestational age babies. Culture positive sepsis was associated with significant drop in platelets with lower platelet nadir, higher incidence, thrombocytopenia when compared to culture negative sepsis & normal neonates.


Introduction
Neonatal Sepsis is a clinical syndrome characterised by signs and symptoms of infection with or without accompanying bacteremia in the first month of life [1]. It is extremely important to make an early diagnosis of neonatal sepsis for the prompt institution of anti-microbial therapy, which improves the outcomes [2]. CRP & Platelet count are diagnostic markers of neonatal sepsis [3,4].
We have conduacted this study to assess the prevalence and course of thrombocytopenia in culture positive and culture negative neonatal sepsis in comparison to normal newborns.

Methodology
This is a retrospective case analysis between January-2012 to December-2014 in a single centre. Blood samples of all the patients included in this study were obtained for CBC and CRP levels. Blood culture was done when indicated. Name, date of admission, age, platelet count, CRP levels, blood culture reports were recorded on a data form.We enrolled 533 eligible neonates. The data was analysed for differences in platelet count in terms of Culture positive, Culture negative sepsis & no sepsis. All patients included in this study received appropriate antibiotics.

Unit Protocol for Investigation of Neonatal Sepsis:
Soon after admission two ml blood sample was taken in EDTA vacutainer and was processed for Platelet count. Another 2 ml blood sample was taken for conventional blood culture. Also 1 ml blood sample was taken for estimation of a qualitative CRP result. Direct counting of platelets in an improved Neubauer`s Chamber was done. Platelet count less than 1.5 Lakh / cumm was considered abnormal. CRP in serum was estimated by CRP Turbi Latex Kit using Latex turbimetry. Test showed positivity when CRP value was more than 6 mg/ L. Blood was collected for blood culture in BD BACTEC bottles & cultured in Sabouraud's Dextrose agar & Brain Heart Infusion Broth and colony growth was observed. Smears were made from peripheral blood and stained by Leishmans stain and examined to confirm thrombocytopenia. The platelet count & CRP used for this study was the one obtained at the same time as the positive blood culture or the one closest to the time the blood culture was drawn in cases of neonatal sepsis and the admission values in those babies with no sepsis.
Interventions: Management of neonatal sepsis as per standard unit protocol. The study was approved by the Hospital Research and Ethics Committee.

Definition of Parameters:
The parameters that were examined in this study were Baseline Platelet Count: Platelet count obtained at least 24 hours before the time that the blood culture was obtained in cases of neonatal sepsis or the admission values in those babies with no sepsis.
Change In Platelet Count: Platelet count at the time of onset of sepsis in cases of neonatal sepsis or the second CBC values in those babies with no sepsis.
Platelet Nadir: Lowest platelet count obtained during a 20-day period starting from the time the initial blood culture was drawn in cases of neonatal sepsis or during a 20-day period since admission in those babies with no sepsis. . Incidence of Thrombocytopenia: Number of episodes with a platelet nadir of less than 1,50,000/mm 3 during a 20-day period starting from the time the initial blood culture was drawn in cases of neonatal sepsis or during a 20-day period since admission in those babies with no sepsis.

Duration of Thrombocytopenia:
Number of continuous days that the platelet count remained less than 1,50,000/mm 3 . If the neonate had no Thrombocytopenia at the time of sepsis, the duration was considered to be zero.

Statistical Analysis
All the data were collected in validated preformatted proforma sheet and analysed using software Statistical Package for Social Sciences. Categorical variables were analyzed using Chi-square analysis with Yates correction. Student't' test was used to compare the means. A p-value of < 0.05 was considered significant. Analysis of variance was used to compare groups, and data are expressed as mean ± standard deviation. Scheffe test was used for pairwise comparisons.  Analysis of variance was used to compare the groups, and data was expressed as mean ± standard deviation. There was a significant fall in platelet counts when compared with baseline values in culture positive patients. Results were statistically significant when compared with culture negative and normal neonates. Similar findings were noticed for platelet nadir. Culture positive sepsis had higher incidence & more prolonged thrombocytopenia along with more severity when compared to culture negative sepsis and normal neonates. There was a significant fall in platelet counts when compared with baseline values in babies with late onset sepsis. Results were statistically significant when compared with early onset sepsis. Similar findings were noticed for platelet nadir. Late onset sepsis had higher incidence & more prolonged thrombocytopenia along with more severity when compared to early onset sepsis.

Discussion
Prevalence of Sepsis: In our study, 21.2% babies had Culture negative sepsis & 9.75% had culture positive sepsis. The overall prevalence of sepsis in our study was 30.95%. Prevalence between 20-30% was noted in studies by Khalessi N et al. [7], Roberts I et al. [8], Beiner ME et al. [9], Bolat F et al. [10]. However lower prevalence of 16% was noted by Jack D.Guida et al. [11]. The prevalence of early onset sepsis in our study was 17.44%. The prevalence of early onset sepsis was between 20-30% in studies by Khalessi N et al. [7], Roberts I et al. [8], Beiner ME et al. [9], Bolat F et al. [10]. The prevalence of late onset sepsis in our study was 13.50%. However Bizzarro MJ et al., [12] & Van den Hoogen etal. [13] observed that late-onset sepsis was more common in their studies.

Conclusion
There are quantitative differences in the platelet response to neonatal sepsis, particularly to culture positive sepsis. Hematological changes in platelet count induced by culture proven and culture negative neonatal sepsis can be used to make an early diagnosis and prompt management of neonatal sepsis.