Thrombocytosis as an additional predictor of serious bacterial infection in febrile young infants
Background: To estimate the incidence of Reactive Thrombocytosis among febrile young infants and to assess the utility of platelet count as a potential predictor of Serious bacterial infection (SBI).Methods: This study was conducted as a prospective study between January 2014 to September 2015 at the tertiary care pediatric unit, Alappuzha, India. The participants were all infants 30 to 89 days of age, admitted with rectal temperature >38°C. The results of the sepsis evaluation on admission were recorded. SBI included cases of occult bacteremia, urinary tract infection, bacterial meningitis, pneumonia, bacterial gastroenteritis and infections of the soft tissues and bones.Results: Of the 120 infants studied, 24 (28%) had SBI. Platelet count was significantly higher in infants with SBI compared to those without {Platelet count ≥ 4.5lakhs /mm3 in SBI (70.3%) vs. Non SBI (30.2%). Mean platelet count 4.82±1.4 in SBI vs. 3.9±1.2 in non SBI which was statistically significant (p<0.05). Thrombocytosis had moderate ability in predicting SBI (Area under curve area under the curve: 0.720). The combination of platelet count ≥450,000/mm3, WBC ≥15,000/mm3, C-reactive protein ≥1 mg/dl, pyuria ≥5 White blood cells (WBC) per High power field (HPF) and erythrocyte sedimentation rate (ESR) >30mm/hr resulted in identification of all infants with SBI.Conclusions: Thrombocytosis in combination with leukocytosis, elevated C-reactive protein, ESR, and pyuria, may help in early recognition of febrile young infants at risk for SBI.