Study of significance of thrombocytosis in lower respiratory tract infections in children

Background: Lower Respiratory Tract Infections (LRTI) continues to threaten the health of children worldwide. Up to 13% of inpatient deaths in pediatric wards are due to LRTI. Platelets play a major role in antimicrobial host defence, the induction of inflammation and tissue repair. Inflammatory thrombocytosis is related to increased levels of several cytokines such as thrombopoietin, interleukin-6, interleukin-1alpha, interleukin-8 and tumour necrosis factor alpha. Methods: A prospective study was done on thrombocytosis in children aged from 2 months to 5 years admitted with lower respiratory tract infections meeting the criteria of ARI control programme. Results: Among 220 cases, 63.2% of the cases were males and 36.8% of the cases were females, with male to female ratio being 1.7: 1. Among total 220 admitted cases of LRTI, 50% of the cases were severe pneumonia, 26.4% were very severe pneumonia and 23.6% were pneumonia. Among 220 cases, thrombocytosis was found in 77 children. Among 4 children with severe thrombocytosis (9.01-10.00 L/mm 3 ), 3 had very severe pneumonia and 1 had severe pneumonia. It indicates that platelet count increases as the severity of pneumonia increases. All 4 cases of severe thrombocytosis (9.01-10.00 Lakhs/mm 3 ) and 1 case of extreme thrombocytosis (>10.00 Lakhs/mm 3 ) had TLC >15000/mm 3 . Conclusions: Children admitted with LRTI having thrombocytosis had longer duration of hospital stay, which indirectly indicate more severity of pneumonia. Children with thrombocytosis have more severe clinical condition and longer hospitalization. Platelet count may be used as a useful marker associated with severity of lower respiratory tract infection and its complications.