Spontaneous platelet recovery time in primary and secondary dengue infection in a tertiary care hospital.

OBJECTIVE To determine the spontaneous platelet recovery time in primary and secondary dengue infection in a tertiary care hospital. METHOD The cross-sectional observational study was conducted at Abbasi Shaheed Hospital, Karachi, from July 2010 to January 2011, and comprised 138 seropositive patients with ages 13 years and above who fulfilled the World Health Organisation criteria of probable dengue infection, and presented with platelet count of <50,000/mm3 were enrolled. Serology was performed using rapid immunochromatographic assay and enzyme-linked immunosorbent assay with differential detection of immunoglobulin M and G. Spontaneous platelet recovery time (days) in both primary and secondary dengue infection was recorded. SPSS 20 was used for statistical analysis. RESULT Of the total 138, patients, 38(27.5%) had primary infection and 100(72.5%) had secondary infection. Male-to-female ratio was 2.3:1. Among primary and secondary infections, platelet count on presentation was not significantly different (p<0.64). Mean spontaneous platelet recovery time was 3±2.6 days and 3±1.87 days in primary and secondary infection respectively. Higher platelet count at presentation was associated with early recovery time (p<0.033). Of 108(78%) patients who presented with platelet count of 20,000-<50,000/mm3, platelet count of 36(33.33%) rose to >50,000/mm3 within 2 days, and 62(57.4%) rose to >50,000 in 3-5 days. In primary and secondary dengue infections, no statistically significant difference was observed in spontaneous platelet recovery time (-=0.87). CONCLUSION Platelet count at presentation and spontaneous platelet recovery time do not significantly differ in primary and secondary dengue infection.