Changes in platelet count and mean platelet volume during infectious and inflammatory disease and their correlation with ESR and CRP.

Background: The measurements of platelet count and mean platelet volume (MPV) are routinely available nowadays. The aim of this study was to evaluate the platelet count and MPV trend in infectious and inflammatory processes. We also investigated whether these parameters were associated with the known markers of disease activity, erythrocyte sedimentation rate (ESR) and C- reactive protein (CRP).

Methods: This cross-sectional study was conducted on 100 children with diagnosis of infectious and inflammatory diseases. Platelet count, MPV, ESR, and CRP were measured at the time of hospitalization and thereafter in the recovery phase.

Results: Mean platelet count increased in the patients at the time of admission in the hospital compared to the recovery and discharge time (mean 430,820 ± 134,643/μl vs. 350,970 ± 99,374/μl, P < 0.001). However, MPV decreased significantly during the same period (8.2 ± 1.1 fl vs. 8.7 ± 0.9, P < 0.001). Platelet count was directly correlated with CRP (mean 6.4 ± 0.3 mg/l), (r = 0.49, P < 0.001) and ESR (mean 10.9 ± 1.1 mm/hr), (r = 0.32, P = 0.003). On the other hand, MPV was inversely correlated with CRP (r = 0.39, P < 0.001) and ESR (r = -0.24, P = 0.034).

Conclusions: This study demonstrated a higher level of platelet count and lower MPV in the patients with active disease compared to the recovered patients. These parameters were well correlated with the known disease activity markers. We propose that platelet parameters can be considered as reliable markers for assessment of disease activity and response to treatment.