Role of Monocyte-to-lymphocyte Ratio, Mean Platelet Volume-to-Platelet Count Ratio, C-Reactive Protein and Erythrocyte Sedimentation Rate as Predictor of Severity in Secondary Traumatic Brain Injury: A Literature Review

BACKGROUND: Secondary traumatic brain injury (TBI) is injury to the brain following primary TBI because of neuroinflammation as consequences of neuronal and glial cell injury which cause release of various inflammation cytokine and chemokine. Biomarker examination to predict the severity of secondary TBI is important to provide appropriate treatment to the patient. This article reviews possibility several common laboratory parameter such as monocyte-to-lymphocyte ratio (MLR), mean platelet volume-to-platelet count (PC) ratio (MPV-PCR), c-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) to predict severity of secondary TBI. LITERATURE REVIEW: TBI activates microglia which increase infiltration and proliferation of monocyte. Neuroinflammation also increases thrombopoiesis which leads to increase megakaryocytes production. In the other hand, due to disruption of brain blood vessels because of trauma, coagulation cascade is also activated and leads to consumptive coagulopathy. These are reflected as high monocyte count, low PC, and high MPV. Lymphocyte count is reported low in TBI especially in poor outcome patients. CRP is an acute phase reactant that increased in inflammation condition. In TBI, increased production of Interleukin-6 leads to increase CRP production. In head injured patients, ESR level does not increase significantly in the acute phase of inflammation but last longer when compared to CRP. CONCLUSION: MLR, MPV-PCR, CRP, and ESR could be predictor of severity in secondary TBI.