Change in platelet indices in patients with Coronavirus disease‐2019 (COVID‐19): A reflection of platelet activation and contribution to immunothrombosis?

In December 2019, several cases of pneumonia of unknown aetiology were reported in Wuhan, China. The causative Coronavirus was subsequently isolated and named the Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) and the disease, Coronavirus disease-2019 (COVID-19). COVID-19 related coagulopathy is a poor prognostic feature and reflects an underlying pathological process termed immunothrombosis. This process differs from infection-related disseminated intravascular coagulation (DIC) as it manifests primarily with thrombosis while thrombocytopenia and bleeding remain modest. The coagulation activation in COVID-19 relates to endothelial dysfunction, complement activation and ensuing cytokine storm with contributions from secondary infections and organ dysfunction. D-dimer values above 0.5 mg/L signifies poor patient outcomes.