Hematological Manifestations in COVID-19: A Comprehensive Review of Pathophysiology, Clinical Implications, Diagnostic Challenges, and Therapeutic Approaches

COVID-19, caused by SARS-CoV-2, has emerged as a multisystem disease with significant hematological implications that influence disease severity and clinical outcomes. Hematological abnormalities, including thrombocytopenia, lymphopenia, hypercoagulability, and disseminated intravascular coagulation, have been widely reported, contributing to the prothrombotic state characteristic of severe COVID-19. The underlying pathophysiology involves immune-mediated hyperinflammation, endothelial dysfunction, and aberrant coagulation cascades, culminating in COVID-19-associated coagulopathy (CAC). Elevated D-dimer, fibrinogen, and inflammatory markers are prognostic indicators, aiding in risk stratification and therapeutic decision-making. The clinical spectrum of hematological dysfunction in COVID-19 includes an increased incidence of venous and arterial thromboembolic events, severe immune suppression due to lymphocyte depletion, and altered erythrocyte morphology contributing to hypoxia. Diagnostic challenges arise in distinguishing CAC from other coagulopathies, necessitating comprehensive laboratory and imaging assessments. Therapeutic approaches primarily focus on anticoagulation strategies, ranging from prophylactic to therapeutic dosing, with ongoing investigations into novel antithrombotic and anti-inflammatory agents. Despite advancements in understanding COVID-19-related hematological complications, gaps remain regarding optimal anticoagulation regimens, risk stratification models, and the long-term hematological consequences of the disease. This review provides a comprehensive analysis of the pathophysiological mechanisms, clinical manifestations, diagnostic approaches, and therapeutic strategies related to hematological abnormalities in COVID-19, emphasizing the need for continued research to refine treatment protocols and improve patient outcomes.