The vaso-occlusive pain crisis in sickle cell patients: A focus on pathogenesis

Vaso-occlusive pain crisis (VOC) is recognized as a prominent complication of sickle cell disease, accompanied by debilitating pain and serious consequences for patients, making it the primary cause of visits to hospital emergency departments. In the etiology of VOC, the intricate interaction of endothelial cells, hypoxia, inflammation, and the coagulation system is pivotal. Hemoglobin S polymerization under hypoxic conditions leads to the formation of rigid and adhesive red blood cells that interact with vascular endothelial cells and other blood cells, causing occlusion and subsequent inflammation. Hemolysis of red blood cells results in anemia and heightened inflammation, whereas oxidative stress and involvement of the coagulation system further complicate matters. In this review, we strive to examine the pathophysiology of VOC from these mentioned aspects by consolidating findings from various studies, as a comprehensive understanding of the causes of VOC is essential for the development of targeted therapeutic interventions and the prevention and management of pain, ultimately improving the quality of life for patients.