Abstract
Sickle cell anemia is a disease in which the erythrocyte changes shape due to a mutation in the beta chain of hemoglobin causing vascular occlusion (vaso-occlusion) and clinical symptoms. In sickle cell patients, intermittent vascular occlusion leads to reperfusion injury associated with granulocyte accumulation and increased production of reactive oxygen species. Sickle cells adhere to endothelial cells and other blood cells more than normal erythrocytes in the microvascular circulation. The increase in thrombin and fibrin decreases the procoagulant activity of tissue factor, which triggers hypercoagulation. Where NO accumulates, oxidative stress reactions occur with vaso-occlusion. This results in decreased NO bioavailability and increased vascular dysfunction. Tissue damage due to vaso-occlusion causes the release of inflammatory mediators that trigger pain. Cytokines are released into the circulation by platelets, white blood cells, and endothelial cells. Patients with this condition are taken to the hospital with various syndromes such as occlusive crisis, acute chest syndrome, infection, multiple organ failure, and acute stroke. Sickle cell anemia effectively illustrates the severity of clinical manifestations caused by hypoxia.