Sickle cell disease is a group of inherited autosomal recessive red blood cell disorders that affects hemoglobin. Normally, red blood cells are disc shaped and flexible to move easily through the blood vessels. In sickle cell disease the red blood cells are crescent or “sickle” shaped. These cells do not bend and move easily and can block blood flow to the rest of the body. In order for sickle cell disease to be passed down both parents must carry the gene mutation and the there is a 25% the child will be affected and a 25% chance the child will be unaffected, then there is a 50% chance that the child will be a carrier but not have the disease. In sickle cell disease a single amino acid substitution in the β-globin chain leads to polymerization of mutant hemoglobin S, impairing erythrocyte rheology and survival. Clinically, erythrocyte abnormalities in sickle cell disease manifest in hemolytic anemia and cycles of microvascular vaso-occlusion leading to end-organ ischemia-reperfusion injury and infarction. Vaso-occlusive events and intravascular hemolysis promote inflammation and redox instability that lead to progressive small- and large-vessel vasculopathy (Sundd et al., 2019).
Sickle disease affects every organ system in the body. Sickle cell crisis is used to describe a group of several acute painful conditions that can happen to many different organ systems. Cerebrovascular complications are an ischemic stroke and it could present with hemiparesis, severe headache and aphasia. Circulatory system complications include splenic sequestration, functional asplenia which would present as splenomegaly and sudden drop in hemoglobin. Genitourinary complications include priapism and renal disfunction which could present as a sustained erection and hematuria. Hepatobiliary issues include cholelithiasis and hepatic fibrosis with a presentation of hepatomegaly and abdominal pain. Ocular issues include proliferative retinopathy and retinal detachment and symptoms include pain, decreased vision, and/or blindness. Pulmonary issues include acute chest syndrome which shows as pulmonary infections, chest pain, cough, and dyspnea. Skeletal issues include dactylitis and aseptic necrosis which present as swollen hands feet, pain, and decreased mobility (Novelli & Gladwin, 2016).
Novelli, E. M., & Gladwin, M. T. (2016). Crises in sickle cell disease. Chest, 149(4), 1082–1093. https://doi.org/10.1016/j.chest.2015.12.016
Sundd, P., Gladwin, M. T., & Novelli, E. M. (2019). Pathophysiology of sickle cell disease. Annual Review of Pathology: Mechanisms of Disease, 14(1), 263–292. https://doi.org/10.1146/annurev-pathmechdis-012418-012838