Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy caused by a point mutation in the beta-globin gene, producing hemoglobin S (HbS). Under conditions of deoxygenation, dehydration, acidosis, or cold exposure, HbS polymerizes into rigid fibers that deform the red blood cell into a crescent (sickle) shape. These rigid cells cannot navigate small capillaries, causing vaso-occlusion, tissue ischemia, and intense pain. Chronic hemolysis leads to baseline anemia, jaundice, and gallstones. The nurse monitors pain levels, administers medications as ordered, maintains hydration, and reports changes in patient condition to the RN.