History

• 21 y/o AA female presents to ED with abdominal pain.

Diagnosis

• Sickle Cell Crisis

Genetics

• Sickle cell trait (HgA-HgS)– Generally a benign condition.– Carriers of the sickle cell trait

have some resistance to malaria caused by Plasmodium falciparum.

• Sickle cell disease (HgS-HgS)

Pathophysiology

• Mutated gene creates instability of the hemoglobin molecule in the deoxygenated state, during which HbS polymerizes and causes red blood cells to change from the usual biconcave disc shape to an irregular sickled shape.

Pathophysiology cont…

• The abnormal shape of these red blood cells and their propensity to adhere to the walls of blood vessels can occlude the vessels, preventing normal blood flow and decreasing the delivery of oxygen to organs, tissues, and bones causing a condition known as crisis.

• The sickled cells are also extremely susceptible to hemolysis, causing individuals with sickle cell disease to have chronic anemia.

Associations

• Vaso-occlusive episodes are associated with dehydration, acidosis, and fever. Cold and systemic illnesses (infections) commonly precipitate sickle cell crises. Sudden changes in altitude and travel in non-pressurized aircraft sometimes precede onset of a vaso-occlusive crisis.