The aplastic crisis or phase is caused by the need of the bone marrow to shut down temporarily due to the continual stimulus for production of erythrocytes. During this time, a severe anemia may be present due to the shortened life span of the red blood cells.
In addition, infections that sickle cell patients encounter may arrest red blood cell production and also produce a pancytopenia. Parvovirus B19 is the most common causitive agent of aplastic crisis in sickle cell disease.
