Aplastic Crises In Sickle Cell Anemia

Because sickle cell anemia is a congenital hemolytic anemia, there is ongoing red cell destruction, which must be supported by endogenous erythropoiesis manifest as reticulocytosis. Any concurrent illness that suppresses endogenous erythropoiesis will result in reticulocytopenia and a decrease in hemoglobin level and hematocrit.

Acute aplastic crises are characterized by a decrease in the level of hemoglobin of >3.0 g per dL in the setting of reticulocytopenia.

Causes :
These crises often occur in association with an infection that leads to transient bone marrow suppression; human parvovirus B19, the etiologic agent of erythema infectiosum (fifth disease), is notorious for causing this complication.

Management:
Patients should be given supportive red cell transfusions when they have hemodynamic instability, which may present with tachycardia, tachypnea, postural hypotension, and unstable blood pressure. Symptomatic anemia, indicative of the need for transfusion, includes dyspnea, dizziness, excessive fatigue, and difficulty in concentrating. Clinical management depends on the degree of anemia and cardiovascular compromise. Aggressive transfusions should be avoided, because transfusion to levels much above the patient's baseline hematocrit may suppress endogenous erythropoiesis further