When Red Blood Cells Are Not Produced
An aplastic crisis (failure of the bone marrow to produce any red blood cells) should not be confused with anemia, which is a constant feature of sickle cell disease. The aplastic crisis is a temporary shutdown of red cell production. Because of the shortened red cell lifespan in patients with sickle cell disease, a rapid drop in hemoglobin occurs when the bone marrow is not producing red blood cells.
Among patients with sickle cell disease, severe aplastic crisis is frequently (86% of cases) associated with parvovirus B19 infections (childhood fifth disease). Other causes may include other viral illness or medication use.