Which feature is most consistent with an aplastic crisis in a patient with sickle cell disease?

An aplastic crisis in a patient with sickle cell disease is characterized by an acute drop in hemoglobin levels. This significant reduction typically occurs due to a decrease in red blood cell production in the bone marrow, often triggered by infection, particularly parvovirus B19, which specifically targets and destroys erythroid progenitor cells.

In sickle cell disease, where patients are already predisposed to anemia due to chronic hemolysis, an additional crisis leads to a rapid worsening of their condition. Therefore, the acute drop in hemoglobin during this crisis is a reflection of both the existing anemia and the exacerbation that occurs when the bone marrow is unable to compensate for the red cell loss.

Other features, such as a high reticulocyte count, would not be consistent with an aplastic crisis, as the bone marrow is not producing sufficient new red cells in response to hemolysis or other stressors. Normal hemoglobin levels would also contradict the scenario since the hallmark of an aplastic crisis is the drop in hemoglobin. Splenomegaly is not typically associated with an acute drop in hemoglobin; instead, the spleen may become non-functional or infarcted in sickle cell disease, which can lead to other complications. Thus