PEDIATRIC HEMATOLOGY MCQS: ANSWER TO MCQ 04

MCQ#04

CORRECT OPTION: 'B'

Anemia of prematurity (AOP) affects most preterm infants, and the onset and severity of anemia are proportional to the degree of prematurity. After delivery, circulating erythropoietin (EPO) normally decreases due to increased oxygen concentration in tissue. Decreased EPO causes decreased reticulocyte production in bone marrow. As a result, a physiologic red blood cell (RBC) nadir is expected and occurs at age 2-3 months in term infants. In preterm infants, however, low EPO levels are exacerbated by short RSC life span (40-50 days) and frequent phlebotomy in the neonatal intensive care unit. This can result in a significant, early-onset anemia. Most infants with AOP are asymptomatic. Those who do have symptoms generally have mild tachycardia, increased apnea, or poor weight gain. AOP often is a diagnosis of exclusion; hemolysis, enzyme defects, hemoglobinopathies, and infection should be ruled out. Laboratory studies show decreased hemoglobin and hematocrit and a low reticulocyte count relative to the degree of anemia. The RBCs appear normal under light microscopy.

Treatment includes minimizing blood draws and ensuring adequate iron intake. RBC transfusions can be given if the infant is symptomatic but will further suppress EPO levels and delay recovery. Supplemental EPO is not effective in preventing the need for transfusions.

(Choices A and C) Patients with alpha or beta thalassemia have hypochromic, microcytic RBCs and abnormal cell morphology (eg, target cells) in their peripheral smears.

(Choice D) Glucose 6-phosphate dehydrogenase deficiency can present with severe hemolytic anemia and hyperbilirubinemia. The peripheral smear shows Heinz bodies and bite cells.

(Choice E) Hemolytic disease of the newborn is due to Rh or ABO incompatibility. The anemia (and subsequent hyperbilirubinemia) generally develops within 48 hours of birth. The reticulocyte count is increased due to hemolysis.

Educational objective:

Anemia of prematurity is the most common cause of anemia in preterm infants. It is due to diminished erythropoietin levels, shortened red blood cell life span, and blood loss. Laboratory studies show decreased hemoglobin and hematocrit and a relatively low reticulocyte count.