ANEMIA IN CHILDREN

ANEMIA

DEF: Hematocrit and hemoglobin concentration below normal levels.
CONDITION: Physiologic anemia of infancy/anemia of prematurity.
ETIOL/CLIN: Soon after birth, erythropoiesis almost ceases because of the oxygen-rich milieu and relative excess of red blood cells (RBCs); this results in a decrease in hemoglobin values during the first several months of life, the severity of which is related to birth weight, perinatal complications, blood transfusion history, and vitamin E deficiency. Nadir hemoglobin values can reach 9.5 g/dL at 3 months in term infants and 6 g/dL in 6- to 8-week-old premature infants. Recovery is heralded by a slight elevation in the reticulocyte count and a rise in hemoglobin levels to those seen throughout the remainder of infancy.
Tx: Healthy term infants and asymptomatic growing premature infants require no therapy. Iron supplementation may be indicated during the recovery phase to support erythropoiesis.

CONDITION: Blood loss.
ETIOL/CLIN: Anemia owing to blood loss is more common in the new-born period than in any other time in childhood. Acute hemorrhage (>20% to 30% blood volume) results in shock. Jaundice is absent. External blood loss commonly occurs from the gastrointestinal (GI) tract. To determine whether hematemesis or melena derives from the infant's or mother's blood, the Apt test for fetal hemoglobin is used. The Kleihauer-Batke stain for fetal hemoglobin–containing RBCs in the mother's blood can provide an estimate of the degree of transplacental hemorrhage. In sick premature infants, the most common cause of blood loss is the iatrogenic withdrawal of multiple specimens for testing.
TX: Treatment depends on the amount and duration of blood loss. Signs of hypovolemia dictate that the infant receive immediate volume replacement [crystalloid, plasma protein fraction, whole blood, packed RBCs (pRBCs)]. pRBCs alone may be indicated for less acute degrees of anemia.

CONDITION: ABO incompatibility.
ETIOL/CLIN: Maternal alloantibody can cross the placenta and may bind antigens on fetal/neonatal RBCs, causing hemolytic anemia. Affected babies present with jaundice during the first several days of life. In some cases, symptomatic anemia does not manifest until 4 to 6 weeks after birth. Although the reticulocyte count is elevated (5% to 15%), anemia is absent or mild. The peripheral smear shows increased nucleated RBCs and microspherocytes. Maternal and fetal blood type testing show the corresponding ABO incompatibility “set-up” (mother is blood group O; baby is A or B). Direct and indirect Coombs testing is positive.
TX: Phototherapy or exchange transfusion may be required to treat hyperbilirubinemia.

CONDITION: Rh incompatibility.
ETIOL/CLIN: Incompatibility between the mother and child in the major antigen of the rhesus complex can cause erythroblastosis fetails. Rh-negative mothers sensitized to D-positive blood produce antibodies that cross the placenta and coat D-positive fetal blood, resulting in hemolytic anemia. Severely anemic fetuses may die in utero, or neonates may be born with hydrops fetails, characterized by anasarca (from hypoalbuminemia and congestive heart failure), severe anemia, and massive hepatosplenomegaly. Less severely affected neonates (benefiting from early detection and vigorous treatment during pregnancy and delivery) may have less severe anemia. Direct and indirect Coombs testing is positive. Hyperbilirubinemia is present. The peripheral smear shows polychromasia, nucleated RBCs, and no microspherocytes.
TX: Early detection during prenatal care and Rhogam therapy prevent maternal sensitization. Intrauterine transfusion of pRBCs can correct fetal anemia. Treatment during the neonatal period consists of exchange transfusion for marked anemia and hyperbilirubinemia and pRBCs for less severe anemia. Careful follow-up is required during the first 2 to 3 months of life to monitor for delayed anemia resulting from persistent anti-D antibody.

CONDITION: Glucose-6-phosphate dehydrogenase (G6PD) deficiency.
ETIOL/CLIN: G6PD deficiency is the most common inherited intrinsic disorder of RBCs. It typically occurs in black, Mediterranean, and Asian males. Oxidant stresses from drugs or infection cause hemoglobin to precipitate, forming Heinz bodies seen on the peripheral smear. Oxidant stresses at delivery and premature birth may trigger neonatal hemolysis and hyperbilirubinemia. The diagnosis is made with specific screening tests and enzyme assays.
TX: Hemolysis and hyperbilirubinemia may require exchange transfusion.

CONDITION: Hereditary spherocytosis.
ETIOL/CLIN: Hereditary spherocytosis is the most common congenital hemolytic anemia presenting with jaundice and anemia during the neonatal period. It is an autosomal dominant disorder common in whites of northern European descent. The blood smear contains numerous microspherocytes. There is no evidence of ABO incompatibility (i.e., negative Coombs test).
TX: Hemolysis and hyperbilirubinemia may require exchange transfusion.

CONDITION: Anemia related to mechanical or toxic factors.
ETIOL/CLIN: Mechanical or toxic factors. Damage to erythrocytes can occur from toxins produced by infection or from mechanical injury mediated by fibrin strands or altered microvasculature, such as in disseminated intravascular coagulation (DIC).
TX: Treatment depends on the etiology. Blood product transfusion may be required.

CONDITION: Decreased RBC production.
ETIOL/CLIN: Anemia resulting from diminished RBC production is uncommon at birth and is reflected by a diminished or absent reticulocyte count. Causes include malignancy, sepsis (relative myelosuppression), iron deficiency, Diamond-Blackfan syndrome (congenital pure RBC aplasia), and a-thalassemia syndromes.
TX: Treatment depends on the etiology. Vigorous resuscitation measures and blood transfusions may be required.