RT Book, Section A1 McCreight, Audra L. A1 Wickiser, Jonathan E. A2 Schafermeyer, Robert A2 Tenenbein, Milton A2 Macias, Charles G. A2 Sharieff, Ghazala Q. A2 Yamamoto, Loren G. SR Print(0) ID 1105685938 T1 Anemia T2 Strange and Schafermeyer's Pediatric Emergency Medicine, 4e YR 2014 FD 2014 PB McGraw-Hill Education PP New York, NY SN 978-0-07-182926-7 LK accesspediatrics.mhmedical.com/content.aspx?aid=1105685938 RD 2024/03/28 AB The mean hemoglobin concentration for normal newborns is 18 g/dL, after which it falls to a nadir of 11 g/dL (mean concentration) at 2 to 3 months of life. Although mean hemoglobin concentrations in children continue to vary somewhat by age, 11 g/dL defines the lower limits of normal for the prepubertal patient population.Anemias are most easily classified based on red blood cell (RBC) size and degree of bone marrow activity. The size of RBCs is measured as mean corpuscular volume (MCV), with the lower limit of normal for the MCV equaling 70 plus the age in years; bone marrow activity is reflected by the reticulocyte count.The most common cause of microcytic anemia in childhood is iron deficiency, usually due to excess intake of cow's milk.Thalassemias are inherited defects resulting in the inability to synthesize sufficient quantities of various globin chains of the hemoglobin molecule. Thalassemia trait produces marked microcytosis out of proportion to the degree of anemia.If the reticulocyte count is high in the presence of a normocytic anemia, blood loss or a hemolytic process must be considered.A low reticulocyte count in the face of significant anemia indicates bone marrow underproduction. If the abnormality is isolated to the RBC line, the primary considerations are transient erythroblastopenia of childhood (TEC) or an aplastic crisis complicating an underlying hemolytic anemia.Thrombocytopenia or white blood cell (WBC) abnormalities associated with normocytic anemia and poor reticulocyte response suggests a marrow infiltrative process such as leukemia or acquired aplastic anemia.Macrocytic anemia is uncommon in pediatric patients. Folate and vitamin B12 deficiencies are rare in otherwise healthy children.