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corpuscular volume is low The RBCs are hypochromic and microcytic, with striking variation in size and shape; nucleated RBCs are present on the peripheral smear Children and adolescents with thalassemia intermedia have a moderate anemia, with hemoglobin levels usually between and 10 g/dL Hemoglobin electrophoresis is used to make the initial diagnosis of β-thalassemia, although in many cases, index of suspicion is high due to family history Hemoglobin electrophoresis may also reveal other variant β-chains such as hemoglobin E or C Independently, these hemoglobins may not cause a significant clinical phenotype; however, in combination with a β0 or β+ mutation, patients may have a β-thalassemia major or intermedia phenotype Patients with β-thalassemia major require lifelong transfusion or bone marrow transplantation Gene therapy options are presently in clinical trials Patients may present to the emergency department with symptoms of severe anemia prior to initial diagnosis or later in life due to toxicity related to iron overload (often due to poor compliance with iron chelation therapy) The β-thalassemia intermedia phenotype is variable, but patients typically only need transfusions for acute exacerbations of their anemia during illness, pregnancy, or perioperatively Patients who carry one mutated βgene are asymptomatic but their red cells are microcytic (low MCV) and a mild anemia may be evident The α-thalassemia gene mutations occur most commonly in populations living in Mediterranean countries, northern Africa, the Middle East, India, and Southeast Asia Loss of one or two of the four α-globin genes is clinically trivial and manifests as a silent carrier or α-thalassemia trait, respectively Loss of three α-globin genes causes hemoglobin H disease, usually associated with a moderate anemia and chronic hemolysis Loss of all four α-globin genes results in production of Hemoglobin Barts (γ4 ) and hydrops fetalis (stillborn or death soon after birth) Hemoglobin electrophoresis does not aid the diagnosis of α-thalassemia trait but can identify hemoglobin H Hemoglobin Barts can be detected on newborn screen Congenital and Acquired Aplastic/Hypoplastic Anemia The differential diagnosis of aplastic and hypoplastic anemias is discussed in Chapter 62 Pallor DBA and transient erythroblastopenia of childhood (TEC) are the more common causes of pure RBC aplasia in early childhood In DBA, the level of RBC adenosine deaminase (ADA) is frequently elevated, and blood samples for this test should be obtained before transfusion TEC typically presents in previously healthy children from infancy to toddlerhood with severe anemia and reticulocytopenia but otherwise normal blood counts For patients with a hypoplastic anemia suggestive of TEC, a bone marrow aspirate may be helpful in predicting the course of the disease during the next few days and, in particular, the likelihood that pRBC transfusions will be required For example, if a patient with TEC has a hemoglobin level of g/dL, low reticulocyte count, and few RBC precursors on bone marrow evaluation, a further decrease in the hemoglobin concentration should be anticipated and pRBC transfusions will almost certainly be required However, if the bone marrow aspirate shows numerous erythrocyte precursors progressing through all levels of erythrocyte maturation, a peripheral reticulocytosis can be expected within 24 hours and RBC transfusions may be unnecessary Nutrition Deficiencies and Excess Nutritional anemias in children constitute more of a public health problem than a hematologic emergency; however, in some cases, the hemoglobin level may be very low at the time of diagnosis Some of the most common micronutrients related to anemia include deficiencies of iron, B12 , folate, zinc, vitamin C, and excess of copper Of these, iron-deficiency anemia is the most common in the pediatric population Severe iron deficiency occurs mainly in toddlers due to excess cow’s milk consumption (more than quart [32 fl oz or ∼1 L] daily) Adolescent girls make up another group at high risk for iron deficiency because a diet normally marginal in iron content becomes inadequate in the face of menstrual blood losses The presenting complaints in severe iron-deficiency anemia include pallor, lethargy, irritability, or poor exercise tolerance Iron replacement therapy consists of to mg/kg/day of elemental iron given orally as ferrous sulfate at night on an empty stomach (and ideally with ascorbic acid) as a single daily dose The hematologic response to parenterally administered iron is no faster than the response to orally administered iron for patients with intact gastrointestinal absorption Historically, intravenously administered iron has been associated with anaphylaxis, but such reactions are rare with modern preparations Vitamin B12 and folate deficiency result in megaloblastic macrocytic anemia Infants exclusively breast-fed by a vegetarian mother may develop vitamin B12 deficiency Nutritional deficiencies may also be seen with other restrictive diets In folic acid deficiency caused by impaired folate absorption, nonhematologic symptoms such as diarrhea, slowed development, or altered mental status and coma may be more prominent than the symptoms of anemia When considering replacement of folic acid or vitamin B12 , traditional replacement doses of mg of folic acid and 100 mcg of vitamin B12 daily are undoubtedly excessive, but their common use reflects the safety and concentrations of the available compounds The administration of supplemental iron, vitamin B12 , or folic acid should not be considered a substitute for adequate dietary intake when nutritional deficiency is recognized Unlike most hematologic emergencies, the rapid improvement after treatment of these disorders may reduce the likelihood of further visits despite attempts to ensure adequate follow-up care Therefore, a strong effort to restructure the diet should begin at the time of the initial contact Clinical Considerations Clinical Recognition Patients with congenital and acquired disorders of RBC production may be detected incidentally, with mild symptoms such as pallor, fatigue or malaise, or due to severe symptoms such as cardiopulmonary compromise Some viral infections, such as parvovirus, may suppress erythropoiesis which can precipitate an anemic crisis in a previously stable patient with a chronic process A mild anemia due to chronic disease may be the presentation of a child with systemic illness Age of onset helps to guide differential diagnosis While acquired etiologies can arise at any age, congenital forms of aplastic anemia and thalassemia major typically present during infancy or early childhood Initial Assessment/H&P History should include a thorough review of systems including general complaints of fatigue or decreased exercised tolerance, dietary history, family history and ethnic origin, and menstrual history where appropriate Physical examination should assess for lymphadenopathy, organomegaly, and signs of bleeding Diagnostic Testing Laboratory testing should include a CBC, reticulocyte count, review of peripheral blood smear, type and cross, concentration of reticulocyte hemoglobin (CHr), indirect antibody test (i.e., indirect Coombs test), and DAT (i.e., Coombs test), total and direct bilirubin, ferritin, plasma iron, total iron-binding capacity (TIBC), chemistry panel, urinalysis, and a stool examination for occult blood Additional testing including hemoglobin electrophoresis, micronutrient levels, ADA activity, genetic testing for congenital aplastic anemias may also be appropriate and should be guided by consultation with a hematologist Often these subspecialized tests are not interpretable in the weeks following a transfusion, so communication with hematology prior to transfusion is preferable if clinical situation permits Management The decision regarding transfusion of pRBCs depends on the etiology and severity of the anemia Replacement of nutrient deficiencies and elimination of toxin exposures are necessary ( Table 93.5 ) If the hemoglobin level is mildly decreased from baseline levels and the patient has no evidence of cardiovascular compromise, transfusion may be unnecessary However, transfusion should be considered in any patient with cardiovascular compromise, or borderline cardiovascular symptoms in the setting of expected ongoing losses The goal of transfusion should be relief of symptoms, not restoration of a normal hemoglobin level If transfusion is necessary, provide small aliquots of pRBCs (5 mL/kg) slowly The administration of a rapid-acting diuretic (furosemide mg/kg/dose, maximum 20 mg/dose) may diminish the risk of fluid overload For patients requiring recurrent or chronic transfusions or patients who may be candidates for bone marrow transplantation, blood bank measures to provide CMVnegative products and reduce the likelihood of alloimmunization by leukoreduction of pRBC units or extended RBC antigen typing are beneficial First-degree relatives should not be chosen as blood donors to avoid allosensitization to family minor HLA antigens SICKLE CELL DISEASE Goals of Treatment Patients with sickle cell disorders suffer from three broad categories of complications: vascular occlusion, infection, and end-organ damage Immediate recognition and early management of these complications can prevent hospitalizations, decrease the need for significant interventions such as exchange transfusions, and avoid long-term morbidity and death  ... Excess Nutritional anemias in children constitute more of a public health problem than a hematologic emergency; however, in some cases, the hemoglobin level may be very low at the time of diagnosis... zinc, vitamin C, and excess of copper Of these, iron-deficiency anemia is the most common in the pediatric population Severe iron deficiency occurs mainly in toddlers due to excess cow’s milk consumption