Neonatal Anemia

Kirsten E. Crowley, MDJune 2005

Definitions• Anemia: Central venous hemoglobin < 13

g/dL or capillary hemoglobin < 14.5 g/dL in infant > 34 weeks and 0-28 days old

• Average value for central venous hemoglobin at birth for > 34 weeks GA is 17 g/dL

• Reticulocyte count in cord blood 3-7%• Average mean corpuscular volume 107 fL

Physiologic anemia of infancy• In healthy term infants,

hemoglobin levels begin to decline around the third week of life

• Reach a nadir of 11 g/dL at 8-12 weeks

Differences in premature infants• At birth they have slightly lower hemoglobin

levels, and higher MCV and retic counts• The nadir is lower and is reached sooner

– Average nadir is 7-9 g/dL and is reached at 4-8 weeks of age

– Related to a combination of decreased RBC mass at birth, increased iatrogenic losses from lab draws, shorter RBC life span, inadequate erythropoietin production, and rapid body growth

Pathophysiology• Anemia in the newborn results

from three processes– Loss of RBCs: hemorrhagic anemia

• Most common cause– Increased destruction: hemolytic

anemia– Underproduction of RBCs: hypoplastic

anemia

Hemorrhagic anemia• Antepartum period (1/1000 live births)

– Loss of placental integrity• Abruption, previa, traumatic amniocentesis

– Anomalies of the umbilical cord or placental vessels

• Velamentous insertion of the cord in twins, communicating vessels, cord hematoma, entanglement of the cord

– Twin-twin transfusion syndrome• Only in monozygotic multiple births• 13-33% of twin pregnancies have TTTS• Difference in hemoglobin usually > 5 g/dL• Congestive heart disease common in anemic twin and

hyperviscosity common in plethoric twin

Hemorrhagic anemia• Intrapartum period

– Fetomaternal hemorrhage (30-50% of pregnancies)

• Increased risk with preeclampsia-eclampsia, need for instrumentation, and c-section

– C-section: anemia increased in emergency c-section

– Traumatic rupture of the cord– Failure of placental transfusion due to cord

occlusion (nuchal or prolapsed cord)– Obstetric trauma causing occult visceral or

intracranial hemorrhage

Hemorrhagic anemia• Neonatal period

– Enclosed hemorrhage: suggests obstetric trauma or severe perinatal distress

• Caput succedaneum, cephalhematoma, intracranial hemorrhage, visceral hemorrhage

– Defects in hemostasis• Congenital coagulation factor deficiency• Consumption coagulopathy: DIC, sepsis• Vitamin K dependent factor deficiency

– Failure to give vit K causes bleeding at 3-4 days of age• Thrombocytopenia: immune, or congenital with absent

radii– Iatrogenic blood loss due to blood draws

Hemolytic anemia• Immune hemolysis: Rh incompatibility or

autoimmune hemolysis• Nonimmune: sepsis, TORCH infection• Congenital erythrocyte defect

– G6PD, thalassemia, unstable hemoglobins, membrane defects (hereditary spherocytosis, elliptocytosis)

• Systemic diseases: galactosemia, osteopetrosis

• Nutritional deficiency: vitamin E presents later

Hypoplastic anemia• Congenital

– Diamond-Blackfan syndrome, congenital leukemia, sideroblastic anemia

• Acquired– Infection: Rubella and syphilis are the

most common– Aplastic crisis, aplastic anemia

Clinical presentation• Determine the following factors

– Age at presentation– Associated clinical features– Hemodynamic status of the infant– Presence or absence of comensatory

reticulocytosis

Presentation of hemorrhagic anemia• Acute hemorrhagic anemia

– Pallor without jaundice or cyanosis and unrelieved by oxygen

– Tachypnea or gasping respirations– Decreased perfusion progressing to

hypovolemic shock• Decreased central venous pressure

– Normocytic or normochromic RBC indices

– Reticulocytosis within 2-3 days of event

Presentation of hemorrhagic anemia• Chronic

– Pallor without jaundice or cyanosis and unrelieved by oxygen

– Minimal signs of respiratory distress– Central venous pressure normal– Microcytic or hypochromic RBC indices– Compensatory reticulocytosis– Enlarge liver d/t extramedullary erythropoiesis– Hydrops fetalis or stillbirth may occur

Presentation of hemolytic anemia• Jaundice is usually the first symptom• Compensatory reticulocytosis• Pallor presents after 48 hours of age• Unconjugated hyperbilirubinemia of

> 10-12 mg/dL• Tachypnea and hepatosplenomegaly

may be present

Presentation of hypoplastic anemia• Uncommon• Presents after 48 hours of age• Absence of jaundice• Reticulocytopenia

Presentation of other forms• Twin-twin transfusion

– Growth failure in the anemic twin, often > 20%• Occult internal hemorrhage

– Intracranial: bulging anterior fontanelle and neurologic signs (altered mental status, apnea, seizures)

– Visceral hemorrhage: most often liver is damaged and leads to abdominal mass

– Pulmonary hemorrhage: radiographic opacification of a hemithorax with bloody tracheal secretions

Diagnosis• Initial studies

– Hemoglobin– RBC indices

• Microcytic or hypochromic suggest fetomaternal or twin-twin hemorrhage, or -thalassemia

• Normocytic or normochromic suggest acute hemorrhage, systemic disease, intrinsic RBC defect, or hypoplastic anemia

– Reticulocyte count• elevation suggests antecedent hemorrhage or

hemolytic anemia while low count is seen with hypoplastic anemia

Diagnosis• Initial studies continued

– Blood smear looking for • spherocytes (ABO incompatibility or

hereditary spherocytosis)• elliptocytes (hereditary elliptocytosis)• pyknocytes (G6PD)• schistocytes (consumption coagulopathy)

– Direct Coombs test: positive in isoimmune or autoimmune hemolysis

Other diagnostic studies• Blood type and Rh in isoimmune hemolysis• Kleihauer-Betke test on maternal blood looking

for fetomaternal hemorrhage• CXR for pulmonary hemorrhage• Bone marrow aspiration for congenital

hypoplastic or aplastic anemia• TORCH: bone films, IgM levels, serologies, urine

for CMV• DIC panel, platelets looking for consumption• Occult hemorrhage: placental exam, cranial or

abdominal ultrasound• Intrinsic RBC defects: enzyme studies, globin

chain ratios, membrane studies

Management• Simple replacement transfusion

– Indications: • acute hemorrhage

– Use 10-15 ml/kg O, RH- packed RBCs or blood cross-matched to mom and adjust hct to 50%

– Give via low UVC or central UVC if time permits– Draw diagnostic studies before transfusion

• ongoing deficit replacement• maintenance of effective oxygen-carrying capacity

– Hct < 35% in severe cardiopulmonary disease– Hct < 30% in mild-moderate cardiopulmonary disease,

apnea, symptomatic anemia, need for surgery– Hct < 21%

Management• Exchange transfusion

– Indications• Chronic hemolytic anemia or hemorrhagic

anemia with increased central venous pressure

• Severe isoimmune hemolytic anemia• Consumption coagulopathy

• Nutritional replacement: iron, folate, vitamin E

Prophylactic management• Erythropoietin

– Increased erythropoiesis without significant side effects

– Decreases need for late transfusions– Will not compensate for anemia due to

labs• Need to have restrictive policy for blood

sampling and micromethods in the lab• Nutritional supplementation: iron,

folate, vitamin E