ANEMIA,POLYCYTHEMIA IN A NEWBORN

-Dr.ApoorvaPediatrics pg

ANEMIA IN NEONATES

Physiologic Anemia Of Infancy

• In utero,due to high oxygen saturation(45%) in fetal aorta,erythropoietin levels are high &hence,RBC production is rapid.

• At one week postnatally, all RBC indices begin declining to a minimum value reached at about 8-12 weeks of age (11g/dl)– decreased RBC production – plasma dilution associated with increasing blood volume– shorter life span of neonatal RBCs (50-70 days)– more fragile RBCs

• Switch from HbF to HbA (switch to HbA provides for greater unloading of oxygen to tissues d/t lower oxygen affinity of HbA relative to HbF.)

• Seldom produces symptoms.

• As the hemoglobin levels reach nadir,oxygen delivery to tissues is impaired,erythropoietin stimulated,RBC production increases.

• Iron stores rapidly utilized for this process. Hence,iron has to be supplied.

Anemia of Prematurity• Occurs in low birth weight infants.• The nadir is lower and is reached sooner. • Average nadir is 7-9 g/dL and is reached at 4-8 weeks of age.

• Due to a combination of :

decreased RBC mass at birth, increased iatrogenic losses from lab draws, shorter RBC life span, inadequate erythropoietin production, low iron stores,rapid rate of growth,Vitamin E deficiency.

• Signs and Symptoms :apneapoor weight gainpallordecreased activityTachycardia.

• Iron administration does not alter nadir reached or its rate of reduction.

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– Loss of placental integrity

• Abruption, previa, traumatic amniocentesis.– Anomalies of the umbilical cord or placental vessels

• Velamentous insertion of the cord , communicating vessels, cord hematoma, entanglement of the cord,vasa previa.

– 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

• Increased risk with ECV,ICV,breech delivery,placental malformations

– 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 hypoxia• Hemorrhagic caput succedaneum, cephalhematoma, intracranial

hemorrhage, visceral hemorrhage– Defects in hemostasis

• Congenital coagulation factor deficiency• Consumption coagulopathy: DIC, sepsis• Vitamin K dependent factor deficiency• Thrombocytopenia: immune, or congenital with absent radii

– Iatrogenic blood loss due to blood draws

Hemolytic anemia• Immune hemolysis: Rh/ ABO /minor blood group incompatibility or

autoimmune hemolysis• Nonimmune: sepsis, TORCH infection• Congenital erythrocyte defect– G6PD, thalassemia, membrane defects (hereditary

spherocytosis,elliptocytosis)• Systemic diseases: galactosemia, osteopetrosis• Nutritional deficiency: vitamin E

Hypoplastic anemia

• Congenital – Diamond-Blackfan syndrome, congenital leukemia,

sideroblastic anemia• Acquired– Infection: Rubella and parvovirus are the most

common– Drug induced

Clinical presentation

• Determine the following factors :– Age at presentation– Associated clinical features– Hemodynamic status of the infant– Presence or absence of compensatory

reticulocytosis– Family history,obstetric history

Presentation of hemorrhagic anemia

• Acute hemorrhagic anemia– Pallor without jaundice,cyanosis unrelieved by

oxygen– Tachypnoea – Decreased perfusion progressing to hypovolemic

shock– Acidosis– Normocytic or normochromic RBC indices– Reticulocytosis within 2-3 days of event

• Chronic– Pallor– Minimal signs of respiratory distress– Microcytic or hypochromic RBC indices– Compensatory reticulocytosis– Enlarged liver d/t extramedullary erythropoiesis

Presentation of hemolytic anemia

• Jaundice is usually the first symptom• Compensatory reticulocytosis• Pallor• Hepatosplenomegaly

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

• 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 chronic hemorrhage or

thalassemia• Normocytic or normochromic suggest acute hemorrhage,

systemic disease, intrinsic RBC defect or hypoplastic anemia

– Reticulocyte count• elevation suggests chronic hemorrhage or hemolytic

anemia while low count is seen with hypoplastic anemia

Diagnosis

– Blood smear to look for • spherocytes (hereditary spherocytosis,immune

hemolysis)• elliptocytes (hereditary elliptocytosis)• pyknocytes ,bite cells,heinz bodies(G6PD)• Schistocytes,fragmented RBC’s (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 to look for

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

aplastic anemia• TORCH: IgM levels, urine for CMV• DIC panel, platelets looking for consumption• Occult hemorrhage: cranial or abdominal ultrasound• Intrinsic RBC defects: enzyme studies, globin chain ratios,

membrane studies

Management• Simple replacement transfusion– Indications: • acute hemorrhage– Use 15-20 ml/kg O, RH- packed RBCs or blood cross-

matched to mother and adjust hct to 50%– Give via UVC– Draw diagnostic studies before transfusion

• ongoing deficit replacement• maintenance of effective oxygen-carrying capacity– Hct >35% in severe cardiopulmonary disease– Hct >40% in mild-moderate cardiopulmonary disease,

apnea, symptomatic anemia, need for surgery

Management

• Exchange transfusion– Indications• Chronic hemolytic anemia• Severe isoimmune hemolytic anemia• Consumption coagulopathy

• Nutritional replacement: iron, folate, vitamin E

• Erythropoietin– Increased erythropoiesis without significant side

effects

POLYCYTHEMIA IN NEONATES

• Polycythemia is increased total RBC mass– Central venous hematocrit > 65%

• Polycythemic hyperviscosity is increased viscosity of the blood resulting from increased numbers of RBCs– Not all polycythemic infants have symptoms of

hyperviscosity

Incidence

• Polycythemia occurs in 2-4% of newborns– Half of these are symptomatic

• Hyperviscosity occurs in 25% of infants with hematocrit 60-64%

Pathophysiology

• Clinical signs result from regional effects of hyperviscosity and from the formation of microthrombi– Tissue hypoxia– Acidosis– Hypoglycemia in the substrate

• Organs affected: CNS, kidneys, adrenals, cardiopulmonary system, GI tract

What affects hyperviscosity?• Hematocrit– Increased hct is the most important single factor– Results from increase in circulating RBCs or decreased

plasma volume (dehydration)• Plasma viscosity– Higher plasma proteins = increased viscosity

• Especially fibrinogen (typically low in neonates)– Not usually an issue in neonates

• RBC aggregation– Occurs in areas of low blood flow = venous

microcirculation– Not a large factor in neonates

• Deformability of RBC membrane: usually normal

Conditions that alter incidence

• Altitude: increased RBC mass• Neonatal age– Physiologic increase in hematocrit due to fluid

shifts away from intravascular compartment with maximum at 2-4 hours of age

• Obstetric factors: delayed cord clamping or “stripping” of the umbilical cord

• High-risk delivery, especially if precipitous

Perinatal processes

• Enhanced fetal erythropoiesis usually related to fetal hypoxia– Placental insufficiency• Maternal hypertension, abruption, post-dates, IUGR,

maternal smoking– Endocrine disorders: due to increased oxygen

consumption• IDM (>40% incidence), congenital thyrotoxicosis, CAH,

Beckwith-Wiedemann syndrome (hyperinsulinism)

DUE TO : Hypertransfusion• Delayed cord clamping

• Should be done within 1 minute

• Gravity: positioning below the placenta will increase placental transfusion

• Meds: oxytocin can increase contractions and thus transfusion

• Decreased in c-section ( no contractions )

• Twin-twin transfusion• Intrapartum asphyxia

• Enhances net umbilical flow toward the infant, while acidosis increases capillary leak leading to reduced plasma volume

Clinical presentation

• Symptoms are non-specific!• CNS: lethargy, hyperirritability, proximal muscle

hypotonia, vasomotor instability, vomiting, seizures, cerebral infarction (rare)

• Cardiopulmonary: respiratory distress, tachycardia, CHF, pulmonary hypertension

• GI: feeding intolerance, sometimes NEC• GU: oliguria, ARF, renal vein thrombosis, priapism• Metabolic: hypo-glycemia/-calcemia/-magnesemia• Heme: hyperbili, thrombocytopenia• Skin: ruddiness

Diagnosis

• Central venous hematocrit > 65%• ALWAYS draw a central venous sample if the

capillary hematocrit is > 65%– Warmed capillary hematrocrit > 65% only

suggestive of polycythemia

Management

• Asymptomatic infants– Expectant observation unless central venous hematocrit

>75% (consider partial exchange transfusion)– Can do a trial of rehydration over 6-8 hr if dehydrated

• Give 130-150 ml/kg/d– Check central hematocrit q6 hourly

Management• Symptomatic infants with central hct > 65%– Partial exchange transfusion is advisable but debatable– For exchange can use normal saline, 5% albumin, or FFP– Volume exchanged =

• (Weight (kg) x blood volume) x (hct - desired hct) / hct

Other investigations

• Serum glucose– Hypoglycemia is common with polycythemia

• Serum bilirubin– Increased bilirubin due to increased RBC turnover

• Serum sodium, BUN, urine specific gravity– Usually high if baby is deyhdrated

• Blood gas to rule-out inadequate oxygenation as cause of symptoms

• Platelets, as thyrombocytopenia can be present• Serum calcium-hypocalcemia can be seen

Prognosis

• Increased risk of GI disorders and NEC with partial exchange transfusion (PET)

• Older trials show decreased neurologic complications from hyperviscosity with PET, but newer trials show no real benefit– PET is controversial!

• Infants with asymptomatic polycythemia have an increased risk for neurologic sequelae– Normocythemic controls with the same perinatal history

have a similarly increased risk

THANK YOU!