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NEONATAL NEONATAL THROMBOCYTOPENIATHROMBOCYTOPENIA

By:Adrian B. Jayawon

Ma. Joselle L. BalasaKatrina Kaye C. BañasNikki Marie O. Blanco

Karleen T. Buenasflores

ThrombocytopeniaThrombocytopenia

• Defined as a reduction of platelet in the peripheral blood count of < 150, 000µL.

• Reconfirmation of the platelet count should be done.

• Confirmation by Blood Film

PathophysiologyPathophysiology

• Decreased platelet production (usually in sick or premature infants)

• Increased platelet destruction (immune or consumptive)

• Platelet pulling to splenomegaly (rare)

Decreased ProductionDecreased Production• Thrombocytopenia in sick neonates is low to

the secondary to decreased megakaryopoiesis as a result of neonatal asphyxia or infection.

• In very sick neonates with disseminated intravascular coagulopathy (DIC), there may be platelet destruction

• Bacterial or viral sepsis with or without disseminated intravascular coaguopathy.

Increased Platelet Increased Platelet DestructionDestruction

• Infants with immune-mediate thrombocytopenia have increased platelet destruction, usually without decreased production.

• Compensatory increase in megakaryopoiesis is often observed in the bone marrow.

• Thrombocytopenia occurs in about 10% of infants whose mothers have ITP.

• Infants with Kasabach-Merrit Syndrome (KMS) usually have severe thrombocytopenia, and often have evidence of DIC.

• Thrombocytopenia and coagulopathy is presumed to be due to platelet trapping on the endothelium of the Kaposiform Hemagioendothelioma (KHE), but can also be a result of DIC.

• May also occur secondary to thrombosis of a major vessel.

• Result from platelet consumption at the site of thrombosis.

2 TYPES2 TYPES

• Neonatal Alloimmune thrombocytopenia

• Neonatal Autoimmune thrombocytopenia

Neonatal Alloimmune Neonatal Alloimmune ThrombocytopeniaThrombocytopenia

• Most frequent cause of thrombocytopenia in the first few days of life of a healthy infants.

• Severe and can cause serious bleeding; such as intracranial hemorrhage (ICH)

EtiologyEtiology

• Antibodies to the HPA-1a is responsible for more than 75% of NAIT cases, while antibodies to the HPA-5b and other platelet antigens being implicated in a minority cases.

• The risk of HPA-1a alloimmunization is highest in women who are HLA class II DRB3*0101


• Maternal IgG alloantibodies formed in the maternal circulation and cross the placenta that leads to the destruction of fetal platelets.

• The mother has a normal platelet count, while the fetus can be severely thrombocytopenic.

Clinical ManifestationClinical Manifestation

• Occur as early as 20 weeks gestation, often severe (platelet count <20, 000/ µL)

• Major bleeding, particularly intracranial hemorrhage (ICH), occurs in 10-20% of untreated NAIT cases.

• Affected infants may present asymptomatic severe thrombocytopenia, or with mild bleeding symptoms such as petechiae or purpura

Diagnosis and Diagnosis and TreatmentTreatment

• Diagnosed when platelet antigen incompatibility is found between the parents, maternal serum of antibody reacts with platelets from the infant and father not with platelets from the mother

• Peripheral smear for the abnormalities and confirmation of thrombocytopenia is important

Autoimmune Neonatal Autoimmune Neonatal ThrombocytopeniaThrombocytopenia

Etiology:

Neonatal autoimmune thrombocytopenia can occur in infants born to women with ITP. Maternal IgG autoantibodies cross the placenta and bind to neonatal (and fetal) platelets, and cause platelet destruction by macrophages in the reticuloendothelial system.


There was a concomitant drop in the level of maternal antiplatelet antibody on the child’s platelets.

Clinical ManifestationClinical Manifestation

• less severe than in NAITP

• risk of ICH is 1% or less

Diagnosis and Diagnosis and TreatmentTreatment

• Blood Test• CBC• Platelet antibody tests • All neonates of mothers with autoimmune disease

should have a cord blood platelet count determined at birth and again at 24 hours.

• IVIG regardless of whether or not there is evidence of bleeding

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