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Approach to the newborn with
thrombocytopenia
Dr. Lourdes Asiain
Nov 2004
Objectives
Define mild, moderate and severe
thrombocytopenia
 List most common causes for the
condition
 List dysmorphic features assoc with
Thrombocytopenia
 Description and management of
neonatal alloimmune thrombocytopenia
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Thrombocytopenia: Definition
Mild
100,000 to 150,000
Moderate
50,000 to 99,000
Severe
Less than 50,000
Thrombocytopenia: Epidemiology
Up to 25 % of infants admitted to NICU
have the condition.
 Mild asymptomatic thrombocytopenia
occurs in 1% healthy term infants
 Severe thrombocytopenia in term infants
rare
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Thrombocytopenia
Increased platelet
consumption
Impaired
Megakaryopoiesis
Thrombocytopenia
Thrombocytopenia: assesment
Term or preterm?
 Other medical conditions
 Are there features suggestive of
congenital infection?
 Congenital anomalies/dysmorphism
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Differential Diagnosis

Sick Neonates, Preterm infants, other medical
complications.
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Hypoxia and acidosis after birth
Chronic hypoxia from placental insufficiency
Hypothermia
Pre-eclampsia
Sepsis
Congenital viral infections (CMV, rubella)
DIC
NEC
Thrombosis
Exchange transfusions
Differential diagnosis

Neonates with physical
abnormalities/dysmorphism
Thrombocytopenia with absent radius Synd
 Fanconi anemia
 Chromosomal disorders (13,18,21, Turner)
 Kasabach-Merritt Syndrome
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Differential diagnosis

Healthy-appearing infant
Occult infection
 Maternal autoimmune thrombocytopenia
 Neonatal alloimmun thrombocytopeni
 Amegakaryocytic thrombocytopenia
 Hereditary macrothrombocytopenia
 Wiskott-Aldrich Sydrome
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Common causes
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Pre-eclampsia
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Magnitude usually correlates with severity of HTN
Often have associated neutropenia
Nadir at 3-4 days of life, recovering to normal levels
by day 7-10
Rarely severe thrombocytopenia
Possible etiology is disruption of hematopoietic
progenitor cell commitment to megakaryopoiesis
Assoc conditions from prematurity may exacerbate
condition
Common causes
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Bacterial Sepsis
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Several mechanisms that include
endothelial damage, immune mediated
destruction, platelet aggregation and
decreased platelet production.
Common causes
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Viral infections
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Viral neuraminidase causes sialic acid loss
from platelet membranes
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Intravascular platelet aggregation
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Congenital infections + Splenomegaly
Assoc with Physical abnormalities or
dysmorphism

TAR Syndrome
Autosomic recessive
 Severe thrombocytopenia and skeletal
abnormalities
 Can be associated with congenital heart
disease
 Platelet nadir during first week generally
improve by 1-3 years of age.
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TAR Syndrome
Anomalies/Dysmorphism
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Fanconi anemia
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Aplastic anemia
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Thumb anomalies
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Anomalies of GU system
Abnormalities/Dysmorphism
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Kasabach-Merrit Syndrome
Hemangioma
 Coagulation is activated locally and platelets
are sequestered in the vascular
malformation
 May not be apparent
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Maternal autoimmune
Thrombocytopenia
ITP, autoimmune diseases
 Maternal antibodies vs. platelet antigens
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Glycoprotein IIb/IIIa and Ib/IX
Antibodies cross placenta and bind to these
antigens on fetal platelets.
 Determine the mother’s platelet count
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Neonatal alloimmune
thrombocytopenia
A mother lacks a platelet antogen that
her fetus inherited from father.
 Maternal IgG vs “foreign” antigen on fetal
platelets cross the placenta and destroy
them.
 Most common platelet antigen HPA-1a
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Management of immune mediated
Thrombocytopenia
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IVIG
In cases of severe thrombocytopenia or
clinical bleeding
 1gram/Kg
 In cases of NAIT Head US and platelet
transfusion with platelets that are free on
HPA1 antigen.
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Less common etiologies
Congenital amegakarocitic
thrombocytopenia (AR)
 Heredetary macrothrmbocytopenias (AD)
 Wiskott Aldrich Syndrome (WAS protein X)
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Immunedefiency
 Eczema
 Thrombocytopenia
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Conclusions
Thrombocytopenia is often encountered
in newborns, specially sick preterm
infants
 Initial assessment should consider
gestational age, co-morbid conditions,
congenital-physical anomalies and
dysmorphism.
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Thank You
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References
NeoReviews.org: Approach to the Newborn
who has thrombocytopenia. Vol.5 2004
 Curr opinion Obst Gynecol: Platelet
disorders in pregnancy. 2001;13:115-119
 Avery’s Diseases of the Newborn. Taesch
et Ballard.
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