Thrombocytopenia - Texas Tech University Health
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Transcript Thrombocytopenia - Texas Tech University Health
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
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
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
Differential Diagnosis
Sick Neonates, Preterm infants, other medical
complications.
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
Differential diagnosis
Healthy-appearing infant
Occult infection
Maternal autoimmune thrombocytopenia
Neonatal alloimmun thrombocytopeni
Amegakaryocytic thrombocytopenia
Hereditary macrothrombocytopenia
Wiskott-Aldrich Sydrome
Common causes
Pre-eclampsia
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
Bacterial Sepsis
Several mechanisms that include
endothelial damage, immune mediated
destruction, platelet aggregation and
decreased platelet production.
Common causes
Viral infections
Viral neuraminidase causes sialic acid loss
from platelet membranes
Intravascular platelet aggregation
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.
TAR Syndrome
Anomalies/Dysmorphism
Fanconi anemia
Aplastic anemia
Thumb anomalies
Anomalies of GU system
Abnormalities/Dysmorphism
Kasabach-Merrit Syndrome
Hemangioma
Coagulation is activated locally and platelets
are sequestered in the vascular
malformation
May not be apparent
Maternal autoimmune
Thrombocytopenia
ITP, autoimmune diseases
Maternal antibodies vs. platelet antigens
Glycoprotein IIb/IIIa and Ib/IX
Antibodies cross placenta and bind to these
antigens on fetal platelets.
Determine the mother’s platelet count
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
Management of immune mediated
Thrombocytopenia
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.
Less common etiologies
Congenital amegakarocitic
thrombocytopenia (AR)
Heredetary macrothrmbocytopenias (AD)
Wiskott Aldrich Syndrome (WAS protein X)
Immunedefiency
Eczema
Thrombocytopenia
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.
Thank You
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.