Thrombocytopenia - Texas Tech University Health

Download Report

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.
