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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
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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
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 Impaired Megakaryopoiesis Increased platelet consumption 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.
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.