1. A newborn with petechiae

2. HPI Newborn male born to 34 y/o G9P2253 mother at 37 weeks via C/S Maternal history: endometriosis, h/o molar pregnancy, anemia, fetal demise Labs: A+, GBS neg, serologies neg/immune Delivery: Apgars 9 and 9 Growth parameters: AGA

3. Physical exam Calm well appearing infant Only pertinent exam finding is skin: warm, no jaundice. Infant with bruising over L shoulder and L posterior thigh. Bilateral anterior thighs with bruise at injection sites of vitamin K and hepatitis B vaccine with underlying firmness concerning for hematoma. R shoulder and back with 1 mm pustules and numerous freckles over inguinal folds. Petechiae over trunk Neuro, MSK, CV, lung exam normal

4. Assessment Term newborn, mother with history of losses, physical exam notable for bruising and petechiae Differential includes?

5. Differential Infection – TORCH – GBS, NEC Thrombocytopenia (consumptive vs destructive) – Maternal ITP, SLE, DM – Maternal medications – Neonatal alloimmune thrombocytopenia – Sepsis, DIC – Kasabach-Merritt syndrome Birth injury Metabolic disease Trisomy 13, 18, 21 Prematurity Vascular malformations Bone marrow infiltration (congenital leukemia, neuroblastoma) Familial thrombocytopenias

6. Work-up in newborn nursery? CBC – WBC 19.2 (range 9-30) – Hgb 14.4 (Mean 16.5, -2 SD 13.5) – Hct 41.8 (Mean 51, -2 SD 42) – Platelets 23 (Mean 290 range 180-327) Coags – INR 1.13 – PT 12.4 (Mean 13.0 range 10.1-15.9) – PTT 39.7 (Mean 42.9 range 31.3-54.3)

7. Next steps NICU transfer Head ultrasound! Repeat platelets IVIG or platelet transfusion

8. Diagnosis? Neonatal Alloimmune Thrombocytopenia Fetal platelets have an antigen inherited from baby’s father that mother lacks. Mother sees these as abnormal and baby’s platelets are destroyed by placenta

9. Patient course Received IVIG x 2, repeat platelets 20, then 142 Reticulated platelet count elevated (60% (suggesting consumptive process) HUS normal Received platelet transfusion Maternal/paternal labs sent to Wisconsin for testing

10. Neonatal alloimmune thrombocytopenia most common cause of severe thrombocytopenia and intracranial haemorrhage in the term newborn NAIT should be considered for any neonate with unexplained thrombocytopenia A head ultrasound (or magnetic resonance imaging (MRI)) should be performed ASAP on all babies with suspected NAIT to exclude intracranial hemorrhage.

11. Incidence in “Well” newborns is ~0.5% Diagnosis: parents’ blood samples looking for maternal-paternal platelet antigen incompatibility and maternal platelet autoantibodies Clinical presentation: no bleeding, petechiae, hematoma, GI bleed, ICH Treatment: platelets or IVIG Future pregnancies