Abstract
Introduction
Fetal and neonatal alloimmune thrombocytopenia (FNAIT) occurs in the setting of maternal
anti-human platelet antigen (anti-HPA) antibodies against paternally derived fetal
platelet antigens. Recent studies have also demonstrated an association between chronic
placental inflammation and FNAIT, specifically low-grade chronic histiocytic intervillositis
(CHI). We present a neonate with profound thrombocytopenia after delivery with co-occurring
CHI, whose platelet counts recovered rapidly with platelet transfusions, born to a
primigravida mother with late-onset preeclampsia.
Case Report
A male neonate was born at 40 weeks to a mother who had no known history of pregnancies,
miscarriages, or transfusions. The mother developed severe preeclampsia during the
induction of labor. Shortly after delivery, a physical exam of the infant showed inappropriate
bruising on the heels of both feet, scattered petechiae on the hard palate, a hematoma
on the left thigh after a vitamin K shot, and a bruise on the upper left abdomen.
His platelet count was found to be 7,000. Platelet count rose to 94K by day 3 of life
following transfusions. Placental pathology confirmed CHI. Maternal testing revealed
anti-HPA-1 antibodies supporting FNAIT.
Conclusion
This case highlights a potential relationship between maternal alloimmune response
and preeclampsia. It also highlights the importance of considering FNAIT as a diagnosis
in a neonate presenting with thrombocytopenia regardless of maternal preeclampsia,
and the importance of submitting the placenta for a pathology exam.
Keywords
FNAIT - CHI - anti-HPA antibody
