Transient Hyperleukocytosis in One of the Extreme Preterm Twins: A Case Report with Review of Literature

Abstract

Background: Although physiological leukocytosis is known in premature neonates, hyperleukocytosis (total leukocyte count more than 100 × 103 /µL) is rarely seen. Commonly known disorders leading to hyperleukocytosis include leukemia, leukocyte adhesion defect, and myeloproliferative disorders. Transient hyperleukocytosis of unidentified etiology or attributed to sepsis has been rarely reported. Clinical Description: One of the extremely preterm twins (delivered at 26 weeks gestation) developed hyperleukocytosis on day 3 of life, without any evidence of blast cells on the peripheral smear, with normal C-reactive protein levels, while Twin 2 had normal leukocyte counts. Management and Outcome: Twin 1 was managed conservatively with mechanical ventilation, supportive care, and broad-spectrum antibiotics. His total leukocyte counts started reducing since day 5 of life and returned to normal after day 18, although he required prolonged respiratory support due to bronchopulmonary dysplasia (BPD). The other twin with a normal leukocyte count had a less difficult course and did not develop BPD. The twins being dichorionic-diamniotic type, and the placental histopathology of Twin 1 showing evidence of chorioamnionitis (the placenta of the other twin was normal), the transient hyperleukocytosis of Twin 1 was attributed to chorioamnionitis. Conclusion: The presence of hyperleukocytosis in only one of the neonates of an extremely preterm delivery highlights the fact that some factors such as chorioamnionitis or early-onset sepsis may contribute to this condition, which is transient, and resolves with supportive conservative care.