Alkan, GülsümEmiroğlu, Melike Keser2020-03-262020-03-2620171300-0381https://dx.doi.org/10.5336/pediatr.2016-52637https://hdl.handle.net/20.500.12395/35794Pertussis, becomes serious when refractory hypoxemia develops from hyperleukocytosis and pulmonary hypertension, especially in infants. Here, we present the case of a 2 monthsold infant with severe pertussis pneumonia and hyperleukocytosis. A double volume exchange transfusion (ET) was needed for cardiopulmonary insufficiency unresponsive to intensive care. Oxygenation gradually improved within 48 hours after the treatment. A high white blood cell count can be a predictor of death in infants with pertussis. We considered that clinical improvement was observed due to a reduction cluster of leukocytes and also toxins, because of pertussis is a toxin-releasing infection. The early use of ET may prevent fatal outcomes in infants with severe pertussis, who failed to respond to standard therapy. Copyright © 2017 by Türkiye Klinikleri.en10.5336/pediatr.2016-52637info:eu-repo/semantics/openAccessBordetella pertussisExchange transfusion, whole bloodLeukocytosisArticle2613234Q4