Rationale: Pertussis has re-emerged on a global scale and is an ongoing public health problem, even in countries with high rates of vaccination. Hyperleukocytosis [white blood cell (WBC) count >100 × 10/L] is a rare complication that strongly predicts mortality in cases of severe pertussis.
Patient concerns: We report a case of severe pertussis in an infant who initially presented with persistent cyanotic cough, tachypnea, and grunting. The infant's condition deteriorated rapidly, and she was transferred to the pediatric intensive care unit (PICU) during her third hour of hospitalization. On the third hospital day, her WBC count had increased to 101.85 × 10/L with a lymphocyte count of 36.76 × 10/L, and her hemoglobin level had fallen to 6.9 g/dL. Bone marrow examination found no evidence of tumor cells. Her initial echocardiogram showed no abnormal findings; however, a subsequent echocardiogram 10 days later revealed pulmonary hypertension.
Diagnoses: The patient was diagnosed with severe pneumonia, which was confirmed to be pertussis based on a persistent cough in the infant's mother and the polymerase chain reaction and culture of the infant's nasopharyngeal secretions being positive for Bordetella pertussis.
Interventions: The infant was treated with supportive care, early macrolide antibiotics, and broad-spectrum antibiotics before being transferred to the PICU for further management, including continuous venovenous hemodiafiltration.
Outcomes: Unfortunately, the infant died as a result of pulmonary hypertension and multiorgan failure.
Lessons: Exchange transfusion should be considered in all infants who present with severe pertussis with hyperleukocytosis. This guideline is supported by the findings of a comprehensive literature review, which is included in this article, as well as newly published criteria for exchange transfusion therapy. Finally, we hope that adults in China will be vaccinated against B. pertussis in order to prevent the infection of infants within their households.