Clinical Analysis of Single-Volume Exchange Transfusion Therapy in 8 Cases of Severe Pertussis in Infants under 3 Months of Age

Objective To characterize the clinical features of severe pertussis in young infants and assess the efficacy and safety of single-volume exchange transfusion (ET) therapy. Methods A retrospective study was performed in eight pediatric patients with severe pertussis who underwent single-volume ET in the Pediatric Intensive Care Unit (PICU) of the Zhuhai Center for Maternal and Child Health Care between March and October 2024. Clinical characteristics, treatment responses, and outcomes were analyzed to assess the therapeutic efficacy and prognosis associated with ET in severe pertussis. Results Among the eight infants and young children with severe pertussis complicated by hyperleukocytosis, the primary source of infection was parental transmission (62.5%). Female patients accounted for 75% of cases. The mean age at disease onset was 58.5 days, and the mean disease duration was 10.87 days. None of the patients had received pertussis vaccination. Clinical manifestations were distinctive. All patients presented with spasmodic coughing of relatively low intensity, accompanied by dyspnea and tachycardia. Severe complications were frequent, including severe pneumonia in all patients (100%), respiratory failure in three patients (37.5%), pertussis encephalopathy in two patients (25.0%), and pulmonary hypertension in two patients (25.0%). Five patients developed mixed infections, predominantly bacterial, with Haemophilus influenzae identified as the most common pathogen. All patients exhibited marked leukocytosis, with a maximum white blood cell (WBC) count of 56.7 × 10⁹/L, characterized primarily by lymphocytosis (maximum 40.8 × 10⁹/L), along with concomitant thrombocytosis. Following single-volume ET, absolute WBC, lymphocyte, and platelet counts decreased significantly (P < 0.05), while arterial oxygen partial pressure markedly elevated (P < 0.05). No significant changes in calcium ion levels were observed. Partial rebound of WBC counts occurred within 1 week after ET. Two patients required a second ET, and one patient required a third ET. No severe adverse events related to ET were reported. All seven infants who received ET during the early stage of cardiopulmonary failure showed clinical improvement and were discharged successfully. In contrast, the single infant who underwent ET at a late stage of cardiopulmonary failure died during follow-up. Conclusion Infants with severe pertussis are at high risk of developing hyperleukocytosis. Early initiation of single-volume ET during pronounced elevations in WBC and lymphocyte counts, before the development of multiple organ failure, can rapidly reduce WBC burden, significantly improve oxygenation, and lead to better clinical outcomes. This approach appears to be a safe and effective therapeutic strategy for severe pertussis in young infants.