目的 提高对重症百日咳合并肺孢子菌肺炎(PCP)的认识，以期早期诊断，改善预后。方法 回顾性分析2020年1月1日至2023年12月31日确诊的重症百日咳合并PCP患儿的临床资料及诊治经过。结果 共纳入5例患儿，男1例、女4例，中位年龄3.0(2.5~10.0)个月，住院时间17.0(7.5~23.5)天，其中死亡3例。5例患儿均有呼吸暂停与低氧血症，3例合并急性呼吸窘迫综合征(ARDS)，3例同时合并肺动脉高压及百日咳脑病，5例白细胞计数(WBC)峰值中位数43.8(25.2~87.8)×10⁹/L，治疗后降至8.5(5.0~36.5)×10⁹/L，乳酸脱氢酶（LDH）中位数942.0(466.5~1 837.0)U/L，明显高于正常。5例患儿在确诊PCP前均给予阿奇霉素治疗，确诊PCP后均加用复方磺胺甲噁唑联合棘白菌素类药物，2例存活者于5日内给药。结论 PCP可发生在无免疫缺陷的重症百日咳患儿中，且重症百日咳合并PCP时死亡风险高，在儿童重症百日咳常规治疗效果不佳时，需警惕合并耶氏肺孢子菌( PJ )感染的可能，早期联合应用复方磺胺甲噁唑与棘白菌素类药物，有望改善预后。

Objective To raise the awareness of Pneumocystis jirovecii pneumonia (PCP) in children complicated with severe pertussis, and to enable early diagnosis for improved prognosis. Methods The clinical data of children diagnosed with severe pertussis complicated by PCP from January 1, 2020 to December 31, 2023 were retrospectively analyzed. Results Five cases were enrolled, with one male and four females. The median age was 3.0(2.5-10.0) months, and the median hospital stay was 17.0(7.5-23.5) days, with three deaths recorded. All cases experienced apnea and hypoxemia, with 3 cases presented acute respiratory distress syndrome (ARDS), and 3 cases developed pulmonary hypertension and pertussis encephalopathy. The peak of leucocyte count were 43.8(25.2-87.8)×10⁹/L, which decreased to a post-treatment median of 8.5(5.0-36.5)×10⁹/L, and the median LDH was 942.0(466.5-1837.0) U/L. All 5 cases were treated with azithromycin before diagnosis of PCP, and co-trimoxazole combined with echinocandin were administered additionally for PCP, while 2 survivors were treated within 5 days. Conclusion PCP can occur in severe pertussis children without immunodeficiency, and there is a high risk of death when severe pertussis is complicated by PCP. When the routine treatment for severe pertussis in children has poor efficacy, it is necessary to be alert for Pneumocystis jirovecii infection. Early combined use of co-trimoxazole with echinocandin may improve prognosis.