Treatment response to pulmonary exacerbation in primary ciliary dyskinesia.

Introduction: Pulmonary exacerbation (Pex) are common in pediatric primary ciliary dyskinesia (PCD), however changes in forced expiratory volume in 1 s precent predicted (FEV1pp) during Pex are not well described.

Aim: To assess the evolution of FEV1pp during Pex and to define factors associated with failure to return to baseline lung function.

Method: This was a retrospective study of patients with PCD between 2010 and 2022. Pex were defined as the presence of increased respiratory symptoms treated with intravenous (IV) antibiotics. The main outcomes were the changes in FEV1 during therapy and the proportion of patients (responders) achieving ≥90% of baseline FEV1pp values at the end of admission.

Results: The study included 52 Pex events in 28 children with PCD. The rate of responders was 32/41 (78%) at the end of admission. Nonresponse was associated with lower median body mass index (BMI) Z-score (-2.4 vs. -0.4, p < .01) and with a history of IV treated Pex in the previous year (p = .06). For the 22 Pex with available FEV1pp measurements at mid admission, the median relative and absolute improvement from admission to Day 7 was 9.1% and 6.2%, respectively (p- .001), and from Days 7 to 14 was 4.4% and 2.8%, respectively (p = .08).

Conclusion: In children with PCD treated with IV antibiotics, the majority of lung function recovery happens during the first week of IV therapy. Lower BMI was associated with nonresponse to therapy.