Clinical features associated with pulmonary exacerbation diagnosis in infants and young children with cystic fibrosis.

Rationale: Diagnosing cystic fibrosis (CF) pulmonary exacerbations (PEx) in very young people with CF <3 years (VY-PwCF) is challenging because of the frequency of respiratory viral infections in this age group, and there are limited data on the clinical features associated with the diagnosis of PEx in this age group. The goal of this study was to identify clinical features associated with the diagnosis of PEx in VY-PwCF.

Methods: We reviewed the medical records of VY-PwCF followed at the Children's Hospital of Philadelphia born between 2013 and 2019. We collected data from all encounters with respiratory symptoms. PEx was defined by treatment with oral or intravenous antibiotics. Clinical features of PEx and non-PEx encounters were compared using descriptive statistics, and odds ratios of PEx diagnosis were calculated.

Results: A total of 78 patients were included in the analysis. The mean (SD) number of PEx per patient was 6.17 (5.88). The presence of a wet or nighttime cough and symptoms >3 days in duration were significantly associated with PEx diagnosis (p < .001). In contrast, symptoms such as sore throat or rhinorrhea were not associated with a higher likelihood of PEx.

Conclusions: The presence of a wet or night-time cough and longer symptom duration are common features of PEx in VY-PwCF, whereas symptoms suggestive of upper respiratory viral infection are not. Our results will be helpful in counseling families of VY-PwCF in the signs and symptoms of PEx and in planning future research in PEx in this age group.