Diagnostic approach to the etiology of recurrent pneumonia in children

Background: Recurrent pneumonia (RP) accounts for 7.7%-9% of childhood pneumonia. Identifying the cause of RP is crucial for infection control and reducing mortality and morbidity. This study aimed to investigate the etiology, risk factors, and diagnostic procedures of RP based on the literature using a diagnostic algorithm. Methods: Our study included RP patients aged 0-18 years who were followed up as outpatients or inpatients between 2018 and 2021. Patients were analyzed retrospectively using the national health database. Patients with RP were identified by ICD diagnosis codes. Etiology and risk factors were determined based on the occurrence of RP in the same or different areas. Results: The rate of RP was found to be 14.4% among the cases of recurrent lower respiratory tract infection. Of these, 27.6% occurred in the same area and 72.4% in different areas. The underlying etiology was identified in 224 of 250 RP patients (89.6%). RP in different areas was mainly due to neuromuscular diseases, whereas asthma, right middle lobe syndrome, and congenital lung or airway structural disease were common causes of RP in the same area. Malnutrition, passive smoke exposure, and prematurity were common risk factors in both groups. Conclusions: Systematic etiological investigations should take into account the characteristics of the patient population and geographical region. The use of diagnostic algorithms based on recurrence in the same or different areas is particularly beneficial. Whether asthma is causally related to RP episodes or is a coincidental association due to inadequate differential diagnosis remains unclear.