DIAGNOSTIC EVALUATION AND CLINICAL FINDINGS IN CHILDREN WITH PERSISTENT TACHYPNEA OF INFANCY/NEUROENDOCRINE CELL HYPERPLASIA OF INFANCY: A EUROPEAN MULTICENTER RETROSPECTIVE STUDY.

Background: Persistent tachypnea of infancy (PTI)/neuroendocrine cell hyperplasia of infancy (NEHI) is a form of childhood interstitial lung disease (chILD) that predominantly affects young children. Although it is one of the most common chILDs, there is no unified diagnostic approach specific to this condition.

Research Question: Is there a difference in the clinical presentation and the diagnostic approach in PTI/NEHI patients between the European countries?

Study Design And Methods: This was a European multicenter, retrospective, observational study. Data on clinical characteristics and diagnostic strategies in PTI/NEHI patients were analyzed and compared across participating countries.

Results: The study included 378 children with PTI/NEHI from 17 countries (63.5% male, 97.4% Caucasian), diagnosed at the median age of 9 months (IQR: 6-13). The most common baseline symptoms were tachypnea, chest retractions, crackles on auscultation, hypoxemia, and failure to thrive. High-resolution computed tomography (HRCT) was performed on all patients, with most undergoing chest X-rays, echocardiography, and immunology tests. Lung biopsy was done on 23.5% of patients, with a decreasing trend over time and variation by country; its use was associated with longer diagnostic delay. Histopathology showed a hyperplasia of pulmonary neuroendocrine cells in 52.8% of cases. Genetic testing was rare, and its application varied significantly between countries. Additional investigations that do not have an established role, such as assessment for gastroesophageal reflux disease and obstructive sleep apnea, infant pulmonary function tests, and lung ultrasounds were limited to single countries.

Interpretation: Diagnosis of PTI/NEHI relies on clinical symptoms and HRCT results, with lung biopsies less commonly performed. Differences exist between countries regarding the number and type of investigations. There is a need for guidelines that will uniform the diagnostic approach.