Persistent tachypnoea of infancy and neuroendocrine cell hyperplasia of infancy: from systematic review to future directions.

Background: Neuroendocrine hyperplasia of infancy (NEHI), also called persistent tachypnoea of infancy (PTI), is one of the most prevalent forms of childhood interstitial lung disease (chILD) and one of the few with an overall favourable prognosis. Nevertheless, there is still much to be understood about the pathophysiology of NEHI and much to be done to harmonise diagnostic work-up and management. Methods: A systematic search was conducted in PubMed, Embase, Cochrane Library, Scopus and Web of Science to identify eligible studies. Results: The results are presented in a narrative format, providing an overview of the current understanding of NEHI epidemiology, clinical presentation, investigations and outcomes. In-depth discussions include the roles of clinical assessment, chest computed tomography scan and lung biopsy, along with prospects for new diagnostic tools. Additionally, the discussion covers the pathophysiology of NEHI, focusing on the possible roles of genetic predisposition and infectious triggers. Conclusions: The morbidity of NEHI is particularly significant in the first months of life, underscoring the need for clinical and basic research to develop new targeted treatments. Some of these are discussed in this review. Finally, the improved diagnosis of this rare lung disease is facilitating the formation of new parent groups, which are becoming a crucial asset for progress.