Delayed Diagnosis of Primary Ciliary Dyskinesia in Low-Middle-Income Countries: The Clinical Value of Nasal Nitric Oxide.

Primary ciliary dyskinesia (PCD) is a rare lung disease that causes chronic oto-sino-pulmonary disease with irreversible lung damage. Several diagnostic methods exist, but electron microscopy (EM) is the most accurate tool, as it visualizes alterations in the axonemal ultrastructure; however, some patients may present a normal ciliary structure. Therefore, other diagnostic methods have been promoted, such as genetic studies or immunofluorescence of specific markers; nonetheless, they are not very accessible and expensive and even present a high level of false negatives. The quantification of nasal nitric oxide (nNO) has been a well-known tool for decades for the screening of this pathology, and recent studies have highlighted its high predictive value in the diagnosis of PCD, as it is a rapid tool in its processing, execution, and accessibility, especially in countries with limited health resources. We present the case of a patient with respiratory symptoms since childhood and extensive lung damage (cystic bronchiectasis); due to lack of access to EM or immunofluorescence, determinations of nNO were performed and found to be compatible with PCD.