Nasal Nitric Oxide Measurement and a Modified PICADAR Score for the Screening of Primary Ciliary Dyskinesia in Adults with Bronchiectasis.

Determining the underlying diagnosis is essential for the targeted and specific treatment of bronchiectasis. Primary ciliary dyskinesia (PCD) is a rare genetic disease, which is characterized by abnormalities in ciliary structure and/or function and which may result in bronchiectasis. The disease is probably underestimated among adults with bronchiectasis due to the fact that extensive diagnostic testing is required and that the recognition of PCD is low.  To evaluate a feasible screening algorithm for PCD among adults with bronchiectasis.  Data from all patients who presented to our bronchiectasis outpatient clinic from June 2010 until July 2016 were retrospectively analysed from our database. Nasal NO (nNO) and a modified PICADAR score (PrImary CiliAry DyskinesiA Rule) were measured and compared in the two groups of PCD-bronchiectasis and non-PCD-bronchiectasis.  185 of 365 patients (75 males, 110 females) had a sufficient measurement of nNO concentration and complete clinical data and were eligible for analysis. The mean (SD) nNO concentration in nL/ml was significant lower in the PCD group compared to the non-PCD group (25 [31] and 227 [112] nL/min, respectively; p < 0.001). A nNO level of 77 nL/min had the best discriminative value to differentiate between the two groups. Patients with PCD had a significant higher modified PIDACAR score than patients without PCD (5 2 and 1 1, respectively [p < 0.001]). Using ROC curve analysis, the modified PICADAR score of 2 had the best discriminative value with a sensitivity of 1.00 and a specificity of 0.89.  Low nNO concentration and the modified PICADAR score are suitable and cheap screening tests for PCD in adults with bronchiectasis.