Thermal and mechanical pain thresholds in children and young adults with cystic fibrosis and primary ciliary dyskinesia

<bold>Background:</bold> In addition to respiratory and gastrointestinal symptoms, many people with cystic fibrosis (pwCF) complain of pain. A preclinical study suggested CFTR-induced effects on nociception. The aim of our study is to investigate whether children and adolescents with CF have lowered pain thresholds compared healthy subjects and people with primary ciliary dyskinesia (pwPCD). <bold>Methods:</bold> In this ongoing study 24 pwCF (18,4 ± 8,7 yrs; 50% fem) and 14 pwPCD (27,1 ± 15,3 ys; 71,4% fem) were included. Relevant clinical data, lung function, HbA1c and iontophoresis were assessed. Additionally thermal/mechanical detection and pain thresholds were measured according to the DFNS-QST protocol (quantitative sensory testing) and the conduction velocity and amplitude of the N. suralis using neurography (ENG). The data were compared against a norm collective (G-test) using age-adjusted standard values of the DFNS database. <bold>Results:</bold> The ENG amplitude was reduced only in 2 and 3 pwCF and pwPCD, respectively, and the conduction velocity was prolonged in 2 pwCF. In 54.2% with CF versus 28.6% with PCD the mechanical detection thresholds were significantly increased than in healthy subjects, whereas the pain thresholds were lowered (29.2% vs. 42.9%). The differences between CF and PCD were not significantly different, and there was no dependence of hyperalgesia on the chloride concentration in sweat. <bold>Discussion:</bold> In both diseases (more frequently in CF), there is evidence of large fiber dysfunction in a certain subgroup, in some cases combined with hyperalgesia. However these occur independently of the extent of impaired CFTR channel function or glucose tolerance.