Upper Respiratory Tract Involvement in Cystic Fibrosis: Genetics and Developmental Basis

Sinonasal disease often occurs as chronic rhinosinusitis (CRS) in children with CF. In patients with CRS, noneosinophilic nasal polyps should suggest CF, even in patients without typical cystic fibrosis findings. The main symptoms of upper airway involvement are nasal congestion, anosmia, runny nose, and headache. Viscoelastic mucus formed secondary to abnormal chloride conduction plays a role in developing sinonasal diseases. Additionally, due to changes in electrolyte levels and pH in the airway surface fluid (ASL), the balance of antimicrobial activity (innate immunity-inhibition of bacterial growth, airway colonization, and biofilm formation) and mucus viscosity is disrupted. As a result, mucosal edema, decreased ciliary function, and bacterial colonization occur. The severity of sinonasal disease can affect pulmonary status and contribute to pulmonary exacerbations. This situation is explained by the “unified airway theory.” The conservative approach is the primary option in treatment. Surgical treatment options are applied in selected cases.