Impact of Nasal Glucocorticoid Therapy on Exhaled Nitric Oxide and Symptom Relief in Chronic Rhinosinusitis with Nasal Polyps: A Randomized Prospective Study

Introduction Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) is a widespread inflammatory disease, classified into Eosinophilic (EosCRSwNP) and non-Eosinophilic (non-EosCRSwNP) types. Nitric oxide (NO) plays a role in pathophysiological processes, with changing levels in airway diseases like asthma and CRS. Intranasal corticosteroids (INCS) are first-line treatments for CRSwNP, providing anti-inflammatory and immunomodulatory effects pre- and post-endoscopic sinus surgery (ESS). This study examines the influence of nasal steroids on nasal exhaled nitric oxide (FnNO) post-ESS in EosCRSwNP and non-EosCRSwNP patients and assesses the prognostic value of FnNO measurement for different CRSwNP types. Methods This randomized, open-label, prospective study included 20 healthy controls, 30 EosCRSwNP patients, and 35 non-EosCRSwNP patients. All CRSwNP subjects underwent ESS following FnNO determination. Post-surgery, both endotypes were randomly assigned to nasal steroid or normal saline groups, receiving budesonide spray or saline irrigation for 90 days. FnNO, nasal endoscopy, and VAS scores were assessed on days 15, 45, and 90. Results This study found pre-ESS FnNO levels to be lower in CRSwNP patients (181.2 ± 142.0 ppb) compared to controls (330.5 ± 98.7 ppb, p < 0.001), and further reduced in non-EosCRSwNP (144.7 ± 91.2 ppb) compared to EosCRSwNP patients (223.3 ± 147.8 ppb, p < 0.05). Post-ESS, EosCRSwNP patients responded better to nasal steroids, with FnNO levels returning to normal within 90 days of intervention (p > 0.05). No significant correlation was found between post-ESS FnNO levels, changes in Lund-Kennedy endoscopy scores, CT Lund-Mackay paranasal sinus scores, and postoperative prognosis in CRSwNP patients. Conclusion The determination of FnNO is helpful for the differential diagnosis of EosCRSwNP, which is more sensitive to nasal spray glucocorticoid, and the use of nasal spray glucocorticoid post-ESS is helpful for early and rapid recovery of FnNO. FnNO measurement could not be used as an indicator to assess the recovery status of the postoperative surgical area.