Sinusitis with nasal polyps linked to increased NO levels
MedWire News: The presence of nasal polyps in patients with chronic rhinosinusitis (CRS) is associated with increased exhaled nitric oxide (ENO) levels, study results show.
Writing in the journal Chest, Enrico Heffler (ASO Ordine Mauriziano “Umberto I,” Turin, Italy) and team explain: “ENO is considered a noninvasive marker of airway inflammation and measuring ENO has been reported to be a useful tool for the screening of patients with suspected diagnosis of asthma.”
They add that previous research has shown that patients with CRS have elevated ENO levels, which can not be fully explained by the high prevalence of asthma among these patients.
To investigate factors associated with increased ENO levels among CRS patients, the researchers studied 93 consecutive patients with the condition who were aged between 13 and 74 years (mean age 48 years). Of these, 63.4% had evidence of nasal polyps.
All the participants were asked about the presence of respiratory symptoms and whether they had been diagnosed with asthma. They also underwent lung function and skin-prick allergy tests, and provided sputum samples for analysis of eosinophil levels.
Overall, 49.5% of patients had asthma, 25.8% had asthma-like symptoms without criteria for a diagnosis of asthma, and 24.7% did not report respiratory symptoms.
The researchers found that the presence of nasal polyps, asthma and/or respiratory symptoms without bronchial hyper-responsiveness (BHR) were the only independent factors associated with increased ENO levels.
Asthma prevalence was significantly higher in patients with than without nasal polyps, at 61% versus 29.4%, respectively, whereas the prevalence of respiratory symptoms without BHR was higher in those without than with nasal polyps, at 44.1% versus 15.3%, respectively.
Respiratory symptoms without BHR were associated with significantly higher ENO levels and prevalence of sputum eosinophilia (eosinophils ≥3% of nonsquamous cells) in patients with nasal polyps compared with those without, at 68.2 versus 24.0 ppb, and 60% versus 8.3%, respectively.
Heffler and team conclude: “Our results show that among patients with CRS, lower airway involvement, assessed by the prevalence of asthma and increased ENO, is more frequent in CRS with nasal polyps compared with CRS without nasal polyps, underlying once again the important clinical and biologic differences between the two types of chronic sinusitis.”
They add: “Respiratory symptoms suggestive of asthma, such as cough, wheezing, and dyspnea, are more often sustained by eosinophilic airway inflammation in CRS with nasal polyps than in CRS without nasal polyps, suggesting a hypothetical role of ENO measurement as a guide to treatment of chronic respiratory symptoms with inhaled corticosteroids in patients with CRS.”
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By Mark Cowen