Nitric oxide (NO) reflects changes in inflammatory state of the airways. In pulmonology fractional exhaled nitric oxide concentration (FeNO) has been linked to eosinophilic asthma and is used to guide overall disease control. The measurement of nasal nitric oxide (nNO) may reflect the disease burden and inflammatory phenotype of the paranasal sinuses.

The aim of our study is to evaluate the relation of chronic rhino sinusitis (CRS) severity and inflammatory status to nNO, maxillary sinus NO, nitrite, nitrate and cone beam computed tomography (CBCT).

Three groups (22 patients in each) of referred patients and and 22 healthy volunteers are recruited. Patients are grouped according to the CBCT score and viewed three times in 4-6 weeks intervals.

Inclusion Criteria:

• Patients willing to participate in the study
• Patients who are referred to ENT clinic due to chronic rhinosinusitis (EPOS criteria) or repeatedly diagnosed and treated acute rhinosinusitis

Exclusion Criteria:

• Endoscopic sinus surgery operation previously
• Septal deviation that would need an operation to correct the air flow
• Other severe disease that could pose a risk for the patient during the measurements based on the judgement of the treating physician
• Pregnancy or breastfeeding
• Allergy to used medications
• Inability to co-operate or to tolerate manipulation of the nose