Retronasal olfaction in chronic rhinosinusitis.

Area of Science:

• Otorhinolaryngology
• Olfactory Science

Background:

• Chronic rhinosinusitis (CRS) is a prevalent condition affecting sinonasal health.
• Olfactory dysfunction is a common but often understudied symptom in CRS patients.
• Retronasal olfaction, the sense of smell via the oral cavity, is poorly understood in CRS.

Purpose of the Study:

• To assess retronasal olfactory function in adult patients diagnosed with chronic rhinosinusitis.
• To identify clinical factors influencing retronasal olfaction in CRS.
• To examine the impact of retronasal olfaction on patient-reported outcomes and its relationship with orthonasal olfaction.

Main Methods:

• Retronasal olfaction was evaluated using odorized powders administered orally.
• Orthonasal olfaction was assessed using the Sniffin' Sticks test.
• Olfactory cleft inflammation was graded via endoscopic evaluation (OCES).
• Quality of life (QOL) and chemosensory function were measured using validated questionnaires.

Main Results:

• A strong correlation was observed between retronasal and orthonasal olfaction scores (r=0.77, P<0.001).
• Retronasal olfactory scores were significantly lower in patients with nasal polyposis, asthma, and aspirin-exacerbated respiratory disease (AERD).
• Olfactory Cleft Endoscopy Scale (OCES) score was the sole independent predictor of retronasal olfaction (r=-0.42, P<0.001).
• Retronasal olfaction correlated significantly with olfactory-specific QOL and chemosensory smell scores.

Conclusions:

• Adult CRS patients exhibit deficits in retronasal olfaction.
• Nasal polyposis, asthma, and AERD are associated with poorer retronasal olfactory function.
• The degree of olfactory cleft inflammation, as indicated by OCES, is a key determinant of retronasal olfaction.
• Retronasal olfaction is closely linked to orthonasal olfaction and patient-perceived smell and taste quality.