Empty Nose Syndrome Pathophysiology: A Systematic Review

Abstract

OBJECTIVE: The pathophysiology of empty nose syndrome (ENS) remains unclear despite significant research. The pathophysiologic mechanism of ENS was systematically reviewed. DATA SOURCES: MEDLINE and Embase. REVIEW METHODS: Data were systematically reviewed for studies that provided original data on pathophysiology. RESULTS: A total of 2476 studies were screened, and 19 met the inclusion criteria: 13 case-control and 6 cross-sectional. Nine pathophysiologic themes were identified.• Demographics: ENS symptoms had no relationship with climatic factors.• Symptomatology: ENS patients demonstrated high symptom severity.• Mental health: Anxiety and depression including hyperventilation were reported in >50% of ENS patients and correlated with ENS symptom severity.• Anatomic features: Structural changes in response to turbinate surgery were similar between ENS and non-ENS patients.• Airflow analysis: Airflow parameters were similar between ENS and non-ENS patients after turbinate surgery. On computational fluid dynamic analysis, differences were found on multiple outcomes.• Diagnostic testing: The menthol detection test was impaired in ENS, and cotton placement in the airway improved ENS symptoms.• Cognitive function: Functional magnetic resonance imaging showed activation in emotional processing area during breathing.• Olfactory function: Subjective impairment was reported in ENS, but quantitative measures were similar to non-ENS patients.• Mucosal physiology/innate immunity: Turbinate histopathology in ENS showed a tissue-remodeling pattern. Nasal nitric oxide level was lower in ENS patients. CONCLUSION: There is evidence of high comorbid mental health disorders in ENS patients. An abnormal trigeminal-thermoreceptor response may be present in some patients. The influence of altered airflow and the evidence of surgery as the cause for ENS are unclear.

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