mechanisms of nasal obstruction
Last reviewed 01/2018
The prime control of nasal resistance and therefore, of physiologic nasal obstruction, is the state of congestion of blood vessels in the inferior turbinates and the anterior nasal septum. Parasympathetic vasodilatation causes engorgement of blood vessels; sympathetic vasoconstriction relieves it.
Factors that increase the sensation of obstruction involve reduced sympathetic, or increased parasympathetic tone, for example:
- infective, allergic and vasomotor rhinitis
- hyperventilation - by causing a decrease in pCO2
- alcohol - by causing peripheral vasodilatation
- supine posture
- aspirin
- cold air
- sympathetic antagonists e.g. reserpine
Factors that alleviate blockage increase sympathetic, or reduce parasympathetic tone. These include:
- exercise - acts systemically and therefore, better than topical decongestants
- sympathomimetrics e.g. ephedrine
- atrophic rhinitis
- erect posture
- rebreathing - by causing an increase in pCO2
- prostanglandin E2