Inhaled Mannitol as a Laryngeal and Bronchial Provocation Test

Area of Science:

• Pulmonology
• Otolaryngology

Background:

• Vocal cord dysfunction (VCD), or inducible laryngeal obstruction, is often misdiagnosed as asthma, leading to delayed treatment.
• Current diagnostic methods for VCD, like laryngoscopy, have limited sensitivity.
• There is a need for improved provocation tests to accurately diagnose VCD.

Purpose of the Study:

• To assess the feasibility of using inhaled mannitol as a provocation test for VCD.
• To concurrently investigate laryngeal and bronchial hyperresponsiveness using mannitol.
• To evaluate the diagnostic performance of mannitol challenge in patients with suspected VCD.

Main Methods:

• Flexible laryngoscopy was performed at baseline and after mannitol challenge in patients with suspected VCD.
• VCD diagnosis was based on observing paradoxical vocal cord movement during laryngoscopy.
• Interrater agreement for post-mannitol laryngoscopy findings was assessed between respiratory specialists and laryngologists.

Main Results:

• Mannitol provocation identified VCD in 42.9% of patients with normal baseline laryngoscopy.
• Only two patients exhibited bronchial hyperresponsiveness after mannitol challenge.
• Substantial interrater agreement (kappa = 0.696) was found between specialists for diagnosing VCD post-mannitol.

Conclusions:

• Inhaled mannitol is a feasible and well-tolerated method for inducing VCD.
• Mannitol can effectively evaluate both laryngeal and bronchial hyperresponsiveness in a single setting.
• This approach may improve the timely and accurate diagnosis of VCD.