Clearing the Air: Vocal Cord Dysfunction or Asthma?
Published Online: November 7, 2013
Vocal Cord Dysfunction (VCD) is often misdiagnosed and mistreated as asthma, leading to increased asthma medication use and healthcare utilization. While laryngoscopy remains the gold standard for VCD diagnosis, it is often not readily available or practiced by many physicians who may encounter this disorder. Additionally, laryngoscopy may be normal if performed when a patient is asymptomatic. A clinical tool to help specialists and non-specialists alike to distinguish between these two disorders would have the potential to decrease healthcare utilization and unnecessary medical treatment.
Traister et al.’s recent article from The Journal of Allergy and Clinical Immunology: In Practice entitled “A Novel Scoring System to Distinguish Vocal Cord Dysfunction from Asthma” aims to do just that. In this largest to date retrospective study, the authors compared demographics, co-morbidities, clinical symptoms, and symptom triggers of patients with isolated VCD or asthma. Using multivariable logistic regression, they developed the Pittsburgh VCD Index, a simple weighted scoring system that identified features of VCD that distinguish it from asthma.
Symptoms of throat tightness and dysphonia, absence of wheezing, and the presence of odors as a symptom trigger were found to be key features of vocal cord dysfunction that distinguish it from asthma. Using the appropriate cut-off, the index had a sensitivity and specificity of 83% and 95% respectively, and its utility was confirmed in a population of patients with laryngoscopy-proven VCD.
The Pittsburgh VCD Index was found to be a simple, valid, and easy to use tool for diagnosing VCD. It has the potential to decrease health care costs, unnecessary medication use, and healthcare utilization by making a timely diagnosis of VCD in a patient mistreated for asthma. Prospective studies will be needed to evaluate its broader use. The authors also caution that no distinguishing features between VCD and asthma could be found when these disorders co-exist, so if there is a strong clinical suspicion for the presence both disorders in the same patient, further evaluation should be performed.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.