CHARLOTTESVILLE, VA—About 5% of patients presenting to the emergency department (ED) with “acute asthma” actually have vocal cord dysfunction (VCD). Cases of VCD are misdiagnosed as acute asthma because VCD may produce asthma-like symptoms, such as wheezing, cough, and dyspnea. “Nationwide, a 5% misdiagnosis rate is a massive problem,” stressed Larry Borish, MD, in an interview.

The misdiagnoses often lead to inappropriate asthma therapies, which are generally ineffective for VCD. When these therapies fail, the patients are often placed on multiple high-dose asthma drugs, which often include systemic corticosteroids. Many patients become frequent urgent care users, and some are unnecessarily intubated.

Distinguishing VCD from acute asthma is clearly important, but until recently the only sure way to do so was by viewing the larynx with laryngoscopy. “However, we do not routinely do that procedure in the emergency room,” acknowledged Dr. Borish, a Professor of Medicine in the Asthma and Allergy Disease Center at the University of Virginia in Charlottesville.

What is the alternative? Sinus computed tomography (CT) may be a good possibility; it accurately differentiated VCD from acute asthma in a recent investigation by Dr. Borish and colleagues.[1] In this study, CT scans showed that extensive sinus disease was common among asthma patients, particularly those with acute asthma, but it was absent in patients with VCD.

The investigators compared four groups: 13 patients with previously diagnosed VCD, 77 patients identified as having acute asthma in the ED, 31 patients with nonacute asthma, and a control population of 65 subjects who had neither asthma nor shortness of breath. All participants underwent coronal helical CT scanning while prone after clearing their noses and using a nasal decongestant. Blood samples were taken and analyzed; nitric oxide concentrations were measured in exhaled breaths.

Extensive sinus disease (defined as a CT score of 12 or higher) was present in about 31% of the patients with acute asthma, 17% of those with nonacute asthma, and only 3.5% of the controls. None of the patients with VCD had extensive sinus disease. Absolute eosinophil counts, immunoglobulin E levels, and exhaled nitric oxide concentrations were increased in all of the asthma patients; the greatest elevations occurred in those with acute asthma. In the VCD group, inflammatory marker levels were normal and indistinguishable from those in the controls.

Results of this study reiterate other findings showing an association between abnormal sinus CT results and asthma. In this study, however, it was the extent of sinus disease that was most telling. Minor abnormalities (CT scores of 3 to 11) were common in all four patient groups, but scores of 12 or higher helped distinguish the asthma patients from those with VCD.

It was also interesting to note that sinusitis symptom scores obtained by questionnaire were poor predictors of sinus disease on CT, as were a clinical diagnosis of acute bacterial sinusitis and antibiotic administration by the ED physician.

—Timothy Begany