SESSION TYPE: Asthma Predictors and Outcomes
PRESENTED ON: Wednesday, October 24, 2012 at 02:45 PM - 04:15 PM
PURPOSE: Wheezing is the best known auscultatory lung finding. It is heard primarily over the lung fields and is thought to reflect lower airway obstruction. A similar finding, stridor, is heard mainly over the larynx and is thought to reflect upper airway obstruction. Both are audible over both chest and throat and are distinguishable only by their timing and relative loudness in the two areas. Thus, what is actually heard when wheezing is reported can be unclear. We have noted confusion occurring during the treatment of asthma and COPD when patients develop apparent wheezing despite clinical improvement. This wheezing has often reflected laryngeal grunting (heard as stridor), which we’ve also seen in CHF and panic disorder. We have studied a series of patients to determine the anatomic origin of their reported wheezing.
METHODS: A consecutive series of patients seen by the pulmonary service after treatment with inhaled bronchodilators were evaluated by 3 examiners with simultaneous lung and laryngeal auscultation using a Littman differential stethoscope. All examiners recorded the relative loudness of wheezing over the chest and larynx as well as the synchrony of the wheezing heard in the two areas. Clinical, physiologic and radiologic data were obtained from the patient charts. A model was used to simulate sounds produced in the peripheral airways. Air was forced through a 2 mm tube (the size of terminal bronchioles) with high pressures. This airflow was auscultated through ½ inch of uncooked steak, simulating auscultation through the chest wall.
RESULTS: 48 patients (17 male and 31 female; aged 64±18 years) were evaluated. 30 had COPD/Asthma and 9 CHF. The remaining 6 had sarcoidosis and neuromuscular disease. The wheezing in all was laryngeal. Of 29 who had pulmonary function testing, 21 demonstrated involuntary laryngeal closure during expiration, demonstrated on the flow volume loop. The ex-vivo model of terminal bronchiolar airflow did not produce auscultatable sound.
CONCLUSIONS: Expiratory laryngeal closure was the source of wheezing in every patient evaluated. It caused misdiagnosis and inappropriate therapy in one third of the patients evaluated. The peripheral airways appear to be too small to produce auscultatable wheezing.
CLINICAL IMPLICATIONS: Wheezing should always be further evaluated with laryngeal auscultation and consideration of alternative causes of dyspnea. PFTs should always be used to confirm a diagnosis of asthma or COPD which is based on the finding of wheezing.
DISCLOSURE: The following authors have nothing to disclose: William Marino, Joan Harigopalan, Satish Nandyala
No Product/Research Disclosure InformationMontefiore Medical Center, Mt. Kisco, NY