Idiopathic Subglottic Stenosis: Improving Diagnosis and Awareness.

Background  Idiopathic subglottic stenosis is a rare condition characterized by a constriction of the airway passage without a known cause. While there may be many contributing factors, no definitive etiology has been established. Due to its rarity, this condition is frequently overlooked by healthcare providers, resulting in an inaccurate and lengthy diagnosis process. This results in detrimental effects for the patient given the symptoms of progressive dyspnea. Our objective was to retrospectively review patients diagnosed with idiopathic subglottic stenosis and analyze key characteristics about each patient. By examining these cases in conjunction with the current literature, we hope to raise awareness of idiopathic subglottic stenosis and support an earlier accurate diagnosis. In particular, female patients with audible turbulent air flow on exam and a lack of response to bronchodilators should be promptly considered for a diagnosis of subglottic stenosis.  Methods  This study retrospectively reviews 10 patients, 18 years or older, diagnosed with idiopathic subglottic stenosis at an otolaryngology clinic in Kansas. Patients were evaluated first with a physical examination that included stroboscopy and flow volume loops. In addition, key variables analyzed included patients' age, gender, other diagnosis/treatment tried, length of time until the stenosis was diagnosed, base peak expiratory flow, symptoms, observed signs, treatment, and improvement after treatment. The data from these variables were then compiled into a table, and mean values were computed.  Results In this study, all patients were Caucasian females between the ages of 26 and 78 years old, with a mean age of 46.7 years old. Ninety percent of the patients had been diagnosed previously with either asthma or chronic obstructive pulmonary disease (COPD) and were treated with corticosteroids as a result. The average time it took for these patients to be diagnosed from the onset of symptoms was approximately 36.8 months. The average base peak expiratory flow, gathered from pulmonary function testing, was 47% of the predicted value. They presented with a mixture of symptoms including dyspnea with exertion or at rest, stridor, a chronic cough, and dysphonia. In the office, the observed sign of turbulent airflow at rest was detected in nine out of the 10 patients. All patients underwent a biopsy, followed by laser excision of stenosis, steroid injection, and balloon dilation. All reported subjective relief in symptoms and, where available, showed objective improvement in pulmonary function testing and endoscopic appearance after the treatment.  Conclusions  A thorough history, a careful physical examination, pulmonary function testing, and visualization with endoscopy can significantly expedite the diagnosis of idiopathic subglottic stenosis. In addition, listening for abnormal upper airway sounds is crucial in guiding clinicians toward this diagnosis quickly.