P3A362: The Clinical Utility of Continuous Laryngoscopy During Exercise Test (CLE) in the Evaluation of Children and Adolescents with Exertional Dyspnea: A Case Report

Introduction: Exertional dyspnea is a common and disabling symptom in otherwise healthy children and adolescents. It may be associated with fatigue and underperformance in sports. Exertional dyspnea is caused by a wide variety of underlying etiologies, ranging from mild to potentially fatal pathologies. In more complex cases where conventional tests such as pulmonary function tests (PFTs), chest imaging, EKG and echocardiography are unrevealing, continuous laryngoscopy during exercise test (CLE) may provide diagnostic utility. In addition to the baseline abnormalities visualized by conventional laryngoscopy, CLE can assess dynamic laryngeal responses during exercise.

Case Description: A 16-year-old female soccer player with a past medical history of asthma presented for evaluation of exertional dyspnea refractory to medical therapies. She had difficulty with inspiration, pharyngitis, and sensation of throat closure over the last month. Chest CT and upper airway CT did not reveal any structural abnormalities. PFTs and a methacholine challenge test were negative. Due to concern for an underlying functional respiratory disorder, she underwent cardiopulmonary exercise testing (CPET) with CLE. CPET spirometry revealed abnormal ventilatory responses during exercise (Figure 1A - D). CLE showed exercise induced laryngeal obstruction with complete glottic closure at peak exercise as well as inspiratory stridor, consistent with exercise-induced laryngeal obstruction (EILO); (Figure 2A, B). As a result, her asthma controllers were decreased, and she was started on a therapeutic exercise program to promote diaphragmatic breathing. On her next follow-up visit, she reported significant improvement of symptoms.

Discussion: CLE utilizes a flexible nasolaryngoscope secured on a head apparatus, and it is usually performed in conjunction with CPET. Since its introduction to clinical practice in 2006, CLE has played a pivotal role in guiding evaluation and management of patients with EILO. EILO is prevalent in adolescents, and it often presents with exertional stridor, cough, and dyspnea which is caused by transient closure of the larynx at various levels. Due to the presence of exertional dyspnea, EILO is frequently misdiagnosed as asthma, and several studies suggest that they often coexist. Inadequate symptom control despite escalation of medical therapy along with normal PFTs and bronchoprovocation tests in our patient effectively ruled out asthma and prompted CLE. Information provided by CLE influenced our therapeutical decision and resulted in successful treatment alteration.

Conclusion: CLE is a safe and well tolerated tool that can aid in evaluation and tailoring management of individual patients with exertional dyspnea. It has become the gold standard in diagnosing EILO that constitutes a serious problem among children and adolescents severely impairing their quality of life.