A 3-month-old girl undergoes flexible fiberoptic laryngoscopy for evaluation of noisy breathing. Two weeks ago, the patient began making squeaky noises when lying on her back, which have been getting progressively louder and more persistent. Her mother has been putting her to sleep on the stomach, which quiets the breathing. The patient is adequately gaining weight, is breastfeeding well, and does not appear to have labored breathing or cyanosis. Flexible fiberoptic laryngoscopy shows that both nasal cavities are patent to the nasopharynx. The adenoids are small and nonobstructive, and the palate functions well with symmetric elevation. The tonsils and base of tongue are small and not obstructive. There is intermittent collapse of the arytenoid cartilages into the airway, which worsens during crying. The vocal cords are mobile. This patient is most likely making which of the following abnormal sounds?

Question

A 3-month-old girl undergoes flexible fiberoptic laryngoscopy for evaluation of noisy breathing.  Two weeks ago, the patient began making squeaky noises when lying on her back, which have been getting progressively louder and more persistent.  Her mother has been putting her to sleep on the stomach, which quiets the breathing.  The patient is adequately gaining weight, is breastfeeding well, and does not appear to have labored breathing or cyanosis.  Flexible fiberoptic laryngoscopy shows that both nasal cavities are patent to the nasopharynx.  The adenoids are small and nonobstructive, and the palate functions well with symmetric elevation.  The tonsils and base of tongue are small and not obstructive.  There is intermittent collapse of the arytenoid cartilages into the airway, which worsens during crying.  The vocal cords are mobile.  This patient is most likely making which of the following abnormal sounds?

Quizplus · Accepted Answer

11ec25c8_d655_b1f3_bc81_29dd4cee13e8_MD0003_00 This infant with laryngoscopy showing intermittent collapse of arytenoid cartilages with inspiration (eg, crying) has laryngomalacia, the most common cause of stridor in infants. Although the etiology of this congenital condition is not precisely understood, patients typically have an omega-shaped (Ω) epiglottis, short aryepiglottic folds, and characteristic inspiratory collapse of the supraglottic tissues (eg, epiglottis, arytenoids), leading to partial obstruction of the airway and thus inspiratory stridor. Dynamic changes to the airway caliber occur with inspiration and expiration due to pressure differentials created by airflow (eg, Bernoulli and Venturi effects). During inspiration, faster airflow causes decreased intraluminal pressure in the airways (eg, drop in intralaryngeal pressure). In patients with a more collapsible extrathoracic airway (eg, laryngomalacia), the decreased pressure beyond the larynx leads to increased airway narrowing, resulting in turbulent flow and inspiratory stridor. Any increase in breathing effort (eg, feeding, crying) increases airflow, worsens supraglottic collapse, and increases stridor. Stridor from laryngomalacia usually begins in the neonatal period and is loudest at age 4-8 months. Most patients also have symptomatic gastroesophageal reflux (eg, vomiting, arching of the back with feeds). Antireflux treatment often improves breathing symptoms (for unclear reasons). Infants who are feeding and growing well may be watched expectantly as laryngomalacia typically resolves spontaneously by age 18 months. Surgery may be needed for moderate to severe cases with respiratory distress, cyanosis, or failure to thrive. (Choice A) Compared with the trachea and supraglottic larynx, the subglottic airway is less flexible because it is supported by a complete ring of cartilage (the cricoid); as a result, there is minimal change in subglottic airway caliber in inspiration compared with expiration. Therefore, conditions that result in subglottic narrowing (eg, subglottic stenosis) often lead to biphasic stridor. (Choice B) Inspiration decreases intrathoracic pressure due to diaphragm contraction (which lowers the diaphragm). In patients with a more collapsible intrathoracic airway (eg, tracheomalacia), the decreased pressure widens the intrathoracic tracheal airway. In contrast, expiration increases intrathoracic pressure. In patients with tracheomalacia, the increased pressure narrows the intrathoracic tracheal airway, leading to expiratory stridor (rather than the inspiratory stridor seen with laryngomalacia). tracheomalacia (Choice C) Expiratory wheezing is a common symptom of asthma. Constriction of the smaller airways of the lungs lead to a whistling noise. Considering that these small airways are intrathoracic, the constriction is more pronounced during expiration because of increased intrathoracic pressure. (Choice D) Rhonchi (low-pitched, rattling sounds that may occur on inspiration or expiration) are often caused by secretions in the bronchi and can be heard often in pneumonia. Educational objective: Laryngomalacia presents with inspiratory stridor due to dynamic collapse of the supraglottic tissues on inspiration. Stridor increases in periods of increased airflow (eg, crying, feeding). References: Laryngomalacia: is there an evidence base for management? (http://www.ncbi.nlm.nih.gov/pubmed/29067893) Laryngomalacia. (http://www.ncbi.nlm.nih.gov/pubmed/27301595) A systematic review of laryngomalacia and acid reflux. (http://www.ncbi.nlm.nih.gov/pubmed/22745201)

A 3-Month-Old Girl Undergoes Flexible Fiberoptic Laryngoscopy for Evaluation of Noisy