A 38-year-old woman presents to the hospital with fever, cough, and shortness of breath. On imaging, a lobar pneumonia is confirmed, but a lung mass is also noted. She is treated with antibiotics and at a later time the mass is biopsied via bronchoscopy. Eventually the patient is discharged to follow up as an outpatient. The biopsy report suggests a benign lesion, and the patient agrees to have the lesion followed with imaging. Several months later, the patient presents with difficulty breathing for a few weeks. Her vitals are normal, but inspiratory and expiratory stridor is heard along with rhonchi on lung auscultation. There are no wheezes or rales. Examination of the oropharynx is unremarkable. Spirometry with flow-volume loops shows a plateau during inspiration and expiration, with decreased peak inspiratory and expiratory flow.
What is the most likely diagnosis?A. Subglottic stenosis
Subglottic stenosis. Auscultation of lung sounds helps to define the site of pathology within the airway anatomy. Rhonchi are lowpitched, sonorous sounds that typically indicate secretions in the upper airway. High-pitched sounds as a result of upper airway obstruction are termed stridor. Wheezes are high-pitched musical sounds caused by narrowing of bronchioles. Rales, also known as crackles, come in two types (wet and dry), and the pathology in both types involve the distal airway. Wet rales are caused by fluid accumulation within alveoli, which overwhelms the mechanism of surfactant to decrease surface tension and causes the alveoli to collapse and open back up during the end of inspiration; dry rales (velcro sound) typically involve the smaller airways leading into the alveoli and are usually due to interstitial processes such as pulmonary fibrosis.
This patient has stridor, which suggests that the problem involves the upper airway. In addition, the reduction in peak inspiratory and expiratory flow with plateaus seen on the flow-volume loops are indicative of a fixed obstruction. The only answer choice that fits with a fixed obstruction of the upper airway is subglottic stenosis, which can be congenital or acquired from trauma during procedures such as bronchoscopy. The rhonchi are likely a result of excess secretion build up below the obstruction. It is likely that the tumor is indeed benign and is not responsible for this patient’s symptoms. (B, C) A carcinoid tumor and viral bronchiolitis would both produce wheezing, which is not heard in this patient. (D) Postobstructive pneumonia could occur in this patient given that she has a lung mass near the airway, however this would produce rales and not stridor.