After suffering a respiratory tract infection, a 64-year-old female biochemist develops chronic lung disease requiring intubation in the ICU for an 8-week period. Tracheal stenosis is noted. What is the most likely cause of tracheal stenosis?

Any object that compromises the blood supply to the tracheal mucosa or cartilage can cause stenosis. When the mean intramural pressure exceeds 20-30 mm Hg, damage may be anticipated. Riedel struma is a rare fibrosing thyroid condition, which must be differentiated from carcinoma and may cause severe tracheal stenosis. Achalasia is a neuromuscular defect at the lower end of the esophagus causing dysphagia, because of nonmechanical esophageal obstruction.