Biphasic Flow-Volume Loop in a Patient With Idiopathic Unilateral Mainstem Bronchus Obstruction

Area of Science:

• Pulmonology
• Respiratory Medicine
• Clinical Case Reports

Background:

• Unilateral mainstem bronchial obstruction is an uncommon cause of dyspnea.
• Spirometry can identify this condition via the "two-compartment phenomenon."

Observation:

• A 48-year-old woman with a history of subglottic stenosis presented with recurrent dyspnea.
• Spirometry revealed a characteristic flattened end-expiratory tail.
• Imaging confirmed left-sided unilateral mainstem bronchial obstruction.

Findings:

• The patient's symptoms resolved after bronchoscopic intervention.
• Spirometry patterns normalized post-procedure.
• The underlying cause of the obstruction remained idiopathic despite thorough investigation.

Implications:

• This case underscores the importance of spirometry in diagnosing uncommon respiratory conditions.
• The co-occurrence of idiopathic subglottic stenosis and unilateral mainstem bronchial obstruction is highly unusual.
• Early diagnosis and intervention can significantly improve patient outcomes for bronchial obstruction.