Communications to the Editor

Tracheobronchomalacia: A Cause of Flow Oscillations on the Flow-Volume Loop

The term tracheobronchomalacia refers to excessively compliant and collapsible central airways leading to symptoms. Although seen as a coexisting condition with various other pulmonary condition, it may cause symptoms by itself. The condition is often misdiagnosed as asthma, bronchitis or just chronic cough due to a lack of specific pathognomonic history and clinical findings. The investigation revolves around different modes of imaging, lung function testing and usually confirmed by flexible bronchoscopy. The treatment widely varies based on the cause, with most cases treated conservatively with non-invasive ventilation. Some may require surgery or stent placement. In this article, we aim to discuss the pathophysiology behind this condition and recognize the common symptoms and causes of tracheobronchomalacia. The article will highlight the diagnostic steps as well as therapeutic interventions based on the specific cause.

The biphasic curve or bicompartmental flow volume obtained during the forced maneuver is the characteristic of the obstruction of a main bronchus. We report the case of a 64-year-old woman, with progressive dyspnea, coughing and wheezing localized in the left hemithorax, who had been diagnosed with bronchial asthma and was not responding to treatment. The flow volume curve showed an end inspiratory arm configuration compatible with unilateral obstruction of a main bronchus. Chest computed tomography with three-dimensional reconstruction showed a left main bronchus compression by a cyst formation, the bronchoscopy confirmed the obstruction. At surgery a bronchogenic cyst was resected.

After the procedure, dyspnea, cough, expectoration and wheezing disappeared. The postoperative flow volume curve showed a normal configuration. We are not aware of a previous report of a biphasic flow volume curve due to a mediastinal bronchogenic cyst.

The flow volume curve is a noninvasive procedure useful in the diagnosis of unilateral obstruction of a main bronchus.

Tracheomalacia and tracheobronchomalacia are disorders that are encountered in both pediatric and adult medicine. Despite increasing recognition of these disease processes, there remains some uncertainty regarding their identification, causes, and treatment. This article is intended to be a comprehensive review of both the adult and pediatric forms of the diseases, and includes sections on the historical aspects of the disorders, and their classification, associated conditions, histopathology, and natural history. We also review the various modalities that are used for diagnosis as well as the state of the art of treatment, including airway stent placement and surgical intervention