What is the definition of Tracheobronchomalacia?
Tracheobronchomalacia (TBM) is a rare condition that occurs when the walls of the airway (specifically the trachea and bronchi) are weak. This can cause the airway to become narrow or collapse. There are two forms of TBM. One typically develops during infancy or early childhood (primary TBM). The other is an acquired form usually seen in adults (acquired or secondary TBM). Some people with TBM may initially have no signs or symptoms. However, the condition typically is progressive (worsening over time) and most people will eventually develop shortness of breath, cough, sputum retention (inability to clear mucus from the respiratory tract), and/or wheezing or stridor with breathing. Most cases of primary TBM are caused by genetic conditions that weaken the walls of the airway, while the acquired form may occur due to trauma, chronic inflammation, and/or prolonged compression of the airways. The acquired form is often seen in adults with common respiratory conditions such as asthma, chronic bronchitis, and emphysema. In many cases, the cause is not known. Treatment may only be needed if signs and symptoms are present, of there is complete or near-complete collapse of the airway. Depending on severity, treatment options may include continuous positive airway pressure (CPAP), stenting, surgical correction (tracheobronchoplasty), and tracheostomy.
What are the alternative names for Tracheobronchomalacia?
What are the causes for Tracheobronchomalacia?
The cause of tracheobronchomalacia (TBM) varies depending on whether a person has primary TBM (also called congenital TBM) or acquired TBM (also called secondary TBM). Most cases of primary TBM are caused by underlying genetic conditions that weaken the walls of the airway (the trachea and bronchi). For example, primary TBM has been reported in people with mucopolysaccharidoses (such as Hunter syndrome and Hurler syndrome), Ehlers-Danlos Syndrome, and a variety of chromosome abnormalities. Primary TBM can also be idiopathic (unknown cause) or associated with prematurity and certain birth defects (such as a tracheoesophageal fistula). A small proportion of adults with TBM have the primary form but are not diagnosed until adulthood.
Acquired TBM is generally caused by the degeneration (break down) of cartilage that typically supports the airways. In most adults with acquired TBM, the underlying cause of this cannot be identified. Many adults diagnosed with acquired TBM have common respiratory conditions such as asthma, chronic bronchitis and emphysema. Acquired TBM may be associated with inflammatory conditions (such as relapsing polychondritis), exposure to toxins (e.g. mustard gas), enlargement of structures near the airway (such as goiter or a tumor), and complications from medical procedures (such as endotracheal intubation).
What are the symptoms for Tracheobronchomalacia?
Tracheobronchomalacia (TBM) occurs when the walls of the airway (specifically the trachea and bronchi) are weak. This can cause the airway to become narrow or collapse. There are two forms of TBM. Primary TBM (also called congenital TBM) typically develops during infancy or early childhood, while secondary TBM (also called acquired TBM) is usually seen in adults.
Some people may initially have no signs or symptoms. However, the condition is typically progressive (becomes worse overtime) and many people will eventually develop characteristic features such as shortness of breath, cough, sputum retention (inability to clear mucus from the respiratory tract), and wheezing or stridor with breathing. Symptoms may become worse during periods of stress (i.e. illness), when reclining, or when forcing a cough. Infants and young children with TBM tend to have more frequent respiratory infections and delayed recovery from these illnesses.
What are the current treatments for Tracheobronchomalacia?
TBM ideally should be managed by a team of specialists working together, which includes interventional pulmonologists, radiologists, and thoracic surgeons. Treatment may only be needed if signs and symptoms are present, quality of life is impaired, and/or there is complete or near-complete collapse of the airway. Initial management of symptoms may depend on whether an underlying condition is contributing to symptoms, and whether that condition can be managed. In some cases, treating the underlying condition improves the symptoms of TBM. Depending on severity, treatment options for TBM that continues to progress may include:
- Silicone and/or long-term stenting.
- Tracheobronchoplasty - this is a surgical procedure used to stabilize the central airway by splinting the posterior wall of the trachea with mesh. The mesh becomes incorporated into the wall of the trachea and then stiffens. A person may be considered a candidate for this procedure depending on results of a short-term trial of stenting.
- Resection and reconstruction - this is a surgical procedure that may be used when TBD is more confined (focal).
- Continuous positive airway pressure (CPAP) - this has shown variable success and requires an external device which may interfere with daily activities.
- Tracheostomy - this may be used as a last resort and can sometimes worsen TBM.
Even with treatment, continued surveillance is recommended to identify any progression or recurrence of symptoms.
What is the outlook (prognosis) for Tracheobronchomalacia?
The long-term outlook associated with tracheobronchomalacia (TBM) varies depending on whether it is primary or acquired, and the underlying cause. In general, the prognosis is good in children with primary TBM who do not have any associated problems. Most cases that develop during infancy resolve on their own when the cartilage of the trachea naturally stiffens (often between ages one and two). However, intervention may be needed in children with episodes of airway obstruction, frequent infections, respiratory failure, and/or failure to thrive. When primary TBM is part of a genetic condition, the prognosis largely depends on the severity of the condition and the other associated signs and symptoms.
Acquired TBM typically is progressive and tends to worsen over time for most people. TBM can cause significant breathing problems and reduced quality of life. Fortunately, treatment options have progressed significantly in recent decades, leading to improvements in prognosis and quality of life. TBD can cause sudden respiratory failure, which can be life-threatening; prompt evaluation of symptoms and appropriate treatment is important.
How is Tracheobronchomalacia diagnosed?
A diagnosis of tracheobronchomalacia (TBM) may be suspected based on the presence of characteristic signs and symptoms or abnormal pulmonary function tests. Additional testing such as CT scan and bronchoscopy can then be performed to confirm the diagnosis and evaluate the severity of the condition. TBM is considered mild if the trachea narrows to 50% of its initial size while the affected person is breathing out, moderate if it narrows to 25%, and severe if the walls of the trachea touch.
Is Tracheobronchomalacia an inherited disorder?
Primary tracheobronchomalacia (TBM) is often associated with certain genetic conditions. In some cases, an affected person inherits the condition from an affected parent. Other cases may result from new (de novo) gene mutations. These cases occur in people with no history of the disorder in their family. When TBM is part of a genetic condition, it can be passed on to future generations.
Secondary TBM (also called acquired TBM) is not inherited. It generally occurs incidentally due to trauma, chronic inflammation and/or prolonged compression of the airways.