Bronchomalacia: Symptoms, Types, Causes and Treatment

Bronchomalacia is a disorder that affects the airways, specifically the bronchi, and can have significant impacts on breathing and overall respiratory health. Whether diagnosed in children or adults, understanding bronchomalacia is critical for prompt recognition and management. In this comprehensive article, we explore the symptoms, types, causes, and treatments for bronchomalacia, drawing on the latest research and clinical experience.

Symptoms of Bronchomalacia

Bronchomalacia can present with a variety of respiratory symptoms that can range from mild to severe, often depending on the extent of airway involvement and the underlying cause. Recognizing these symptoms early can be vital in obtaining the right diagnosis and treatment.

Symptom	Description	Frequency or Context	Source(s)
Dyspnea	Shortness of breath	Common in adults	1 3 7
Chronic Cough	Persistent cough, often brassy	Adults and children	1 7 2
Wheeze	Inspiratory or expiratory wheezing	Early onset in children, dogs	7 2 8
Infections	Recurrent lower airway infections	Especially in children	3 7 8
Sputum	Productive cough with phlegm	Seen in bronchiectasis cases	3 8
Hemoptysis	Coughing up blood	Sometimes in severe cases	1
Stridor	Noisy breathing	Often in children	7 5
Crackles	Pulmonary crackles on auscultation	Noted in some animal cases	2
Near-death attacks	Acute respiratory distress	Rare, severe pediatric cases	7

Table 1: Key Symptoms

Understanding the Symptoms

Bronchomalacia’s hallmark is airway collapse, leading to various respiratory complaints. Below, we dive deeper into the key symptoms and their clinical significance.

Dyspnea and Cough

• Dyspnea, or difficulty breathing, is one of the most frequent and distressing symptoms in adults. It often worsens during physical activity or respiratory infections 1 3.
• A chronic cough is also common, described as persistent and sometimes brassy or barking in quality. This cough may be productive, especially if bronchiectasis (permanent airway dilation) has developed 1 3 7.

Wheeze and Stridor

• Both wheezing and stridor are characteristic sounds produced by narrowed airways. Wheezing is more commonly associated with bronchial involvement, while stridor is typically heard when the trachea or larynx is affected. Intractable wheeze can sometimes mimic asthma, making diagnosis challenging 7 8.

Recurrent Respiratory Infections

• Repeated episodes of lower respiratory tract infections are a red flag for underlying airway malacia, particularly in children. These infections may be accompanied by increased cough, fever, and mucus production 3 7 8.

Hemoptysis and Crackles

• In more severe cases, hemoptysis (coughing up blood) can occur, especially in adults with chronic bronchitis or related lung diseases 1.
• Crackles, detected during lung auscultation, are less common but can be heard in animal models and may indicate associated inflammation or infection 2.

Rare Severe Presentations

• In rare pediatric cases, bronchomalacia can lead to acute life-threatening respiratory distress or “near-death attacks,” especially if both the trachea and bronchi are involved 7.

Types of Bronchomalacia

Bronchomalacia does not present as a single disease but rather encompasses several types, depending on the segment of the airway affected and the nature of the collapse.

Type	Airway Involvement	Features/Patterns	Source(s)
Congenital	Bronchi (often with cartilage defect)	Often in children, may co-exist with other anomalies	5 7 8
Acquired	Bronchi (due to other diseases)	Adults, linked with chronic bronchitis, cancer, infection	1 3
Static Collapse	Bronchi	Airway collapse present even at rest	4
Dynamic Collapse	Bronchi	Collapse occurs during breathing/coughing	4 6
Williams–Campbell Syndrome	Subsegmental bronchi (cartilage deficiency)	Leads to bronchiectasis and infection	3 8
Tracheobronchomalacia	Trachea + Bronchi	Combined involvement, more severe symptoms	1 7

Table 2: Types of Bronchomalacia

Congenital vs Acquired

• Congenital bronchomalacia is due to developmental defects in the bronchial cartilage. It's often seen in infants and young children and may be associated with other anatomical anomalies (e.g., bifid ribs, left bronchial isomerism) 5 7 8.
• Acquired bronchomalacia develops later in life, commonly as a result of chronic diseases like bronchitis, lung cancer, or infections such as tuberculosis 1 3.

Static vs Dynamic Collapse

• Static collapse means the bronchus remains partially collapsed even when the person is at rest 4.
• Dynamic collapse occurs primarily during breathing, coughing, or forced expiration, and is often more difficult to diagnose since it may not be visible on static imaging 4 6.

Williams–Campbell Syndrome

• A rare form of congenital bronchomalacia, Williams–Campbell syndrome is characterized by a deficiency of cartilage in the subsegmental bronchi, leading to distal airway collapse and bronchiectasis (permanent dilation and scarring of the airways). This syndrome often presents with chronic infections and a productive cough 3 8.

Tracheobronchomalacia

• When both the trachea and bronchi are affected (tracheobronchomalacia), symptoms can be more severe and complex, requiring more specialized management 1 7.

Causes of Bronchomalacia

Understanding the root causes of bronchomalacia is key for effective prevention and treatment. The condition can arise from a variety of congenital, acquired, and secondary factors.

Cause	Mechanism / Association	Typical Age / Context	Source(s)
Congenital cartilage defect	Failure of cartilage development	Infancy, childhood	5 8 3
Chronic bronchitis	Weakening of airway walls	Adults, smokers	1 6
Infections	Damage from tuberculosis, bronchitis	Both children and adults	1 2 3
Compression	Vascular or cystic external pressure	Pediatric and adult cases	12 7
Associated anomalies	Congenital syndromes (isomerism, bifid ribs)	Mainly pediatric	8 3
Inflammation	Neutrophilic or mixed inflammation	Animal and human cases	2 6
Cancer	Direct invasion or obstruction	Adults	1
Medical procedures	Tracheostomy, prolonged ventilation	Both pediatric/adult	7

Table 3: Causes of Bronchomalacia

Congenital Causes

• Many cases diagnosed in infants and young children are due to congenital defects in bronchial cartilage. This may occur alone or as part of a syndrome involving other airway or skeletal abnormalities 5 8.
• Williams–Campbell syndrome is a classic example, where the subsegmental bronchi lack sufficient cartilage, making them prone to collapse 3 8.

Acquired Causes

• Chronic bronchitis is a leading cause of acquired bronchomalacia in adults, especially those with a long history of smoking or exposure to airborne irritants. The chronic inflammation weakens the airway walls over time 1 6.
• Infectious diseases such as tuberculosis or chronic bronchitis in both humans and animals can directly damage the structural support of the bronchi 1 2 3.

External Compression

• Vascular rings, bronchogenic cysts, or other mediastinal masses can externally compress the bronchi, leading to localized bronchomalacia. Once the compressing structure is removed, the airway may recover or require surgical stabilization 12 7.

Inflammatory and Other Factors

• Chronic inflammation (sometimes detected as neutrophilic infiltration in airway biopsies) may contribute directly to the weakening of bronchial walls 2 6.
• Cancer can invade the airway structure, causing localized collapse 1.
• Iatrogenic causes, such as prolonged intubation or tracheostomy, can also predispose to airway malacia, particularly in vulnerable pediatric patients 7.

Treatment of Bronchomalacia

Managing bronchomalacia requires a tailored approach depending on severity, cause, and patient characteristics. While many cases improve over time or respond to conservative therapy, others may necessitate surgical intervention.

Treatment	Description/Approach	Indication/Outcome	Source(s)
Observation	Watchful waiting, monitoring	Mild, stable cases	5 7
Medical therapy	Bronchodilators, mucolytics, antibiotics, physiotherapy	Symptom relief, infection control	7 6 10
CPAP	Continuous positive airway pressure	Severe collapse, respiratory distress	7
Surgery (Aortopexy)	Lifting the aorta to relieve compression	Severe cases, tracheo/bronchomalacia	9
Airway splints	Internal/external stents or mesh splints	Severe, refractory cases	11 12
Bronchopexy	Surgical suspension of bronchial wall	Isolated bronchomalacia	12
Treat comorbidities	Manage underlying diseases	Improves outcomes	6 7 1

Table 4: Treatment Options

Observation and Conservative Management

• For many mild or moderate cases, especially in children, conservative management is sufficient. This includes watchful waiting as the airway cartilage matures, and supportive care to manage symptoms 5 7.
• Parents may be reassured that most children improve with time, though monitoring for complications is essential.

Medical Therapy

• Bronchodilators, mucolytics, and antibiotics may be used to relieve symptoms and treat secondary infections, though the evidence for their benefit is limited and sometimes controversial 7 6 10.
• Chest physiotherapy is commonly prescribed to help clear secretions, but again, robust data supporting its effectiveness are lacking 7.

Respiratory Support

• In moderate to severe cases, non-invasive respiratory support like continuous positive airway pressure (CPAP) can help keep the airways open and improve breathing, especially during sleep or acute exacerbations 7.

Surgical Interventions

• Aortopexy is a specialized surgical procedure in which the aorta is lifted and fixed to relieve compression of the airway. This is particularly effective in children with severe tracheobronchomalacia and has a high rate of success, though outcomes are worse in those with major comorbidities 9.
• Airway splinting—using internal stents or surgically placed mesh—can provide structural support in cases where collapse is localized and not responsive to conservative therapy. These methods can be highly effective but require careful consideration of potential long-term effects 11.
• Bronchopexy, or surgical suspension of the bronchial wall, may be used for isolated bronchomalacia 12.

Treating Underlying and Associated Conditions

• Addressing co-morbidities such as chronic bronchitis, infections, or heart disease is crucial in improving overall quality of life and reducing the frequency of exacerbations 6 7 1.
• In both children and adults, comprehensive care involving respiratory specialists, surgeons, and primary care providers is often needed.

Conclusion

Bronchomalacia is a complex, often under-recognized disorder of the bronchial airways with a wide spectrum of presentations and outcomes. Early recognition and appropriate management are essential, especially in vulnerable pediatric populations.

Key points covered:

• Symptoms include dyspnea, chronic cough, wheeze, recurrent infections, and sometimes severe respiratory distress 1 3 7.
• Types range from congenital to acquired, with distinctions between static and dynamic collapse, and rare syndromic forms like Williams–Campbell syndrome 3 4 7.
• Causes include congenital cartilage defects, chronic bronchitis, infections, external compression, and other underlying diseases or anomalies 1 3 8 12.
• Treatment is tailored to severity and cause, with options from conservative observation and medical therapy to advanced surgical interventions like aortopexy and airway splinting 5 7 9 11 12.

Understanding bronchomalacia’s varied symptoms, types, causes, and treatments empowers patients, caregivers, and clinicians to work together for optimal respiratory health.