How is bronchomalacia diagnosed in adults with a history of respiratory issues?

Diagnosis of Bronchomalacia in Adults

Bronchoscopy with forced expiratory maneuvers is the gold standard for diagnosing bronchomalacia in adults, with dynamic expiratory CT serving as the primary complementary imaging modality. 1, 2

Diagnostic Criteria

The diagnosis requires demonstrating >50% reduction in cross-sectional airway area during expiration, though severe disease warranting intervention typically shows >90% collapse. 2, 3 During bronchoscopy in conscious patients, coronal narrowing with coughing exceeds 50%, compared to <40% in healthy individuals. 1

Primary Diagnostic Approach

Bronchoscopy (Gold Standard)

• Flexible bronchoscopy with forced expiratory maneuvers provides direct visualization of excessive dynamic airway collapse during expiration. 1, 2
• Allows examination of both inspiratory and expiratory phases to assess the degree of collapse. 4, 5
• Enables obtaining lower airway cultures when infection is suspected. 1
• Combined procedures with upper endoscopy are encouraged when evaluating associated conditions like GERD or recurrent tracheoesophageal fistula. 1

Dynamic Expiratory CT (First-Line Imaging)

• CT chest without IV contrast during end-expiration or forced expiration is the recommended initial imaging study. 1, 4, 5
• Modern multidetector CT can detect dynamic airway collapse and provides objective measurements of airway dimensions. 4, 2
• Low-dose volumetric CT is comparable to standard higher-dose techniques for demonstrating tracheal collapse. 4
• Dynamic CT can change treatment approach in approximately 40% of patients compared to bronchoscopy alone. 1, 5

Complementary Diagnostic Studies

Pulmonary Function Testing

• Flow-volume curves are more helpful than standard chest radiography in detecting large airway disorders. 1
• PFT with bronchodilator response helps differentiate bronchomalacia from classical asthma, as bronchodilators may worsen dynamic airway collapse in malacia. 1, 5
• Baseline PFT should be obtained at initial evaluation and monitored serially in symptomatic patients. 1

Chest Radiography

• Standard chest X-ray has limited value for diagnosing bronchomalacia but may identify associated conditions or complications. 1
• Annual chest X-rays should be considered for ongoing monitoring in high-risk patients. 1

Clinical Presentation Requiring Evaluation

Suspect bronchomalacia in adults presenting with:

• Chronic cough and expiratory wheeze (present in almost all patients with airway malacia). 1, 5
• Dyspnea, stridor, or recurrent respiratory infections. 5, 6
• Symptoms misdiagnosed as asthma or chronic bronchitis that fail to respond to standard treatment. 1, 6
• History of prolonged intubation, COPD, radiation therapy, or connective tissue disorders. 1, 7

Important Diagnostic Pitfalls

Avoid misdiagnosing bronchomalacia as asthma when wheezing is present, as beta-agonists may worsen airway dynamics in patients with malacia. 4, 5 The 50% collapse threshold has limited specificity since many healthy volunteers meet this criterion; therefore, clinical correlation with symptoms is essential. 2

Imaging studies like chest radiography and standard CT have limited value without dynamic expiratory technique, as static images cannot capture the dynamic collapse that defines this condition. 1

Special Populations

In patients with esophageal atresia-tracheoesophageal fistula (EA-TEF), worsening respiratory status should prompt investigation for tracheomalacia along with aspiration, recurrent TEF, and GERD. 1 Testing should include bronchoscopy, upper GI series, pH-impedance testing, and objective swallow assessment. 1

For patients with COPD, recognize that airway collapse in COPD does not represent true tracheobronchomalacia from cartilage loss, though COPD is the most common associated condition in adults with acquired malacia. 1, 7

Emerging Modalities

Respiratory-gated MRI without IV contrast using cine imaging shows promise for depicting tracheal dynamics during inspiration and expiration, with moderate correlation to bronchoscopy findings. 1 However, this remains limited to research settings and select academic centers. 1