Synopsis
Recognise dynamic and fixed central-airway obstruction behind unexplained stridor, cough or refractory wheeze, secure the airway safely when unstable, and use dynamic imaging and bronchoscopy to select cause-directed specialist treatment.
- Large-airway obstruction may be fixed, variable or dynamic and can masquerade as asthma or COPD when the main sound is labelled simply as wheeze.
- Tracheobronchomalacia describes weakness of cartilaginous airway support, whereas excessive dynamic airway collapse is exaggerated inward movement of the posterior membranous wall; both can produce symptomatic expiratory narrowing.
- A barking cough, monophonic central wheeze, positional breathlessness, secretion retention, recurrent infection or symptoms triggered by forced expiration should prompt a central-airway assessment.
- Inspiratory or biphasic stridor, focal haemoptysis, voice change, dysphagia, unilateral wheeze or progressive symptoms raise concern for tumour, stenosis, foreign body or extrinsic compression.
- Routine inspiratory CT and resting spirometry can miss expiratory collapse; dynamic expiratory CT and functional flexible bronchoscopy answer different, complementary questions.
- Percentage collapse alone must not define disease because substantial expiratory narrowing can occur in healthy people and varies with technique; symptoms, distribution and functional consequence are essential.
- Flow-volume loop flattening can localise a fixed or variable obstruction, but a normal loop does not exclude tracheobronchomalacia or an intermittently obstructing lesion.
- Management ranges from treating a cause and optimising secretion clearance to CPAP as a pneumatic splint, endoscopic therapy, carefully selected stenting or reconstructive surgery in an expert centre.
Key red flags
Increasing stridor, suprasternal recession, inability to lie flat, drooling, exhaustion, agitation or declining air entry signals diminishing reserve. Escalate before complete obstruction makes transfer or conventional intubation impossible.
New focal or unilateral wheeze, haemoptysis, weight loss, hoarseness or recurrent pneumonia in the same lobe may reflect endoluminal tumour or extrinsic compression and needs urgent cancer-pathway imaging and bronchoscopy.
Investigation priorities
Determine physiological danger and likely level before moving an unstable patient.
Management branches
Stridor, rapidly increasing work of breathing, hypoxaemia, exhaustion or imaging shows a critically narrow central airway.
- Keep the patient monitored in the position that best preserves breathing, call senior anaesthesia and airway specialists, and identify the level and likely mechanism from available information.
- Agree a primary and rescue airway plan before sedation or transfer, including rigid bronchoscopy, surgical airway or extracorporeal support availability where the anatomy makes conventional intubation unsafe.
- Relieve the obstruction through the appropriate expert technique, obtain tissue only when safe, and manage post-procedure oedema, bleeding, secretion load and recurrent narrowing in a critical-care-capable setting.