Airway disease

What are the airways?

The airways are the tubes that take air from the atmosphere into our lungs. The upper airways include the nose and throat. The lower airways are airways in the chest. They consist of the large airways such as the trachea (also known as the windpipe) and bronchi, as well as smaller airways like the bronchioles and alveolar ducts.

What diseases affects the airways?

Tracheobronchomalacia refers to weakness of the wall of the trachea and, or bronchi. This results in collapse of the trachea or bronchi when negative pressure is generated in the airways or excessive pressure is generated from outside the airways during forceful manoeuvres. The narrowing of the trachea may cause stridor whilst the narrowing of the bronchi may result in wheezing. Tracehobonchomalacia may be congenital and the individual is born with this or it may be due to infections, exposures to irritantts such as mustard gas, gastric acid reflux, and even tobacco smoke. A condition known as relapsing polychondritis  that destroys the cartilagenous structure of the trachea is also a cause. Treating the underlying causes such as infection or inflammation is important. CPAP (continuous positive airway pressure) helps keep the airways open and facilitates the clearance of mucus to reduce infection risk. Sometimes stenting of the airways or surgery is needed. 

Tracheitis is inflammation of the trachea. It is more often seen in children but can occur in adults. The cause is usually a bacterial infection (e.g. Staphylococcus aureus, Mycoplasma pneumoniae, Chlamydia pneumoniae) but fungal infections (e.g. Aspergillus fumigatus) are also a known cause that is often overlooked, particularly if there is a history of potential exposure to mould spores or a lack of improvement to antibiotics. 

Acute bronchitis is caused by infection of the lower respiratory tract without evidence of pneumonia. Viral bronchitis is more common and doesn’t require specific treatment as it resolves on its own over time. The cough can be protracted and home remedies may help. Bacterial bronchitis can be caused by bacteria such as Bordetella pertussis with the condition known as Whooping cough.  Bacterial bronchitis may also occur following viral bronchitis where retained mucus gets infected with bacteria. This can also lead to bronchopneumonia. In acute bronchitis there may be airway hyper-responsiveness which is transient and inhaler therapy may help releif symptoms but this should not be confused with asthma. 

Chronic bronchitis is a type of irritative bronchitis, where the airways have been irritated by noxious environmental stimuli. Most commonly this is due to the longterm exposure to tobacco smoke. The airways become inflammed and secrete mucus. This results in COPD, lung function decline and shortness of breath. 

Bronchiectasis is a heterogenous condition of the airways caused by several other diseases. Most often it is due to previous infections and in some cases a cause is never identified. The airways are dilated and don’t taper normally in the lung. This results in reduced mucus clearance, inflammation, infections and the production of excess mucus. If you have symptoms such as a chronic cough that is productive of phlegm or frequent chest infections that require courses of antibiotics to get better it is important that you see a specialist with expertise in bronchiectasis so that you receive the correct diagnosis and best treatment. Although there is no cure for bronchiectasis, specialist management reduces the symptom burden, frequency of chest infections and improves quality of life. For more information on bronchiectasis click here

Chronic obstructive pulmonary disease results in obstructive airway disease that is irreversible and causes lung function to decline over time. The inflammation of the airways causes narrowing of the airways and obstruction with mucus. Frequently people with COPD may have exacerbations of the airway disease that in some cases is triggered by viral or bacterial infections. The cause in most cases is due to smoking but in some it is due to the inhalation of fumes form biomass fuel. A similar condition is seen in people that were born premature and have bronchopulmonary dysplasia. It is important to see a specialist for the correct diagnosis and treatment. Smoking cessation is highly encouraged and is the best intervention to impact on survival. Treatment includes the use of inhalers, pulmonary rehabilitation, keeping up to date with vaccinations, oxygen therapy, non-invasive ventilation and lung volume reduction.  

Asthma is a common condition affecting the chest of children and adults. The airways of people with asthma are inflammed, narrow and blocked with mucus. Common symptoms are shortness of breath, wheeze and cough. The symptoms may be more pronounced during exercise or at night. As many chest conditions may appear to be asthma it is important to get an evaluation and diagnosis by a specialist so that correct treatment can be prescribed. 

What are the symptoms of airway disease?

  • Shortness of breath
  • Wheeze
  • Stridor
  • Cough
  • Chest tightness or pain

What are the risk factors for a chest infection?

  • Respiratory disease (e.g. bronchiectasis, COPD, asthma, interstitial lung disease)
  • Smoking
  • Advanced age
  • Immunodeficiency (e.g. Primary immunodeficiency, HIV, cancer, immunosuppressant medication)
  • Malnutrition
  • Neurological conditions affecting swallow (e.g. Stroke)

What investigations are needed in airway disease?

  • Radiological  – Chest x-ray or Computed Tomography (CT) scan of the chest
  • Lung function – Spirometery, flow volume loop, FeNo
  • Microbiological investigations – Sputum cultures for bacteria, mycobacteria and fungi, PCR for viruses
  • Blood tests – markers of inflammation
  • Other investigations may be needed if co-existing co-morbidities are identified.
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