Baseline Investigations for Suspected Bronchial Disease
For suspected bronchial disease, obtain a chest X-ray first, followed by spirometry with bronchodilator response testing, and confirm any suspected bronchiectasis with thin-section CT chest. 1
Initial Imaging
Perform a baseline chest X-ray in all patients with suspected bronchial pathology, as approximately 31% of chest radiographs requested for persistent cough reveal abnormalities that guide further investigation. 1
Obtain thin-section CT chest (high-resolution CT) when bronchiectasis is clinically suspected, as this is the gold standard for confirming the diagnosis—chest X-ray alone is insufficient. 1
Perform CT imaging during clinically stable disease to optimize diagnostic accuracy and allow reliable serial comparison. 1
CT diagnostic criteria for bronchiectasis include: bronchoarterial ratio >1, lack of bronchial tapering, or airway visibility within 1 cm of the pleural surface. 1
Pulmonary Function Testing
Perform spirometry in all patients with chronic cough or suspected bronchial disease. 1
Measure FEV1 before and after inhalation of a short-acting β2-agonist (salbutamol 400 mcg by metered dose inhaler with spacer or 2.5 mg by nebulizer) if obstructive pattern is identified. 1
Avoid using single peak expiratory flow (PEF) measurements for assessing bronchodilator response, as they are less accurate than FEV1 in diagnosing airflow obstruction. 1
Recognize that normal spirometry does not exclude asthma as a cause of chronic cough, and many asthma patients lack sufficient reversibility to meet diagnostic criteria. 1
Bronchoscopy Indications
Perform bronchoscopy immediately in all patients with suspected foreign body inhalation or aspiration. 1
Consider bronchoscopy for localized disease to exclude endobronchial lesions or foreign bodies as the cause of bronchiectasis. 1
Bronchoscopy may be useful when other targeted investigations are normal, though diagnostic yield for chronic cough is low (1-6%) in unselected patients. 1
Obtain bronchial aspiration or wash targeting CT-identified bronchiectatic areas in non-expectorating patients, particularly helpful for diagnosing non-tuberculous mycobacterial disease. 1
Advanced Imaging
Consider high-resolution CT scanning in patients with persistent atypical cough when other targeted investigations are normal, as it may be diagnostic in up to 24% of such cases. 1
HRCT is more sensitive and specific than plain chest radiography for diagnosing bronchiectasis and diffuse pulmonary diseases, showing abnormalities in up to 42% of patients with normal chest radiographs. 1
Include expiratory CT cuts when evaluating for small airways disease or air-trapping, as indirect signs like mosaic attenuation may be the only radiographic finding in conditions like cryptogenic bronchiolitis obliterans. 1
Laboratory Investigations for Bronchiectasis
Obtain sputum cultures for routine bacterial pathogens and mycobacterial organisms while the patient is clinically stable. 2
Measure serum IgG, IgA, and IgM levels to screen for primary immunodeficiency. 2
Obtain baseline pneumococcal capsular polysaccharide antibody titers; if low, administer 23-valent pneumococcal vaccine and recheck titers 4-8 weeks later to assess specific antibody deficiency. 2
Measure serum total IgE and Aspergillus-specific IgE or perform skin-prick testing to exclude allergic bronchopulmonary aspergillosis. 2
Perform serum protein electrophoresis in all patients with bronchiectasis who have raised immunoglobulins. 1
Common Pitfalls to Avoid
Do not rely on chest X-ray alone to exclude bronchiectasis—thin-section CT is mandatory for confirmation. 1
Do not use PEF measurements for bronchodilator response assessment in primary care, as they lack accuracy compared to FEV1. 1
Do not assume normal spirometry excludes asthma or eosinophilic bronchitis as causes of chronic cough. 1
Do not perform bronchoscopy routinely for chronic cough without specific indications, as the diagnostic yield is low (0.3% for foreign body in patients without inhalation history). 1