What is the most likely diagnosis for a non-smoking patient with a 2-year history of productive cough, who is vitally stable, has rhonchi on auscultation, and a history of occupational exposure to dust and chemicals in a factory?

Occupational Chronic Bronchitis (Byssinosis)

The most likely diagnosis is occupational chronic bronchitis (byssinosis), given the 2-year history of productive cough occurring most days in a non-smoker with prolonged factory exposure, rhonchi on auscultation, and symptom onset coinciding with retirement. 1

Clinical Reasoning

Why Occupational Chronic Bronchitis is Most Likely

This patient meets the diagnostic criteria for chronic bronchitis: productive cough for at least 3 months per year for 2 consecutive years, occurring "most days." 1 The key distinguishing features are:

• Non-smoking status makes occupational etiology highly specific, as 85-90% of chronic bronchitis cases are tobacco-related 2
• Prolonged factory exposure represents significant occupational dust/chemical exposure, with approximately 15% of chronic bronchitis and COPD cases attributable to workplace exposures 1, 3, 4
• Rhonchi on auscultation indicates chronic airway inflammation and mucus hypersecretion, consistent with chronic bronchitis rather than reversible airway obstruction 1
• Symptom onset at retirement suggests chronic inflammation persisting after cessation of exposure 1

Why Other Diagnoses Are Less Likely

Asthma (Option A) is unlikely because:

• The patient lacks typical asthma features such as wheezing, episodic dyspnea, or reversible symptoms 1
• Rhonchi rather than wheezes suggest chronic bronchitis with fixed mucus production, not reversible airway obstruction 1
• The constant productive cough for 2 years is inconsistent with asthma's variable presentation 1

COPD (Option B) is less precise because:

• COPD diagnosis requires spirometry confirmation showing fixed airflow obstruction (post-bronchodilator FEV₁/FVC <0.70), which has not been performed 5, 1, 6
• While occupational exposure contributes to 15% of COPD cases, this patient may have chronic bronchitis without meeting spirometric criteria for COPD 5, 7
• COPD is a broader diagnosis that requires objective pulmonary function testing for confirmation 6, 8

Chronic eosinophilic pneumonia (Option C) is unlikely because:

• The patient lacks systemic symptoms such as fever, weight loss, or night sweats 1
• No mention of peripheral eosinophilia or infiltrates on chest X-ray 1
• The clinical presentation does not suggest eosinophilic lung disease 1

Chronic aspergillosis (Option D) is unlikely because:

• The patient lacks immunocompromise, prior tuberculosis, or cavitary lung disease 1
• The clinical presentation does not suggest fungal infection 1

Essential Next Steps

Spirometry with bronchodilator testing must be performed to:

• Objectively confirm or exclude fixed airflow obstruction consistent with COPD 1, 6
• Assess severity using FEV₁ and FEV₁/FVC ratio 1
• Determine if the patient has chronic bronchitis alone or COPD with chronic bronchitis 8

Obtain detailed occupational history documenting:

• Specific exposures to dust, chemicals, fumes, or other respiratory irritants 1, 3
• Duration and intensity of exposures 3
• Temporal relationship between work exposure and symptom onset 3

Review or obtain chest radiograph to:

• Exclude other pathology such as malignancy, interstitial lung disease, or bronchiectasis 5, 1
• Rule out alternative diagnoses 8

Management Considerations

If spirometry confirms airflow obstruction:

• Initiate bronchodilator therapy starting with short-acting beta-2 agonists or anticholinergics as needed 1
• Consider corticosteroid trial if moderate to severe airflow obstruction is documented 1

Emphasize avoidance of further occupational exposures or environmental irritants 1

Document the occupational etiology, as occupational chronic bronchitis is included in the European list of occupational diseases (code 304.02), facilitating recognition and compensation 1

Common Pitfalls

• Clinicians rarely determine that occupational exposures contribute to chronic bronchitis, with only 5% of cases being recognized as work-related despite 15% being attributable to occupational factors 3
• Do not attribute all symptoms to smoking-related disease without considering occupational exposures in non-smokers 2, 3
• Avoid diagnosing COPD without spirometric confirmation, as clinical findings alone are insufficient 6, 8