Most Likely Diagnosis: 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, meeting clinical criteria for chronic bronchitis that began precisely when occupational exposure ceased. 1
Diagnostic Reasoning
Why Occupational Chronic Bronchitis is Most Likely
The patient meets the classic definition of chronic bronchitis: productive cough for at least 3 months per year for 2 consecutive years, occurring "most days" 2, 1
Occupational exposure is the key risk factor: prolonged factory work represents significant exposure to industrial dusts, vapors, gases, or fumes that can cause chronic airway inflammation and mucus hypersecretion 1, 3
Non-smoking status makes occupational etiology more specific: approximately 15% of chronic bronchitis and COPD cases are attributable to occupational exposures, and the absence of smoking history strengthens this diagnosis 1, 3
Ronchi on auscultation indicates chronic airway inflammation with mucus hypersecretion, which is the hallmark of occupational chronic bronchitis rather than reversible airway obstruction 1
Timing is consistent: symptoms began 2 years ago when he retired, suggesting chronic inflammation persists even after cessation of exposure 1
Why Other Options Are Less Likely
Asthma (Option A) is unlikely because:
- The patient lacks typical asthma features such as episodic symptoms, wheezing, dyspnea, or chest tightness 1
- Ronchi rather than wheezes suggest chronic bronchitis with fixed mucus production rather than reversible airway obstruction 1
- The constant productive cough for 2 years is not characteristic of asthma 1
COPD (Option B) is possible but less precise because:
- COPD diagnosis requires spirometry confirmation showing fixed airflow obstruction (post-bronchodilator FEV1/FVC <0.7), which has not been performed 2, 1
- While up to 15% of COPD cases are attributable to occupational exposure, COPD is a broader diagnosis that requires objective pulmonary function testing 2, 3
- The patient may have occupational chronic bronchitis that could progress to COPD, but without spirometry, COPD cannot be confirmed 4, 5
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 is inconsistent with this diagnosis 1
Chronic aspergillosis (Option D) is unlikely because:
- No evidence of immunocompromise, prior tuberculosis, or cavitary lung disease 2
- The clinical presentation does not suggest fungal infection 2
Critical Next Steps
Mandatory Investigations
Spirometry with bronchodilator testing must be performed to objectively confirm or exclude fixed airflow obstruction consistent with COPD, and to assess severity using FEV1 and FEV1/FVC ratio 1, 4
Detailed occupational history documenting specific exposures (cotton, hemp, linen, jute, sisal, organic dusts, chemicals, fumes) is crucial for confirming the diagnosis 1, 6
Chest radiograph should be reviewed or obtained if not already done to exclude other pathology 2, 6
Management Approach
Initiate bronchodilator therapy if spirometry confirms airflow obstruction, starting with short-acting beta-2 agonists or anticholinergics as needed 1
Emphasize avoidance of further occupational exposures or environmental irritants, even though the patient is retired 1
Consider corticosteroid trial if moderate to severe airflow obstruction is documented on spirometry 1
Common Pitfall to Avoid
Occupational chronic bronchitis is commonly missed by clinicians because they fail to obtain a detailed occupational history, especially in non-smokers with chronic respiratory symptoms 1, 3. The diagnosis requires active inquiry about workplace exposures, as approximately 15% of chronic bronchitis cases are occupational in origin but remain underdiagnosed 1, 3.