Byssinosis

Byssinosis ("brown lung", Monday fever) is an occupational airway disease caused by inhalation of dusts from raw cotton, flax or hemp.

• Occurs in cotton mill workers (carding, spinning, ginning), prevalent in low and middle income countries; exposure to endotoxin (from gram negative bacteria on cotton) and plant material.
• Mechanisms: endotoxin induced inflammation, histamine release from mast cells, bronchoconstriction.
• Early stage: reversible airflow obstruction on first day of the work week; progression to chronic airflow obstruction and COPD like disease after years.
• Risk factors: smoking, atopy, dust concentration, length of exposure.
• Schilling grading: grade 0 no symptoms; 1/2 occasional chest tightness on Mondays; 1 chest tightness every Monday; 2 chest tightness on Mondays and other days; 3 as grade 2 with permanent reduced lung function.

• Chest tightness, cough, wheeze, and dyspnoea on return to work after a break, improving during the week and absent on days off.
• Chronic stage: persistent cough, sputum, exertional dyspnoea.
• Fever and malaise ("mill fever") on initial exposures.
• Examination normal early; wheeze or hyperinflation later.

• Occupational history of cotton, flax or hemp dust exposure; symptom pattern linked to work.
• Spirometry before and after the work shift (fall in FEV1 of 5% or more across Monday shift supports diagnosis); serial peak flow charting at and away from work.
• Chest radiograph generally normal or shows hyperinflation; exclude other lung diseases.
• Bronchial provocation testing rarely needed. Rule out asthma, COPD, hypersensitivity pneumonitis.
• Exposure assessment (dust and endotoxin levels).

• Reduce or eliminate exposure: dust control (ventilation, humidification, steaming of cotton, mechanised handling), respirators, job rotation or change of occupation. Early removal prevents progression.
• Smoking cessation.
• Bronchodilators: salbutamol 100 to 200 micrograms inhaled as needed, long acting agents (formoterol 12 micrograms twice daily), tiotropium 18 micrograms daily; inhaled corticosteroids (budesonide 400 micrograms twice daily) for persistent symptoms.
• Pulmonary rehabilitation, vaccination (influenza, pneumococcal), treat infections.
• Oxygen for chronic respiratory failure.
• Medical surveillance with annual spirometry in exposed workers.
• Compensation and occupational health notification.
• Prognosis good if exposure ceases in early grades; irreversible obstruction in advanced disease.