Graphite Pneumoconiosis

Graphite pneumoconiosis (graphitosis) is a pneumoconiosis from inhaled natural or artificial graphite. Pure graphite is weakly fibrogenic, and most severe disease reflects silica or other mineral contamination.

Exposure. Graphite mining and milling, electrode, crucible, battery, lubricant, brake lining and pencil manufacture, and foundry work.

Epidemiology. Rare. Cases occur after many years of exposure and are often mixed with silicosis.

Classification. Pure graphite disease is usually mild with black pigment deposition. Disease with fibrosis or masses generally reflects quartz or other dust.

Complications. Progressive massive fibrosis, emphysema, tuberculosis and chronic airflow obstruction.

Pathophysiology.

Graphite particles accumulate in macrophages around bronchioles and in the interstitium, producing black pigmented macules and peribronchiolar fibrosis.

Silica or other co-exposures drive nodular fibrosis and conglomerate masses. Focal emphysema surrounds the lesions.

• Often asymptomatic with abnormal imaging at surveillance.
• Exertional dyspnoea and chronic cough with black sputum in advanced disease.
• Examination is often unremarkable until fibrosis is extensive.

• Exposure history including graphite type and any quartz content.
• Chest radiograph: small rounded or irregular opacities, upper zone masses in advanced disease.
• HRCT: nodules, masses, emphysema, sometimes cavitation.
• Spirometry and gas transfer: restrictive, obstructive or mixed.
• Sputum and molecular tests for tuberculosis when cavitation or systemic symptoms arise.
• Biopsy only when atypical; mineral analysis separates carbon from silica.

Differential diagnosis. Silicosis, coal workers' pneumoconiosis, mixed dust pneumoconiosis, sarcoidosis, tuberculosis, lung cancer, metastases.

• No therapy reverses fibrosis. Remove from further exposure and control dust at source.
• Smoking cessation; influenza and pneumococcal vaccination; pulmonary rehabilitation.
• Airflow obstruction: inhaled bronchodilators and corticosteroids by usual practice for obstructive disease.
• Long term oxygen when resting PaO2 is under 7.3 kPa, or 7.3 to 8 kPa with polycythaemia or cor pulmonale.
• Investigate cavitation or new systemic symptoms for tuberculosis and cancer.

Monitoring. Spirometry and radiograph every 1 to 2 years.

Referral and escalation. Respiratory and occupational physician; transplant assessment in advanced progressive disease; notification and compensation where required.