Environmental lung disease

COAL

Pulmonary anthracosis is asymptomatic -- see anthracotic deposits in interstitium and hilar lymph nodes, dust cells. Don't have to work in a coal mine to get this, living in Chicago will do it.

Simple coal worker's pneumoconiosis (CWP) is characterized by small fibrotic (less than 1cm) lesions in the lung, mostly in upper lobes and upper parts of lower lobes. This can lead to centriacinar emphysema (not just a restrictive disease, but also obstructive).

Complicated CWP is characterized by large fibrotic (greater than 1cm) lesions in the lung, and in its severe form is called black lung disease. This can lead to right heart failure (cor pulmonale), and Caplan syndrome (large, cavitating rheumatoid nodules), but there is no increased risk for TB or cancer.

SILICOSIS

Quartz is highly fibrogenic because it activates macrophages to secrete cytokines. Acute exposure leads to "ground glass" appearance in all lung fields. Chronic exposure leads to formation of nodular opacities (on CXR) of quartz and concentric layers of collagen in upper lung lobes, with or without central cavitation, as well as "egg-shell" dystrophic calcification of hilar lymph nodes. Silicosis is associated with cor pulmonale, Caplan syndrome, and higher TB and cancer incidence.

ASBESTOSIS

Asbestos fibers come in two types: the curly, flexible serpentine type; the straight, stiff, amphibole type, which is the worst type and the type that causes mesothelioma. Asbestos is found in insulation materials, as well as roofing, ceiling and floor tiles. Exposure causes macrophages to coat fibers with ferritin. Pathologies associated with asbestos: (1) benign pleural plaques, not associated with cancer; (2) diffuse interstitial fibrosis with or without pleural effusions -- lower lobe preference, unlike CWP or silicosis; (3) bronchogenic carcinoma ~20 years post exposure; (4) mesothelioma (pleural effusion, pleuritic chest pain, dyspnea due to compression) ~25-40 years post exposure. There is no risk for TB, but cor pulmonale and Caplan syndrome are possible complications, as with the other pneumoconioses. Mesothelioma risk is not affected by smoking. Synergistic effect of smoking and asbestos on lung carcinoma, however.

BERYLLIOSIS

Nuclear and aerospace industries. Diffuse interstitial fibrosis with noncaseating granulomas. No additional risk for TB, but primary lung cancer risk is increased. Cor pulmonale risk.

HYPERSENSITIVITY PNEUMONITIS

Organic antigens. Both Type III (IgG immune complexes form in response to inhaled antigen, causing inflammatory damage in lung) and type IV hypersensitivities (dysfunctional granulomatous response that causes widespread fibrosis; diffuse lymphocytic interstitial infiltrate) involved.

Farmer's lung -- thermophilic actinomycetes

Silo filler's disease -- oxides of nitrogen

Byssinosis -- bacterial endotoxin of gram negative bacteria growing in cotton, linen, hemp; cause "Monday morning blues"

Treatment: face mask, dust removal, corticosteroids

DRUG-INDUCED INTERSTITIAL FIBROSIS

Amiodarone, methotrexate, cyclophosphamide, bleomycin.

RADIATION-INDUCED LUNG DISEASE

Occurs 1-6 months after treatment. Fever, dyspnea, pleural effusions, infiltrates on CXR.