SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 018
1. What
are the main consequences of occupational exposure to asbestos?
Occupational asbestos exposure causes several important
pulmonary and pleural diseases. Asbestosis is a diffuse interstitial pulmonary
fibrosis resulting from inhalation of asbestos fibers. Pleural plaques are the
most common manifestation and indicate previous asbestos exposure.
Benign pleural effusions and diffuse pleural fibrosis may
also occur. Asbestos markedly increases the risk of bronchogenic carcinoma,
particularly in smokers. It is the principal cause of malignant mesothelioma
involving the pleura or peritoneum.
Chronic exposure may produce restrictive lung disease with
progressive dyspnea. Pulmonary function tests demonstrate reduced lung volumes
and diffusion capacity.
Disease often appears decades after initial exposure. Strict
occupational safety measures are essential for prevention.
2. Define
asbestos bodies and pleural plaques.
Asbestos bodies are asbestos fibers coated with
iron-containing proteinaceous material deposited by macrophages.
Microscopically, they appear as golden-brown, beaded or dumbbell-shaped rods
with a translucent central fiber.
Their presence indicates previous asbestos exposure but does
not necessarily confirm asbestosis. Pleural plaques are localized areas of
dense hyalinized collagen on the parietal pleura, commonly involving the
diaphragm and lower chest wall.
They are usually calcified and asymptomatic. Pleural plaques
are the most frequent manifestation of asbestos exposure. They do not usually
impair lung function but serve as markers of occupational exposure.
Identification of asbestos bodies and pleural plaques is important in
occupational pathology. Both lesions support a history of asbestos inhalation.
PROFESSOR OF MEDICINE
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