Silicosis

Overview
  • Silicosis is a respiratory disease caused by a chronic, high-level inhalation of silica dust and may occur in workers of glass, mining, or stone cutting industries.
Pathogenesis
  • The pathogenesis of silicosis is similar to other pneumoconioses (see page); however, several unique features should be mentioned. High-dose exposure to silica dust can result in symptomology within a year and is characterized by filling of alveoli with a protein-rich fluid. In contrast, low-level exposure over many years leads to the development of silica-rich nodules within the pulmonary interstitium that can calcify over time and thus display a characteristic "eggshell"-like morphology on chest radiography. These silica nodules can coalesce over time, grow, and undergo extensive fibrosis, eventually evolving into a picture of "Progressive Massive Fibrosis (PMF)".
Clinical Consequences
  • Acute silicosis, associated with the presence of protein-rich alveolar fluid, can result in rapidly progressive respiratory dysfunction and failure. In contrast, symptomology of chronic silicosis, associated with PMF, usually develops insidiously and is characterized by the gradual onset of restrictive lung disease. Additionally ,chronic silicosis may be associated with pulmonary hypertension and, with time, right heart failure.