Occupational ILD - Diagnosis

• The clinical, radiologic, and pathologic presentations of occupational ILDs are similar to non-occupational lLDs due to the lung’s general response to injury
• A thorough, lifetime, work, and environmental history is critical to identify potential occupational exposures
• Characteristic radiographic changes in combination with a work history is sufficient to make diagnosis
  • Occupational ILD should be considered for any new ILD cases in the absence of a known cause
  • Material safety data sheets should be obtained where possible
• Pulmonary function tests are useful to determine severity and pharmacologic treatment

PRESENTING SYMPTOMS

• Most common symptoms in patients with significant disease⁸
  • Shortness of breath
  • Cough
  • Chest tightness
  • Wheezing
• Patients with less significant disease will have no respiratory symptoms⁹
• Diagnosis is often made based on occupational history and routine chest X-ray (CXR)⁸

DIAGNOSIS REQUIRES:³

• History of exposure to a known ILD-inducing agent
• An appropriate latency period following exposure
• Consistent clinical disease course
• Pattern of physiologic and radiologic evidence of disease
• Exclusion of other known ILD-causing factors
• Lung biopsy is not needed if these tests come back positive, but recommended for atypical cases or cases arising from new or poorly understood causative agents

DIAGNOSTIC TESTS

• After an occupational history is collected, ILD is typically detected through use of radiologic imaging, usually a CXR¹⁰
  • Spirometric testing, high-resolution computed tomography (HRCT), sputum analysis, and bronchoalveolar lavage are also recommended¹⁰
• The International Labor Office (ILO) provides guidelines for the systematic scientific classification of pneumoconiosis⁵
• The CXR is classified and scored on the following features:⁵
  1. Film quality⁵
  2. Rounded small opacities (diameter)⁵
  3. Irregular small opacities (width)⁵
  4. Profusion (concentration of small opacities in affected area of the lung)⁵
  5. Large opacities (longest dimension >10 mm)⁵