Bilateral pleural thickening in lower and middle lung zone is radiological feature of
**Core Concept**
Bilateral pleural thickening in the lower and middle lung zones is a radiological feature associated with a specific occupational lung disease. This condition results from the inhalation of asbestos fibers, leading to chronic inflammation and fibrosis of the pleura.
**Why the Correct Answer is Right**
The correct answer is due to the pathophysiological process of asbestos exposure. When asbestos fibers are inhaled, they cause chronic inflammation and fibrosis of the pleura, leading to pleural thickening. This is a hallmark feature of asbestosis, an occupational lung disease caused by prolonged exposure to asbestos. The lower and middle lung zones are more commonly affected due to the gravitational settling of asbestos fibers in these areas.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because pulmonary edema is characterized by fluid accumulation in the alveoli, not pleural thickening.
**Option B:** This is incorrect because pulmonary embolism typically presents with acute onset of shortness of breath, pleuritic chest pain, and tachycardia, not chronic pleural thickening.
**Option C:** This is incorrect because emphysema is characterized by destruction of alveolar walls, not pleural thickening.
**Clinical Pearl / High-Yield Fact**
Asbestos exposure is a classic example of an occupational hazard with a long latency period. Doctors should always inquire about a patient's occupational history, particularly if they present with respiratory symptoms.
**Correct Answer:** D. Asbestosis.