Question

Which one of the following is NOT correct regarding Silicosis?

• A. Egg shell calcification is seen on chest X-ray
• B. It is more marked in the lower zone
• C. May lead to progressive massive fibrosis
• D. The disease may progress even after the exposure has ceased

Hint:

Silicosis is an upper zone disease; find the one statement that gets this backwards.

Answer 1

The Correct Option is B

Step 1: Recall what silicosis is.
Silicosis is an occupational lung disease caused by breathing in fine crystalline silica dust, seen in workers such as miners, stone cutters, and sandblasters. The dust triggers fibrosis, mainly around the small airways and lymph nodes.

Step 2: Check the egg shell calcification finding.
Chronic silicosis often shows calcification around the rim of the enlarged hilar lymph nodes, giving a thin curved line of calcium that looks like the shell of an egg on chest X-ray. This is a well recognised and correct feature, so statement (A) is true.

Step 3: Check the zone of distribution.
Silica dust, because of its particle size and the pattern of lymphatic drainage in the lung, is carried mainly to the upper and posterior zones. Silicotic nodules and fibrosis are classically more marked in the upper zones, not the lower zones. Saying it is more marked in the lower zone is incorrect.

Step 4: Check progressive massive fibrosis.
When individual silicotic nodules enlarge and merge together, they form large conglomerate masses called progressive massive fibrosis. This is an accepted complication of silicosis, so statement (C) is true.

Step 5: Check progression after exposure stops.
Silica particles are not cleared from the lung and continue to provoke inflammation and fibrosis long after the worker has left the dusty job, so the disease can keep progressing even after exposure has ended, making statement (D) true.

Step 6: Final answer.
Since silicosis is upper zone predominant and not lower zone predominant, the incorrect statement is
\[ \boxed{\text{It is more marked in the lower zone}} \]