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Dermatology · Viral infections: wart cryotherapy
Sample itemA child has a common wart treated with liquid nitrogen cryotherapy. What is the approximate temperature of liquid nitrogen?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
C. Minus 196 degrees C
Liquid nitrogen boils at minus 196 degrees C and is the most widely used cryogen for warts and other superficial lesions. Cell death results from ice crystal formation and vascular stasis.
Option by option
A. Minus 79 degrees C
Minus 79 degrees C is the temperature of solid carbon dioxide (dry ice).
B. Minus 89 degrees C
Minus 89 degrees C is that of nitrous oxide.
C. Minus 196 degrees C (correct)
Correct. Liquid nitrogen is at minus 196 degrees C.
D. Minus 50 degrees C
Minus 50 degrees C is too warm to be a standard cryogen.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.
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