Question:medium
Which of the following stones is hard to break by ESWL?
Which of the following stones is hard to break by ESWL?
Show Hint
The dense monohydrate crystal resists shock waves; soft uric acid and struvite break easily.
Updated On: Jun 24, 2026
- Calcium oxalate monohydrate
- Calcium oxalate dihydrate
- Uric acid
- Struvite
Show Solution
The Correct Option is A
Solution and Explanation
Think of ESWL as hammering a stone from outside the body; the harder and denser the stone, the more it resists shattering. So the question becomes, which of these four is the toughest crystal.
The soft, lithotripsy-friendly stones are uric acid and struvite (infection stones); they crumble with relatively few shocks. Among the two calcium oxalate forms, the dihydrate (weddellite) is the brittle, more breakable one. The monohydrate form (whewellite) is the dense, compact, mechanically tough variety, and along with cystine and brushite it is notoriously resistant to shock waves.
Because calcium oxalate monohydrate often will not fragment well even with repeated high-energy shocks, urologists frequently move straight to ureteroscopic laser lithotripsy or another mechanical method for these stones. That resistance is exactly what the question is testing.
So of the listed options, the stone hardest to break with ESWL is calcium oxalate monohydrate.
\[\boxed{\text{Calcium oxalate monohydrate}}\]
The soft, lithotripsy-friendly stones are uric acid and struvite (infection stones); they crumble with relatively few shocks. Among the two calcium oxalate forms, the dihydrate (weddellite) is the brittle, more breakable one. The monohydrate form (whewellite) is the dense, compact, mechanically tough variety, and along with cystine and brushite it is notoriously resistant to shock waves.
Because calcium oxalate monohydrate often will not fragment well even with repeated high-energy shocks, urologists frequently move straight to ureteroscopic laser lithotripsy or another mechanical method for these stones. That resistance is exactly what the question is testing.
So of the listed options, the stone hardest to break with ESWL is calcium oxalate monohydrate.
\[\boxed{\text{Calcium oxalate monohydrate}}\]
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