Question:medium
What is NOT true with regard to 'triple' stones?
What is NOT true with regard to 'triple' stones?
Show Hint
Struvite (triple phosphate) stones need alkaline urine from urease producing bacteria to form.
Updated On: Jul 8, 2026
- Struvite stones are composed of triple phosphate
- They are called staghorn calculi when they are formed in the renal pelvis
- Form in acidic urine
- Associated with UTI
Show Solution
The Correct Option is C
Solution and Explanation
Step 1: Recall what a triple stone is made of.
"Triple phosphate" means the stone has three parts, magnesium, ammonium and phosphate, so this describes a struvite stone. That part of the naming is correct.
Step 2: Recall the growth pattern.
When these stones fill the whole collecting system of the renal pelvis and calyces, they take on a branching shape called a staghorn calculus. This is also correctly stated.
Step 3: Check the urine pH needed.
Struvite forms only when urine is alkaline. This alkaline shift happens because urease producing bacteria, mainly Proteus, break urea into ammonia. Acidic urine actually dissolves struvite rather than forming it, so calling it an acidic urine stone is wrong.
Step 4: Check the infection link.
Because the alkaline state depends on bacterial urease, struvite stones are always tied to urinary tract infection. This statement holds true.
Step 5: Conclude.
The one false claim is that these stones form in acidic urine.
\[ \boxed{\text{Form in acidic urine, is FALSE}} \]
"Triple phosphate" means the stone has three parts, magnesium, ammonium and phosphate, so this describes a struvite stone. That part of the naming is correct.
Step 2: Recall the growth pattern.
When these stones fill the whole collecting system of the renal pelvis and calyces, they take on a branching shape called a staghorn calculus. This is also correctly stated.
Step 3: Check the urine pH needed.
Struvite forms only when urine is alkaline. This alkaline shift happens because urease producing bacteria, mainly Proteus, break urea into ammonia. Acidic urine actually dissolves struvite rather than forming it, so calling it an acidic urine stone is wrong.
Step 4: Check the infection link.
Because the alkaline state depends on bacterial urease, struvite stones are always tied to urinary tract infection. This statement holds true.
Step 5: Conclude.
The one false claim is that these stones form in acidic urine.
\[ \boxed{\text{Form in acidic urine, is FALSE}} \]
Was this answer helpful?
0
