Struvite nephrolithiasis — ESENeph MCQ

Correct answer: D — Struvite infection stone from urease activity in alkaline urine

The best answer is “Struvite infection stone from urease activity in alkaline urine”. Urease-producing organisms split urea, raise urine pH and promote struvite precipitation; complete stone clearance and infection control are important because residual infected fragments drive recurrence. “Uric-acid infection stone forming in persistently acidic urine” is less appropriate because the urine is alkaline and the composition is magnesium ammonium phosphate “Cystine infection stone from impaired dibasic amino-acid transport” is less appropriate because the infection, pH and composition identify another mechanism “Indinavir infection stone from protease-inhibitor crystal deposition” is less appropriate because there is no relevant medicine exposure and the analysed composition is different “Calcium-oxalate infection stone from marked intestinal hyperoxaluria” is less appropriate because the urease-positive infection and phosphate composition are decisive

Reference: EAU guideline on urolithiasis: https://uroweb.org/guidelines/urolithiasis/chapter/guidelines