Which condition involves kidney stones formed from metabolic abnormalities such as calcium, uric acid, struvite, and cystine?

• A. Placenta Previa
• B. Anemia
• C. Mittelschmerz
• D. Renal Calculi

Answer: (D)

This item tests understanding of renal calculi, which are stones formed in the kidney due to metabolic abnormalities. When urine becomes supersaturated with certain salts—calcium, uric acid, struvite, or cystine—these compounds precipitate and crystallize, eventually forming stones. These stones can cause intense, intermittent flank or groin pain as they obstruct the urinary tract, and they may be seen with blood in the urine. The other options don’t involve kidney stone formation: placenta previa is a pregnancy complication where the placenta covers the cervix, anemia is a deficiency in red blood cells or hemoglobin, and mittelschmerz is ovulatory pain mid-cycle. Therefore, the condition described is renal calculi.