All are indicated in a patient with cystinuria with multiple renal stones except:
**Core Concept**
Cystinuria is a rare genetic disorder characterized by the abnormal reabsorption of cystine and other dibasic amino acids (lysine, arginine, and ornithine) in the kidneys, leading to their excessive excretion in the urine. This results in the formation of cystine stones, which are radiolucent and can cause significant morbidity.
**Why the Correct Answer is Right**
The management of cystinuria involves reducing cystine excretion and preventing stone formation. This is typically achieved through the use of medications that reduce cystine excretion, such as penicillamine and tiopronin, which form complexes with cystine, making it more soluble. Another approach is to increase the pH of the urine, which can be achieved with medications like sodium bicarbonate or potassium citrate.
**Why Each Wrong Option is Incorrect**
**Option A:** Potassium citrate is actually used in the management of cystinuria to increase the pH of the urine, making it less conducive to cystine stone formation.
**Option B:** Sodium bicarbonate is also used to increase the pH of the urine and prevent cystine stone formation.
**Option C:** Allopurinol is used in the treatment of hyperuricemia, not cystinuria.
**Clinical Pearl / High-Yield Fact**
The treatment of cystinuria requires a multidisciplinary approach, including medical therapy, dietary modifications, and regular follow-up to prevent complications.
**Correct Answer:** C. Allopurinol