Overview
Cystine calculi are a type of kidney stone caused by cystinuria, a genetic disorder characterized by excessive excretion of the amino acid cystine in the urine 2. This leads to the formation of cystine crystals and stones, which can cause significant morbidity if not managed appropriately 2.Diagnosis
Management
Medical management aims at complete stone clearance and prevention of recurrence through alkalizing agents (potassium citrate, citric acid) and cysteine-binding thiol agents (tiopronin, penicillamine) 1.
Surgical management options include extracorporeal shock wave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL) 1.
SWL shows inferior results for cystine stones 1.
URS and PCNL are safe and effective procedures in the pediatric population with low rates of major complications 1.
Successful treatment involves a multidimensional approach to stone eradication and long-term follow-up for prevention 2.Special Populations
In the pediatric population, URS and PCNL are safe and effective with low complication rates 1. SWL achieves inferior results in this group 1. Adherence to medical prevention therapies may prolong recurrence-free periods 1.Key Recommendations
Treatment of pediatric cystine stones should aim for complete stone clearance, preservation of renal function, and prevention of further recurrences 1. (Evidence: Moderate)
Ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) are safe and effective procedures for pediatric cystine stones, with low rates of major complications 1. (Evidence: Moderate)
Medical prevention therapies, including alkalizing agents and cysteine-binding thiol agents, should be utilized to prolong recurrence-free periods 1. (Evidence: Moderate)References
1 Ripa F, Pietropaolo A, Geraghty R, Griffin S, Cook P, Somani B. Outcomes of Paediatric Cystine Stone Management: Results of a Systematic Review. Current urology reports 2023. link
2 Singer A, Das S. Therapeutic dilemmas in management of cystine calculi. Urology 1991. link80257-8)
3 Charles JC. Nephrocutaneous fistula. Journal of the National Medical Association 1990. link
4 Klevansky AB, Keogan PG, Bruinette HR. Haemorrhage due to rupture of the kidney with intraparenchymal calculi, chronic pyelonephritis and acute obstructive uropathy. A case report. South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde 1988. link