Cystine nephrolithiasis: contemporary approaches to patient management

Introduction. Cystinuria is a rare genetic disorder characterised by a markedly elevated concentration of cystine in the urine. Due to the low solubility of cystine in urine, patients with cystinuria face a lifelong increased risk of urinary stone formation. The exceptionally high recurrence rate necessitates the implementation of preventive measures. Given that most practising urologists have limited experience managing patients with cystine nephrolithiasis due to the disease’s rarity, the development of clinical guidelines for recurrence prevention represents a pressing need. Objective. To summarize the world literature on managing patients with cystine nephrolithiasis and present an algorithm for preventing the disease. Materials & methods . A systematic review of the literature in foreign and domestic scientific databases was conducted using the keywords: “cystine”, “cystine stones”, “cystinuria”, “cystine”, “cystine nephrolithiasis”, “cystinuria”. Two hundred forty-seven sources of literature were processed, 45 of which were included in the review. Results . Despite the currently irreversible genetic cause of cystinuria, the implementation of stone prevention strategies significantly reduces the recurrence rate of urolithiasis in affected patients. Prevention of cystine nephrolithiasis involves a multimodal, stepwise treatment approach. This includes reducing urinary cystine concentration through dietary modifications and increasing its solubility by alkalinising the urine, as well as the use of cystine-binding agents. This article presents a step-by-step algorithm for the prevention of cystine nephrolithiasis, based on the clinical course of the disease and objective parameters such as 24-hour cystine excretion and urinary pH. Conclusion. Current algorithms for preventing cystine nephrolithiasis, which combine both non-pharmacological and pharmacological strategies, are readily applicable in clinical practice and have been shown to effectively reduce the recurrence of this condition.