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Kidney Week

Abstract: PO1996

Experience from a Single Centre Following a Large Cohort of Children with Cystinuria (1996-2019)

Session Information

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology

Authors

  • Lopez Garcia, Sergio Camilo, Great Ormond Street Hospital for Children NHS Foundation Trust, London, London, United Kingdom
  • Smeulders, Naima, Great Ormond Street Hospital for Children NHS Foundation Trust, London, London, United Kingdom
  • Hayes, Wesley Nathan, Great Ormond Street Hospital for Children NHS Foundation Trust, London, London, United Kingdom
  • Cho, Alexander, Great Ormond Street Hospital for Children NHS Foundation Trust, London, London, United Kingdom
  • Watson, Tom A., Great Ormond Street Hospital for Children NHS Foundation Trust, London, London, United Kingdom
  • Barnacle, Alex, Great Ormond Street Hospital for Children NHS Foundation Trust, London, London, United Kingdom
  • Easty, Marina J., Great Ormond Street Hospital for Children NHS Foundation Trust, London, London, United Kingdom
  • Bockenhauer, Detlef, Great Ormond Street Hospital for Children NHS Foundation Trust, London, London, United Kingdom
Background

Cystinuria is a rare monogenic disorder accounting for 5-10% of all paediatric urolithiasis cases. This study reviews epidemiologic, clinical and management data of a large, single centre cohort of cystinuric children.

Methods

Respective data collection from children with cystinuria between June 1996 to April 2019 in our centre.

Results

A total of 52 (54% female) patients were identified with a median (IQR: interquartile range) age at presentation of 6.2 (1.9-10.3) years. 24/52 (46%) had affected family members. Common presenting symptoms were abdominal pain 21/51(41%), urinary tract infection (39%), haematuria (18%); 14/51(28%) cases were diagnosed by family screening or incidentally. 9/52(17%) had cystinuria but did not form a stone. At presentation stone location was upper tract in 30/43(70%), bladder stones were found in 10/43(23%). Estimated GFR was <90ml/min/1.73m2 in 14/52(27%) at diagnosis.

Hyperhydration fluid target was met by 63% and 76% were prescribed alkali, median (IQR) dose was 0.5(0.3-0.7) mEq/kg/day and urine pH 7.0(7.0-8.0). 24/52(46%) patients had 26 treatment periods with cystine-binding thiol drugs (CBTD) for a median (IQR) duration of 34(18-65) months; 7/24(29%) patients on CBTD developed adverse effects leading to discontinuation in 3(13%). Median (IQR) urine cystine was lower (p=0.006) at 0.7 (0.5-0.9) mmol/L after CBTD was started compared to diagnosis at 1.3 (0.7-2.0) mmol/L. Stone removal procedure was performed in 37/43(86%) cases, those treated with CBTD had a higher median (IQR) number of surgical interventions of 4(2-8) vs no CBTD 1(0-2), p<0.001. The annual median (IQR) rate of stone removal procedures/patient was 0.2(0.1-0.4). At the end of follow up eGFR<90 was present in 12/35(34%).

Conclusion

Bladder stones were seen in a 23% of paediatric patients with cystinuria. Median stone removal procedure rate was 0.2/year in our cohort. CBTD significantly decreased free urine cystine levels, but was associated with complications in almost a third. The vast majority underwent a surgical intervention during follow-up, highlighting the burden of disease. Fortunately, eGFR remained stable in most of the patients.