Cystine analyses of separate day and night urine as a basis for the management of patients with homozygous cystinuria

Research output: Contribution to journalArticle

Abstract

Based on previous observations of the diurnal variation of urinary cystine excretion, the use of separate day and night urine collections was proposed. To improve the medical treatment of patients with cystinuria, this strategy was performed to guide the fluid intake and the administration of SH compounds (tiopronin, D-penicillamine, and MESNA).Twenty-six patients (19 treated with SH compounds and seven with alkalinization and hydration only) were followed during two 3.5-year periods. During Period 1, 24-h urine was collected and during Period 2, separate day and night urine was collected. There were 56 episodes of high urinary cystine supersaturation (> 1,200 micromol/l) during Period 2, 47% of which would have evaded detection with 24-h urine analysis. In comparison with Period 1, the urinary cystine concentration was lower (P < 0.05), and the urinary volume was higher (P < 0.05) during Period 2. Patients treated with tiopronin had reduced cystine excretion (P < 0.05) and at the end of Period 2, an increased dose of tiopronin, reflecting a more aggressive treatment. Furthermore, a reduced number of stone episodes and need of active stone removal (P < 0.05) was noted in the whole group of patients. Analyses of separate day and night urine samples can be used advantageously to reveal episodes of high supersaturation with cystine not detected in 24-h urine samples. Such a procedure might be useful for optimizing the treatment of patients with cystinuria.

Details

Authors
External organisations
  • Skåne University Hospital
  • Linköping University Hospital
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Urology and Nephrology

Keywords

  • Adult, Aged, Circadian Rhythm, Cystinuria/genetics, Dose-Response Relationship, Drug, Female, Homozygote, Humans, Male, Mesna/therapeutic use, Middle Aged, Osmolar Concentration, Penicillamine/therapeutic use, Specimen Handling/methods, Sulfhydryl Compounds/therapeutic use, Tiopronin/administration & dosage, Urinary Calculi/prevention & control
Original languageEnglish
Pages (from-to)303-10
Number of pages8
JournalUrological Research
Volume29
Issue number5
Publication statusPublished - 2001 Oct
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes