Cystinuria is an autosomal recessive defect in transepithelial transport of
dibasic amino acids (e.g.
cystine) which involves the proximal canaliculi, small intestine and central nervous system. It is the least common cause of
nephrolithiasis, accounting for 1 to 3% of
renal calculi. The natural course of the disease, characterised by recurrent stone formation, can frequently lead to
renal failure, if left untreated. Until recently, treatment of
cystinuria has been limited to symptomatic management including intensive hydration and urine alkalinisation. Different drugs that react with
cystine to form soluble complexes have been used but their efficacy remains questionable. We present the case of a 6-year-old boy with severe, recurrent
cystine urolithiasis treated with
captopril. The diagnosis of
cystine urolithiasis was established after a 3-year course of clinically apparent
nephrolithiasis, characterised by stone passage. At the age of 5 years he underwent
lithotripsy and nephrolithotomy for removal of
staghorn calculi. Since then treatment with
citrate and
magnesium supplementation combined with
captopril was introduced. After a follow-up of 12 months the patient remained stone-free. Urinary
cystine decreased from 230 to 136 mg per gram
creatinine. We conclude that
captopril can be useful in the treatment of
cystine urolithiasis in children.