An unusual patient with kidney stones composed of 1-methyluric acid.

Abstract

An unusual case with kidney stones composed mainly of 1-methyluric acid is described. The patient, a Caucasian male of Celtic descent, reportedly drank at least eight cups of coffee per day and had a long history of rheumatoid arthritis, gouty attacks and renal colics--the latter attributed to nephrocalcinosis and analgesic nephropathy. He was treated with allopurinol. At 54 years, a bilateral nephrolithotomy was performed. Stone samples were analysed by thermogravimetry and infrared spectroscopy and reported to be 12-25% calcium oxalate, the remainder being organic uric acid-like material. Analysis of the extracts by HPLC confirmed that the organic material contained 67% of 1-methyluric acid and 33% of uric acid. Possible mechanisms leading to the precipitation of 1-methyluric acid from urine are discussed. We conclude that the high caffeine intake resulted in extremely elevated urinary concentrations of 1-methyluric acid favouring the formation of 1-methyluric acid stones.

• Authors: Phillip M Davies, Lynette D Fairbanks, Krzysztof Safranow, Michael R Bending, H Anne Simmonds
• Journal: Urological research (Urol Res) Vol. 34 Issue 1 Pg. 58-60 (Feb 2006) ISSN: 0300-5623 [Print] Germany
• PMID: 16397778 (Publication Type: Case Reports, Journal Article)

Chemical References

• Central Nervous System Stimulants
• Coffee
• Uric Acid
• 1-methyluric acid
• Caffeine

Topics

• Adult
• Caffeine (pharmacokinetics)
• Central Nervous System Stimulants (pharmacokinetics)
• Coffee
• Humans
• Kidney Calculi (complications, urine)
• Kidney Failure, Chronic (etiology, therapy)
• Male
• Peritoneal Dialysis, Continuous Ambulatory
• Uric Acid (analogs & derivatives, metabolism, urine)