Staghorn Stone Composition Changes Reported

A single-center study found that most staghorn stones have a metabolic composition rather than an infectious cause.
A single-center study found that most staghorn stones have a metabolic composition rather than an infectious cause.
The following article is part of conference coverage from the 2017 American Urological Association meeting in Boston. Renal and Urology News' staff will be reporting live on medical studies conducted by urologists and other specialists who are tops in their field in kidney stones, prostate cancer, kidney cancer, bladder cancer, enlarged prostate, and more. Check back for the latest news from AUA 2017. 

BOSTON—Staghorn calculi historically have been considered to be stones associated with urinary tract infections, but a new single-center study suggests that most staghorn calculi have a metabolic composition, researchers reported at the American Urological Association 2017 annual meeting.

Tyler D. Haden, MD, and colleagues at the University of Missouri-Columbia studied 71 patients who underwent percutaneous nephrolithotomy for complete staghorn calculi from 2010 to 2015. Of these patients, 28 (39%) had infectious stones (either carbonate or struvite) and 44 (61%) had metabolic stones. The composition of these stones was calcium phosphate (52% of stones), calcium oxalate (18%), uric acid (18%), and cystine (12%).

“We feel this is an important differentiating factor as patients forming metabolic stones may require complete work up to allow for appropriate treatment to prevent further stone formation,” Dr Haden told Renal & Urology News. “We were able to identify patient characteristics that increased the risk of a patient having a historically common infectious staghorn calculus, including neurogenic bladder and a positive preoperative urine culture.”

Study results showed that patients with neurogenic bladder were 3.7 times more likely to have infectious stones than metabolic stones. Patients with a preoperative positive urine culture were 18 times more likely to have infectious stones. Proteus species were the most common bacteria associated with infectious stones. Complications were 3.2 times more likely with infectious stones than metabolic stones.

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Reference

Haden TD, Kuhlmann P, Ross J, et al. Is there a shift from infectious stones in staghorn calculi? [abstract]. J Urol 2017;197(4S):e5-e6. Poster presented at the American Urological Association 2017 annual meeting in Boston on May 12, 2017. Poster MP01-13

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