A new review published in Current Urology Reports documents the coexistence of kidney stone disease and urinary tract infection. Evidence suggests that kidney stone disease may lead to urinary tract infection, and that urinary tract infection may give rise to kidney stones. Study findings support stone removal and stone culture for eradication of infection.
In their systematic review of 17 papers, Bhaskar K. Somani, MRCS, of the University Hospital Southampton NHS Trust in the United Kingdom, and colleagues found “a strong association” between kidney stone disease and recurrent urinary tract infection ranging from 18.7% to 36% of cases. In the longest running study with a median follow-up of 19 years, published in the World Journal of Urology, stone formers had a significant 5.7-fold increased risk of developing a urinary tract infection, the reviewers highlighted.
Colonized urine or stone samples were observed in almost all chemical stone compositions, not just struvite and infection stones, Dr Somani’s team reported. Bacteria producing the enzyme urease splits urea into ammonia and carbon dioxide. In water, ammonium and hydroxide ions form and react with magnesium and phosphate to form magnesium ammonium phosphate stones, or struvite, they explained. Common bacteria involved in struvite formation include Proteus, Staphylococcus, Pseudomonas, Providencia, Klebsiella, and Serratia. Other processes of crystal formation are also being studied. A recent study implicated non-urealytic Enterobacteriaceae in the onset of metabolic stones.
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Urinary tract infection was more likely to resolve after surgical removal of kidney stones whether by ureteroscopy, percutaneous nephrolithotomy, or extracorporeal shock wave lithotripsy, as long as there were no residual stones. For example, a 2019 study published in the World Journal of Urology found that removal of nonobstructive, nonstruvite stones was 89.1% successful in preventing recurrent urinary tract infections. Dr Somani and colleagues recommended a stone culture to identify the offending bacteria and guide antibiotic treatment, based on the evidence.
Dr Somani’s team concluded that their systematic review clearly shows that urinary tract infection and kidney stone disease “are mutually coexisting, and reciprocally causal and such patients should be counselled for proactive intervention by stone removal especially when UTIs are recurrent or additional risk factors are present irrespective of stone composition.
Reference
Ripa F, Pietropaolo A, Montanari E, Zeeshan Hameed BM, Gauhar V, Somani BK. Association of kidney stones and recurrent UTIs: the chicken and egg situation. A systematic review of literature. Curr Urol Rep. Published online July 25, 2022. doi:10.1007/s11934-022-01103-y
