Asymptomatic Renal Stones: Do they really Exist?

Background: Asymptomatic renal calculi without any history of colic, hematuria or infection can be found as an incidental finding during preventive check-ups. The aim of our study was to evaluate whether these stones provoke symptoms with the need for further treatment during the follow-up and whether they cause cortical defects which may consecutively affect the renal function. Patients and Methods: In a prospective study we evaluated 104 patients with renal calculi. The medical history, radiological findings and functional imaging as well as urine and blood analyses were recorded and evaluated. The influence of stone size and localisation on the development of acute stone-related symptoms, renal function and renal scarring were evaluated. Furthermore, we analysed whether localised pathological findings in radiographic or functional imaging may influence the creatinine level. The follow-up was between 12 and 48 months (median: 25 months). Results: During the study period 27/104 of our patients (26 %) developed symptomatic events (renal colic, hematuria, infection) in which patients with middle pole calculi with a mean cumulative stone diameter of 9.8mm had the highest risk. A localised renal scarring could be found in 36.6 %. These patients had a significantly higher risk in presenting an increased creatinine level. Increasing stone size was diagnosed in 39 cases (37.5%). Conclusions: Asymptomatic renal stones have to be controlled regularly in order to prevent the patient from loss of renal function and hypertension caused by increasing stones or urinary tract infection.