Calyceal microlithiasis in children: report on 196 cases

Recognition of children at greatest risk for urolithiasis may allow early detection or prevention of stone formation. We report clinical data from 196 children aged 0.9–15.9 years in whom renal ultrasound examination revealed hyperechogenic spots in renal calyces less than 3 mm in diameter. We called this finding “calyceal microlithiasis” (CM). There was a history of urolithiasis in 70.4% of patients in at least one first- or second-degree relative. Presenting symptoms were recurrent abdominal pain, dysuria, and hematuria, occurring alone or in combination. Hematuria was the presenting symptom in 41% of patients and was the only urinary finding in more than one-third. Hypercalciuria was present in about one-third and hyperuricuria in one-fifth of the patients. Of 29 patients who were followed for at least 2 years, 9 developed calculi 4–7 mm in diameter. CM possibly represents the first step in calculus formation. The finding of CM might explain a number of symptoms and signs that are often mild and non-specific, thus reducing invasive diagnostic procedures. Received November 26, 1996; received in revised form August 7, 1997; accepted November 5, 1997