title: Silent renal stones in primary hyperparathyroidism: prevalence and clinical features.
abstract: OBJECTIVE
  (1) To evaluate the prevalence of silent nephrolithiasis in patients with primary hyperparathyroidism (PHPT) compared with controls, and (2) To characterize clinically PHPT patients with silent renal stones.
  
  
  METHODS
  We reviewed clinical data for 141 patients with PHPT and without symptoms or history of nephrolithiasis in whom renal ultrasonography was performed at diagnosis. A total of 141 sex- and age- matched subjects with abdomen ultrasonography obtained for reasons different from urinary symptoms served as controls.
  
  
  RESULTS
  Silent nephrolithiasis was more prevalent in PHPT patients than in controls (11.35% vs. 2.13%; P = .003). Among patients with PHPT, those with silent renal stones showed higher serum calcium and parathyroid hormone levels and met surgical criteria, regardless of nephrolithiasis, more frequently than those without renal stones.
  
  
  CONCLUSIONS
  The prevalence of silent nephrolithiasis is increased in patients with PHPT as compared with controls. Moreover, it seems likely that silent renal stone disease could identify a subset of PHPT patients with more severe disease. Accordingly, we suggest ultrasonographic screening of nephrolithiasis in all PHPT patients. Further studies are needed to better characterize this clinical entity.
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Santa Croce and Carle, Cuneo, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Cassibba
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Santa Croce and Carle, Cuneo, Italy.
authors.forename: Micaela
authors.initials: M
authors.lastname: Pellegrino
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Santa Croce and Carle, Cuneo, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Gianotti
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Santa Croce and Carle, Cuneo, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Baffoni
authors.affiliation: Department of Radiology, Santa Croce and Carle, Cuneo, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Baralis
authors.affiliation: Endocrinology Service, Galeazzi Institute IRCCS, Milan, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Attanasio
authors.affiliation: Division of Nephrology, Santa Croce and Carle, Cuneo, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Guarnieri
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Santa Croce and Carle, Cuneo, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Borretta
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Santa Croce and Carle, Cuneo, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Tassone