title: Revisiting nephrocalcinosis: A single-centre perspective. A northern Italian experience.
abstract: OBJECTIVE
  Nephrocalcinosis is a clinical-pathological entity characterized by the deposition of calcium salts within the kidney parenchyma. Both the protean presentation and multiple causes may explain the lack of data regarding its prevalence. The aim of this study is to report the prevalence and main clinical features of nephrocalcinosis diagnosed in a newly opened nephrology outpatient unit.
  
  
  METHODS
  Analysis on the data we prospectively gathered from the start of activity (2007-2013) was carried out. Clinical and laboratory data were collected from the medical records and from the general laboratory; diagnosis was based upon imaging data reviewed by the same radiologists.
  
  
  RESULTS
  Sixty-five of 2695 patients referred to our unit were diagnosed with nephrocalcinosis (2.4%). The affected patients were younger than the overall out-patient population (median: 37.7 (min-max: 8-82) vs 63 years (2-102) P < 0.001), with higher female prevalence (68% vs 51.4%: P < 0.05) and better preserved kidney function (CKD-EPI 103 (23-165) vs 60 mL/min (3.2-169) P < 0.001). Kidney stones were the main reason for referral (35.4%), followed by electrolyte disturbances (22.7%), acute pyelonephritis (4.6%), AKI or CKD (4.6%). Nephrocalcinosis was associated with autoimmune diseases in 29% and with microcythaemia in 23%, while positive family history was present in 23% of patients. Various electrolyte disturbances were observed, with hypercalciuria being the hallmark of beta thalassaemic patients.
  
  
  CONCLUSIONS
  Nephrocalcinosis is a rare, but not exceptional disease in nephrology. In Mediterranean countries, microcythaemia would appear to be a major cause of this disease. Greater awareness of nephrocalcinosis is needed for an integrated approach involving various branches of internal medicine and radiology.
authors.affiliation: SS Nephrology, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Giorgina Barbara
authors.initials: GB
authors.lastname: Piccoli
authors.affiliation: Radiology, ASOU San Luigi, Department of Oncology, University of Torino, Torino, Italy.
authors.forename: Agostino
authors.initials: A
authors.lastname: De Pascale
authors.affiliation: SS Nephrology, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Olga
authors.initials: O
authors.lastname: Randone
authors.affiliation: SS Nephrology, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Federica Neve
authors.initials: FN
authors.lastname: Vigotti
authors.affiliation: Radiology, ASOU San Luigi, Department of Oncology, University of Torino, Torino, Italy.
authors.forename: Adriano Massimiliano
authors.initials: AM
authors.lastname: Priola
authors.affiliation: Interregional Center for Rare Diseases, G Bosco Hospital, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Naretto
authors.affiliation: SS Nephrology, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Ferraresi
authors.affiliation: Laboratory, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Aroasio
authors.affiliation: Laboratory, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Silvana
authors.initials: S
authors.lastname: Gonella
authors.affiliation: SS Nephrology, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Mongilardi
authors.affiliation: SS Nephrology, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Scognamiglio
authors.affiliation: SS Nephrology, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Consiglio
authors.affiliation: Microcythemia Unit, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Roggero
authors.affiliation: Microcythemia Unit, ASOU San Luigi, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Piga
authors.affiliation: Interregional Center for Rare Diseases, G Bosco Hospital, Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Roccatello
authors.affiliation: Radiology, ASOU San Luigi, Department of Oncology, University of Torino, Torino, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Veltri
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000453:epidemiology; D002648:Child; D005260:Female; D020022:Genetic Predisposition to Disease; D040941:Heredity; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009397:Nephrocalcinosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000628:therapy; D009398:Nephrology; D010044:Outpatient Clinics, Hospital; D015995:Prevalence; D012017:Referral and Consultation; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D013789:Thalassemia / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
keywords: Chronic kidney disease; nephrocalcinosis; stone disease; tubular disturbances; ultrasound analysis