title: Idiopathic hypercalcemia in infants with renal dysplasia.
abstract: BACKGROUND
  We have observed infants with renal dysplasia who developed sustained hypercalcemia, without vitamin D or calcium supplementation (idiopathic). This has not been previously described.
  
  
  OBJECTIVE
  1) Define incidence, severity and duration of idiopathic hypercalcemia in infants with renal dysplasia below 12 months of age. 2) Evaluate phosphate, parathyroid hormone (PTH) and vitamin D levels in these infants.
  
  
  METHODS
  A retrospective study was conducted from June 2005 to June 2008. Patients receiving calcium-containing phosphate binders or daily supplemental vitamin D in excess of 400 IU were excluded. Hypercalcemia was defined as at least three corrected calcium values above normal lab values for age, in a one-week interval.
  
  
  RESULTS
  15 of 99 (15%) infants with renal dysplasia had hypercalcemia. All were males; 10/15 (67%) were below one month of age at presentation; 9/15 (60%) had posterior urethral valves (PUV). Mean hypercalcemia duration was 5.2 ± 6.0 months. Mean corrected calcium was 3.07 mmol/l (12.3 mg/dl). Only 3/10 infants had elevated PTH levels. None had elevated phosphate levels and only 1/8 patients who had 25-hydroxyvitamin D measured had an elevated level.
  
  
  CONCLUSIONS
  Idiopathic hypercalcemia in infants with renal dysplasia is common. Neonates and those with PUVs are at greatest risk. Most have normal levels of 25-hydroxyvitamin D, phosphate and PTH.
authors.affiliation: The Hospital for Sick Children, Division of Nephrology, Toronto, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Al Kalbani
authors.forename: M
authors.initials: M
authors.lastname: Frieling
authors.forename: J C
authors.initials: JC
authors.lastname: Teh
authors.forename: E
authors.initials: E
authors.lastname: Harvey
authors.forename: D F
authors.initials: DF
authors.lastname: Geary
mesh_terms: D006801:Humans; D006934:Hypercalcemia / Q000209:etiology*; D007223:Infant; D007668:Kidney / Q000002:abnormalities*; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D012189:Retrospective Studies; D013997:Time Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D