title: Hypocalcemia following treatment with radioiodine in a child with Graves' disease.
abstract: BACKGROUND
  Hypocalcemia is a rarely recognized complication of (131)I therapy that has been previously reported in only one child with Graves' disease treated with radioiodine (RAI). Here we report a second child with this occurrence.
  
  
  METHODS
  A 12-year-old African American girl with hyperthyroidism due to Graves' disease and moderate persistent asthma, requiring oral prednisone, was treated with 11.1 mCi of RAI. While normocalcemic initially, the patient developed symptomatic hypocalcemia (6.6 mg/dL), within 3 months postablation. Concomitant findings included hyperphosphatemia, an inappropriately normal parathyroid hormone (PTH) level, vitamin D deficiency, and normal axial bone mineral density. After 2 weeks of treatment with calcium and calcitriol the symptoms of hypocalcemia resolved, and the calcium level returned to normal. PTH levels remained within the reference range throughout.
  
  
  CONCLUSIONS
  In this child with Graves' disease, who was normocalcemic on presentation, RAI treatment was followed by compromised function of the parathyroid glands which was sufficient to produce symptomatic hypocalcemia. It is noteworthy and likely pertinent that the patient had a background of vitamin D deficiency and was receiving prednisone for asthma.
  
  
  CONCLUSIONS
  Patients scheduled to receive (131)I should be evaluated for risk factors for hypocalcemia in order to minimize the likelihood of this potentially serious complication.
authors.affiliation: Division of Endocrinology Metabolism and Diabetes, University of Louisville, Louisville, Kentucky, USA.
authors.forename: Kateryna
authors.initials: K
authors.lastname: Komarovskiy
authors.forename: Susan
authors.initials: S
authors.lastname: Raghavan
mesh_terms: D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy; D002117:Calcitriol / Q000627:therapeutic use; D002118:Calcium / Q000627:therapeutic use; D002648:Child; D005260:Female; D006111:Graves Disease / Q000532:radiotherapy*; D006801:Humans; D054559:Hyperphosphatemia / Q000209:etiology; D006996:Hypocalcemia / Q000139:chemically induced* / Q000175:diagnosis*; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use; D010280:Parathyroid Glands / Q000293:injuries; D010281:Parathyroid Hormone / Q000097:blood; D011241:Prednisone / Q000627:therapeutic use; D011832:Radiation Injuries / Q000097:blood / Q000378:metabolism; D016896:Treatment Outcome; D014808:Vitamin D Deficiency / Q000209:etiology
chemical_list: D018927:Anti-Asthmatic Agents; D007457:Iodine Radioisotopes; D010281:Parathyroid Hormone; D002117:Calcitriol; D002118:Calcium; D011241:Prednisone