Hypocalcemia in Infants and Children

1. Ping Zhou, MD 2. Morri Markowitz, MD 1. Children's Hospital at Montefiore Bronx, NY Disorders of Calcium and Phosphorus Homeostasis. Gertner JM. Pediatr Clin North Am. 1990;37 :1441– 1465[OpenUrl][1][PubMed][2][Web of Science][3] Clinical Review 69: Evaluation of Hypocalcemia in Children and Adults . Guise TA, Mundy GR. J Clin Endocrinol Metab. 1995;80 :1473– 1478[OpenUrl][4][CrossRef][5][PubMed][6][Web of Science][7] Neonatal Hypocalcemia: To Treat or Not To Treat? Mimouni F, Tsang RC. J Am Coll Nutr. 1994;13 :408– 415[OpenUrl][8][PubMed][9] The Investigation of Hypocalcaemia and Rickets. Singh J, Moghal N, Pearce SH, Cheetham T. Arch Dis Child. 2003;88 :403– 407[OpenUrl][10][Abstract/FREE Full Text][11] Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism. 6th ed. Favus MJ, ed. Washington, DC: American Society for Bone Mineral Research; 2006 Approximately 99% of the total body calcium (Ca) is in the form of hydroxyapatite crystal in the skeleton; the remaining 1% resides in extracellular fluid. About 50% of the Ca in the circulation is in the free ionized form, 40% is bound to protein (predominantly albumin), and 10% is complexed with anions (eg, citrate). It is the plasma ionized calcium (iCa) fraction that is biologically active, and its concentration is tightly controlled. Ca concentrations in blood are reported in various units: mg/dL, mmol/L, and mEq/L. Because Ca is found as the divalent cation in humans, the conversion factor between mmol/L and mEq/L is 2; that is, 1 mmol/L=2 mEq/L. Because the molecular weight of Ca is approximately 40, the conversion factor between mmol/L and mg/dL is 4; that is, 1 mmol/L=4.0 mg/dL. For example, a value of 9.0 mg/dL is the equivalent of 2.25 mmol/L or 4.5 mEq/L. Despite the iCa fraction being the biologically important component, total serum Ca is measured most commonly. iCa values should be determined when abnormalities in Ca homeostasis are suspected. iCa is measured … [1]: {openurl}?query=rft.jtitle%253DPediatric%2Bclinics%2Bof%2BNorth%2BAmerica%26rft.stitle%253DPediatr%2BClin%2BNorth%2BAm%26rft.aulast%253DGertner%26rft.auinit1%253DJ.%2BM.%26rft.volume%253D37%26rft.issue%253D6%26rft.spage%253D1441%26rft.epage%253D1465%26rft.atitle%253DDisorders%2Bof%2Bcalcium%2Band%2Bphosphorus%2Bhomeostasis.%26rft_id%253Dinfo%253Apmid%252F2259548%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [2]: /lookup/external-ref?access_num=2259548&link_type=MED&atom=%2Fpedsinreview%2F30%2F5%2F190.atom [3]: /lookup/external-ref?access_num=A1990EP88300013&link_type=ISI [4]: {openurl}?query=rft.jtitle%253DJournal%2Bof%2BClinical%2BEndocrinology%2B%2526%2BMetabolism%26rft.stitle%253DJ.%2BClin.%2BEndocrinol.%2BMetab.%26rft.issn%253D0021-972X%26rft.aulast%253DGuise%26rft.auinit1%253DT.%2BA.%26rft.volume%253D80%26rft.issue%253D5%26rft.spage%253D1473%26rft.epage%253D1478%26rft.atitle%253DClinical%2Breview%2B69%253A%2BEvaluation%2Bof%2Bhypocalcemia%2Bin%2Bchildren%2Band%2Badults%26rft_id%253Dinfo%253Adoi%252F10.1210%252Fjc.80.5.1473%26rft_id%253Dinfo%253Apmid%252F7744987%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [5]: /lookup/external-ref?access_num=10.1210/jc.80.5.1473&link_type=DOI [6]: /lookup/external-ref?access_num=7744987&link_type=MED&atom=%2Fpedsinreview%2F30%2F5%2F190.atom [7]: /lookup/external-ref?access_num=A1995QW61100001&link_type=ISI [8]: {openurl}?query=rft.jtitle%253DJournal%2Bof%2Bthe%2BAmerican%2BCollege%2Bof%2BNutrition%26rft.stitle%253DJ.%2BAm.%2BColl.%2BNutr.%26rft.issn%253D0731-5724%26rft.aulast%253DMimouni%26rft.auinit1%253DF.%26rft.volume%253D13%26rft.issue%253D5%26rft.spage%253D408%26rft.epage%253D415%26rft.atitle%253DNeonatal%2Bhypocalcemia%253A%2Bto%2Btreat%2Bor%2Bnot%2Bto%2Btreat%253F%2B%2528A%2Breview%2529%26rft_id%253Dinfo%253Apmid%252F7836618%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [9]: /lookup/external-ref?access_num=7836618&link_type=MED&atom=%2Fpedsinreview%2F30%2F5%2F190.atom [10]: {openurl}?query=rft.jtitle%253DArchives%2Bof%2BDisease%2Bin%2BChildhood%26rft.stitle%253DArch.%2BDis.%2BChild.%26rft.issn%253D0003-9888%26rft.aulast%253DSingh%26rft.auinit1%253DJ%26rft.volume%253D88%26rft.issue%253D5%26rft.spage%253D403%26rft.epage%253D407%26rft.atitle%253DThe%2Binvestigation%2Bof%2Bhypocalcaemia%2Band%2Brickets%26rft_id%253Dinfo%253Adoi%252F10.1136%252Fadc.88.5.403%26rft_id%253Dinfo%253Apmid%252F12716711%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [11]: /lookup/ijlink?linkType=ABST&journalCode=archdischild&resid=88/5/403&atom=%2Fpedsinreview%2F30%2F5%2F190.atom