Neonatal hypocalcemia is defined as serum calcium (S-Ca) < 2.0 mmol/l in full-term newborns and <1.75 mmol/l in preterm newborns. Neonatal hypocalcemia is either early onset (<3 days of age) or late onset (>3 days of age). Newborns with hypocalcemia are often asymptomatic but may present with hypotonia, apnea, poor feeding, jitteriness, seizures, and cardiac failure. Signs of hypocalcemia rarely occur unless S-Ca drops below 1.75 mmol/l. Neonatal hypocalcemia can be a result of hypoparathyroidism (transient or primary), increased serum calcitonin, sepsis, asphyxia, hepatopathy, hypomagnesemia, high phosphate load, transient hypoparathyroidism, and, rarely, transient neonatal pseudohypoparathyroidism [transient resistance to biological actions of parathyroid hormone (PTH)]. We present the case of three boys (two with gestational age 39 weeks, one 36 weeks; none of them with either asphyxia or sepsis) with mild hypotonia, where S-Ca in the range of 1.67-1.9 mmol/l was detected within the first 3 days of life, together with hyperphosphatemia [serum phosphate (P) 2.5-2.6 mmol/l], normomagnesemia [serum magnesium (S-Mg) 0.77-0.88 mmol/l], normal alkaline phosphatase (ALP) activity (2.8-4.5 μkat/l), and high serum PTH (40-51 pg/ml; normal = 5-28). In spite of the gradual increase of S-Ca, the elevated serum PTH persisted beyond days 3, 4, and 6 in all three boys, together with normal or low-to-normal S-Ca, high or normal-to-high serum P, and no increases in serum ALP. The mothers S-Ca, P, Mg, ALP, and PTH levels were within normal reference ranges. With regard to laboratory results, the diagnosis of transient neonatal pseudohypoparathyroidism (due to immaturity of PTH-receptors) is highly probable in these three neonates.

Department of Clinical Biochemistry Klatovy Hospital Klatovy Czech Republic

Department of Pediatrics Klatovy Hospital Klatovy Czech Republic

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Hussain SM, Mughal MZ. Mineral transport across the placenta. Arch Dis Childh. 1992;67:874–8. https://doi.org/10.1136/adc.67.7_Spec_No.874. PubMed PMC

Kruse K. Der perinatale kalziumstoffwechsel. Mschr Kinderheilk. 1992;140:S1–S7. PubMed

Bishop N, Fewtrell M, Harvey NC. In: Glorieux FH, Pettifor JM, Juppner H, editors. Pediatric bone. Biology and diseases. 2nd ed. San Diego, CA: Elsevier—Academic Press; 2012. Metabolic bone disease in the neonatal period and its later sequelae; pp. 655–77. https://doi.org/10.1016/B978-0-12-382040-2.10024-3.

Hsu BC, Levine MA. Perinatal calcium metabolism: physiology and pathophysiology. Semin Neonatol. 2004;9:23–36. https://doi.org/10.1016/j.siny.2003.10.002. PubMed

Kopelman AE. Metabolic problems in the newborns. Hypocalcemia. In: The Merck Manual 1992. Merck&Co Inc. 1992:2004–2005.

Lantzy A. Neonatal Hypocalcemia. Merck Manual 2015. Merck&Co Inc; 2015. Available from: http://www.msdmanuals.com/professional/pediatrics/metabolic,-electrolyte,-and-toxic-disorders-in-neonates/neonatal-hypocalcemia.

Minagawa M, Yasuda T, Kobayashi Y, Niimi H. Transient pseudohypoparathyroidism of the neonate. Eur J Endocrinol. 1995;133:151–5. https://doi.org/10.1530/eje.0.1330151. PubMed

Jain A, Agarwal R, Sankar MJ, Deorari A, Paul VK. Hypocalcemia in the newborn. Indian J Pediatr. 2010;77:1123–8. https://doi.org/10.1007/s12098-010-0176-0. PubMed

Kruse K, Küstermann W. Evidence for transient peripheral resistance to parathyroid hormone in premature infants. Acta Paediatr Scand. 1987;76:115–8. https://doi.org/10.1111/j.1651-2227.1987.tb10425.x. PubMed

Schaumberger E, Hohenauer L, Sommer R. Transitory pseudohypoparathyroidism in the newborn infant. Klin Padiatr. 1986;198:349–52. https://doi.org/10.1055/s-2008-1033886. PubMed

Fujisawa Y, Yamashita K, Hirai N, Terada K, Kida K. Transient late neonatal hypocalcemia with high seum parathyroid hormone. J Pediatr Endocrinol Metab. 1997;10:433–6. https://doi.org/10.1515/JPEM.1997.10.4.433. PubMed

Lee CT, Tsai WY, Tung YC, Tsau YK. Transient pseudohypoparathyroidism as a cause of late-onset hypocalcemia in neonates and infants. J Formos Med Assoc. 2008;107:806–10. https://doi.org/10.1016/S0929-6646(08)60194-1. PubMed

Manzar S. Transient pseudohypoparathyroidism and neonatal seizure. J Trop Pediatr. 2001;47:113–4. https://doi.org/10.1093/tropej/47.2.113. PubMed

Jesić M, Jesić M, Sajić S, Maglajić S, Jesić M, Tomanović S. Transient neonatal pseudohypoparathyroidism. Srp Arh Celok Lek. 2007;135:566–8. https://doi.org/10.2298/SARH0710566J. PubMed

Sajitha S, Krishnamoorthy PN, Shenoy UV. Psedohypoparathyroidism in newborn—a rare presentation. Indian Pediatr. 2003;40:47–9. PubMed

Narang M, Salota R, Sachdev SS. Neonatal pseudohypoparathyroidism. Indian J Pediatr. 2006;73:97–8. https://doi.org/10.1007/BF02758270. PubMed

Koklu E, Kurtoglu S. Natal teeth and neonatal transient pseudohypoparathyroidism in a newborn. J Pediatr Endocrinol Metab. 2007;20:971. https://doi.org/10.1515/JPEM.2007.20.9.971. PubMed

Ergin H, Karaca A, Ergin S, Cördük N, Karabulut N. Calcinosis cutis in a newborn with transient pseudohypoparathyroidism. Indian J Pediatr. 2011;78:1424–6. https://doi.org/10.1007/s12098-011-0446-5. PubMed

Dowa Y, Kawai M, Kanazawa H, Iwanaga K, Matsukura T, Heike T. Screening for secondary hyperparathyroidism in preterm infants. Pediatr Int. 2016;58:988–92. https://doi.org/10.1111/ped.12961. PubMed