Correspondence
Recombinant PTH for Initial Management of Neonatal Hypocalcemia
N Engl J Med 2007; 356:1687-1688April 19, 2007
- Article
To the Editor:
Neonatal hypocalcemia due to hypoparathyroidism can present as life-threatening seizures or tetany. Currently, initial management consists of the administration of calcitriol and high doses of calcium. In symptomatic children, to avoid extravasation, intravenous calcium is best administered through a central line, a procedure that requires proper expertise. However, central access carries the risks of infection and thrombosis. Correction of hypocalcemia with intravenous and oral calcium often takes a day or longer to achieve, leaving the infant at risk for seizures and tetany. Therefore, recombinant parathyroid hormone (teriparatide) should be a faster, safer, and more physiologic means of correcting hypocalcemia due to hypoparathyroidism.
A 17-day-old Hispanic boy was taken to an outlying emergency room with generalized seizure and profound hypocalcemia. A review of his history showed that he had had muscle twitches since the second day of life. The workup for sepsis, which included lumbar puncture, was negative. He was transferred to Children's Hospital in San Diego, having already received a few intravenous boluses of calcium. A nadir calcium level of 4.9 mg per deciliter (with normal albumin) was associated with an elevated phosphorus level (10.1 mg per deciliter), a low magnesium level (1.6 mg per deciliter), and a normal alkaline phosphatase level (178 U per liter [normal range, 110 to 300 U per liter]).
Since the results of laboratory studies suggested hypoparathyroidism or pseudohypoparathyroidism, calcitriol was added, with a first dose of 0.5 μg, followed by 0.25 μg per day. The child was no longer having seizures, so a central line was not placed. Despite the administration of oral calcium glubionate every 4 hours and continuous peripheral infusion of diluted calcium gluconate (105 mg of elemental calcium per kilogram of body weight per day), his calcium level rose from 6.2 mg per deciliter to only 6.9 mg per deciliter one day after the addition of calcitriol. When teriparatide became available the next day, he received 5 μg subcutaneously, and his calcium level rose from 6.9 mg per deciliter to 9.3 mg per deciliter in less than 4 hours. Hypoparathyroidism was subsequently confirmed by test results showing an inappropriately low intact parathyroid hormone level (41 pg per milliliter), with a calcium level of 4.9 mg per deciliter and a normal magnesium level after supplementation (2.2 mg per deciliter). The results were negative on fluorescence in situ hybridization for the DiGeorge syndrome and 46XY karyotype. The child is currently being evaluated for a calcium-sensor–activating mutation, although there is no family history of the disease. His initial ratio of urinary calcium to creatinine of 0.12 could have reflected the mildly low 25-hydroxyvitamin D level (17 ng per milliliter) due to mild maternal vitamin D deficiency.
Although teriparatide has been available to treat osteoporosis in adults, its use in pediatrics has been hampered by concern about long-term exposure and the risk of osteosarcoma. This case demonstrates that after obtaining the diagnostic samples, short-term use of teriparatide can raise calcium levels faster and more safely than can other commonly used methods. This approach may represent an advance in the management of hypocalcemia, particularly in infancy, and should be further evaluated.
Ron S. Newfield, M.D.
University of California, San Diego, San Diego, CA 92123
rnewfield@ucsd.edu - Citing Articles (1)
Citing Articles
1
Yoon Hi Cho, Michel Tchan, Bithi Roy, Robert Halliday, Meredith Wilson, Shoma Dutt, Susan Siew, Craig Munns, Neville Howard. (2012) Recombinant Parathyroid Hormone Therapy for Severe Neonatal Hypoparathyroidism. The Journal of Pediatrics 160:2, 345-348
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