Perinatal calcium metabolism: physiology and pathophysiology

A Case of Severe Neonatal Hypocalcemia Treated With Continuous Enteral Calcium

Background/Objective

Hypocalcemia is a common, treatable cause of neonatal seizures. The rapid repletion of calcium is essential for restoring normal calcium homeostasis and resolving seizure activity. The accepted approach to administer calcium to a hypocalcemic newborn is via peripheral or central intravenous (IV) access.

Case Report

We discuss a case of a 2-week-old infant who presented with hypocalcemia and status epilepticus. The etiology was determined to be neonatal hypoparathyroidism secondary to maternal hyperparathyroidism. Following an initial dose of IV calcium gluconate, the seizure activity abated. However, stable peripheral intravenous access could not be maintained. After weighing the risks and benefits of placing a central venous line for calcium replacement, it was decided to use continuous nasogastric calcium carbonate at a rate of 125 mg of elemental calcium/kg/d. Ionized calcium levels were used to guide the course of the therapy. The infant remained seizure-free and was discharged on day 5 on a treatment regimen that included elemental calcium carbonate, calcitriol, and cholecalciferol. He remained seizure free since discharge and all medications were discontinued by 8 weeks of age.

Discussion

Continuous enteral calcium is an effective alternate therapy for restoration of calcium homeostasis in a neonate presenting with hypocalcemic seizures in the intensive care unit (ICU).

Conclusion

We propose that continuous enteral calcium be considered as an alternative approach for calcium repletion in neonatal hypocalcemic seizures, one that avoids the potential complications of peripheral or central IV calcium administration.

Early pregnancy vitamin D status and risk of select congenital anomalies in the National Birth Defects Prevention Study

INTRODUCTION

Vitamin D deficiency is associated with adverse pregnancy events. However, its role in the etiology of congenital anomalies remains unclear. We examined the association between vitamin D status, measured through prepregnancy diet, UV exposure, season of conception, and congenital anomalies.

METHODS

We used data from the National Birth Defects Prevention Study, a U.S. population-based case-control study (1997-2011). Prepregnancy dietary vitamin D was calculated from food frequency questionnaires and evaluated using tertiles, based on the distribution in controls. We used the National Oceanic and Atmospheric Administration Weather Service to assign UV indices based on location and estimated date of conception, then dichotomized UV exposure (low vs. high). Seasons of conception was categorized as fall/winter spring/summer. We used logistic regression to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI).

RESULTS

Lower prepregnancy dietary vitamin D intake (<65.21 IU/d vs. >107.55 IU/d) was associated with increased odds of anencephaly (aOR = 1.28, 95% CI 1.01, 1.63), hypospadias (aOR = 1.21, 95% CI 1.04, 1.40), septal defects (aOR = 1.16, 95% CI 1.05, 1.30), diaphragmatic hernia (aOR = 1.42, 95% CI 1.13, 1.79), and gastroschisis (aOR = 1.27, 95% CI 1.07, 1.52). Findings were consistent when we stratified by UV exposure and season of conception.

CONCLUSIONS

Our findings suggest lower dietary intake of vitamin D may be associated with increased risk of select congenital anomalies. Further investigations are warranted to evaluate the effects of other nutrients and appropriate thresholds and sources of vitamin D using serum.

Transient neonatal hypocalcaemia caused by maternal hyperparathyroidism

Hypocalcaemia in neonates can range from asymptomatic to a potentially life-threatening condition. We present a case of a 36 weeks gestational age boy, admitted to our neonatal intensive care unit for jitteriness, mild hypotonia and breastfeeding difficulties. By the ninth day of life, he presented with late-onset hypocalcaemia, hypomagnesaemia, low 25-OH-vitamin D and inappropriately normal parathyroid hormone. Further investigation revealed maternal hypercalcaemia with high parathyroid hormone. Maternal asymptomatic hyperparathyroidism was diagnosed and admitted as the cause of neonatal hypocalcaemia. There was a clinical improvement and calcium levels stabilisation after treatment with calcium gluconate and vitamin D3 This case highlights the importance of careful evaluation of neonatal late-onset hypocalcaemia in uncovering asymptomatic maternal hyperparathyroidism.

Hypoparathyroidism in Pregnancy and Lactation: Current Approach to Diagnosis and Management

Background: Hypoparathyroidism is an uncommon endocrine disorder. During pregnancy, multiple changes occur in the calcium-regulating hormones, which may affect the requirements of calcium and active vitamin D during pregnancy in patients with hypoparathyroidism. Close monitoring of serum calcium during pregnancy and lactation is ideal in order to optimize maternal and fetal outcomes. In this review, we describe calcium homeostasis during pregnancy in euparathyroid individuals and also review the diagnosis and management of hypoparathyroidism during pregnancy and lactation. Methods: We searched the MEDLINE, CINAHL, EMBASE, and Google scholar databases from 1 January 1990 to 31 December 2020. Case reports, case series, book chapters, and clinical guidelines were included in this review. Conclusions: During pregnancy, rises in 1,25-dihydroxyvitamin D (1,25-(OH)2-D3) and PTH-related peptide result in suppression of PTH and enhanced calcium absorption from the bowel. In individuals with hypoparathyroidism, the requirements for calcium and active vitamin D may decrease. Close monitoring of serum calcium is advised in women with hypoparathyroidism with adjustment of the doses of calcium and active vitamin D to ensure that serum calcium is maintained in the low-normal to mid-normal reference range. Hyper- and hypocalcemia should be avoided in order to reduce the maternal and fetal complications of hypoparathyroidism during pregnancy and lactation. Standard of care therapy consisting of elemental calcium, active vitamin D, and vitamin D is safe during pregnancy.

Metabolic Bone Disease in Premature Neonates: An Unmet Challenge

Metabolic bone disease (MBD) is an important cause of morbidity in premature, very low birth weight (VLBW) and sick infants and, if left undiagnosed, may lead to structural deformities and spontaneous fractures. MBD is defined as impaired bone mineralization in a neonate with lower than expected bone mineral levels in either a fetus or a neonate of comparable gestational age and/or weight, coupled with biochemical abnormalities with or without accompanying radiological manifestations. MBD has been reported to occur in 16% to 40% of extremely low birth weight neonates and presents by 6-16 weeks after birth. Insufficient calcium and phosphorous stores during the phase of accelerated growth predispose to MBD in neonates along with the use of some medications such as caffeine or steroids, prolonged parenteral nutrition and chronic immobilization. Enhanced physical activity in preterm infants facilitates bone mineralization and weight gain. Biochemical abnormalities tend to worsen significantly, as the severity of disease progresses. These abnormalities may include hypocalcemia, hypophosphatemia, hyperphosphatasia and secondary hyperparathyroidism. In addition, urinary phosphate wasting and hypovitaminosis D can be additional complications. Conversely, biochemical abnormalities may not be accompanied by rachitic changes. Newer diagnostic modalities include non-invasive bone densitometry by quantitative ultrasound over the mid-tibial shaft. The management of MBD includes adequate calcium, phosphorous and vitamin D supplementation, along with optimum nutrition and physical activity. Similarly, preventive strategies for MBD should target nutritional enhancement in combination with enhanced physical activity. MBD usually results in preventable morbidity in preterm and VLBW neonates. Treatment consists of optimum nutritional supplementation and enhanced physical activity.

Hypocalcemia and a Positive Metabolic Screen for Severe Combined Immunodeficiency in an 11-Day-Old Male With DiGeorge Syndrome

22q11 deletion syndrome (22q11DS), also known as DiGeorge syndrome or velocardiofacial syndrome, is the most common human genetic microdeletion. Hypocalcemia secondary to hypoparathyroidism is a common finding in this condition and may present with seizures. We describe a case of an 11-day-old male presenting with hypocalcemic seizures and a positive newborn screen for severe combined immunodeficiency as the primary manifestations of 22q11DS. Given the potential for wide phenotypic variability, clinicians should maintain a high index of suspicion for this syndrome, especially in the neonate presenting with hypocalcemia.

Neonatal Hypocalcemic Seizures in Offspring of a Mother With Familial Hypocalciuric Hypercalcemia Type 1 (FHH1)

CONTEXT

Familial hypocalciuric hypercalcemia type 1 (FHH1) is caused by loss-of-function mutations of the calcium-sensing receptor (CaSR) and is considered a benign condition associated with mild-to-moderate hypercalcemia. However, the children of parents with FHH1 can develop a variety of disorders of calcium homeostasis in infancy.

OBJECTIVE

The objective of this work is to characterize the range of calcitropic phenotypes in the children of a mother with FHH1.

METHODS

A 3-generation FHH kindred was assessed by clinical, biochemical, and mutational analysis following informed consent.

RESULTS

The FHH kindred comprised a hypercalcemic man and his daughter who had hypercalcemia and hypocalciuria, and her 4 children, 2 of whom had asymptomatic hypercalcemia, 1 was normocalcemic, and 1 suffered from transient neonatal hypocalcemia and seizures. The hypocalcemic infant had a serum calcium of 1.57 mmol/L (6.28 mg/dL); normal, 2.0 to 2.8 mmol/L (8.0-11.2 mg/dL) and parathyroid hormone of 2.2 pmol/L; normal 1.0 to 9.3 pmol/L, and required treatment with intravenous calcium gluconate infusions. A novel heterozygous p.Ser448Pro CaSR variant was identified in the hypercalcemic individuals, but not the children with hypocalcemia or normocalcemia. Three-dimensional modeling predicted the p.Ser448Pro variant to disrupt a hydrogen bond interaction within the CaSR extracellular domain. The variant Pro448 CaSR, when expressed in HEK293 cells, significantly impaired CaSR-mediated intracellular calcium mobilization and mitogen-activated protein kinase responses following stimulation with extracellular calcium, thereby demonstrating it to represent a loss-of-function mutation.

CONCLUSIONS

Thus, children of a mother with FHH1 can develop hypercalcemia or transient neonatal hypocalcemia, depending on the underlying inherited CaSR mutation, and require investigations for serum calcium and CaSR mutations in early childhood.

Clinical Approach to Hypocalcemia in Newborn Period and Infancy: Who Should Be Treated?

Introduction

Hypocalcemia is a common metabolic problem in newborn period and infancy. There is consensus on the treatment of the symptomatic cases while the calcium level at which the treatment will be initiated and the treatment options are still controversial in asymptomatic hypocalcemia.

Methods

This review article will cover hypocalcemia with specific reference to calcium homeostasis and definition, etiology, diagnosis, and treatment of hypocalcemia in newborn and infancy period.

Results

Hypocalcemia is defined as total serum calcium <8 mg/dL (2 mmol/L) or ionized calcium <4.4 mg/dL (1.1 mmol/L) for term infants or preterm infants weighing >1500 g at birth and total serum calcium <7 mg/dL (1.75 mmol/L) or ionized calcium <4 mg/dL (1 mmol/L) for very low birth weight infants weighing <1500 g. Early-onset hypocalcemia is generally asymptomatic; therefore, screening for hypocalcemia at the 24th and 48th hour after birth is warranted for infants with high risk of developing hypocalcemia. Late-onset hypocalcemia, which is generally symptomatic, develops after the first 72 h and toward the end of the first week of life. Excessive phosphate intake, hypomagnesemia, hypoparathyroidism, and vitamin D deficiency are commonest causes of late-onset hypocalcemia. Hypocalcemia should be treated according to etiology. Calcium replacement is the cornerstone of the treatment. Elementary calcium replacement of 40 to 80 mg/kg/d is recommended for asymptomatic newborns. Elementary calcium of 10 to 20 mg/kg (1–2 mL/kg/dose 10% calcium gluconate) is given as a slow intravenous infusion in the acute treatment of hypocalcemia in patients with symptoms of tetany or hypocalcemic convulsion.

Conclusion

Since most infants with hypocalcemia are usually asymptomatic, serum total or ionized calcium levels must be monitored in preterm infants with a gestational age <32 weeks, small for gestational age infants, infants of diabetic mothers, and infants with severe prenatal asphyxia with a 1 min Apgar score of <4. The treatment of hypocalcemia should be initiated immediately in infants with reduced calcium levels while investigating the etiology.

Synchrotron X-ray fluorescence mapping of Ca, Sr and Zn at the neonatal line in human deciduous teeth reflects changing perinatal physiology

OBJECTIVES

Our first objective was to review the evidence describing the appearance and microstructure of the neonatal line in human deciduous teeth and to link this with known changes in neonatal physiology occurring at and around birth. A second objective was to explore ways to improve identification of the neonatal line by mapping the pre- and postnatal distribution of Ca, Sr and Zn in deciduous cuspal enamel and superimposing these maps onto transmitted light micrographs that included a clear true section of the neonatal line.

MATERIALS AND METHODS

We used synchrotron X-ray fluorescence to map elemental distributions in pre- and postnatal enamel and dentine. Two deciduous canines and 5 deciduous molars were scanned with an X-ray beam monochromatised to 17.0 keV at either 10.0, 2.5 or 1.0 μm resolution and 10 ms integration time.

RESULTS

Calcium maps distinguished enamel and dentine but did not clearly demarcate tissues formed pre- or postnatally. Strontium maps reflected presumed pre- and postnatal maternal serum levels and what are likely to be diet-dependent regions of Sr enrichment or depletion. Prenatal Zn maps, particularly for dentine, mirror elevated levels in the fetus and in colostrum during the first few days of life.

CONCLUSIONS

The neonatal line, enamel dentine junction and surface enamel were all Zn-rich. Within the neonatal line Zn may be associated with increased crystallinity but also with caries resistance, both of which have been reported previously. Elemental mapping may improve the identification of ambiguous NNLs and so be useful in forensic and archaeological studies.

Intrauterine Growth Restriction: Postnatal Monitoring and Outcomes

Intrauterine growth restriction (IUGR) is an important cause of fetal, perinatal and neonatal morbidity and mortality. IUGR occurs because of multiple reasons. Neonates with IUGR experience acute problems in the perinatal and early neonatal period that can be life-threatening. The unfavorable uterine environment causing growth restriction results in programming that predisposes IUGR infants to long-term health issues such as poor physical growth, metabolic syndrome, cardiovascular disease, neurodevelopmental impairment and endocrine abnormalities, warranting careful monitoring. It is imperative to strike the balance between achieving optimal catch-up to promote normal development, while preventing the onset of cardiovascular and metabolic disorders in the long-term.

Standards of care for hypoparathyroidism in adults: a Canadian and International Consensus

PURPOSE

To provide practice recommendations for the diagnosis and management of hypoparathyroidism in adults.

METHODS

Key questions pertaining to the diagnosis and management of hypoparathyroidism were addressed following a literature review. We searched PubMed, MEDLINE, EMBASE and Cochrane databases from January 2000 to March 2018 using keywords 'hypoparathyroidism, diagnosis, treatment, calcium, PTH, calcidiol, calcitriol, hydrochlorothiazide and pregnancy'. Only English language papers involving humans were included. We excluded letters, reviews and editorials. The quality of evidence was evaluated based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. These standards of care for hypoparathyroidism have been endorsed by the Canadian Society of Endocrinology and Metabolism.

RESULTS

Hypoparathyroidism is a rare disease characterized by hypocalcemia, hyperphosphatemia and a low or inappropriately normal serum parathyroid hormone level (PTH). The majority of cases are post-surgical (75%) with nonsurgical causes accounting for the remaining 25% of cases. A careful review is required to determine the etiology of the hypoparathyroidism in individuals with nonsurgical disease. Hypoparathyroidism is associated with significant morbidity and poor quality of life. Treatment requires close monitoring as well as patient education. Conventional therapy with calcium supplements and active vitamin D analogs is effective in improving serum calcium as well as in controlling the symptoms of hypocalcemia. PTH replacement is of value in lowering the doses of calcium and active vitamin D analogs required and may be of value in lowering long-term complications of hypoparathyroidism. This manuscript addresses acute and chronic management of hypoparathyroidism in adults.

MAIN CONCLUSIONS

Hypoparathyroidism requires careful evaluation and pharmacologic intervention in order to improve serum calcium and control the symptoms of hypocalcemia. Frequent laboratory monitoring of the biochemical profile and patient education is essential to achieving optimal control of serum calcium.

Three cases of transient neonatal pseudohypoparathyroidism

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.

Life-threatening Dilated Cardiomyopathy Induced by Late-onset Neonatal Hypocalcemia

Neonatal seizures caused by hypocalcemia may be associated with cardiopulmonary dysfunction and may require specific management other than calcium supplementation. Severe dilated cardiomyopathy is an extremely rare complication in neonatal hypocalcemia and often results in high morbidity and mortality. We report here a 14-day-old neonate presenting with a gradually increasing frequency of tonic seizures. After admission, arterial desaturation was found despite supplying oxygen (4 L/min) through nasal prongs and the patient developed life-threatening respiratory distress and heart failure secondary to dilated cardiomyopathy. His critical cardiopulmonary derangements rapidly improved after respiratory support, the administration of diuretic and inotropic drugs, and the correction of his hypocalcemia and hypomagnesemia. The patient responded to treatment and was well during the 1-year follow-up period. We present this unique case history of seizure, respiratory distress, and heart failure induced by transient hypocalcemia to remind clinicians about the importance of this rare, life-threatening, but reversible, disorder.

Delayed Introduction of Parenteral Phosphorus Is Associated with Hypercalcemia in Extremely Preterm Infants

BACKGROUND

Early parenteral nutrition (PN) provides essential macro- and micronutrients for extremely low birth weight (ELBW) infants <1000 g. Frequent cases of hypercalcemia [whole blood ionized calcium (iCa) > 1.45 mmol/L] in the first week of life while receiving PN solutions at our large quaternary center prompted investigation and 2 plan-do-study-act (PDSA) cycles to reduce rates of hypercalcemia.

OBJECTIVE

We compared 2 cohorts of ELBW infants separated by PDSA cycles to evaluate and reduce the incidence of abnormal iCa concentration.

METHODS

Data were recorded for 150 premature infants with mean birth weight of 726 ± 164 g, 48% male, and mean gestational age of 26 ± 2.1 wk. This process included an internal practice analysis and PDSA cycles monitored prospectively over 3 y. From December 2011 to September 2012, 66 infants received 0-1.2 mmol parenteral phosphorus supplementation/(kg ⋅ d) beginning at 72 h of life. In the second protocol, 84 infants born September 2012 to July 2013 received earlier phosphorus supplementation within 24 h of life. The peak whole blood iCa and serum phosphorus concentrations in the first week of life were monitored.

RESULTS

Early introduction of phosphorus was significantly associated with a decreased mean peak iCa (1.64 ± 0.27 mmol/L to 1.50 ± 0.23 mmol/L, P = 0.001), and the incidence of severe hypercalcemia (iCa > 1.60 mmol/L) decreased from 50.0% to 21.4% (P = 0.002) in the first week of life. There was no difference in mortality, bronchopulmonary dysplasia, renal calcifications, seizures within 7 d of birth, brain calcifications, or intracranial hemorrhage between cohorts.

CONCLUSION

Early introduction of phosphorus in PN solutions is associated with reduced incidence of whole blood iCa abnormalities in the first week of life and should be considered for ELBW infants. Ongoing evaluation of optimal mineral provision to this population after birth should be performed.

Management of hypoparathyroidism in pregnancy and lactation - A report of 10 cases

INTRODUCTION

Hypoparathyroidism in pregnancy is rare, but important, as it is associated with maternal morbidity and foetal loss. There are limited case reports and no established management guidelines. Optimal maintenance of calcium levels during pregnancy is required to minimise the risk of related complications. This study aims to identify causes and examine outcomes of hypoparathyroidism in pregnancy in a cohort of women delivering at a large referral centre.

DESIGN AND METHOD

The Monash Health maternity service database captures pregnancy and birthing outcomes in over 9000 women each year. We audited this database between 2000 and 2014 to examine the clinical course, treatment and outcomes of pregnant women with hypoparathyroidism.

RESULTS

We identified 10 pregnancies from 6 women with pre-existing hypoparathyroidism secondary to idiopathic hypoparathyroidism (n = 3), autosomal dominant branchial arch disorder with hypoparathyroidism (n = 3) and autosomal dominant hypocalcaemia (n = 1), surgery for thyroid cancer (n = 2) and Graves' disease (n = 1). Maternal calcium levels were monitored through pregnancy and management adjusted to maintain normocalcaemia. One woman was delivered by caesarean section at 34 weeks' gestation because of intrauterine growth restriction, and oligohydramnios complicated two other pregnancies. The postpartum period was complicated by severe hypercalcaemia in one woman and by symptomatic, labile serum calcium levels during lactation in another woman, requiring close monitoring over a 6 month period.

CONCLUSION

Although rare, hypoparathyroidism in pregnancy poses a management challenge for clinicians, and co-ordinated care is required by obstetricians and endocrinologists to ensure optimal outcomes for both mother and baby. Continued monitoring of maternal calcium levels during lactation and weaning is essential to avoid the potential complications of either hypercalcaemia or hypocalcaemia.

Clinical and laboratory characteristics of neonatal hypocalcemia

PURPOSE

To describe the clinical characteristics of full-term neonates with hypocalcemia and to suggest factors associated with neonatal hypocalcemia.

METHODS

The medical records of full-term neonates with hypocalcemia were reviewed. Hypocalcemia was defined as an ionized calcium (iCa) concentration of <4 mg/dL. Parathyroid hormone (PTH) insufficiency was defined as a serum PTH level of <60 pg/mL or a serum phosphorus level higher than the serum calcium level in the presence of hypocalcemia.

RESULTS

Fifty-three neonates were enrolled. The median age at diagnosis of hypocalcemia was 3 days. In all the neonates, formula feeding predominance was observed. Thirty-eight neonates (69.8%) were compatible with PTH insufficiency. The number of formula-fed neonates was significantly higher than that of breast-fed patients among neonates with PTH insufficiency (P=0.017). Intact PTH was negatively correlated with serum phosphorus levels. Twelve out of 14 neonates (85.7%) had 25-hydroxy vitamin D (25OHD) levels <20 ng/mL and 9 neonates (64.3%) had 25OHD levels <10 ng/mL. Twenty-one neonates had hypocalcemic tetany. The serum calcium and iCa concentrations of neonates with tetany were 4.2-8.3 mg/dL and 1.85-3.88 mg/dL, respectively. Three neonates showed symptomatic hypocalcemia with calcium levels over 7.5 mg/dL. Among the 16 neonates who underwent electroencephalography (EEG), 12 had abnormalities, which normalized after 1-2 months.

CONCLUSION

Formula milk feeding, PTH insufficiency and low serum vitamin D concentration are associated with the development of neonatal hypocalcemia. Symptoms such as tetany and QT interval prolongation can develop in relatively mild hypocalcemia. Moreover, transient neonatal hypocalcemia can cause transient EEG abnormalities.

Neonatal hypocalcemic seizures due to excessive maternal calcium ingestion

Hypocalcemia is a common, treatable cause of neonatal seizures. A term girl neonate with no apparent risk factors developed seizures on day 5 of life, consisting of rhythmic twitching of all extremities in a migrating pattern. Physical examination was normal except for jitteriness. Laboratory evaluation was unremarkable except for decreased total and ionized serum calcium levels and an elevated serum phosphorus level. The mother had ingested 3-6 g of calcium carbonate daily during the final 4 months of pregnancy to control morning sickness. The baby's electroencephalogram showed multifocal interictal sharp waves and intermittent electrographic seizures consisting of focal spikes in the left hemisphere accompanied by rhythmic jerking of the right arm and leg. Treatment with intravenous calcium gluconate over several days resulted in cessation of seizures and normalization of serum calcium. The child has remained seizure free and is normal developmentally at 9 years of age. Hypocalcemic seizures in this newborn were likely secondary to excessive maternal calcium ingestion, which led to transient neonatal hypoparathyroidism and hypocalcemia. Inquiry about perinatal maternal medication use should include a search for over-the-counter agents that might not be thought of as "drugs," as in this case, antacids.

Perinatal and early postnatal factors underlying developmental delay and disabilities

A delay in meeting developmental milestones may be secondary to perinatal events, involving complicated interactions between mother and fetus during delivery. Maternal factors including weight, diet, and morbidities can affect neonatal adaptation and later development. Prematurity, low birth weight, and previous intrauterine insults as well as complications during delivery of a previously normal fetus increase the risk for perinatal stress. In this article, the literature on perinatal and early postnatal factors that underlie risks for developmental delay and disabilities is reviewed. Studies that concern neuroprotective therapies and prediction of long-term neurologic outcome by clinical examination, neuroimaging techniques, and electroencephalographic studies are reviewed as well.

A temporary decrease in mineral density in perinatal mouse long bones

Fetal and postnatal bone development in humans is traditionally viewed as a process characterized by progressively increasing mineral density. Yet, a temporary decrease in mineral density has been described in the long bones of infants in the immediate postnatal period. The mechanism that underlies this phenomenon, as well as its causes and consequences, remain unclear. Using daily μCT scans of murine femora and tibiae during perinatal development, we show that a temporary decrease in tissue mineral density (TMD) is evident in mice. By monitoring spatial and temporal structural changes during normal growth and in a mouse strain in which osteoclasts are non-functional (Src-null), we show that endosteal bone resorption is the main cause for the perinatal decrease in TMD. Mechanical testing revealed that this temporary decrease is correlated with reduced stiffness of the bones. We also show, by administration of a progestational agent to pregnant mice, that the decrease in TMD is not the result of parturition itself. This study provides a comprehensive view of perinatal long bone development in mice, and describes the process as well as the consequences of density fluctuation during this period.

Transient neonatal hypocalcemia: presentation and outcomes

OBJECTIVE

To determine the incidence of moderate-to-severe transient neonatal hypocalcemia in term neonates and to describe the characteristics of affected infants and the outcomes of their management.

METHODS

We reviewed medical records of all term infants <31 days of age who presented to Children's Medical Center Dallas from 2001 to 2009 with hypocalcemia (ionized calcium <1.00 mmol/L [4.00 mg/dL]).

RESULTS

Seventy-eight infants met criteria. Median (interquartile range) age at admission was 8.0 (7.0-10.0) days, and median duration of admission was 3.0 (2.0-4.0) days. Most infants were male (71.8%) and Hispanic (62.8%). Neonates were generally severely hypocalcemic and hyperphosphatemic. Seventy-five of 78 were hypomagnesemic, and the majority had low or inappropriately normal parathyroid hormone responses. Levels of 25-hydroxyvitamin D were ≤ 62.4 nmol/L (25 ng/mL) in all 42 infants in whom they were determined. All infants responded to therapy of limited duration with 1 or more of the following: calcium supplements, calcitriol, low phosphorus formula, and magnesium supplementation. Neuroimaging did not affect management decisions in any neonate.

CONCLUSIONS

Moderate-to-severe late-onset neonatal hypocalcemia is more common in Hispanic and male infants, is often a sign of coexistent vitamin D insufficiency or deficiency and hypomagnesemia, and is readily managed with therapy of limited duration. Neonates presenting with seizures who are found to be hypocalcemic are unlikely to benefit from neuroimaging evaluations.

Changes in serum parathyroid hormone-related protein in breastfed preterm infants

BACKGROUND

Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcemia. In a previous study we have demonstrated high concentrations of PTHrP in both term and preterm human milk (HM). PTHrP intestinal absorption and its influence upon calcium homeostasis of the preterm infant have not been studied yet. This study assessed the correlation between PTHrP concentrations in preterm HM and PTHrP in maternal and neonatal serum.

STUDY DESIGN

We collected samples of expressed HM obtained from 16 mothers of preterm infants (25-34 weeks of gestation) and drew blood samples from both mothers and infants on postpartum days 2 and 10. PTHrP concentrations were measured by two-site immunoradiometric assay. Blood calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP) concentrations were also measured.

RESULTS

Neither maternal nor neonatal PTHrP serum concentrations varied significantly after 10 days of breastfeeding. There was a correlation between PTHrP concentrations in maternal serum and HM concentrations (R² = 0.24, p = 0.04), but not between HM and neonatal serum concentrations or between PTHrP concentrations in HM and preterm serum concentrations of Ca, P, and ALP.

CONCLUSIONS

Despite high concentrations of PTHrP in preterm HM, serum concentrations of PTHrP of breastfed preterm infants did not increase over time. There was no correlation between PTHrP concentrations in HM and neonatal serum Ca concentration.

Hypercalcemia in extremely low birth weight neonates

Hypercalcemia is rare in neonates but may be associated with hypophosphatemia in Extremely low birth weight (ELBW) neonates who are on parenteral nutrition without adequate phosphate supplementation.

Perinatal endocrinology: common endocrine disorders in the sick and premature newborn

Endocrine disorders are common in infants in the neonatal ICU. They often are associated with prematurity, low birth weight or very low birth weight, and small size for gestational age. They also frequently occur in infants who are critically ill or stressed. This article describes the most common conditions and current knowledge regarding management.

MafB interacts with Gcm2 and regulates parathyroid hormone expression and parathyroid development

Serum calcium and phosphate homeostasis is critically regulated by parathyroid hormone (PTH) secreted by the parathyroid glands. Parathyroid glands develop from the bilateral parathyroid-thymus common primordia. In mice, the expression of transcription factor Glial cell missing 2 (Gcm2) begins in the dorsal/anterior part of the primordium on embryonic day 9.5 (E9.5), specifying the parathyroid domain. The parathyroid primordium then separates from the thymus primordium and migrates to its adult location beside the thyroid gland by E15.5. Genetic ablation of gcm2 results in parathyroid agenesis in mice, indicating that Gcm2 is essential for early parathyroid organogenesis. However, the regulation of parathyroid development at later stages is not well understood. Here we show that transcriptional activator v-maf musculoaponeurotic fibrosarcoma oncogene homologue B (MafB) is developmentally expressed in parathyroid cells after E11.5. MafB expression was lost in the parathyroid primordium of gcm2 null mice. The parathyroid glands of mafB(+/-) mice were mislocalized between the thymus and thyroid. In mafB(-/-) mice, the parathyroid did not separate from the thymus. Furthermore, in mafB(-/-) mice, PTH expression and secretion were impaired; expression levels of renal cyp27b1, one of the target genes of PTH, was decreased; and bone mineralization was reduced. We also demonstrate that although Gcm2 alone does not stimulate the PTH gene promoter, it associates with MafB to synergistically activate PTH expression. Taken together, our results suggest that MafB regulates later steps of parathyroid development, that is, separation from the thymus and migration toward the thyroid. MafB also regulates the expression of PTH in cooperation with Gcm2.

Hypoparathyroidism in pregnancy

Pregnancy and lactation are associated with remarkable changes in calcium homeostasis, resulting from pregnancy-induced alterations in the production, metabolism and excretion of calcium and calcitropic hormones. Therefore, the clinical course of disorders affecting the parathyroid glands during pregnancy and lactation is often atypical. As the symptoms experienced by patients with parathyroid disorders are not specific, their diagnosis during gestation and breastfeeding may be sometimes very difficult. If left untreated, parathyroid disorders may pose a significant risk to the mother and fetus associated with increased perinatal and maternal morbidity and mortality. Hypoparathyroidism is a disorder rarely observed during pregnancy, resulting in most cases from surgical thyroidectomy. In our article, we present the case of a 32-year-old female with primary hypoparathyroidism diagnosed for the first time during pregnancy. We describe in details the treatment strategies undertaken in this patient and their impact on the outcome of pregnancy and lactation.

Neonatal hyperparathyroidism with a heterozygous calcium-sensing receptor (CASR) R185Q mutation: clinical benefit from cinacalcet

Neonatal hyperparathyroidism can be caused by a heterozygous inactivating mutation in the calcium-sensing receptor. Calcimimetics, allosteric activators of the calcium-sensing receptor, may provide an effective means of reducing PTH secretion in such patients. OBJECTIVE/PATIENT: The objective of the study was to identify the molecular defect and to monitor the postnatal course of a 1-wk-old infant with elevated blood ionized calcium, serum PTH, and alkaline phosphatase and low calcium excretion. The parents were normocalcemic.

METHODS

CASR gene mutation analysis was performed on genomic DNA of the proband and her parents. The infant was treated initially with pamidronate and then cinacalcet.

RESULTS

A heterozygous mutation (R185Q, CGA > CAA) in exon 4 of the CASR gene was identified in the proband. The CASR gene of both parents was normal. At 1 wk of age, iv fluids and furosemide were initiated, but hypercalcemia, hyperparathyroidism, and low calcium excretion persisted. At 2 wk of age, a single iv dose of pamidronate resulted in hypocalcemia and further increase in PTH levels, but hypercalcemia recurred within 1 wk. At 3 wk of age, a single oral dose of cinacalcet resulted in decreased PTH levels at 2 h; blood-ionized calcium reached a nadir at 10 h. Three days later daily cinacalcet was initiated, resulting in normalization of ionized calcium. The suppression of serum PTH and reduction in total serum calcium was maintained long term.

CONCLUSIONS

In neonatal hyperparathyroidism secondary to presumed de novo heterozygous CASR mutation, treatment with cinacalcet decreases PTH secretion and serum calcium levels and mitigates the need for parathyroidectomy.

Dietary calcium restriction affects mesenchymal stem cell activity and bone development in neonatal pigs

The effects of dietary calcium (Ca) deficiency on skeletal integrity are well characterized in growing and mature mammals; however, less is known about Ca nutrition during the neonatal period. In this study, we examined the effects of neonatal Ca nutrition on bone integrity, endocrine hormones, and mesenchymal stem cell (MSC) activity. Neonatal pigs (24 ± 6 h of age) received either a Ca-adequate (1.2 g/100 g) or an ~40% Ca-deficient diet for 18 d. Ca deficiency reduced (P < 0.05) bone flexural strength and bone mineral density without major differences in plasma indicators of Ca status. There were no meaningful differences in plasma Ca, phosphate (PO(4)), parathyroid hormone, or 1,25-dihydroxycholecalciferol due to Ca nutrition throughout the study. Calcium deficiency also reduced (P < 0.05) the in vivo proliferation of MSC by ~50%. In vitro studies utilizing homologous sera demonstrated that MSC activity was affected (P < 0.05) by both the Ca status of the pig and the sera as well as by their interaction. The results indicate that neonatal Ca nutrition is crucial for bone integrity and suggest that early-life Ca restriction may have long-term effects on bone integrity via programming of MSC.

Neonatal outcomes in a population of late-preterm infants

The late-preterm infants are a group of premature steadily increasing, different from term infants as immature in terms of respiratory, metabolic, neurological, and immunological features. They may present at birth and during the first week of life various diseases and brain lesions echographically evident. We analyzed the neonatal outcomes of 417 late-preterm infants, born in our Department of Neonatology in a period of two and a half years, evaluating respiratory problems (RDS, transient tachypnea, pneumonia, pneumothorax, and apnea), metabolic problems (hypoglycemia, hypomagnesemia, hypo-hypernatremia, dehydration, hypocalcemia, and hyperbilirubinemia), infections, neurological symptoms associated with electrolyte disturbances, the disease patterns observed by ultrasound examination of the brain, the kidney ultrasound images, genital malformations.

Parathyroid hormone-related protein in preterm human milk

BACKGROUND

Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcemia. High concentrations of PTHrP are found in human breastmilk of mothers of term-infants. It is not known whether PTHrP is excreted in preterm human milk. This study tested the hypothesis that PTHrP concentrations in milk obtained from mothers of preterm infants are similar to those found in milk from mothers of term infants.

METHODS

We collected samples of expressed human milk obtained from 27 mothers of preterm infants (27-34 weeks' gestation) and from 16 mothers of full-term infants. Samples were collected within the first 72 hours postpartum (colostrum) and again at 1 and 2 weeks postpartum. PTHrP concentrations in these samples were measured by two-site immunoradiometric assay.

RESULTS

PTHrP concentrations were significantly higher in samples obtained after 1 week postpartum than in samples obtained during the first 72 hours of life in breastmilk obtained from mothers of both term and preterm infants (P < 0.0001). PTHrP concentrations were similar in colostrum and after 1 week in term and preterm milk. PTHrP concentrations after 2 weeks of lactation were significantly higher in samples obtained from mothers of term infants (P < 0.006).

CONCLUSION

Human milk expressed by mothers of preterm infants contains amounts of PTHrP similar to those measured in milk expressed by mothers of term infants.

Parathyroid surgery in pregnancy: review of the literature and localization by aspiration for parathyroid hormone levels

OBJECTIVE

To review the management of primary hyperparathyroidism in pregnant women by focusing on the use of preoperative localization procedures and minimally invasive parathyroid surgery during pregnancy.

STUDY DESIGN

We report the clinical course of two pregnant women with severe hypercalcemia due to primary hyperparathyroidism, as well as review the literature.

RESULTS

Primary hyperparathyroidism in pregnant women is associated with high prevalence of maternal and neonatal complications. In women, with severe hypercalcemia, parathyroid surgery during pregnancy reduces fetal and maternal morbidities. Preoperative localization of parathyroid adenomas during pregnancy remains challenging. In selected cases aspiration of nodules suspected of being parathyroid adenomas with the measurement of the parathyroid hormone (PTH) from the aspirate can localize the adenoma, and allow the surgeon to carry out a minimally invasive parathyroidectomy.

CONCLUSION

Localization of a suspected parathyroid adenoma by ultrasound-guided aspiration of a lesion and the measurement of the PTH has previously been described in non-pregnant women. Our review of the literature did not identify any previous case of a pregnant woman with primary hyperparathyroidism, where preoperative localization of a parathyroid adenoma was accomplished by aspiration of a suspected lesion followed by a successful minimally invasive parathyroidectomy carried out during pregnancy.

The physiologic development of fetuin-a serum concentrations in children

Fetuin-A prevents tissue calcification by forming soluble complexes with calcium and phosphate. A pathological depletion of serum fetuin-A has been observed in children on dialysis or after renal transplantation but knowledge on physiologic age-related changes in serum fetuin-A is limited. We prospectively evaluated serum fetuin-A in 133 infants and children, ranging from very low birth weight infants to adolescents. Highest serum fetuin-A levels were present between 23 and 30 wk of gestation (1 +/- 0.33 mg/mL). Thereafter, the values decreased. This decrease was linked to biological rather than chronological age. At 32 to 36 and 37 to 40 wk of gestation, the serum fetuin-A concentration was 0.63 +/- 0.26 and 0.63 +/- 0.21 mg/mL, respectively. Thereafter, the concentrations remained stable until adolescence at 0.58 +/- 0.12 mg/mL. Intercurrent infections were associated with a transient decrease of serum fetuin-A levels. The high serum fetuin-A concentrations in preterm children suggest that fetuin-A is of high physiologic impact for the fetal and the preterm-born organism, showing extensive tissue formation. This might point to a new mechanism contributing to organ damage in these patients, comparable with children on dialysis.

Perinatal endocrinology: common endocrine disorders in the sick and premature newborn

Endocrine disorders are common in infants in the neonatal ICU. They often are associated with prematurity, low birth weight or very low birth weight, and small size for gestational age. They also frequently occur in infants who are critically ill or stressed. This article describes the most common conditions and current knowledge regarding management.

Metabolic Bone Disease in preterm newborn: an update on nutritional issues

Osteopenia, a condition characterised by a reduction in bone mineral content, is a common disease of preterm babies between the tenth and sixteenth week of life. Prematurely born infants are deprived of the intrauterine supply of minerals affecting bone mineralization.The aetiology is multifactorial: inadequate nutrients intake (calcium, phosphorus and vitamin D), a prolonged period of total parenteral nutrition, immobilisation and the intake of some drugs.The diagnosis of metabolic bone disease is done by biochemical analysis: low serum levels of phosphorus and high levels of alkaline phosphatase are suggestive of metabolic bone disease. The disease can remain clinically silent or presents with symptoms and signs of rachitism depending on the severity of bone demineralisation.An early nutritional intervention can reduce both the prevalence and the severity of osteopenia.This article reviews the pathophysiology of foetal and neonatal bone metabolism, focuses on the nutrient requirements of premature babies and on the ways to early detect and treat osteopenia.

Transient pseudohypoparathyroidism as a cause of late-onset hypocalcemia in neonates and infants

BACKGROUND/PURPOSE

Transient pseudohypoparathyroidism is a rare cause of late-onset hypocalcemia in neonates and infants. The purpose of this study was to investigate the clinical presentation and natural course of transient pseudohypoparathyroidism in neonates and infants.

METHODS

From 1995 to 2006, 21 patients under 3 months of age were admitted to our department because of late-onset neonatal hypocalcemia. Among these, five were noted to have transient hypocalcemia, hyperphosphatemia and elevated serum parathyroid hormone levels. Their clinical data, biochemical findings and natural course were thoroughly analyzed.

RESULTS

All five patients were boys with increased neuromuscular irritability as their initial clinical manifestation. Initial biochemical data showed calcium 1.5 +/- 0.16 mmol/L, phosphorus 9.6 +/- 1.5 mg/dL, intact parathyroid hormone 182 +/- 93 pg/mL and tubular reabsorption of phosphorus 94.8 +/- 3.7%. Two of the patients had magnesium deficiency. After reduction of phosphorus intake and supplementation with calcium and/or magnesium as indicated, the biochemical derangements resolved in 28 +/- 3 days.

CONCLUSION

Neuromuscular irritability is usually the initial clinical presentation of transient pseudohypoparathyroidism. Aside from delayed renal maturation, pseudohypoparathyroidism is also caused by magnesium deficiency. Such a disturbance usually resolves before 3 months of age.

Hypocalcemia is common in the first 48 h of life in ELBW infants

BACKGROUND

The incidence of early hypocalcemia in extremely low birthweight (ELBW) infants is unknown because the distribution of serum calcium values in this population is not defined.

OBJECTIVE

To determine the range of serum calcium values in ELBW infants during the first 48 h of life and the risks associated with low values.

DESIGN/METHODS

Retrospective analysis of all ELBW infants admitted on day 1 of life from April 2004 to October 2006. Demographic variables, therapy, serum calcium (Ca), pH, albumin, and blood ionized Ca were recorded.

RESULTS

There were 381 Ca levels obtained from 111 patients. Mean Ca was 6.90 mg/dL (1.73 mmol/L) (5(th)-95(th) percentile: 5.16-8.80). Ca levels rose after 24 h of life. Almost one quarter (23.1%) of the Ca levels were low by current standards. The majority of subjects (59.9%) had at least one hypocalcemic value.

CONCLUSIONS

Serum Ca values are lower in ELBW infants and inconsequential. Thus, hypocalcemia should be re-defined for ELBW infants.

Serum calcium values in term and late-preterm neonates receiving gentamicin

Since noting an apparent increase in hypocalcemia in neonates receiving gentamicin every 24 h (q 24 h) for > or = 4 days, we have prospectively monitored serum calcium (Ca) values in these patients receiving prolonged gentamicin therapy. This study is a retrospective analysis of those values measured during gentamicin treatment. The study included neonates with gestational age > or = 35 weeks who received > or = 4 days of gentamicin therapy and in whom at least one serum Ca value was measured > or = 47 h after initiation of therapy. Hypocalcemia was defined as a serum Ca level < 8 mg/dl (2 mmol/l). Data were analyzed by Student t-test, chi-square test, and Pearson product moment correlation. There were 1,624 neonates that met the study criteria. Ca was < 8 mg/dl in 241 (15%). Ca < 8 mg/dl was more likely in boys than in girls (16.4% vs 11.8%, P = 0.01) and in neonates < 37 weeks gestational age (GA) than in those > or = 37 weeks GA (23.9% vs 14.1%, P = 0.01). A second Ca value was obtained in 883 neonates (54%); 23.2% of neonates with initial Ca < 8 mg/dl remained hypocalcemic, and 30% of these were receiving oral Ca supplementation. The second Ca value was < 8 mg/dl in eight neonates in whom initial Ca was > or = 8 mg/dl. Hypocalcemia is not uncommon in neonates receiving gentamicin therapy, and it may occur more frequently in boys and late-preterm infants. These data suggest that the monitoring of serum Ca levels should be considered when gentamicin is given > or = 4 days.

Neonatal hypocalcemic seizures in siblings exposed to topiramate in utero

We describe two siblings with neonatal hypocalcemic seizures whose mother took topiramate during both pregnancies. Apart from hypocalcemia, the patients had no identifiable etiology for their seizures. Although biochemical data suggested that the hypocalcemia was caused by hypoparathyroidism, no disorders typically associated with this condition were identified in the patients. We propose that topiramate exposure in utero led to hypoparathyroidism and subsequent hypocalcemia via effects on protein kinase A signaling, resulting in hypocalcemic seizures. Neonates exposed to topiramate in utero should be monitored for hypocalcemic seizures.

The relationship between birthweight, 25-hydroxyvitamin D concentrations and bone mineral status in neonates

BACKGROUND

Calcium (Ca), phosphorus (P) and 25-hydroxyvitamin D (25-OHD) are the major micronutrients for fetal skeletal development.

AIMS

To compare whole body bone mineral density (WB BMD) and bone mineral content (WB BMC) in different birthweights of term neonates and to determine correlations of biological criteria of bone health between neonates and their mothers.

SUBJECTS AND METHODS

Serum Ca, P, alkaline phosphatase (ALP) and 25-OHD levels were measured in 30 small-for-gestational-age (SGA, group 1), 40 appropriate-for-gestational-age (AGA, group 2) and 30 large-for-gestational-age (LGA, group 3) neonates and their mothers in winter. WB BMD and WB BMC of neonates were estimated by dual-energy X-ray absorptiometry (DEXA) in the 1st 24 hrs after delivery.

RESULTS

Mean (SD) serum 25-OHD levels in the mothers [8.7 (3.0), 8.6 (3.0) and 7.7 (2.8) microg/L, respectively] and their infants [6.3 (2.5), 6.0 (2.2) and 5.7 (1.8) microg/L, respectively] in groups 1, 2 and 3 were similar. Compared with the mothers, the mean 25-OHD levels of the neonates in all groups were significantly lower (p<0.05), and they were highly correlated (r=0.755, p<0.05). Ninety-three per cent of the neonates and 82% of their mothers had 25-OHD levels <10 microg/L, the lowest limit of normal. Mean (SD) WB BMD and WB BMC were higher in LGA infants [0.442 (0.025) g/cm(2), 71.6 (9.0) g, p<0.01, p<0.001, respectively] but lower in SGA [0.381 (0.027) g/cm(2), 29.1 (9.1) g, p<0.001, p<0.001, respectively] than in AGA infants [0.426 (0.022) g/cm(2), 53.7 (9.6) g, respectively]. The percentage of WB BMC was lower in SGA than in AGA and LGA infants. WB BMC and WB BMD were positively correlated with birthweight (r=0.910, p<0.05) and gestational age (r=0.707, p<0.05) but not with serum 25-OHD.

CONCLUSIONS

The neonates' bone indices increased significantly with gestational age and birthweight but this was not related to serum 25-OHD levels in the infants and their mothers.

Prevention and treatment of infant and childhood vitamin D deficiency in Australia and New Zealand: a consensus statement

Vitamin D deficiency has re-emerged as a significant paediatric health issue, with complications including hypocalcaemic seizures, rickets, limb pain and fracture. A major risk factor for infants is maternal vitamin D deficiency. For older infants and children, risk factors include dark skin colour, cultural practices, prolonged breastfeeding, restricted sun exposure and certain medical conditions. To prevent vitamin D deficiency in infants, pregnant women, especially those who are dark-skinned or veiled, should be screened and treated for vitamin D deficiency, and breastfed infants of dark-skinned or veiled women should be supplemented with vitamin D for the first 12 months of life. Regular sunlight exposure can prevent vitamin D deficiency, but the safe exposure time for children is unknown. To prevent vitamin D deficiency, at-risk children should receive 400 IU vitamin D daily; if compliance is poor, an annual dose of 150,000 IU may be considered. Treatment of vitamin D deficiency involves giving ergocalciferol or cholecalciferol for 3 months (1000 IU/day if < 1 month of age; 3000 IU/day if 1-12 months of age; 5000 IU/day if > 12 months of age). High-dose bolus therapy (300,000-500,000 IU) should be considered for children over 12 months of age if compliance or absorption issues are suspected.

Low vitamin D status in mother-newborn pairs in Greece

Adequate vitamin D status during pregnancy is crucial to assure normal fetal skeletal growth and to provide the vitamin D needed for infants' stores. To determine the actual situation in Greece, we evaluated serum 25-hydroxyvitamin D (25[OH]D), calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH), osteocalcin (OC), and calcitonin (CT) concentrations in 123 healthy mother-newborn pairs recruited from a public hospital of the sunny Athenian region. Blood samples were obtained from pregnant women at term and their neonates (cord blood). The study was conducted between June 2003 and May 2004. None of the mothers has been prescribed vitamin D supplements. Maternal 25(OH)D levels (16.4 [11-21.1] ng/mL) were significantly lower than umbilical venous blood concentrations (20.4 [13.9-30.4] ng/mL) (P < 0.001). A strong correlation was observed between maternal and infant 25(OH)D concentrations (r = 0.626, P < 0.001). Twenty-four (19.5%) mothers and 10 (8.1%) neonates had 25(OH)D <10 ng/mL. Pregnant women who delivered in summer and autumn reported higher levels of 25(OH)D (18.9 [12.9-23.3] ng/mL) than those who delivered in winter and spring (14.6 [10.1-18.5] ng/mL) (P = 0.006). Mothers with a darker phototype had lower levels of serum 25(OH) D than those with a fair phototype (P = 0.023). Umbilical venous blood Ca, P, OC, and CT levels were significantly higher than maternal venous blood levels (P < 0.001). PTH umbilical levels were lower than maternal levels (P < 0.001). Apparently, the abundant sunlight exposure in Athens is not sufficient to prevent hypovitaminosis D. Pregnant women should be prescribed vitamin D supplementations, and the scientific community should consider vitamin D supplementation of foods.

Subcutaneous fat necrosis of the newborn: be aware of hypercalcaemia

Subcutaneous fat necrosis of the newborn is an uncommon, self-limiting panniculitis that usually occurs in full-term infants as a consequence of perinatal asphyxia. The cutaneous involvement may be associated with metabolic complications such as hypoglycaemia, thrombocytopenia, hypertriglyceridemia, anemia and hypercalcaemia. The delayed onset of hypercalcaemia, 1-6 months after the development of the skin manifestations, imposes a prolonged follow-up to avoid its acute toxic effects on cardiovascular and renal systems and the more durable metastatic calcifications.