Oral bisphosphonate therapy for vitamin D intoxication of the infant

Vitamin D: sources, physiological role, biokinetics, deficiency, therapeutic use, toxicity, and overview of analytical methods for detection of vitamin D and its metabolites

Vitamin D has a well-known role in the calcium homeostasis associated with the maintenance of healthy bones. It increases the efficiency of the intestinal absorption of dietary calcium, reduces calcium losses in urine, and mobilizes calcium stored in the skeleton. However, vitamin D receptors are present ubiquitously in the human body and indeed, vitamin D has a plethora of non-calcemic functions. In contrast to most vitamins, sufficient vitamin D can be synthesized in human skin. However, its production can be markedly decreased due to factors such as clothing, sunscreens, intentional avoidance of the direct sunlight, or the high latitude of the residence. Indeed, more than one billion people worldwide are vitamin D deficient, and the deficiency is frequently undiagnosed. The chronic deficiency is not only associated with rickets/osteomalacia/osteoporosis but it is also linked to a higher risk of hypertension, type 1 diabetes, multiple sclerosis, or cancer. Supplementation of vitamin D may be hence beneficial, but the intake of vitamin D should be under the supervision of health professionals because overdosing leads to intoxication with severe health consequences. For monitoring vitamin D, several analytical methods are employed, and their advantages and disadvantages are discussed in detail in this review.

Subacute Gummy Vitamin Overdose as a Rare Manifestation of Child Neglect

ABSTRACT

We present a case of a 20-month-old girl who presented to the emergency department with anorexia, progressive weakness, and lethargy who was found to have severe hypercalcemia (20.7 mg/dL) and vitamin D hypervitaminosis. Further questioning revealed that this was secondary to a subacute toxic ingestion of "L'il Critters" calcium and vitamin D3 gummy vitamins that were being administered by the patient's mother multiple times a day for several weeks or even months. This occurred in the setting of child neglect due to the mother's mental illness. The patient required intensive care unit admission and had a prolonged hospital course complicated by hypomagnesemia, hyperphosphatemia, weight loss, and persistent weakness. Her hypercalcemia was initially refractory to standard treatment of intravenous fluids, prednisone, multiple trials of calcitonin, and zoledronic acid. Our patient had the highest calcium level we are aware of in a toddler and is the only case we know of that occurred as a result of a prolonged, intentional exposure in the setting of child neglect and a complex social situation. This case reviews the causes and management of hypercalcemia and vitamin D intoxication. It also highlights the need for a comprehensive social history and exposes the vulnerabilities of children living in homes afflicted by parental depression and severe mental illness.

Comparison of Treatment Regimens in Management of Severe Hypercalcemia Due to Vitamin D Intoxication in Children

OBJECTIVE

No large study has been conducted to date to compare the effectiveness of prednisolone, alendronate and pamidronate as first-line treatment in children with hypercalcemia due to vitamin D intoxication. The aim was to perform a multicenter, retrospective study assessing clinical characteristics and treatment results.

METHODS

A standard questionnaire was uploaded to an online national database system to collect data on children with hypercalcemia (serum calcium level >10.5 mg/dL) due to vitamin D intoxication [serum 25-hydroxyvitamin D (25(OH)D) level >150 ng/mL] who were treated in pediatric endocrinology clinics.

RESULTS

Seventy-four children [median (range) age 1.06 (0.65-1.60) years, 45 males (61%) from 11 centers] were included. High-dose vitamin D intake was evident in 77% of the cases. At diagnosis, serum calcium, phosphorus, alkaline phosphatase, 25(OH)D and parathyroid hormone concentrations were 15±3.2 mg/dL, 5.2±1.2 mg/dL, 268±132 IU/L, 322 (236-454) ng/mL, and 5.5 (3-10.5) pg/mL, respectively. Calcium levels showed moderate correlation with 25(OH)D levels (r_s=0.402, p<0.001). Patients were designated into five groups according to the initial specific treatment regimens (hydration-only, prednisolone, alendronate, pamidronate, and combination). Need for another type of specific drug treatment was higher in children who initially received prednisolone (p<0.001). Recurrence rate of hypercalcemia was significantly lower in children who were treated with pamidronate (p=0.02).

CONCLUSION

Prednisolone is less effective in the treatment of children with severe hypercalcaemia secondary to vitamin D intoxication and timely implementation of other treatment regimens should be considered.

A Pediatric Patient with a CYP24A1 Mutation: Four Years of Clinical, Biochemical, and Imaging Follow-Up

BACKGROUND

A female infant was admitted to hospital due to failure to thrive. She presented hypercalcemia (4.09 mmol/L, normal range: 2.2-2.65 mmol/L), high 25-hydroxyvitamin D (283 nmol/L, normal range: 75-250 nmol/L), 1,25-dihydroxyvitamin D in the upper normal range, and low parathyroid hormone. Vitamin D intoxication was suspected. The patient had received routine rickets prophylaxis.

METHODS

Williams-Beuren syndrome was genetically excluded. Sequencing of CYP24A1 showed 2 mutations: c.443T>C and c.1186C>T.

RESULTS

The patient's clinical status improved after intravenous rehydration, cessation of supplementation, and on a low-calcium diet. 25-Hydroxyvitamin D concentrations normalized within days, while 1,25-dihydroxyvitamin D remained in the upper normal range. We also investigated our patient's bone health.

CONCLUSION

The patient was hospitalized initially on suspicion of vitamin D intoxication but proved to be a case of compound heterozygosity. Data on the long-term clinical and biochemical evolution of patients with idiopathic infantile hypercalcemia are sparse. Our follow-up showed seasonal variations of vitamin D and calcium parameters, with no influence on kidney function or bone health for the investigated period.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describes the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Efficacy and safety of pamidronate in children with vitamin D intoxication

BACKGROUND

Bisphosphonates are used in the treatment of vitamin D intoxication (VDI) after failure of conventional therapy including prednisolone. Safety concerns restrict the use of bisphosphonates from being used as first-line therapy for VDI in children. The aim of this study was to evaluate the efficacy and safety of pamidronate in comparison with prednisolone in children with VDI.

METHODS

We reviewed the hospital records of children consecutively diagnosed with VDI at two medical centers in a 15 year period.

RESULTS

The subjects consisted of 21 children (age, 0.3-4.2 years) who were treated with prednisolone and/or bisphosphonates. Pamidronate (n = 18) or alendronate (n = 3) was used in six patients after unsuccessful prednisolone treatment, and in 15 patients from baseline. Initial serum calcium and 25-hydroxyvitamin D were 16.1 ± 1.9 mg/dL and 493 ± 219 ng/mL, respectively. The median time to reach normocalcemia in the pamidronate, alendronate and prednisolone groups was 3 days (range, 2-12 days), 4 days (range, 3-6 days) and 17 days (range, 12-26 days), respectively (P = 0.013). The pamidronate group had a fivefold shorter hospital stay than the prednisolone group. Three patients initially treated with prednisolone developed nephrocalcinosis but this did not occur in any patient treated with bisphosphonates from baseline. Apart from transient fever and moderate hypophosphatemia, no side-effect of bisphosphonate treatment was observed.

CONCLUSIONS

Pamidronate is efficient and safe for the treatment of VDI in children. Pamidronate use significantly shortens the duration of treatment, and thereby may prevent the development of nephrocalcinosis. Instead of prednisolone, pamidronate should be used together with hydration and furosemide as the first-line therapy for VDI.

Calcium and Phosphorous in Pediatric Parenteral Nutrition

Calcium (Ca) and phosphorus (P) are essential for various systemic functions, including bone mineralization. Adequate provision of Ca and P in pediatric parenteral nutrition (PN) solutions is necessary for skeletal growth and for the prevention of metabolic bone disease. The provision of adequate doses of Ca and P in pediatric PN solutions is complicated by the increased needs in preterm and term infants, solubility limitations, and venous access. Clinicians should be aware of the evidence that supports the optimal use of Ca and P in pediatric PN solutions, including studies that have evaluated dosing and solubility. The aim of this article is to review relevant literature and practices for the use of these two minerals in pediatric PN solutions. The vitamin D endocrine system, a critical component for Ca homeostasis and bone mineralization, is discussed, as well as clinical manifestations of metabolic bone disease and methods for its prevention, assessment, and treatment in pediatric patients receiving PN.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describe the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Vitamin D supplementation and risk of toxicity in pediatrics: a review of current literature

CONTEXT

Although vitamin D toxicity is rare in children, increased use of vitamin D formulations, re-examination of optimal vitamin D levels, and use of higher doses lend potential for an increased incidence of vitamin D toxicity.

EVIDENCE ACQUISITION

A PubMed search was conducted through May 2013 for cases of vitamin D intoxication and vitamin D trials in pediatrics. Safety data were collected and reviewed.

EVIDENCE SYNTHESIS

A small number of pediatric studies tested vitamin D doses at or above the currently recommended upper tolerable intake. In children and adolescents, vitamin D excess was rare and usually asymptomatic. Recent cases of intoxication relate to errors in manufacturing, formulation, or prescription; involve high total intake in the range of 240,000 to 4,500,000 IU; and present with severe hypercalcemia, hypercalciuria, or nephrocalcinosis. However, mild hypercalcemia and hypervitaminosis using currently recommended doses have been reported in infants with rickets.

CONCLUSIONS

Although rare, cases of vitamin D intoxication that present with dramatic life-threatening symptoms still occur in children. Moreover, recent studies in infants raise a potential need for monitoring vitamin D levels when doses at or above the currently recommended upper range are used. Further studies are needed to clarify these findings. The Drugs and Therapeutics Committee of the Pediatric Endocrine Society suggests obtaining serum 25-hydroxyvitamin D levels in infants and children who receive long-term vitamin D supplementation at or above the upper level intake that is currently recommended.

Vitamin D intoxication due to an erroneously manufactured dietary supplement in seven children

Pediatric cases of vitamin D intoxication (VDI) with dietary supplements have not been previously reported. We report on 7 children with VDI caused by consumption of a fish oil supplement containing an excessively high dose of vitamin D due to a manufacturing error. Seven children aged between 0.7 and 4.2 years were admitted with symptoms of hypercalcemia. Initial median (range) serum concentrations of calcium and 25-hydroxyvitamin D were 16.5 (13.4-18.8) mg/dL and 620 (340-962) ng/mL, respectively. Repeated questioning of the parents revealed use of a fish oil that was produced recently by a local manufacturer. Analysis of the fish oil by gas chromatography/mass spectrometry revealed that the vitamin D3 content was ~4000 times the labeled concentration. Estimated daily amounts of vitamin D3 intake varied between 266,000 and 800,000 IU. Patients were successfully treated with intravenous hydration, furosemide, and pamidronate infusions. With treatment, serum calcium returned to the normal range within 3 days (range: 2-7 days). Serum 25-hydroxyvitamin D levels normalized within 2 to 3 months. Complications, including nephrocalcinosis, were not observed throughout the 1-year follow-up. In conclusion, errors in manufacturing of dietary supplements may be a cause of VDI in children. Physicians should be aware of this possibility in unexplained VDI cases and repeatedly question the families about dietary supplement use. To prevent the occurrence of such unintentional incidents, manufacturers must always monitor the levels of ingredients of their products and should be rigorously overseen by governmental regulatory agencies, as is done in the pharmaceutical industry.

Medullary nephrocalcinosis in an adult patient with idiopathic infantile hypercalcaemia and a novel CYP24A1 mutation

Idiopathic infantile hypercalcaemia (IIH) is an autosomal recessively inherited disease, presented in the first year of life with hypercalcaemia, precipitated by normal amounts of vitamin D supplementation. Recently loss-of-function mutations in the CYP24A1 gene, which encodes the vitamin D-metabolizing enzyme 24-hydroxylase, have been found in these patients. We describe a young man homozygous for a novel missense mutation (c.628T>C) of the CYP24A1 gene. He had suffered from severe hypercalcaemia in early childhood. At age 29 he presented with medullary nephrocalcinosis, chronic kidney disease (CKD) stage 2, microalbuminuria, mild hypertension and nephrogenic diabetes insipidus. He had mild hypercalcaemia and moderate hypercalciuria. As a novel finding, fibroblast growth factor 23 (FGF23) was elevated.

Bisphosphonates use in children

Bisphosphonates are synthetic analogues of pyrophosphate that inhibit bone resorption by their action on osteoclasts. In recent years, bisphosphonates have been used in children for treatment of a growing number of disorders associated primarily with generalized or localized osteoporosis, genetic and acquired metabolic bone diseases, heterotopic calcifications in soft tissues, and for hypercalcemia. In this review, the authors address the role of and experience with bisphosphonate therapy in disorders of childhood.

Comparison of oral alendronate versus prednisolone in treatment of infants with vitamin D intoxication

AIM

The aim of this report was to compare the efficacy of oral alendronate versus prednisolone treatment in addition to conventional measures in infants with vitamin D intoxication.

METHODS

In six infants (aged 8.0 ± 2.1 months) with vitamin D intoxication, time to achieve normocalcemia with prednisolone treatment (Group I, n = 4) or alendronate treatment (Group II, n = 4, two infants started treatment from the baseline and two after unsuccessful prednisolone treatment) in addition to intravenous hydration and diuretic therapy were compared.

RESULTS

Baseline serum calcium levels ranged between 3.8 and 4.77 mmol/L. In the prednisolone group, although two patients reached normocalcemia on 7th and 12th days of treatment, other two patients did not despite 23 and 15 days of treatment and therefore switched to alendronate treatment. The mean duration of prednisolone treatment in these four patients was 14.2 ± 6.7 days (range 7-23). In the alendronate group, two patients who started treatment from the baseline achieved normocalcemia on the 5th day. Other two patients achieved normocalcemia 2 days after switching to alendronate. Thus, the mean time to reach normocalcemia after single oral alendronate administration was 3.5 ± 1.7 days (range 2-5) (p < 0.01 versus Group I).

CONCLUSION

Alendronate treatment achieves normocalcemia four times earlier than prednisolone treatment and shortens hospital stay in infants with vitamin D intoxication.

Vitamin D deficiency and prevention: Turkish experience

A nationwide 'vitamin D prophylaxis augmentation programme' initiated in 2005 in Turkey reduced the prevalence of rickets from 6% in 1998 to 0.1% in 2008 in children under 3 years of age. The programme included free distribution of vitamin D drops to all newborns and infants (0-12 months) visiting primary health stations throughout the country. Free disposal of vitamin D to infants is an effective strategy for preventing vitamin D-deficient rickets.

Infantile hypercalcemia and hypercalciuria: new insights into a vitamin D-dependent mechanism and response to ketoconazole treatment

OBJECTIVE

To analyze vitamin D metabolism and response to ketoconazole, an imidazole derivative that inhibits the vitamin D-1-hydroxylase, in infants with idiopathic hypercalcemia, and hypercalciuria.

STUDY DESIGN

Twenty infants (4 days-17 months) with hypercalcemia, severe hypercalciuria, and low parathyroid hormone level, (10 had nephrocalcinosis), including 10 treated with ketoconazole (3-9 mg/kg/day), were followed to the age of 2 to 51 months. Vitamin D receptor expression (VDR), 24-hydroxylase activity, and functional gene polymorphisms of vitamin D metabolism regulators VDR(rs4516035), 1-hydroxylase(rs10877012), 24-hydroxylase(rs2248359), FGF23(rs7955866), Klotho(rs9536314, rs564481, rs648202), were evaluated.

RESULTS

Serum calcium levels, which occurred faster in the ketoconazole group (0.7 +/- 0.2 versus 2.4 +/- 0.6 months; P = .0076), and urinary calcium excretion (2.5 +/- 0.5 versus 4.2 +/- 1.7 months) normalized in all patients. Serum 1,25-(OH)2D levels were high normal and positively correlated to 25-(OH)D levels. Serum 24,25-(OH)2D levels were low normal, and skin fibroblasts from 1 patient showed defective up-regulation of the 24-hydroxylase by 1,25-(OH)2D despite normal VDR binding ability. An abnormally low prevalence of haplotype CC/CC for H589H/A749A in Klotho gene was found in patients and family members.

CONCLUSIONS

Ketoconazole is a potentially useful and safe agent for treatment of infantile hypercalcemia. Abnormal vitamin D metabolism is suggested as the mechanism, possibly involving defective up-regulation of the 24-hydroxylase by 1,25-(OH)2D3, and the klotho-FGF23 axis.

Benefit-risk assessment of vitamin D supplementation

Current intake recommendations of 200 to 600 IU vitamin D per day may be insufficient for important disease outcomes reduced by vitamin D.

INTRODUCTION

This study assessed the benefit of higher-dose and higher achieved 25-hydroxyvitamin D levels [25(OH)D] versus any associated risk.

METHODS AND RESULTS

Based on double-blind randomized control trials (RCTs), eight for falls (n = 2426) and 12 for non-vertebral fractures (n = 42,279), there was a significant dose-response relationship between higher-dose and higher achieved 25(OH)D and greater fall and fracture prevention. Optimal benefits were observed at the highest dose tested to date for 700 to 1000 IU vitamin D per day or mean 25(OH)D between 75 and 110 nmol/l (30-44 ng/ml). Prospective cohort data on cardiovascular health and colorectal cancer prevention suggested increased benefits with the highest categories of 25(OH)D evaluated (median between 75 and 110 nmol/l). In 25 RCTs, mean serum calcium levels were not related to oral vitamin D up to 100,000 IU per day or achieved 25(OH)D up to 643 nmol/l. Mean levels of 75 to 110 nmol/l were reached in most RCTs with 1,800 to 4,000 IU vitamin D per day without risk.

CONCLUSION

Our analysis suggests that mean serum 25(OH)D levels of about 75 to 110 nmol/l provide optimal benefits for all investigated endpoints without increasing health risks. These levels can be best obtained with oral doses in the range of 1,800 to 4,000 IU vitamin D per day; further work is needed, including subject and environment factors, to better define the doses that will achieve optimal blood levels in the large majority of the population.

Dihydrotachysterol intoxication treated with pamidronate: a case report

Introduction

Hypoparathyroidism is a chronic condition which requires a lifelong substitution with vitamin D analogues and careful monitoring. This is especially true for older patients and older compounds as dihydrotachysterol with longer half-life that might lead to long-lasting hypercalcemic episodes.

Case presentation

A 74-year old male patient with postsurgical hypoparathyroidism who has been successfully supplemented with dihydrotachysterol (1.7 ml/day) for over 50 years presented with neuropsychiatric disturbances, constipation, renal insufficiency and polyuria. Laboratory investigation demonstrated serum calcium 3.7 mmol/L, serum creatinine 180 micromol/L, urine calcium excretion 1.1 mmol/mmol of the creatinine, normal 25 OH vitamin D₃ and low parathormone and 1,25 di OH vitamin D₃. Careful history revealed that he has been erroneously taking 2.5 ml of dihydrotachysterol per day for at least 6 to 8 weeks that caused vitamin D intoxication and symptomatic hypercalcemia. He was treated with intravenous saline infusion, prednisolone and 60 mg of intravenous sodium pamidronate. On the fourth day after admission serum calcium dropped rapidly within the reference range. The treatment for hypoparathyroidism had to be reinstituted 10 days after dihydrotachysterol had been discontinued when the patient was switched to shorter acting calcitriol.

Conclusions

Here we reported that the immediate use of pamidronate in addition to classic treatment of dihydrotachysterol intoxication with intravenous saline, diuretics and glucocorticoids is an effective treatment choice that leads to rapid resolution of hypercalcemia.

Pamidronate treatment of hypercalcemia caused by vitamin D toxicity

We present a 16 month-old previously healthy boy with refractory hypercalcemia due to an overdose of an over-the-counter vitamin supplement. The patient presented to the emergency department with a few weeks' history of irritability, constipation and intermittent vomiting. His serum calcium was found to be 18 mg/dl. He was first treated with intravenous fluids, furosemide and glucocorticoids without significant improvement, but became eucalcemic within 24 hours after receiving a single dose of pamidronate. This case highlights the potential danger of high dose vitamin supplements in children, and the salutary effects of treatment with bisphosphonate.

Alendronate treatment in osteogenesis imperfecta

AIMS

Osteogenesis imperfecta (OI) is a chronic, disabling condition characterized by bone fragility resulting from defective production of type I collagen. Pamidronate therapy is the most extensively studied treatment and has proved beneficial. Our objective was to evaluate the effect of alendronate, a more potent bisphosphonate than pamidronate, in OI.

MATERIALS AND METHODS

Three patients (age, 3-7 years; mean, 5 years) (one case, type III; 2 cases, type IV) have been given alendronate (0.3-0.56 mg/kg per day orally) for 2 years. Number of fractures, ambulation, height growth, and bone mineral density by dual-energy x-ray absorptiometry (DXA) were followed up.

RESULTS

Bone mineral density improved significantly after the 2-year alendronate treatment, which increased by 47.8% to 106.6% in the lumbar spine and by 24% to 51.4% in forearm bones. The z-score of lumbar spine DXA values increased from -5.26 +/- 0.84 to -3.1 +/- 0.59. The mean of fracture rates did not change significantly. Only one of the patients was highly limited in ambulation. She had curved legs and could not sit without support before the treatment. She improved to walk with help by the treatment. Serum parathormone and alkaline phosphatase concentrations did not change significantly. No side effect was detected in clinical and laboratory evaluations.

CONCLUSION

The study suggests that alendronate is a safe and well-tolerated drug and that it could increase bone density in children with OI, all of which encourage further studies with the bisphosphonates that are more potent than pamidronate and can be used orally. In addition, this study is the first report using the forearm bone mineral density measurement in OI.

Les hypercalciuries

The frequency of hypercalciuria is increasing in western countries with an incidence of nephrolithiasis which can reach 13%. Hypercalciuria appears as an alteration of the calcium transport system (kidney, bowel, bone) which is regulated by calcitriol and parathormone. The aim of this review was to screen etiologies of hypercalciuria taking into account recent genetic advances (calcium epithelial channel and calcium sensing receptor). Hypercalciuria may be favored by nutritional causes (diet rich in calcium, sodium, carbohydrates, proteins, poor in phosphates and potassium). It may also be related to an increase in calcium absorption (vitamin D excess, primary hyperparathyroidism, sarcoidosis, lymphoma, estrogens, and certain genetic causes), an increase in osteoresorption (bone metastasis, myeloma, Paget, hyperthyroidism, immobilization, hypercortisolism and corticosteroid therapy), or a decrease of kidney tubular resorption (diuretics, Cacci and Ricci, acromegally, Bartter, familial dominant hypocalcemia, Fanconi, Dent, familial hypomagnesemia-hypercalciuria syndrome, type 1 distal tubular acidosis, pseudohypoaldosteronism, diabetes). If no cause is identified, persistence of hypercalciuria after instituting a correct diet is defined as idiopathic hypercalciuria. Treatment of the cause is essential in secondary hypercalciuria, in addition to diet (low sodium intake, normocalcic diet, hydration), associated with thiazide diuretics and biphosphonates if necessary.

Effect of alendronate therapy in children with osteogenesis imperfecta

OBJECTIVE

To evaluate the effect of orally administered alendronate in children with osteogenesis imperfecta.

METHODS

Thirty children (16 girls and 14 boys; mean age at baseline 10.7 +/- 6.0 years; range 4-16 years) with osteogenesis imperfecta type I (n = 22), III (n = 2), or IV (n = 6) were treated with alendronate (5 mg/day in patients aged 4-10 years and 10 mg/day in children >10 years of age) for 3 years.

RESULTS

After 1 year of alendronate therapy we observed a significant increase in areal and volumetric bone mineral density Z-scores (from -2.03 +/- 1.51 to -1.04 +/- 1.20, and from -1.91 +/- 1.38 to -1.33 +/- 1.30, respectively, P < 0.001), together with a significant drop in fracture rate (from 3.77 +/- 1.57 to 0.13 +/- 0.57, P < 0.000001), relief of chronic pain (from 3.83 +/- 1.44 days of pain/week to 0.73 +/- 0.77, P < 0.000001) and improvement in ambulation/mobility (P < 0.00002). After additional 2 years of therapy there were no further significant changes in these parameters, however the improvement was still remarkable in comparison to the pretreatment values (P < 0.003, P < 0.004, P < 0.000001, P < 0.000001 and P < 0.00001, respectively). A significant drop in markers of bone turnover (urinary deoxypyridinoline and serum osteocalcin) occurred after 3 years of therapy (P < 0.003 and 0.004, respectively). No adverse reactions were observed throughout the treatment.

CONCLUSIONS

Alendronate has positively influenced quality of life in paediatric patients with osteogenesis imperfecta. Bisphosphonate therapy should be used only in the context of a well-defined protocol.

Pamidronate treatment in acute vitamin D intoxication

Management with glucocorticoid, high iv fluid saline intake, furosemide and calcitonin may not result in a favorable reduction of hypercalcemia and may cause several side effects in infants with acute vitamin D intoxication. The bisphosphonate pamidronate, a specific inhibitor of bone resorption through osteoclast mediation was successfully used in a 6-month old infant with acute vitamin D intoxication managed in the Pediatric Emergency and Intensive Care Unit, after an ineffective trial of hydration, furosemide, calcitonin and prednisolone. After a double infusion of pamidronate on two consecutive days (1 mg/kg/day), an early and safe correction of hypercalcemia/hypercalciuria was supplied. Pamidronate therapy may be considered in patients with hypercalcemia secondary to acute vitamin D poisoning.

Pamidronate Treatment for Hypercalcemia in an Infant Receiving Parenteral Nutrition

A 17-day-old infant who was delivered 8 weeks premature underwent small bowel resection for necrotizing enterocolitis. During treatment with continuous infusions of furosemide and hydrocortisone, his total calcium concentration had increased. The calcium dose in his parenteral nutrition solution was decreased and then finally withheld. At 7 weeks of age and after 10 days of calcium-free parenteral nutrition, pamidronate 3 mg (1.1 mg/kg) in 60 ml of normal saline was infused over 6 hours. The infant's total serum calcium concentration decreased, but then 6 days later it had increased again; pamidronate 2 mg (0.7 mg/kg) in 40 ml of normal saline over 4 hours was administered. The patient demonstrated no signs or symptoms of adverse reactions to pamidronate. His serum calcium concentration returned to normal, and calcium-containing parenteral nutrition was tolerated. The use of pamidronate for treatment of hypercalcemia and chronic conditions that affect normal bone growth is increasing in children. Clinical trials in pediatric patients are necessary to determine how best to use bisphosphonates in this patient population.