Bisphosphonates: from grandparents to grandchildren

Drug-induced osteopetrosis

Osteopetrosis (OPT) denotes the consequences from failure of osteoclasts to resorb bone and chondroclasts to remove calcified physeal cartilage throughout growth. Resulting impairment of skeletal modeling, remodeling, and growth compromises widening of medullary spaces, formation of the skull, and expansion of cranial foramina. Thus, myelophthisic anemia, raised intracranial pressure, and cranial nerve palsies complicate OPT when severe. Osteopetrotic bones fracture due to misshaping, failure of remodeling to weave the collagenous matrix of cortical osteons and trabeculae, persistence of mineralized growth plate cartilage, "hardening" of hydroxyapatite crystals, and delayed healing of skeletal microcracks. Teeth may fail to erupt. Now it is widely appreciated that OPT is caused by germline loss-of-function mutation(s) usually of genes involved in osteoclast function, but especially rarely of genes necessary for osteoclast formation. Additionally, however, in 2003 we published a case report demonstrating that prolonged excessive dosing during childhood of the antiresorptive aminobisphosphonate pamidronate can sufficiently block osteoclast and chondroclast activity to recapitulate the skeletal features of OPT. Herein, we include further evidence of drug-induced OPT by illustrating osteopetrotic skeletal changes from repeated administration of high doses of the aminobisphosphonate zoledronic acid (zoledronate) given to children with osteogenesis imperfecta.

Oral bisphosphonate treatment for osteogenesis imperfecta—an Indian perspective

BACKGROUND

Various treatments for the management of osteogenesis imperfecta (OI) have been tried, of which bisphosphonates seem to have the maximum benefit in reducing fracture rate and improving bone density. This study investigated the value of oral alendronate for treating OI in Indian children.

METHODS

Between 2002 and 2005, 11 patients with OI were referred for bisphosphonate therapy. The various types of OI were classified using the Sillence criteria. All patients underwent baseline biochemistry, radiographic studies and bone mineral density (BMD) measurements before commencing therapy. Patients were commenced on oral alendronate (0.5 mg/kg/day) and followed up for a period ranging from 1 month to 2 years. A retrospective analysis of pre- and post-treatment changes in fracture rate and bone density was undertaken using the paired sample t-test.

RESULTS

One patient lost to follow-up was excluded from the study and three completed only 2 months of therapy. Pre-treatment fracture rate per year before treatment ranged from 0.5 to 6 with a mean (SD) of 2.95 (1.57) and median of 2.5. The post-treatment fracture rate was 1.1 (0.59)/year (p=0.02). Seven children underwent BMD analysis while on treatment and all had a rise in BMD, of which the change in lumbar spine BMD was statistically significant (p=0.001), and lumbar (p=0.005) and femoral neck t-score (p=0.04) showed a significant change. No significant change was seen in serum biochemistry except for disappearance ofhypercalciuria (p=0.04). No child had an adverse reaction to alendronate.

CONCLUSION

After a median of 9.5 months of treatment, oral alendronate is associated with a lower fracture rate, improvement in BMD and a decrease in hypercalciuria.

Hypercalcemia in children and adolescents

PURPOSE OF REVIEW

In this review, we define hypercalcemia levels, common causes for hypercalcemia in children, and treatment in order to aid the practicing pediatrician.

RECENT FINDINGS

One rare cause of hypercalcemia in the child is familial hypocalciuric hypercalcemia (also termed familial benign hypercalcemia). Mutations that inactivate the Ca-sensing receptor gene FHH have been described as an autosomal dominant disorder, but recently milder mutations in the CASR have been shown to cause hypercalcemia when homozygous.

SUMMARY

Normal serum levels of calcium are maintained through the interplay of parathyroid, renal, and skeletal factors. In this review, we have distinguished the neonate and infant from the older child and adolescent because the causes and clinical features of hypercalcemia can differ in these two age groups. However, the initial approach to the medical treatment of severe or symptomatic hypercalcemia is to increase the urinary excretion of calcium in both groups. In most cases, hypercalcemia is due to osteoclastic bone resorption, and agents that inhibit or destroy osteoclasts are, therefore, effective treatments. Parathyroid surgery, the conventional treatment for adults with symptomatic primary hyperparathyroidism, is recommended for all children with primary hyperparathyroidism.

Pregnancy outcome following in utero exposure to bisphosphonates

BACKGROUND AND AIM

The safety of bisphosphonates in human pregnancy has not been well established. To characterize pregnancy outcome in women receiving bisphosphonates, we conducted a multi-centre, prospective cohort study with a comparison group.

METHODS

Patients were recruited through 3 teratogen information centres in Canada and South Korea. We followed 21 women exposed to bisphosphonates during or <3 months before pregnancy, and 21 matched-comparison group women without exposure to known teratogens. Pregnancy/neonatal outcome data were collected by interview. The primary endpoint was neonatal outcome including major birth defects. The secondary endpoints included other pregnancy outcomes such as spontaneous abortions.

RESULTS

Indication of the therapy was osteoporosis in all patients. There was no difference in the maternal demographics between the 2 groups. In the bisphosphonate group, there were 18 live births, 2 spontaneous abortions and 1 therapeutic abortion, which were not significantly different from the comparison group. The mean gestational age (mean+/-SD) of the bisphosphonate group was 38.7+/-1.9 weeks (comparison group: 39.3+/-1.9 weeks; P=0.42), and the mean birth weight was 3.1+/-0.3 kg (comparison group: 3.3+/-0.5 kg; P=0.11). In the bisphosphonate group, there was a child diagnosed with Apert syndrome, an autosomal dominant acrocephalosyndactyly, with a fibroblast growth factor 2 mutation.

CONCLUSION

Coupled with existing data in the literature, our findings suggest that preconceptional and first-trimester use of bisphosphonates may not pose substantial fetal risks.

No osteonecrosis in jaws of young patients with osteogenesis imperfecta treated with bisphosphonates

BACKGROUND

Recent reports of osteonecrosis of the jaw (ONJ) after dental surgery in patients treated with second- and third-generation nitrogen-containing bisphosphonates instigated this retrospective study. As treatment with bisphosphonates in patients with osteogenesis imperfecta (OI) has become an important symptomatic therapy, especially for severe forms of the disease, we found it important to investigate whether healing after surgical exposure of jaw bone was influenced by the bisphosponate treatment in our group of children, adolescents and young adults with OI.

SUBJECTS AND METHODS

Disodiumpamidronate was given as monthly intravenous infusion to 64 patients with OI aged 3 months to 20.9 years at the start of treatment (mean 8.1, median 7.7). During 0.5-12.5 years of treatment (mean 4.5, median 4.0), a total individual dose of 140-4020 mg/m(2) disodiumpamidronate was given (mean 1623 and median 1460). Ten patients continued with oral alendronate and two with zoledronic acid therapy. In 22 of these patients, 38 dental surgery procedures were performed at the age of 3.4-31.9 years (mean 12.2, median 12.3) after 0.03-7.9 years of treatment (mean 3.6, median 3.4).

RESULTS

Despite long-term intravenous monthly disodiumpamidronate treatment, none of the 64 patients had any clinical signs of ONJ.

CONCLUSIONS

The risk of ONJ in these patients must be considered so low that the patients with indications for treatment should be treated and get the chance to experience the well-documented beneficial effect for children with severe OI.

Cyclic pamidronate therapy in children with osteogenesis imperfecta: results of treatment and follow-up after discontinuation

BACKGROUND

Cyclic intravenous pamidronate treatment is widely used for symptomatic therapy of osteogenesis imperfecta (OI). However, data after discontinuation are very limited.

AIM

The results of cyclical pamidronate treatment in 14 patients with moderate/severe OI and follow up of six of them after discontinuation are presented to assess the effects of pamidronate and its discontinuation.

PATIENTS AND METHODS

Pamidronate was administered at a dosage of 0.5 mg/kg for 3 successive days every 2 months in 14 patients with OI aged 5.10 +/- 3.68 years. Treatment was stopped in six patients after a duration of 16.33 +/- 4.63 months, due to stable bone mineral density (BMD) values and/or no fracture in the last 6 months, or due to family demand. The main outcome measures were areal BMD (aBMD) of the lumbar spine, biochemical markers of bone metabolism, fracture rate, and clinical evaluation.

RESULTS

Areal BMD and aBMD z-scores showed significant improvement during the treatment period. Both serum and bone-specific alkaline phosphatase values were significantly decreased. Fracture rate reduced significantly from 3.5 +/- 1.01 to 0.83 +/- 0.77 fractures/year. Bone pain, which was severe in five patients, disappeared just after the first cycle, and the activity and mobility of patients increased. aBMD and aBMD z-scores were decreased 1.5 years after discontinuation, although not statistically significant. Annual fracture rate increased significantly. Bone pain recurred in four patients. Pamidronate treatment was reinstituted in five of these patients at the end of 1.5 years.

CONCLUSION

Cyclical pamidronate treatment is very effective in children with moderate/severe OI. This treatment should be started early enough before the occurrence of irreversible deformities and must be given for a longer time during the growth period.

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.

Osteopenia and cancer in children and adolescents: the fragility of success

The attainment of a satisfactory peak bone mass, which is accomplished largely by the end of adolescence, is the best protection against excessive bone mineral loss in late adulthood. Factors that influence this process include age, race, sex, body size, pubertal status, diet, physical activity, and other lifestyle elements. Cancer and its treatment in children and teenagers adversely impact bone mineralization. In particular, chemotherapy (especially glucocorticosteroids and methotrexate) and cranial irradiation (apparently by reducing growth hormone secretion and by causing hypogonadotropic hypogonadism) interfere with normal bone turnover. Resorption often exceeds formation, resulting in net bone mineral loss and providing a rational basis for the use of antiresorptive drugs. Such osteopenia may be symptomatic, with pain and abnormal gait, and increases the risk of fractures several fold. The disorder is compounded by reduced physical activity, so programs to reduce this deficit are of measurable benefit. All of those engaged in the care of children and adolescents with cancer have an opportunity to improve the bone health of these young people and to limit their risk of developing osteoporosis and fragility fractures in adult life.

Intravenous pamidronate treatment of infants with severe osteogenesis imperfecta

OBJECTIVE

Children with the severe forms of osteogenesis imperfecta have in several studies been treated with intravenous pamidronate, but there are only few reports of the effect of early treatment.

AIM

To evaluate the effect of treatment started in infancy.

METHODS

In a prospective observational study, with a historic control group, intravenous disodium pamidronate (APD) was given as monthly infusions to 11 children with osteogenesis imperfecta aged 3-13 (median 3.6) months, who had severe osteogenesis imperfecta with congenital bowing of the femora and vertebral compression fractures.

RESULTS

During treatment of children aged between 3 and 6 (median 4.5) years, dual-energy x ray absorptiometry measurements of the lumbar spine showed a gradual increase in bone density. Bone metabolism parameters in serum (alkaline phosphatase, osteocalcin, procollagen 1 carboxy-terminal peptide, collagen 1 teleopeptide) and in urine (deoxypyridinoline) indicated a decrease in bone turnover. An improvement of mobility was seen and at the latest recording, at the age of 3.3-6.5 (median 4.8) years, the children could all walk. Vertebral remodelling was seen, with increased vertebral height, and no child developed scoliosis, kyphosis or basilar impression. All children required femoral intramedullar rods for fractures, and five needed tibial rodding for extreme curvatures that prevented functional standing and walking. No adverse effects were seen on growth, fracture healing or blood chemistry.

CONCLUSIONS

APD is an efficient symptomatic treatment for infants with severe osteogenesis imperfecta, but additional orthopaedic surgery is often needed. Early treatment may prevent scoliosis and basilar impression. Long-term follow-up is important.

Short-term efficacy of monthly pamidronate infusion in patients with osteogenesis imperfecta

We evaluated the efficacy of a monthly infusion of pamidronate on the frequency of fractures, biochemical effects, and bone mineral density in children with osteogenesis imperfecta. Eleven patients from 0.9 to 13.8 yr of age were included in this study. The patients were administered pamidronate intravenously (30 mg/m(2)) over a 4-hr period monthly for a period ranging from 6 to 37 months. Height and weight Z-scores did not change significantly. The frequency of fractures was decreased from 2.3+/-1.01 times per year before treatment to 0.6+/-0.69 times per year during treatment. There were no long-term changes in biochemical markers during pamidronate therapy. The mean bone mineral density of the spine and femur increased significantly. Monthly intravenous pamidronate therapy decreased frequencies of fracture and increased bone mineral density without significant adverse events in Korean patients with osteogenesis imperfecta.

Preventing organ-specific chemotherapy toxicity

Recent advances in treatment for pediatric cancers has increased overall survival rates. As more and more survive pediatric cancer, we continue to see the emergence of late effects of treatment within pediatric and the growing adult survivor population. The evaluation of late effects was initiated approximately two decades ago, and has become an extremely important facet of pediatric oncology. This review delves into several of the most serious organ-specific late effects of pediatric cancer treatment, outline what we know and what we do not currently understand about preventing or reducing them. Clinical and bench research are necessary to develop interventions that will avoid or mitigate late effects and improve the health of pediatric cancer survivors.

Osteoporosis at presentation of childhood ALL: management with pamidronate

Vertebral fractures at diagnosis of childhood acute lymphoblastic leukemia (ALL) are an uncommon but recognized problem. Clinical issues associated with pathological fractures in these children include pain control and the potential for further treatment-associated fractures and long-term bony morbidity. The authors report the successful use of pamidronate in two children who presented with vertebral compression fractures at diagnosis of ALL. Both patients had pain and low bone mineral density at baseline. In addition to standard chemotherapy, pamidronate (1 mg/kg, IV) was given bimonthly. Initial rapid symptom relief and gradual improvement of bone mineral density was demonstrated in both patients.

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.

Oral bisphosphonates to treat disuse osteopenia in children with disabilities: a case series

Children with congenital conditions who are nonambulatory have been observed to have pathologic fractures due to disuse osteopenia. Data support the use of intravenous bisphosphonates to treat this in children with disabilities, but there are no data to guide the use of oral bisphosphonate medication. Ten nonambulatory children with disuse osteopenia secondary to either static brain injury or spina bifida were started on alendronate. Investigators completed a chart review of each subject. There were 17 fractures before starting alendronate and 1 fracture in the follow-up period. All children with nociceptive behavior or pain complaints (5/10) had their symptoms resolve after treatment. Despite the presence of gastrointestinal comorbidities (7/10 with a history of gastroesophageal reflux disease, 5/10 taking reflux medication, and 4/10 with PEG tubes), only 1 of the 10 children discontinued the medication secondary to gastrointestinal complaints. This case series offers evidence that disabled nonambulatory children tolerate alendronate, and it may decrease fractures in those at risk from severe disuse osteopenia.

[Diagnosis and treatment of juvenile osteoporosis]

Bone mass is primarily genetically determined, but exogenous factors also play a major role. The prevention of osteoporosis can start from childhood, and optimal achievement of peak bone mass during childhood and adolescence is important in order to minimise future fracture risks. Chronic inflammatory diseases can have a detrimental effect on bone mass, by means of several mechanisms. Different diagnostic methods for detection and monitoring of osteoporosis are in use or under investigation. The role of calcium and vitamin D supplementation for the prevention and treatment of osteoporosis associated with paediatric rheumatic diseases remains to be established. New treatments such as bisphosphonates and calcitonin are now available, although their use in the paediatric age has been limited.

Alendronate in the treatment of low bone mass in steroid-treated boys with Duchenne’s muscular dystrophy

OBJECTIVE

To examine alendronates side-effect profile and effect on bone mineral density (BMD) in deflazacort-treated boys with Duchennes muscular dystrophy (DMD) and low BMD.

DESIGN

Before-after trial.

SETTING

Neuromuscular clinic at a children's hospital in Canada between 1999 and 2000.

PARTICIPANTS

All consenting boys with DMD who had z scores less than -1.00 (spine and/or total body) and in whom BMD testing was feasible.

INTERVENTION

Boys received .08 mg.kg(-1) .d(-1) of alendronate orally, with 750 mg of daily calcium and 1000 IU of vitamin D. BMD, height, weight, physical activity, Tanner stage, and adverse effects were followed for 2 years.

MAIN OUTCOME MEASURES

BMD z scores at the lumbar spine (L1-4) and total body.

RESULTS

Of the 42 eligible boys assessed, 23 had low BMD; for 16 of the 23, future BMD testing was feasible. Mean age was 10.8 years (range, 6.9-15.6 y). Mean baseline z scores at the total body and spine were -0.80 and -1.94, respectively. At 2 years, mean z scores were unchanged. Furthermore, alendronate response varied by baseline age. In multivariable analysis, improvement in total body and spine z scores was associated with younger age at baseline ( P =.01 for both).

CONCLUSIONS

In deflazacort-treated boys, alendronate had a positive effect on BMD z scores; the effect was greatest when given early in the course of disease.

Pamidronate treatment of less severe forms of osteogenesis imperfecta in children

BACKGROUND

Bisphosphonate therapy improves bone quality in children with severe osteogenesis imperfecta (OI). Children with milder phenotypes also have prepubertal fractures, bone pain and reduced bone mass, predisposing them to adult osteoporosis.

OBJECTIVE

To evaluate treatment effects of pamidronate in children with mild phenotypes of OI.

METHODS

Open label, 2-year observational study of 18 patients, using pamidronate, with clinical, biochemical and radiological monitoring.

RESULTS

Over 2 years, bone pain decreased from 16 to 1 patient and disturbed sleep from 12 children to 0. Independent mobility improved from 10 to 17 children. Fracture incidence decreased from 1.6 to 0.5 fractures/child/year. Surgical interventions decreased from a mean 1.3 procedures/patient to 0 in the second year of treatment. Growth velocity remained stable at a mean 4.8 cm/year. Mean lumbar vertebral bone mineral density improved by 40.8%, from 0.375 to 0.528 g/cm2 (p <0.0001), z-score from -3.77 to -2.44 (p <0.0001). Mean vertebral height improved by 17.3%, from 15.6 to 18.38 mm (p = 0.07); plasma alkaline phosphatase decreased from 222 to 169 U/l (p = 0.0009) and urinary deoxypyridinoline crosslinks decreased from 26.7 to 21.8 nmol/mmol creatinine (p = 0.21). Two children with vitamin D insufficiency were concurrently treated. A significant association (r = -0.6, p = 0.008) was shown between age at start of treatment and percentage change in BMD after 2 years.

CONCLUSIONS

Pamidronate treatment improves bone quality in children with mild types of OI. It ameliorates clinical symptoms, improves mobility, reduces fracture frequency and thus improves quality of life and in future is likely to reduce the severity and consequences of adult osteoporosis by improved peak bone mass in these children.

Severe infantile hypercalcemia associated with Williams syndrome successfully treated with intravenously administered pamidronate

Infantile hypercalcemia occurs in approximately 15% of children with Williams syndrome (WS) and is typically not clinically severe. We report on 3 children with WS (confirmed with fluorescent in situ hybridization probes) who presented with severe symptomatic hypercalcemia. The first patient's severe hypercalcemia resolved with traditional therapies, whereas the subsequent 2 patients were treated with intravenously administered pamidronate after traditional measures proved only partially successful. Besides asymptomatic mild hypocalcemia, there were no complications resulting from pamidronate administration. We conclude that WS-associated hypercalcemia can be quite severe and symptomatic and that it can be successfully and safely treated with intravenously administered bisphosphonate in some cases.

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.

Osteogenesis imperfecta

Osteogenesis imperfecta is a genetic disorder of increased bone fragility, low bone mass, and other connective-tissue manifestations. The most frequently used classification outlines four clinical types, which we have expanded to seven distinct types. In most patients the disorder is caused by mutations in one of the two genes encoding collagen type 1, but in some individuals no such mutations are detectable. The most important therapeutic advance is the introduction of bisphosphonate treatment for moderate to severe forms of osteogenesis imperfecta. However, at present, the best treatment regimen and the long-term outcomes of bisphosphonate therapy are unknown. Although this treatment does not constitute a cure, it is an adjunct to physiotherapy, rehabilitation, and orthopaedic care. Gene-based therapy presently remains in the early stages of preclinical research.

Perinatal calcium metabolism: physiology and pathophysiology

Disturbances in mineral homeostasis are common in the neonatal period, especially in premature infants and infants who are hospitalised in an intensive care unit. In many cases these disturbances are thought to be exaggerated responses to the normal physiological transition from the intrauterine environment to neonatal independence. By contrast, some disturbances in calcium homeostasis are the result of genetic defects, which in many instances can now be identified at the molecular level. In other cases hypocalcaemia or hypercalcaemia may result from pathological intrauterine conditions, birth trauma or stress, or fetal immaturity. Diagnosis and management of hypocalcaemia and hypercalcaemia in the neonate and infant requires specific knowledge of perinatal mineral physiology and the unique clinical and biochemical features of newborn mineral metabolism. In this chapter we will provide a brief overview of calcium metabolism with an emphasis on the neonatal transition, followed by discussion of the common causes of hypercalcaemia and hypocalcaemia.

Height and weight development during four years of therapy with cyclical intravenous pamidronate in children and adolescents with osteogenesis imperfecta types I, III, and IV

OBJECTIVES

Treatment with pamidronate improves the clinical course in children with osteogenesis imperfecta (OI), but theoretically might affect longitudinal growth. In this study we analyzed growth during cyclical intravenous pamidronate treatment in children and adolescents (age.04-15.6 years at baseline) with moderate to severe forms of OI types I, III, and IV.

METHODS

The effect of 1 year of pamidronate treatment on height and weight was analyzed in 116 patients (OI-I, N = 29; OI-III, N = 42; OI-IV, N = 45). The results of 4 years of therapy were evaluated in 41 children (OI-I, N = 12; OI-III, N = 14; OI-IV, N = 15).

RESULTS

Baseline height was low for age in all OI types. After 1 year of pamidronate therapy, height z scores had increased significantly in OI-III (by 0.3 +/- 0.8, mean +/- standard deviation; P =.04) and did not change in OI-I and OI-IV. Weight z scores increased significantly in OI-I (by 0.2 +/- 0.4, P =.01). After 4 years of pamidronate therapy, mean height z scores increased significantly in OI-IV (by 0.41 +/- 0.71, P =.04), whereas nonsignificant trends to increase were found for OI-I and OI-III. When height was expressed as a percentage of the result expected for untreated patients with the same OI type, long-term pamidronate therapy was associated with a significant height gain in all 3 OI types (P <.001). Eight patients who reached final height after 3.0 +/- 1.0 years of treatment were taller on average than expected for untreated patients (P =.04).

CONCLUSIONS

Four years of cyclical intravenous pamidronate treatment led to a significant height gain in moderately to severely affected OI patients.

Treatment of symptomatic pediatric osteoporosis with cyclic single-day intravenous pamidronate infusions

OBJECTIVES

To examine the response to single-day intravenous pamidronate in a heterogeneous population with symptomatic osteoporosis.

STUDY DESIGN

Patients (n = 18) 6 to 21 years of age, meeting treatment criteria were offered treatment with a single-day infusion of pamidronate every 3 months. Baseline and follow-up data were recorded and compared between persons with risk factors of progressive chronic illness or ongoing glucocorticoid usage (group 1) and persons with neither risk factor (group 2). We also examined the association between changes in urinary N-telopeptide percentile and spinal bone mineral density (BMD).

RESULTS

Spinal BMD Z score increased in all patients after 6 months of treatment. Although patients had an average of 1.9 fractures in the year preceding treatment, only 2 patients had fractures once treatment began. No significant differences in baseline data were noted between the two groups. However, group 1 had significantly less gain in BMD (P =.04) than group 2. No evidence of growth impairment was seen, and no association between changes in urinary N-telopeptide percentile and changes in BMD were noted.

CONCLUSIONS

Single-day intravenous infusion of pamidronate is efficacious and well tolerated in a heterogeneous group of pediatric patients with symptomatic osteoporosis.

Treatment of children with Osteogenesis imperfecta in Estonia

AIM

To analyse the changes in fracture rate, bone density and histology in children with Osteogenesis imperfecta receiving treatment with alendronate (oral bisphosphonate) and calcitriol.

METHODS

Children treated at Tartu University Hospital from 1995 to 2001 were examined for Osteogenesis imperfecta. Radiographs and bone density measurements were obtained for all patients at the beginning of the study. Four patients also had bone biopsies prior to and one year after beginning treatment. The children were then given alendronate in weight-dependent dosages and also calcitriol. The number of fractures during the treatment period was recorded and follow-up bone density measurements were made.

RESULTS

Fifteen patients were treated during the 6-y period; mean follow-up approximately 3 y. It was found that the number of bone fractures had decreased significantly (p < 0.0001). Bone density improved in all 15 patients. Histologic studies revealed an increased number of osteoblasts and thickness of bone trabeculae as well as a more regular bone lamellar structure at the time of the second operation.

CONCLUSION

The complex treatment of Osteogenesis imperfecta should include alendronate and calcitriol to decrease fractures and improve bone mineral density.

Bisphosphonates, a new treatment for glucocorticoid-induced osteoporosis in children

BACKGROUND

Long-term corticoids used as a treatment for rheumatic diseases are the most frequent cause of osteoporosis in the pediatric population. Bisphosphonates have been proved to be useful in treating osteoporosis.

OBJECTIVE

To investigate the efficacy of pamidronate in corticoid-induced osteoporosis in children.

PATIENTS AND METHODS

Ten children affected with rheumatic diseases and osteoporosis underwent biannual cycles of intravenous pamidronate (4 to 12 cycles). Complete clinical, radiological, biochemical and densitometric follow-up was performed at every treatment cycle.

RESULTS

Good clinical and radiological evolution was observed in most of our patients; no new vertebral fractures were reported. Good densitometric evolution has been linked to the onset of puberty (rise in IGF-I levels) and low values for inflammatory activity markers (ESR and CRP). Self-limited hyperthermia and mild abdominal pain were observed during pamidronate infusion, but no other side effects were reported.

CONCLUSIONS

Pamidronate is a safe and useful treatment for corticoid-induced osteoporosis in the pediatric population.

Bisphosphonates to treat osteopenia in children with quadriplegic cerebral palsy: a randomized, placebo-controlled clinical trial

OBJECTIVE

To evaluate in a double-blind, placebo-controlled clinical trial the safety and efficacy of intravenous pamidronate to treat osteopenia in nonambulatory children with cerebral palsy.

STUDY DESIGN

Six pairs of subjects generally matched within each pair for age, sex, and race completed the protocol. One member of each pair randomly received plain saline placebo, the other pamidronate. Drug/placebo was administered intravenously daily for 3 consecutive days, and this 3-day dosing session was repeated at 3-month intervals for one year. Evaluations were continued for 6 months after the year of treatment. Bone mineral density (BMD) was measured in the distal femur, a site specifically developed for use in this contracted population, and the lumbar spine.

RESULTS

In the metaphyseal region of the distal femur, BMD increased 89% +/- 21% (mean +/- SEM) over the 18-month study period in the pamidronate group compared with 9% +/- 6% in the control group. Age-normalized z scores increased from -4.0 +/- 0.6 to -1.8 +/- 1.0 in the pamidronate group and did not significantly change in the control group (-4.2 +/- 0.3 to -4.0 +/- 0.3). The first dosing with pamidronate caused a transient drop in serum calcium that was asymptomatic and not treated. No other potentially adverse effects were noted.

CONCLUSIONS

In this small controlled clinical trial, pamidronate was found to be a safe and very effective agent to increase BMD in nonambulatory children with cerebral palsy.

Treatment of rheumatic diseases in children: special considerations

The goals of treatment of rheumatic diseases in children are to control the disease process while ensuring normal nutrition, growth, and development. The choice of antirheumatic drugs is similar in children and adults, but the doses, treatment schedules, and susceptibility to toxicity can differ considerably. In addition to differences between adult and pediatric diseases themselves, it is important for the rheumatologist who treats children to be cognizant of the impact of nutritional, developmental, and growth issues and differential susceptibility to toxicity of various treatments.

[Biphosphonates in children: present and future]

Biphosphonates are synthetic analogs of the natural pyrophosphate molecule, introduced primarily for the treatment of Paget disease of bone. Their main mechanism of action consisting in an inhibition of osteoclastic activity is critical for treatment of disorders including an increased bone resorption. In childhood osteoporosis (especially osteogenesis imperfecta), hypercalcemia and heterotopic calcifications are the three main situations in which they have been successfully used, with however few follow-up and no controlled studies. The evolution of these compounds generating more potent products, given orally, with limited effect on bone mineralization should allow an extension of their use in pediatric patients. Multicentric studies are now necessary to specify their efficacy and guidelines for use in children.

Beneficial effect of long term intravenous bisphosphonate treatment of osteogenesis imperfecta

AIM

To find an effective symptomatic treatment for osteogenesis imperfecta (OI).

METHODS

In a prospective observational study disodium pamidronate (APD) was given as monthly intravenous infusions to 28 children and adolescents (aged 0.6-18 years) with severe OI or a milder form of the disease, but with spinal compression fractures.

RESULTS

During treatment for 2-9 years, dual energy x ray absorptiometry measurements of the total body and of the lumbar spine showed a gradual increase in bone density. All bone metabolism variables in serum (alkaline phosphatase, osteocalcin, procollagen 1 C-terminal peptide, collagen 1 teleopeptide) and urine (deoxypyridinoline) indicated that there was a decrease in bone turnover. All patients experienced beneficial effects and the younger patients reported a major improvement in wellbeing, pain, and mobility without significant side effects. Vertebral remodelling was also seen.

CONCLUSIONS

APD seems to be an efficient symptomatic treatment for children and adolescents with OI.

Osteoporosis

Bone mass is determined primarily by genetic influences, but exogenous factors may also play a major role. The prevention of osteoporosis can start at childhood. Optimal achievement of peak bone mass during childhood and adolescence is important to minimize future fracture risk. Chronic inflammatory diseases can have a detrimental effect on bone mass through a variety of mechanisms. Different diagnostic methods for detecting osteoporosis (eg, dual x-ray absorptiometry, quantitative computed tomography, ultrasounds) are in use or under investigation. New treatment options are available; among these, the use of bisphosphonates seems to be the more promising approach.

Severe osteopenia in a young boy with Kostmann's congenital neutropenia treated with granulocyte colony-stimulating factor: suggested therapeutic approach

Kostmann's syndrome is a congenital disorder that causes an impairment of myeloid differentiation in the bone marrow characterized by severe neutropenia, which can be treated with recombinant human granulocyte colony-stimulating factor (G-CSF). We present the case of a 13-year-old boy with Kostmann's syndrome who was treated with recombinant human G-CSF from age 3.5 years. His growth and development was normal, although complicated by intermittent infections. Bone mineral density (BMD) measurement revealed severe osteopenia at the spine and hips (lumbar spine BMD 0.486 g/cm(2); Z score -3.6), and he was referred to the Endocrine Service. Relevant laboratory evaluation showed a pretreatment ionized calcium level at the upper limit of normal (1.28 mmol/L; range: 1.13-1.32 mmol/L), suppressed intact parathyroid hormone (iPTH) level (12 pg/mL; range: 10-65 pg/mL), and a low 1,25-dihydroxy vitamin D level (21 pg/mL; range: 24-65 pg/mL). He had evidence of increased bone turnover evidenced by elevated urinary deoxypyridinoline (DPD) cross-links (46.9 nmol/mmol creatinine; range: 2-34 nmol/mmol creatinine) and a simultaneous increase in markers of bone formation with elevated osteocalcin level (200 ng/mL; normal: 20-80 ng/mL) and alkaline phosphatase level (236 IU/mL; normal: 38-126 IU/mL). Because of clinical concern for his skeletal health, bisphosphonate therapy with intravenous pamidronate was initiated. One month after treatment, the iPTH and DPD cross-links were in the normal range (54 pg/mL and 17.7 nmol/mmol creatinine, respectively) and the 1,25-dihydroxy vitamin D level was elevated (111 pg/mL). Four months after treatment, there was a striking increase in BMD at the lumbar spine (+30.86%), femoral necks (left, +20.02%; right, +17.98%), and total hips (left, +18.40%; right, +15.94%). Seven months after bisphosphonate therapy, his biochemical parameters showed a return toward pretreatment levels with increasing urinary DPD cross-links (28.7 nmol/mmol creatinine) and decreasing iPTH (26 pg/mL). However, the BMD continued to increase (8 months posttreatment), but the magnitude of the increment was attenuated (lumbar-spine, +4.8%; left total hip, +1.2% and right total hip +2.4%), relative to BMD at 4 months. Eight months after the initial treatment, his iPTH was suppressed at 14 pg/mL and he again received pamidronate (at a lower dose); 3 months later, he had an additional increase in BMD (lumbar spine +7.4%, left total hip +3.9%, right total hip +2.7%), relative to the previous study. We hypothesize that prolonged administration of G-CSF as treatment for Kostmann's syndrome is associated with increased bone resorption, mediated by osteoclast activation and leading to bone loss. In children, the resulting osteopenia can be successfully managed with antisreorptive bisphosphonate therapy with significant improvement in bone density. Measurements of biochemical parameters of bone turnover can be used to monitor the magnitude and duration of the therapeutic response and the need for BMD reassessment and, perhaps, retreatment.

Osteoporosis in children and adolescent girls: case report of idiopathic juvenile osteoporosis and review of the literature

The diagnosis and treatment of osteoporosis is an important aspect of gynecologic training and practice. Idiopathic juvenile osteoporosis (IJO) is a rare disease of children and adolescents that resolves after the onset of puberty. A case report is presented and current methods of diagnosis and treatment of IJO are discussed as well as the differential diagnosis. A MEDLINE search was performed of the following terms: idiopathic juvenile osteoporosis, pediatric osteoporosis, adolescent osteoporosis, bisphosphonates pediatric adolescent, and pregnancy osteoporosis, and references from bibliographies of selected papers were used as well. All papers in English, French, and German are considered in this review. There were 114 papers selected as relevant to the topic. Data relevant to the diagnosis, pathogenesis, methods of imaging, laboratory evaluation, differential diagnosis, and treatment of IJO are presented. IJO is a diagnosis of exclusion in the pediatric and adolescent patient with osteoporosis. Although bone density gradually improves after the onset of puberty, treatment of currently affected children and adolescents involves activity restriction, calcium, vitamin D, and bisphosphonate therapy. Future reproductive concerns are discussed and areas requiring additional study are reviewed.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader will be able to describe the condition idiopathic juvenile osteoporosis, compare the clinical features of this condition to other similar conditions, outline the diagnostic workup of a child with this condition, and list the potential therapeutic options for a patient with idiopathic juvenile osteoporosis.

Preservation of bone mass in pediatric dialysis and transplant patients

Renal osteodystrophy continues to be a major challenge to the physician treating the child with end-stage renal disease (ESRD). The gold standard for the assessment of bone status is bone histomorphometry, which divides bone pathology into 3 main types; high-turnover, low-turnover, and mixed disease. The high-turnover disease, related to hyperparathyroidism, has been the one most extensively investigated; however, optimal therapy, especially in the growing child, is yet unclear. Overzealous treatment might result in adynamic bone disease (an extreme example of low-turnover disease), and further interference with statural growth. Pre-existent bone disease after kidney transplantation seems to worsen immediately, probably because of the high dose of corticosteroids used. In children who attain normal kidney function in the allograft, bone status seems to improve over time. Little is known about bone in transplanted patients with reduced glomerular filtration rate (GFR). The correlation between bone histology and its main surrogates, bone remodeling markers and bone mineral density, is yet unclear, but it might serve to follow the progress of an individual patient. New therapeutic modalities aimed at suppressing hyperparathyroidism, and consequently bone resorption, as well as agents directly attenuating bone resorption, should be further investigated for their effect on bone in patients with ESRD or after transplantation. Similarly, agents stimulating bone formation, particularly growth hormone, require further attention for their potential to improve bone status. Bone health and the child's somatic growth at ESRD or after kidney transplantation are closely related, and therapy should be aimed at achieving optimal results for both.

Treatment of osteoporosis with bisphosphonates

Bisphosphonates are safe and effective agents for treatment and prevention of osteoporosis. Alendronate and risedronate are the best studied of all agents for osteoporosis in terms of efficacy and safety. They increase bone mass. In patients who have established osteoporosis, they reduce the risk of vertebral fractures. They are the only agents shown in prospective trials to reduce the risk of hip fractures and other nonvertebral fractures. They are approved by the US FDA for prevention of bone loss in recently menopausal women, for treatment of postmenopausal osteoporosis, and for management of glucocorticoid-induced bone loss. Other bisphosphonates (e.g., etidronate for oral use, pamidronate for intravenous infusion) are also available and can be used off-label for patients who cannot tolerate approved agents. Bisphosphonates combined with estrogen produce greater gains in bone mass compared with either agent used alone; whether there is a greater benefit of combination therapy on fracture risk is not clear. Combining a bisphosphonate with raloxifene or calcitonin is probably safe, although data on effectiveness are lacking.