Low bone mass in patients with motor disability: prevalence and risk factors in 59 Finnish children

Fifteen-minute consultation: Fractures in non-ambulant children with cerebral palsy

OBJECTIVE

To describe a safeguarding decision pathway for the assessment of osteopenic fractures in non-ambulant children with cerebral palsy.

METHOD

Literature review and consensus practice of a child safeguarding team, including clinicians and social workers.

CONCLUSION

Low-energy fractures of the lower limb in non-ambulant children with cerebral palsy are relatively common and explained by the presence of reduced bone strength, in the absence of any other unexplained injuries or safeguarding concerns.

Part I: Which Child with a Chronic Disease Needs Bone Health Monitoring?

PURPOSE OF THE REVIEW

Underlying conditions which adversely affect skeletal strength are one of the most common reasons for consultations in pediatric bone health clinics. The diseases most frequently linked to fragility fractures include leukemia and other cancers, inflammatory disorders, neuromuscular disease, and those treated with osteotoxic drugs (particularly glucocorticoids). The decision to treat a child with secondary osteoporosis is challenged by the fact that fractures are frequent in childhood, even in the absence of risk factors. Furthermore, some children have the potential for medication-unassisted recovery from osteoporosis, obviating the need for bisphosphonate therapy.

RECENT FINDINGS

Over the last decade, there have been important advances in our understanding of the skeletal phenotypes, fracture frequencies, and risk factors for bone fragility in children with underlying disorders. With improved knowledge about the importance of fracture characteristics in at-risk children, there has been a shift away from a bone mineral density (BMD)-centric definition of osteoporosis in childhood, to a fracture-focused approach. As a result, attention is now drawn to the early identification of fragility fractures, which includes asymptomatic vertebral collapse. Furthermore, even a single, long bone fracture can represent a major osteoporotic event in an at-risk child. Fundamental biological principles of bone strength development, and the ways in which these go awry in chronic illnesses, form the basis for monitoring and diagnosis of osteoporosis in children with underlying conditions. Overall, the goal of monitoring is to identify early, rather than late, signs of osteoporosis in children with limited potential to undergo medication-unassisted recovery. These are the children who should undergo bisphosphonate therapy, as discussed in part 1 (monitoring and diagnosis) and part 2 (recovery and the decision to treat) of this review.

The Utility of DXA Assessment at the Forearm, Proximal Femur, and Lateral Distal Femur, and Vertebral Fracture Assessment in the Pediatric Population: 2019 ISCD Official Position

Dual-energy X-ray absorptiometry (DXA) is widely used in the evaluation of bone fragility in children. Previous recommendations emphasized total body less head and lumbar spine DXA scans for clinical bone health assessment. However, these scan sites may not be possible or optimal for all groups of children with conditions that threaten bone health. The utility of DXA scans of the proximal femur, forearm, and radius were evaluated for adequacy of reference data, precision, ability of predict fracture, and applicability to all, or select groups of children. In addition, the strengths and limitations of vertebral fracture assessment by DXA were evaluated. The new Pediatric Positions provide guidelines on the use of these additional measures in the assessment of skeletal health in children.

Diagnosis and management of Duchenne muscular dystrophy, part 2: respiratory, cardiac, bone health, and orthopaedic management

A coordinated, multidisciplinary approach to care is essential for optimum management of the primary manifestations and secondary complications of Duchenne muscular dystrophy (DMD). Contemporary care has been shaped by the availability of more sensitive diagnostic techniques and the earlier use of therapeutic interventions, which have the potential to improve patients' duration and quality of life. In part 2 of this update of the DMD care considerations, we present the latest recommendations for respiratory, cardiac, bone health and osteoporosis, and orthopaedic and surgical management for boys and men with DMD. Additionally, we provide guidance on cardiac management for female carriers of a disease-causing mutation. The new care considerations acknowledge the effects of long-term glucocorticoid use on the natural history of DMD, and the need for care guidance across the lifespan as patients live longer. The management of DMD looks set to change substantially as new genetic and molecular therapies become available.

Should the Gross Motor Function Classification System be used for children who do not have cerebral palsy?

This literature review addressed four questions. (1) In which populations other than cerebral palsy (CP) has the Gross Motor Function Classification System (GMFCS) been applied? (2) In what types of study, and why was it used? (3) How was it modified to facilitate these applications? (4) What justifications and evidence of psychometric adequacy were used to support its application? A search of PubMed, MEDLINE, and Embase databases (January 1997 to April 2017) using the terms: 'GMFCS' OR 'Gross Motor Function Classification System' yielded 2499 articles. 118 met inclusion criteria and reported children/adults with 133 health conditions/clinical descriptions other than CP. Three broad GMFCS applications were observed: as a categorization tool, independent variable, or outcome measure. While the GMFCS is widely used for children with health conditions/clinical description other than CP, researchers rarely provided adequate justification for these uses. We offer recommendations for development/validation of other condition-specific classification systems and discuss the potential need for a generic gross motor function classification system.

WHAT THIS PAPER ADDS

The Gross Motor Function Classification System should not be used outside cerebral palsy or as an outcome measure. The authors provide recommendations for development and validation of condition-specific or generic classification systems.

Low bone mineral density and fractures are highly prevalent in pediatric patients with spinal muscular atrophy regardless of disease severity

Patients with Spinal Muscular Atrophy (SMA) are at risk for poor bone health. The prevalence of fractures, low areal bone mineral density (aBMD; Z-score ≤-2.0) of the lateral distal femur and of osteoporosis by SMA subtype is not known. We aimed to describe the natural history of bone health in patients with SMA prior to bisphosphonate treatment. We reviewed data from 85 eligible patients with SMA ages 12 months to 18 years, seen at a single institution between January 2005 and July 2016. Fracture history was reported at annual clinic visits. aBMD was obtained from dual energy x-ray absorptiometry scans of the lumbar spine, total body, and lateral distal femur. 85% of patients had aBMD Z-scores ≤-2.0 SD and were progressively lower with worsening SMA severity. Longitudinal aBMD Z-scores of the lateral distal femur decreased with age. Fractures occurred in 38% (32/85) of patients with the femur being the most common location (25 of 57 fractures). Thirteen percent of patients fulfilled criteria for osteoporosis. Low aBMD and femur fractures are highly prevalent in all SMA subtypes from a young age; however, few patients met the criteria for osteoporosis. Poor bone health may be an under-recognized comorbidity of SMA.

The management of osteoporosis in children

This article reviews the manifestations and risk factors associated with osteoporosis in childhood, the definition of osteoporosis and recommendations for monitoring and prevention. As well, this article discusses when a child should be considered a candidate for osteoporosis therapy, which agents should be prescribed, duration of therapy and side effects. There has been significant progress in our understanding of risk factors and the natural history of osteoporosis in children over the past number of years. This knowledge has fostered the development of logical approaches to the diagnosis, monitoring, and optimal timing of osteoporosis intervention in this setting. Current management strategies are predicated upon monitoring at-risk children to identify and then treat earlier rather than later signs of osteoporosis in those with limited potential for spontaneous recovery. On the other hand, trials addressing the prevention of the first-ever fracture are still needed for children who have both a high likelihood of developing fractures and less potential for recovery. This review focuses on the evidence that shapes the current approach to diagnosis, monitoring, and treatment of osteoporosis in childhood, with emphasis on the key pediatric-specific biological principles that are pivotal to the overall approach and on the main questions with which clinicians struggle on a daily basis. The scope of this article is to review the manifestations of and risk factors for primary and secondary osteoporosis in children, to discuss the definition of pediatric osteoporosis, and to summarize recommendations for monitoring and prevention of bone fragility. As well, this article reviews when a child is a candidate for osteoporosis therapy, which agents and doses should be prescribed, the duration of therapy, how the response to therapy is adjudicated, and the short- and long-term side effects. With this information, the bone health clinician will be poised to diagnose osteoporosis in children and to identify when children need osteoporosis therapy and the clinical outcomes that gauge efficacy and safety of treatment.

A Piece of the Puzzle: The Bone Health Index of the BoneXpert Software Reflects Cortical Bone Mineral Density in Pediatric and Adolescent Patients

INTRODUCTION

Suspected osteopathology in chronically ill children often necessitates the assessment of bone mineral density. The most frequently used methods are dual-energy X-ray-absorption (DXA) and peripheral quantitative computed tomography (pQCT). The BoneXpert software provides an automated radiogrammatic method to assess skeletal age from digitalized X-rays of the left hand. Furthermore, the program calculates the Bone Health Index (BHI), a measure of cortical thickness and mineralization, which is obtained from indices of three metacarpal bones. In our study, we analyzed the manner in which BHI information provided by BoneXpert compares with DXA or pQCT measurements in youths.

STUDY DESIGN

The BHI was retrospectively obtained using digitalized X-rays of the left hand and compared with the results of 203 corresponding DXA readings (Lunar Prodigy, GE Healthcare) of the lumbar vertebrae and femur as well as 117 pQCT readings (XCT 900, Stratec) of the distal radius.

RESULTS

The BHI values showed a strong positive correlation with the DXA readings at each and all lumbar vertebrae (L1 -L4: r = 0.73; P < 0.0001). The age-adjusted Z-score of L1 -L4 and the height-adjusted score showed a positive correlation with the BHI-SDS (standard deviation score, r = 0.23; P < 0.002 and r = 0.27; P < 0.001, respectively). Total bone mineral density, as assessed via pQCT, also positively correlated with the BHI (r = 0.39; P < 0.0001), but the trabecular values displayed only a weak correlation.

CONCLUSIONS

The BHI obtained using BoneXpert can be a useful parameter in the assessment of bone health in children in most cases. This technique provides observer-independent information on cortical thickness and mineralization based on X-ray imaging of the hands.

The choice of normative pediatric reference database changes spine bone mineral density Z-scores but not the relationship between bone mineral density and prevalent vertebral fractures

OBJECTIVES

Our objectives were to assess the magnitude of the disparity in lumbar spine bone mineral density (LSBMD) Z-scores generated by different reference databases and to evaluate whether the relationship between LSBMD Z-scores and vertebral fractures (VF) varies by choice of database.

PATIENTS AND DESIGN

Children with leukemia underwent LSBMD by cross-calibrated dual-energy x-ray absorptiometry, with Z-scores generated according to Hologic and Lunar databases. VF were assessed by the Genant method on spine radiographs. Logistic regression was used to assess the association between fractures and LSBMD Z-scores. Net reclassification improvement and area under the receiver operating characteristic curve were calculated to assess the predictive accuracy of LSBMD Z-scores for VF.

RESULTS

For the 186 children from 0 to 18 years of age, 6 different age ranges were studied. The Z-scores generated for the 0 to 18 group were highly correlated (r ≥ 0.90), but the proportion of children with LSBMD Z-scores ≤-2.0 among those with VF varied substantially (from 38-66%). Odds ratios (OR) for the association between LSBMD Z-score and VF were similar regardless of database (OR = 1.92, 95% confidence interval 1.44, 2.56 to OR = 2.70, 95% confidence interval 1.70, 4.28). Area under the receiver operating characteristic curve and net reclassification improvement ranged from 0.71 to 0.75 and -0.15 to 0.07, respectively.

CONCLUSIONS

Although the use of a LSBMD Z-score threshold as part of the definition of osteoporosis in a child with VF does not appear valid, the study of relationships between BMD and VF is valid regardless of the BMD database that is used.

Fractures in children with cerebral palsy

Children with moderate to severe cerebral palsy are at increased risk of sustaining fracture following minimal trauma. Such fractures predominantly occur in lower limb bones and are associated with low bone mineral density. Risk factors for fracture in this group include nonambulatory status, anticonvulsant use, presence of a joint contractures, immobilization after surgery, and poor nutrition. Aims of this review are to describe the prevalence and pathogenesis of fractures in nonambulant children with cerebral palsy. Interventions and treatments that improve low bone mineral density and which may help to reduce the fracture risk in this population are also discussed.

Endocrine problems in children and adolescents who have disabilities

The consequences of disability span almost all aspects of life, for families and for an affected individual. Endocrine aspects of disability cover disorders of hypothalamic pituitary dysfunction, bone health, puberty, fertility, sexual function and contraceptive needs. Adequate endocrine assessment for a child with a disability requires extensive and sensitive history to address social issues, general nutrition, vitamin D status, specific hypothalamic pituitary problems, together with parental concerns regarding puberty and contraception. Bone health assessment includes history of minimal trauma fracture, need for intervention or fitness for surgery. Strategic interventions to improve outcome include management of puberty, vitamin D status, biomechanical stimulation with vibration and standing and possible consideration for bisphosphonate in special circumstances. Both early and late puberty cause major family concerns. The paediatrician must be aware of a range of management options to improve outcomes for the child and family.

Long-term skeletal consequences of childhood acute lymphoblastic leukemia in adult males: a cohort study

OBJECTIVE

Long-term health sequelae of childhood-onset acute lymphoblastic leukemia (ALL) remain largely unknown. Low bone mineral content (BMC) and bone mineral density (BMD) are recognized complications, but it is unknown whether these persist until adulthood. We evaluated skeletal characteristics and their association with ALL therapy in long-term male ALL survivors.

DESIGN

This cross-sectional cohort study included 49 long-term male ALL survivors and 55 age-matched healthy males.

METHODS

BMD and compression fractures were assessed by dual-energy X-ray absorptiometry; blood biochemistry was obtained for parameters of calcium homeostasis.

RESULTS

The ALL survivors (median age 29 years, range 25-38 years), assessed 10-38 years after ALL diagnosis, had lower lumbar spine (P<0.001), femoral neck (P<0.001), and whole-body (P=0.017) BMD than expected based on normative values. When compared with the controls (median age 30 years, range 24-36 years), the ALL survivors had lower lumbar spine BMC (P=0.014), lower whole-body BMC (P<0.001), and lower whole-body BMD (P<0.001), but the differences were partly explained by differences in height. Altogether, 20% of the ALL survivors had spinal compression fractures, but these were equally prevalent in the controls. Males diagnosed with ALL before age 5 years had significantly lower BMD values. Other recognized risk factors included untreated hypogonadism, vitamin D deficiency, hypophosphatemia, low IGF-binding protein-3, and low physical activity.

CONCLUSIONS

At young adulthood, long-term male ALL survivors have significantly reduced BMC and BMD and a high prevalence of spinal compression fractures. Careful follow-up and active treatment of the recognized risk factors are warranted.

The thoracic and lumbar spine in severe juvenile idiopathic arthritis: magnetic resonance imaging analysis in 50 children

OBJECTIVE

To determine the prevalence of vertebral fractures as a complication of juvenile idiopathic arthritis (JIA).

STUDY DESIGN

This cross-sectional study evaluated the prevalence and characteristics of spinal abnormalities in 50 children (aged 7.0-18.7 years) with treatment-resistant JIA by magnetic resonance imaging. Vertebral deformities, endplate irregularities, intervertebral disc involvement, spinal canal, neural foramina, and back muscles were analyzed and correlated with clinical characteristics and bone mineral density.

RESULTS

Magnetic resonance imaging revealed various abnormalities in 31 patients (62%). Vertebral compression was seen in 28%, disc degeneration in 46%, protrusions in 14%, prolapses in 4%, endplate changes in 26%, and anterior vertebral corner lesions in 16%. Two patients (4%) had mild spinal canal narrowing without medullar involvement; none had neural root compression. Six patients (12%) had mild back muscle atrophy. No correlation was observed between spinal fractures or other vertebral changes and disease activity or duration, pain or bone mineral density; patients with spinal fractures tended to have a higher recent glucocorticoid exposure (P=.086).

CONCLUSION

Children with severe JIA have a high prevalence of compression fractures and other vertebral, endplate, and disc abnormalities in the thoracic and lumbar spine.

Aging and bone health in individuals with developmental disabilities

Low bone mass density (BMD), a classical age-related health issue and a known health concern for fair skinned, thin, postmenopausal Caucasian women, is found to be common among individuals with developmental/intellectual disabilities (D/IDs). It is the consensus that BMD is decreased in both men and women with D/ID. Maintaining good bone health is important for this population as fractures could potentially go undetected in nonverbal individuals, leading to increased morbidity and a further loss of independence. This paper provides a comprehensive overview of bone health of adults with D/ID, their risk of fractures, and how this compares to the general aging population. We will specifically focus on the bone health of two common developmental disabilities, Down syndrome (DS) and cerebral palsy (CP), and will discuss BMD and fracture rates in these complex populations. Gaining a greater understanding of how bone health is affected in individuals with D/ID could lead to better customized treatments for these specific populations.

Lumbar spine and total-body dual-energy X-ray absorptiometry in children with severe neurological impairment and intellectual disability: a pilot study of artefacts and disrupting factors

BACKGROUND

Children with severe neurological impairment and intellectual disability (ID) are susceptible for developing low bone mineral density (BMD) and fractures. BMD is generally measured with dual-energy X-ray absorptiometry (DXA).

OBJECTIVE

To describe the occurrence of factors that may influence the feasibility of DXA and the accuracy of DXA outcome in children with severe neurological impairment and ID.

MATERIALS AND METHODS

Based on literature and expert opinion, a list of disrupting factors was developed. Occurrence of these factors was assessed in 27 children who underwent DXA measurement.

RESULTS

Disrupting factors that occurred most frequently were movement during measurement (82%), aberrant body composition (67%), small length for age (56%) and scoliosis (37%). The number of disrupting factors per child was mean 5.3 (range 1-8). No correlation was found between DXA outcomes and the number of disrupting factors.

CONCLUSION

Factors that may negatively influence the accuracy of DXA outcome are frequently present in children with severe neurological impairment and ID. No systematic deviation of DXA outcome in coherence with the amount of disrupting factors was found, but physicians should be aware of the possible influence of disrupting factors on the accuracy of DXA.

Prevalence of vertebral compression fractures and associated factors in children and adolescents with severe juvenile idiopathic arthritis

OBJECTIVE

Vertebral fractures occur in patients with juvenile idiopathic arthritis (JIA), but data on their frequency and causes are scarce. Our cross-sectional study evaluated prevalence of compression fractures and associated factors in a high-risk pediatric population with severe JIA.

METHODS

Children and adolescents with a history of treatment-resistant polyarticular-course JIA for ≥ 5 years or systemic arthritis for ≥ 3 years were recruited. Clinical examination, dietary recall, laboratory measurements, bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry, and spinal radiography were performed.

RESULTS

Our study included 50 patients (41 girls), of whom 6 (12%) had systemic arthritis, with a median age of 14.8 years (range 7.0-18.7 yrs) and median disease duration of 10.2 years (range 3.9-16.8 years). Ninety-four percent had used systemic glucocorticoids (GC); the median total duration of GC treatment was 7.1 years (range 0-15.5 yrs). The median weight-adjusted cumulative GC dose for the preceding 3 years was 72 mg/kg (range 0-911 mg/kg). The median bone age-corrected lumbar spine and whole-body areal BMD Z-scores were -0.8 and -1.0, respectively. Twenty-two percent had vertebral fractures, mostly thoracic. Compression fractures were associated with high disease activity, high body mass index (BMI), and high recent cumulative GC dose, but not with disease duration or BMD. Thirty percent had sustained at least 1 peripheral low energy fracture. Twenty-six percent were deemed to have significantly compromised bone health.

CONCLUSION

Severe JIA is associated with a significant risk of vertebral compression fractures. Associated factors include high disease activity, high BMI, and high recent GC exposure. Further studies are needed to establish optimal prevention and treatment guidelines.