Successful treatment approaches for tumoral calcinosis in children and young people: A condition of diverse pathogenesis

BACKGROUND

Ectopic calcification is inappropriate biomineralization of soft tissues occurring due to genetic or acquired causes of hyperphosphataemia and rarely in normophosphataemic individuals. Tumoral Calcinosis (TC) is a rare metabolic bone disorder commonly presenting in childhood and adolescence with periarticular extra-capsular calcinosis. Three subtypes of TC have been recognised: primary hyperphosphataemic familial TC (HFTC), primary normophosphataemic familial TC and secondary TC most commonly seen in chronic renal failure. In the absence of established treatment, management is challenging due to variable success rates with medical therapies and recurrence following surgery.

AIM

We outline the successful treatment approaches in four children with TC (2 normophosphatemic TC, 2 HFTC) aged 2.5-10 years at initial presentation.

CASES

Patient 1 (P1) presented at 10 years with a painless lump behind the right knee, P2 with swelling of the right knee anteriorly at 9 years, P3 and P4 with pain and swelling over the right elbow at 5 and 2.5 years respectively. All patients were of Black African-Caribbean origin and were previously reported to be fit and well with no family history of TC.

RESULTS

P1, P2 had normophosphataemic TC and P3, P4 had HFTC with genetically confirmed GALNT3 mutation. All four patients had initial surgical resection with TC confirmed on histology. P1 had complete surgical resection with no recurrence at 27 months post-operatively. P2 had significant overgrowth of the tumour following surgery and was subsequently successfully managed with 25 % topical sodium metabisulphite (total duration of 8 months with a 4 month gap during which there was recurrence). P3 had post-surgical recurrence of TC on the right elbow and a new lesion on left elbow which resolved with oral acetazolamide monotherapy (15-20 mg/kg/day). P4 had recurrence of right elbow lesion following surgery and developed an extensive new hip lesion on sevelamer therapy which resolved completely with additional acetazolamide therapy (18-33 mg/kg/day). Acetazolamide was well tolerated with normal growth for 5 years in P3 and 6.5 years in P4 and no recurrence of lesions.

CONCLUSION

The frequent post-surgical recurrence in TC and successful medical therapy on the other hand indicates that medical management as first line therapy should be adopted. Monotherapies with topical 25 % sodium metabisulphite in normophosphataemic and oral acetazolamide in HFTC are effective treatment strategies which are well tolerated.

Cessation of ambulation results in a dramatic loss of trabecular bone density in boys with Duchenne muscular dystrophy (DMD)

Glucocorticoids are currently used to improve muscle strength and prolong ambulation in boys with DMD although the effect on bone health is still unclear. The aim of this study was to compare bone strength in healthy children and boys with DMD and investigate the interaction between diminished muscle function, loss of ambulation and high dose oral steroids, over a two year time frame. Fifty children were studied, 14 healthy boys (HB), 13 boys with DMD who remained ambulant (DMD-RA) and 23 boys with DMD who lost ambulation (DMD-LA). All boys with DMD had taken oral glucocorticoids. Peripheral quantitative computed tomography was used to measure bone geometry, density, strength and muscle mass of the non-dominant tibia and radius. Measurements were made at baseline, 12 and 24 months at the distal metaphysis and mid diaphysis sites. Differences between the three groups were evaluated using ANOVA and a repeated measures model. There were no significant differences in age between the groups: mean age was 9.4, 8.7 and 8.8 years for HB, DMD-RA and DMD-LA, respectively. There was no significant difference in steroid exposure between the DMD groups. However, boys who lost ambulation had significantly lower muscle function at baseline (North Star Ambulatory Assessment DMD-RA 23.6 vs. DMD-LA 18.8; p < 0.05). At baseline, healthy boys had significantly greater trabecular bone density at the distal radius /ulna (23%/27%) and distal tibia/fibula (30%/46%) than boys with DMD (p < 0.05). They also had significantly larger diaphyseal tibiae/fibulae (74%/36%) and radii/ulnae (49%/31%) with thicker corticies and consequently greater bone strength. In contrast, boys with DMD had greater cortical density (4%). Over time, there were small significant differences in the rate of change of both muscle and bone parameters between healthy boys and boys with DMD. For both ambulant and non-ambulant boys with DMD the greatest changes in cortical bone were evident at the tibia. After two years boys with DMD had on average, 63% less bone strength than healthy boys. However, the most strikingly significant difference was in trabecular bone density for boys who became non-ambulant. By 2 years non-ambulant DMD boys had 53% less trabecular bone density at distal tibia than their healthy age matched peers compared with boys who remained ambulant who had 27% less trabecular bone density. In conclusion, bone and muscle strength is reduced for all boys with DMD even while they remain ambulant. However, tibia trabecular bone density loss is significantly accelerated in DMD boys who lose independent ambulation compared to DMD boys who remain ambulant despite equivalent levels of corticosteroid exposure.

Zoledronic Acid vs Placebo in Pediatric Glucocorticoid-induced Osteoporosis: A Randomized, Double-blind, Phase 3 Trial

CONTEXT

Glucocorticoids (GCs) prescribed for chronic pediatric illnesses are associated with osteoporotic fractures.

OBJECTIVE

This study aims to determine the efficacy and safety of intravenous (IV) zoledronic acid (ZA) compared with placebo to treat pediatric GC-induced osteoporosis (GIO).

METHODS

Children aged 5 to 17 years with GIO were enrolled in this multinational, randomized, double-blind, placebo-controlled phase 3 trial (ClinicalTrials.gov NCT00799266). Eligible children were randomly assigned 1:1 to 6 monthly IV ZA 0.05 mg/kg or IV placebo. The primary end point was the change in lumbar spine bone mineral density z score (LSBMDZ) from baseline to month 12. Incident fractures and safety were assessed.

RESULTS

Thirty-four children were enrolled (mean age 12.6 ± 3.4 years [18 on ZA, 16 on placebo]), all with low-trauma vertebral fractures (VFs). LSBMDZ increased from -2.13 ± 0.79 to -1.49 ± 1.05 on ZA, compared with -2.38 ± 0.90 to -2.27 ± 1.03 on placebo (least squares means difference 0.41 [95% CI, 0.02-0.81; P = .04]); when corrected for height z score, the least squares means difference in LBMDZ was 0.75 [95% CI, 0.27-1.22; P = .004]. Two children on placebo had new low-trauma VF vs none on ZA. Adverse events (AEs) were reported in 15 of 18 children (83%) on ZA, and in 12 of 16 (75%) on placebo, most frequently within 10 days after the first infusion. There were no deaths or treatment discontinuations due to treatment-emergent AEs.

CONCLUSION

LSBMDZ increased significantly on ZA compared with placebo over 1 year in children with GIO. Most AEs occurred after the first infusion.

Higher prevalence of non-skeletal comorbidity related to X-linked hypophosphataemia: a UK parallel cohort study using CPRD

OBJECTIVES

X-Linked hypophosphataemic rickets (XLH) is a rare multi-systemic disease of mineral homeostasis that has a prominent skeletal phenotype. The aim of this study was to describe additional comorbidities in XLH patients compared with general population controls.

METHODS

The Clinical Practice Research Datalink (CPRD) GOLD was used to identify a cohort of XLH patients (1995-2016), along with a non-XLH cohort matched (1 : 4) on age, sex and GP practice. Using the CALIBER portal, phenotyping algorithms were used to identify the first diagnosis (and associated age) of 273 comorbid conditions during patient follow-up. Fifteen major disease categories were used and the proportion of patients having ≥1 diagnosis was compared between cohorts for each category and condition. Main analyses were repeated according to the Index of Multiple Deprivation (IMD).

RESULTS

There were 64 and 256 patients in the XLH and non-XLH cohorts, respectively. There was increased prevalence of endocrine [OR 3.46 (95% CI: 1.44, 8.31)] and neurological [OR 3.01 (95% CI: 1.41, 6.44)] disorders among XLH patients. Across all specific comorbidities, four were at least twice as likely to be present in XLH cases, but only depression met the Bonferroni threshold: OR 2.95 (95% CI: 1.47, 5.92). Distribution of IMD among XLH cases indicated greater deprivation than the general population.

CONCLUSION

We describe a higher risk of mental illness in XLH patients compared with matched controls, and greater than expected deprivation. These findings may have implications for clinical practice guidelines and decisions around health and social care provision for these patients.

Monitoring response to conventional treatment in children with XLH: Value of ALP and Rickets Severity Score (RSS) in a real world setting

INTRODUCTION

X-linked hypophosphataemia (XLH) is conventionally managed with oral phosphate and active vitamin D analogues.

OBJECTIVES

To evaluate long term treatment response by assessing biochemical disease activity [serum alkaline phosphatase (ALP)], radiological rickets severity score (RSS), growth and morbidity in patients with XLH on conventional therapy and assess the correlation between serum ALP and RSS.

METHODS

XLH patients from 3 UK tertiary centres with ≥3 radiographs one year apart were included. Data was collected retrospectively. The RSS was assessed from routine hand and knee radiographs and ALP z scores were calculated using age-specific reference data.

RESULTS

Thirty-eight (male = 12) patients met the inclusion criteria. The mean ± SD knee, wrist and total RSS at baseline (median age 1.2 years) were 2.0 ± 1.2, 1.9 ± 1.2 and 3.6 ± 1.3 respectively; and at the most recent clinic visit (median age 9.0 years, range 3.3-18.9) were 1.6 ± 1.0, 1.0 ± 1.0 and 2.5 ± 1.5 respectively. The mean ± SD serum ALP z scores at baseline and the most recent visit were 4.2 ± 2.3 and 4.0 ± 3.3. Median height SDS at baseline and most recent visit were -1.2 and -2.1 (p = 0.05). Dental abscess, craniosynostosis, limb deformity requiring orthopaedic intervention and nephrocalcinosis were present in 31.5%, 7.9%, 31.6% and 42.1% of the cohort respectively. There was no statistically significant (p > 0.05) correlation between ALP z scores and knee (r = 0.07) or total (r = 0.12) RSS.

CONCLUSIONS

Conventional therapy was not effective in significantly improving biochemical and radiological features of disease. The lack of association between serum ALP and rickets severity on radiographs limits the value of ALP as the sole indicator of rickets activity in patients receiving conventional therapy.

Prevalence and Mortality of Individuals With X-Linked Hypophosphatemia: A United Kingdom Real-World Data Analysis

BACKGROUND

X-linked hypophosphatemia (XLH) is a rare multisystemic disease with a prominent musculoskeletal phenotype. We aim here to improve understanding of the prevalence of XLH across the life course and of overall survival among people with XLH.

METHODS

This was a population-based cohort study using a large primary care database in the United Kingdom (UK) from 1995 to 2016. XLH cases were matched by age, gender, and practice to up to 4 controls. Trends in prevalence over the study period were estimated (stratified by age) and survival among cases was compared with that of controls.

FINDINGS

From 522 potential cases, 122 (23.4%) were scored as at least possible XLH, while 62 (11.9%) were classified as highly likely or likely (conservative definition). In main analyses, prevalence (95% CI) increased from 3.1 (1.5-6.7) per million in 1995-1999 to 14.0 (10.8-18.1) per million in 2012-2016. Corresponding estimates using the conservative definition were 3.0 (1.4-6.5) to 8.1 (5.8-11.4). Nine (7.4%) of the possible cases died during follow-up, at median age of 64 years. Fourteen (2.9%) of the controls died at median age of 72.5 years. Mortality was significantly increased in those with possible XLH compared with controls (hazard ratio [HR] 2.93; 95% CI, 1.24-6.91). Likewise, among those with likely or highly likely XLH (HR 6.65; 1.44-30.72).

CONCLUSIONS

We provide conservative estimates of the prevalence of XLH in children and adults within the UK. There was an unexpected increase in mortality in later life, which may have implications for other fibroblast growth factor 23-related disorders.

Growth, bone health & ambulatory status of boys with DMD treated with daily vs. intermittent oral glucocorticoid regimen

Oral glucocorticoids (GC) preserve muscle strength and prolong walking in boys with Duchenne muscular dystrophy (DMD). Although vertebral fractures have been reported in boys taking GC, fracture rates for different GC regimes have not been investigated. The aim of this pragmatic longitudinal study was to compare growth, body mass, bone mineral density (BMD), vertebral fractures (VF) and ambulatory status in boys with DMD on daily (DAILY) or intermittent (INTERMITTENT), oral GC regimens. A convenience sample of 50 DMD boys from two centres was included in the study; 25 boys each were on the DAILY or INTERMITTENT regimen. Size adjusted lumbar spine BMD (LS BMAD), total body less head BMD (TBLH), by DXA and distal forearm bone densities by pQCT, GC exposure, VF assessment and ambulatory status were analysed at three time points; baseline, 1 and 2 years. At baseline, there were no differences in age, GC duration or any bone parameters. However, DAILY boys were shorter (height SDS DAILY = -1.4(0.9); INTERMITTENT = -0.8(1.0), p = 0.04) with higher BMI (BMI SDS DAILY = 1.5(0.9); INTERMITTENT = 0.8(1.0), p = 0.01). Over 2 years, DAILY boys got progressively shorter (delta height SDS DAILY = -0.9(1.1); INTERMITTENT = +0.1(0.6), p < 0.001). At their 2 year assessment, 5 DAILY and 10 INTERMITTENT boys were non-ambulant. DAILY boys had more VFs than INTERMITTENT boys (10 versus 2; χ² p = 0.008). BMAD SDS remained unchanged between groups. TBLH and radius BMD declined significantly but the rate of loss was not different. In conclusion, there was a trend for more boys on daily GCs to remain ambulant but at the cost of more VFs, greater adiposity and markedly diminished growth. In contrast, boys on intermittent GCs had fewer vertebral fractures but there was a trend for more boys to loose independent ambulation.

Elemental formula associated hypophosphataemic rickets

OBJECTIVES

Hypophosphataemic rickets (HR) is usually secondary to renal phosphate wasting but may occur secondary to reduced intake or absorption of phosphate. We describe a series of cases of HR associated with the use of Neocate^®, an amino-acid based formula (AAF).

METHODS

A retrospective review of cases with HR associated with AAF use presenting to centres across the United Kingdom.

RESULTS

10 cases were identified, over a 9 month period, all associated with Neocate^® use. The age at presentation was 5 months to 3 years. The majority (8/10) were born prematurely. Gastro oesophageal reflux disease (6/10) was the most frequent indication for AAF use. Radiologically apparent rickets was observed after a median of 8 months (range 3-15 months) of exclusive Neocate^® feed. The majority (7/10) were diagnosed on the basis of incidental findings on radiographs: rickets (6/10) or fracture with osteopenia (5/10). All patients had typical biochemical features of HR with low serum phosphate, high alkaline phosphatase, normal serum calcium and 25 hydroxyvitamin D. However, in all cases the tubular reabsorption of phosphate (TRP) was ≥96%. Phosphate supplementation resulted in normalisation of serum phosphate within 1-16 weeks, and levels remained normal only after Neocate^® cessation. In patients with sufficient follow up duration (4/10), normalisation of phosphate and radiological healing of rickets was noted after 6 months (range: 6-8 months) following discontinuation of Neocate^®.

CONCLUSION

The presence of a normal TRP and resolution of hypophosphataemia and rickets following discontinuation of Neocate^® indicates this is a reversible cause likely mediated by poor phosphate absorption. Close biochemical surveillance is recommended for children on Neocate^®, especially in those with gastrointestinal co-morbidities, with consideration of a change in feed or phosphate supplementation in affected children.

Healthcare resource utilization in the management of hypophosphatasia in three patients displaying a spectrum of manifestations

Background

Hypophosphatasia (HPP) is a rare, heterogeneous disease caused by low tissue-nonspecific alkaline phosphatase activity and associated with a range of signs and symptoms, including bone mineralization defects, respiratory problems, seizures, premature tooth loss, and fractures. Data from patients with HPP and their healthcare resource utilization are lacking. We evaluated healthcare utilization for 3 patients with differing severities of HPP.

Results

Patient 1 had perinatal HPP (received enzyme replacement therapy asfotase alfa under a compassionate use program), Patient 2 had infantile HPP, and Patient 3 had childhood HPP. Healthcare resources used in the National Health Service, England, were identified from coded activities in the hospital database and detailed medical records. These data showed that healthcare utilization was directly related to disease severity. Patient 1 had respiratory complications necessitating prolonged admission for ventilation from birth. Over 2.5 years, this patient was hospitalized 725 days, with visits from 16 specialists. Patient 2 had HPP-associated signs and symptoms starting in infancy, was treated for craniosynostosis, experienced multiple fractures, and required outpatient management for > 18 years. Patient 3 developed signs and symptoms of HPP in childhood and received outpatient and day case treatment for dental, orthopedic, and cardiovascular problems over 24 years. Healthcare utilization varied with severity and complexity of disease manifestations between these patients.

Conclusions

With the recent approval of asfotase alfa for HPP, data from this analysis may help mobilize multidisciplinary healthcare resources for management of HPP by elucidating healthcare resource needs of patients who show a spectrum of clinical manifestations of HPP.

The use of magnetically controlled growing rods in paediatric Osteogenesis Imperfecta with early onset, progressive scoliosis

Osteogenesis Imperfecta (OI) is a condition of bone fragility and can present with early onset scoliosis that can cause respiratory complications in later life. The fear of instrumenting the spine in OI is the possibility of fracture either on primary insertion or subsequent lengthening. Magnetically controlled growing rods were inserted to control a scoliosis in a 6-year old with OI type IV. Fixation was obtained using pedicle screws proximally and distally with sublaminar bands around the ribs proximally. These rods have been remotely lengthened on multiple occasions over a 2-year period. This has controlled the scoliosis whilst also allowing the spine to grow. There are no complications to report. This case reports the use of magnetically controlled growth rods used to manage early onset scoliosis in OI. Frequent lengthening, achieving small increases in length on every occasion protects against the risk of fracture during the lengthening procedure.

Phenotypic Spectrum in Osteogenesis Imperfecta Due to Mutations in TMEM38B: Unraveling a Complex Cellular Defect

CONTEXT

Recessive mutations in TMEM38B cause type XIV osteogenesis imperfecta (OI) by dysregulating intracellular calcium flux.

OBJECTIVES

Clinical and bone material phenotype description and osteoblast differentiation studies.

DESIGN AND SETTING

Natural history study in pediatric research centers.

PATIENTS

Eight patients with type XIV OI.

MAIN OUTCOME MEASURES

Clinical examinations included bone mineral density, radiographs, echocardiography, and muscle biopsy. Bone biopsy samples (n = 3) were analyzed using histomorphometry, quantitative backscattered electron microscopy, and Raman microspectroscopy. Cellular differentiation studies were performed on proband and control osteoblasts and normal murine osteoclasts.

RESULTS

Type XIV OI clinical phenotype ranges from asymptomatic to severe. Previously unreported features include vertebral fractures, periosteal cloaking, coxa vara, and extraskeletal features (muscular hypotonia, cardiac abnormalities). Proband lumbar spine bone density z score was reduced [median -3.3 (range -4.77 to +0.1; n = 7)] and increased by +1.7 (1.17 to 3.0; n = 3) following bisphosphonate therapy. TMEM38B mutant bone has reduced trabecular bone volume, osteoblast, and particularly osteoclast numbers, with >80% reduction in bone resorption. Bone matrix mineralization is normal and nanoporosity low. We demonstrate a complex osteoblast differentiation defect with decreased expression of early markers and increased expression of late and mineralization-related markers. Predominance of trimeric intracellular cation channel type B over type A expression in murine osteoclasts supports an intrinsic osteoclast defect underlying low bone turnover.

CONCLUSIONS

OI type XIV has a bone histology, matrix mineralization, and osteoblast differentiation pattern that is distinct from OI with collagen defects. Probands are responsive to bisphosphonates and some show muscular and cardiovascular features possibly related to intracellular calcium flux abnormalities.

Vertebral fractures assessment in children: Evaluation of DXA imaging versus conventional spine radiography

Vertebral fracture assessment (VFA) by DXA is an accepted tool in adults. However, its use in children has not been assessed. The aim of this study was to evaluate DXA VFA and morphometric analysis (MXA) using a GE Lunar iDXA bone densitometer against spinal radiographic assessment (RA) for the identification of vertebral fractures in children. Spine RA and VFA (T3-L5) were acquired on the same day in 80 children. Forty children considered high risk for fracture by their metabolic bone specialist were referred for spinal RA. Another 40 children were recruited as part of a prospective fracture study and were considered low risk for vertebral fracture. Agreement between RA and VFA was assessed by an expert paediatric radiologist and two paediatricians with expertise in bone pathology. Agreement between RA and MXA was assessed by an expert paediatric radiologist, two clinical scientists and an experienced paediatric radiographer. Vertebrae were ranked as normal, mild, moderate or severe if they had <10%, 11-25%, 26-50% and >50% deformity, respectively. Levels of agreement were calculated using the Cohen kappa score. Evaluating the data from all readable vertebrae, 121 mild, 44 moderate and 16 severe vertebral fractures were identified; with 26, 8, and 5 subjects having at least one mild, moderate or severe fracture, respectively. Depending on rater, 92.8-94.8% of the vertebrae were evaluable by RA. In contrast, 98.4% were evaluable by VFA and only 83.6% were evaluable by MXA. Moderate agreement was found between raters for RA [kappa 0.526-0.592], and VFA [kappa 0.601-0.658] and between RA and VFA [kappa 0.630-0.687]. In contrast, only slight agreement was noted between raters for MXA [kappa 0.361-0.406] and between VFA and MXA [kappa 0.137-0.325]. Agreement substantially improved if the deformities were dichotomised as normal or mild versus moderate or severe [kappa 0.826-0.834]. For the detection of moderate and/or severe fractures the sensitivities & specificities were 81.3% & 99.3%, and 62.5% & 99.2% for VFA and MXA, respectively. This study demonstrates that VFA is as good as RA for detecting moderate and severe vertebral fractures. Given the significant radiation dose saving of VFA compared with RA, VFA is recommended as a diagnostic tool for the assessment of moderate or severe vertebral fracture in children.

Loss of Functional Osteoprotegerin: More Than a Skeletal Problem

INTRODUCTION

Juvenile Paget's disease (JPD), an ultra-rare, debilitating bone disease due to loss of functional osteoprotegerin (OPG), is caused by recessive mutations in TNFRFSF11B. A genotype-phenotype correlation spanning from mild to very severe forms is described.

AIM

This study aimed to describe the complexity of the human phenotype of OPG deficiency in more detail and to investigate heterozygous mutation carriers for clinical signs of JPD.

PATIENTS

We investigated 3 children with JPD from families of Turkish, German, and Pakistani descent and 19 family members (14 heterozygous).

RESULTS

A new disease-causing 4 bp-duplication in exon 1 was detected in the German patient, and a microdeletion including TNFRFSF11B in the Pakistani patient. Skeletal abnormalities in all affected children included bowing deformities and fractures, contractures, short stature and skull involvement. Complex malformation of the inner ear and vestibular structures (2 patients) resulted in early deafness. Patients were found to be growth hormone deficient (2), displayed nephrocalcinosis (1), and gross motor (3) and mental (1) retardation. Heterozygous family members displayed low OPG levels (12), elevated bone turnover markers (7), and osteopenia (6). Short stature (1), visual impairment (2), and hearing impairment (1) were also present.

CONCLUSION

Diminished OPG levels cause complex changes affecting multiple organ systems, including pituitary function, in children with JPD and may cause osteopenia in heterozygous family members. Diagnostic and therapeutic measures should aim to address the complex phenotype.

Prevention and treatment of nutritional rickets

Nutritional rickets continues to be a significant health problem for children worldwide with recent evidence of increasing incidence in many developed countries. It is due to vitamin D deficiency and/or inadequate dietary calcium intake with variation in the relative contributions of each of these dependant on environmental factors such a dietary intake and sunlight exposure. Key to the prevention of rickets is ensuring that pregnant women and their infants receive vitamin D supplementation with good evidence from randomised controlled trials that infants who receive 400iu daily can achieve levels of 25 hydroxyvitamin D of >50nmol/l. However, public health implementation of daily supplementation is more challenging with a need to revisit food fortification strategies to ensure optimal vitamin D status of the population. Treatment of nutritional rickets has traditionally been with vitamin D2 or D3, often given as a daily oral dose for several weeks until biochemical and radiological evidence of healing. However, other treatment regimes with single or intermittent high doses have also proved to be effective. It is now recognised that oral calcium either as dietary intake or supplements should be routinely used in conjunction with vitamin D for treatment.

Nutritional rickets in immigrant and refugee children

Immigrant and refugee populations bring public health challenges to host nations. In the current global refugee crisis, children are the most vulnerable subpopulation. Diseases that were considered rare in the host nation may be highly prevalent among immigrant children. The prevalence of nutritional rickets is increasing in high-income countries, largely driven by an influx of immigrant populations. Nutritional rickets is a bone disease in early childhood resulting in bone pain, delayed motor development, and bending of the bones, caused by vitamin D deficiency and/or inadequate dietary calcium intake. The consequences of nutritional rickets include stunted growth, developmental delay, lifelong bone deformities, seizures, cardiomyopathy, and even death. Nutritional rickets is most commonly seen in children from the Middle East, Africa, and South Asia in high-income countries. Dark skin pigmentation, sun avoidance, covering the skin, and prolonged breast feeding without vitamin D supplementation, are important risk factors for vitamin D deficiency, and combined with a lack of dairy products in the diet, these deficiencies can result in insufficient calcium supply for bone mineralization. We recommend screening all immigrant and refugee children under 5 years of age from these ethnic groups for nutritional rickets, based on clinical features, and confirming the diagnosis with radiographs of the wrists and knees. Because nutritional rickets is entirely preventable, public health policies must address the need for universal vitamin D supplementation and adequate dietary calcium to protect children from this scourge. Vitamin D supplementation of all infants and children with 400 IU/d during the first year of life and dietary or supplemental intakes of at least 600 IU/d of vitamin D and 500 mg/d of calcium thereafter, will effectively prevent nutritional rickets. We call on national health authorities of host countries to implement health check lists and prevention programs that include screening for micronutrient deficiencies, in addition to assessing infections and vaccination programs. Due to their high prevalence of vitamin D deficiency, refugee children of all ages from these ethnic groups should be supplemented with vitamin D, beginning upon arrival.

Vitamin D in childhood and adolescence: an expert position statement

Vitamin D is a key hormone in the regulation of calcium and phosphorus metabolism and plays a pivotal role in bone health, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur. Great interest has been placed in recent years on vitamin D's extraskeletal actions. However, while recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious and autoimmune diseases, the actual impact of vitamin D status on the global health of children and adolescents, other than bone, remains a subject of debate. In the meantime, pediatricians still need to evaluate the determinants of vitamin D status and consider vitamin D supplementation in children and adolescents at risk of deficiency. This review is the result of an expert meeting that was held during the congress "Update on vitamin D and bone disease in childhood" convened in Pisa, Italy, in May 2013.

CONCLUSION

The collaboration of the international group of experts produced this "state of the art" review on vitamin D in childhood and adolescence. After dealing with vitamin D status and its determinants, the review outlines the current debate on vitamin D's health benefits, concluding with a practical approach to vitamin D supplementation during childhood and adolescence.

WHAT IS KNOWN

• Vitamin D deficiency is a worldwide health problem. • Vitamin D deficiency affects not only musculoskeletal health but also a potentially wide range of acute and chronic diseases. What is New: • We reviewed the literature focusing on randomized controlled trials of vitamin D supplementation during childhood and adolescence. • This review will help pediatricians to appreciate the clinical relevance of an adequate vitamin D status and it will provide a practical approach to vitamin D supplementation.

Case Histories

Conditions related to abnormalities of calcium and bone metabolism are large in number and are characterised by hypocalcaemia, hypercalcaemia, primary and secondary osteoporosis, rickets resulting from both vitamin D and phosphate metabolism disorders, and a series of miscellaneous conditions. Included in this chapter is a series of cases drawn from our clinics and from colleagues who have presented these clinical problems at the recent Advanced Courses in Paediatric Bone and Calcium Metabolism run by the British Paediatric and Adolescent Bone group. This series of cases is not fully comprehensive but is designed to cover the major aspects of bone- and calcium-related disorders.

A Practical Approach to Vitamin D Deficiency and Rickets

Rickets is a condition in which there is failure of the normal mineralisation (osteomalacia) of growing bone. Whilst osteomalacia may be present in adults, rickets cannot occur. It is generally caused by a lack of mineral supply, which can either occur as a result of the deficiency of calcium (calciopaenic rickets, now known as parathyroid hormone-dependent rickets) or of phosphate (phosphopaenic rickets, now called FGF23-dependent rickets). Renal disorders may also interfere with the process of mineralisation and cause rickets. Only parathyroid hormone-dependent rickets and distal renal tubular disorders will be discussed in this chapter. The most common cause of rickets is still vitamin D deficiency, which is also responsible for other problems. Disorders of vitamin D metabolism or responsiveness may also cause similar issues. Distal renal tubular acidosis may also be caused by a variety of metabolic errors similar to those of osteoclasts. One form of distal renal tubular acidosis also causes a type of osteopetrosis. This chapter describes these conditions in detail and sets out a logical approach for treatment.

A Practical Approach to Hypocalcaemia in Children

Hypocalcaemia is one of the commonest disorders of mineral metabolism seen in children and may be a consequence of several different aetiologies. These include a lack of secretion or function of parathyroid hormone, disorders of vitamin D metabolism and abnormal function of the calcium-sensing receptor. A practical approach to the investigation, diagnosis and subsequent management of hypocalcaemic disorders is presented.

Outcomes following prosthetic patch repair in newborns with congenital diaphragmatic hernia

Background

The anatomical defect in congenital diaphragmatic hernia (CDH) can usually be closed primarily but prosthetic patch repair may be required in newborns with a deficient diaphragm. High rates of patch failure and hernia recurrence (up to 50 per cent) have been reported. This study evaluated contemporary outcomes following patch repair of CDH at a UK paediatric surgical centre.

Methods

Medical records of newborns undergoing surgery for CDH between 1 February 1990 and 1 November 2010, and attending a multidisciplinary follow-up clinic, were examined. Operative details and patch utilization are reported.

Results

Of 118 newborns with CDH, 37 required a patch to the diaphragmatic defect. Gore-Tex® patches were used in 35 and biological Surgisis® patches in two. Eight babies additionally required an abdominal wall patch. Seven infants had an abdominal patch alone with primary diaphragm repair. A total of 102 infants (86·4 per cent) survived after surgery. Two early recurrences were both related to the use of biological patches, leading to revisional surgery with Gore-Tex® patch reconstruction. Diaphragmatic patch use was associated with a greater requirement for intensive cardiovascular and respiratory support, although there was no significant difference in mortality between patch versus primary diaphragm repair. The mortality rate was significantly higher among infants requiring abdominal wall patching (with or without a diaphragmatic patch): 40 per cent (6 of 15) versus 9·7 per cent (10 of 103) (P = 0·006). Postoperative survival rates for infants with a diaphragmatic patch alone, abdominal wall patch alone, and both abdominal and diaphragmatic patches were 86 per cent (25 of 29), 57 per cent (4 of 7) and 63 per cent (5 of 8) respectively.

Conclusion

Prosthetic diaphragmatic hernia repair at this centre has a good outcome and low rate of recurrence (5 per cent). The recognition of an inadequate abdominal domain prenatally may additionally prove to be a useful marker for predicting increased mortality in newborns with CDH.

Diagnostic evaluation of bone densitometric size adjustment techniques in children with and without low trauma fractures

Several established methods are used to size adjust dual-energy X-ray absorptiometry (DXA) measurements in children. However, there is no consensus as to which method is most diagnostically accurate. All size-adjusted bone mineral density (BMD) values were more diagnostically accurate than non-size-adjusted values. The greatest odds ratio was estimated volumetric BMD for vertebral fracture.

INTRODUCTION

The size dependence of areal bone density (BMDa) complicates the use of DXA in children with abnormal stature. Despite several size adjustment techniques being proposed, there is no consensus as to the most appropriate size adjustment technique for estimating fracture risk in children. The aim of this study was to establish whether size adjustment techniques improve the diagnostic ability of DXA in a cohort of children with chronic diseases.

METHODS

DXA measurements were performed on 450 children, 181 of whom had sustained at least one low trauma fracture. Lumbar spine (L2-L4) and total body less head (TBLH) Z-scores were calculated using different size adjustment techniques, namely BMDa and volumetric BMD for age (bone mineral apparent density (BMAD)); bone mineral content (BMC) and bone area for height; BMC for bone area; BMC for lean mass (adjusted for height); and BMC for bone and body size.

RESULTS

Unadjusted L2-L4 and TBLH BMDa were most sensitive but least specific at distinguishing children with fracture. All size adjustments reduced sensitivity but increased post-test probabilities, from a pre-test probability of 40 % to between 58 and 77 %. The greatest odds ratio for fracture was L2-L4 BMAD for a vertebral fracture and TBLH for lean body mass (LBM) (adjusted for height) for a long bone fracture with diagnostic odds ratios of 9.3 (5.8-14.9) and 6.5 (4.1-10.2), respectively.

CONCLUSION

All size adjustment techniques improved the predictive ability of DXA. The most accurate method for assessing vertebral fracture was BMAD for age. The most accurate method for assessing long bone fracture was TBLH for LBM adjusted for height.

Vitamin D and child health: part 2 (extraskeletal and other aspects)

The first part of this review focused on the skeletal aspects of vitamin D. This second part reviews some of the available evidence that vitamin D may have a physiological extraskeletal role beyond its traditional effect on the skeleton. This aspect has influenced the definition of vitamin D deficiency and what level of vitamin D should be regarded as optimal. The recognition of the prevalence of vitamin D deficiency and insufficiency has led to debate as to whether and how we should be treating asymptomatic individuals. This review discusses the potential extraskeletal effects of vitamin D, the definition of vitamin D deficiency and our thoughts on indications for measurement and treatment.

Vitamin D and child health part 1 (skeletal aspects)

Currently, there is considerable clinical and academic interest in vitamin D as a consequence of a number of developments over the past decade. This was initially related to a recognised resurgence of symptomatic vitamin D deficiency in children in the UK and other countries. The potential importance of maternal vitamin D status on bone mass in early childhood and the effect of vitamin D supplementation on peak bone mass has been the subject of much research. An additional development has been the recognition that vitamin D may have a physiological extraskeletal role. This aspect has influenced the definition of vitamin D deficiency, and what level should be regarded as optimal. The recognition of the prevalence of vitamin D deficiency and insufficiency has led to debate as to whether and how we should be treating asymptomatic individuals. This review consists of two parts, the first focuses on the skeletal aspects of vitamin D, while the second will review some of the potential extraskeletal aspects, the definition of vitamin D deficiency, and our thoughts on indications for measurement and treatment.

Do trainees value feedback in case-based discussion assessments?

BACKGROUND

Feedback is important in learning, including in workplace-based assessments.

AIM

To explore trainee's perceptions of the educational value of case-based discussions (CBDs) specifically focusing on feedback.

METHODS

An online questionnaire and interviews obtaining detailed descriptions of paediatric trainees at UK specialist training levels 1 and 2 views and experiences were used. Qualitative data were analysed using a thematic framework analysis.

RESULTS

Trainees viewed CBDs as educationally valuable, aiding reflective learning, improving decision making skills and effecting a change in practice. Opinions varied regarding how useful they found the feedback. Feedback was perceived as more valuable from assessors who had a positive attitude towards CBDs, understood the process and had experience in leading them. Time constraints and assessments performed in less suitable environments had a negative impact on feedback. Trainees felt the choice of case played an important role, with challenging cases resulting in more beneficial feedback.

CONCLUSIONS

CBD assessments provide a new opportunity for good quality learning and feedback, providing there is a commitment to the educational aspects of the process by both trainer and trainee. Trainers being aware of the qualities of the discussions that result in successful feedback, could significantly improve their educational value.

TSHR is the main causative locus in autosomal recessively inherited thyroid dysgenesis

Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder and results in mental retardation if untreated. Eighty-five percent of CH cases are due to disruptions in thyroid organogenesis and are mostly sporadic, but about 2% of thyroid dysgenesis is familial, indicating the involvement of genetic factors in the aetiology of the disease. In this study, we aimed to investigate the Mendelian (single-gene) causes of non-syndromic and non-goitrous congenital hypothyroidism (CHNG) in consanguineous or multi-case families. Here we report the results of the second part (n=105) of our large cohort (n=244), representing the largest such cohort in the literature, and interpret the overall results of the whole cohort. Additionally, 50 sporadic cases with thyroid dysgenesis and 400 unaffected control subjects were included in the study. In familial cases, first, we performed potential linkage analysis of four known genes causing CHNG (TSHR, PAX8, TSHB, and NKX2-5) using microsatellite markers and then examined the presence of mutations in these genes by direct sequencing. In addition, in silico analyses of the predicted structural effects of TSHR mutations were performed and related to the mutation specific disease phenotype. We detected eight new TSHR mutations and a PAX8 mutation but no mutations in TSHB and NKX2-5. None of the biallelic TSHR mutations detected in familial cases were present in the cohort of 50 sporadic cases. Genotype/phenotype relationships were established between TSHR mutations and resulting clinical presentations. Here we conclude that TSHR mutations are the main detectable cause of autosomal recessively inherited thyroid dysgenesis. We also outline a new genetic testing strategy for the investigation of suspected autosomal recessive non-goitrous CH.

Oxygen saturation profile in healthy preterm infants

AIM

To establish a reference range for oxygen saturation (SpO(2)) in well preterm infants to guide home oxygen therapy using a pulse oximeter and Pulse Oximetry Data Analysis Software (PODS).

METHODS

SpO(2) and heart-rate profiles of healthy preterm infants receiving mechanical ventilation for less than 6 h and supplemental oxygen for less than 48 h were monitored using a pulse oximeter. The stored data were downloaded from the monitor to a personal computer as individual files. Each infant's files of SpO(2) were subsequently displayed in graphic form, and a reference range was constructed using dedicated software, PODS.

RESULTS

43 infants were studied. The median value of all infants mean SpO(2) values was 95% (range 92-99%). The median duration of saturations less than 85% and between 85% and 90 % were 1% and 2% respectively. Using the study group median, 5th and 95th percentiles, a cumulative frequency curve of time against SpO(2) value was constructed (representing the reference range of SpO(2) profiles in healthy preterm infants).

CONCLUSION

The SpO(2) reference range can be used as an easy and practical guide to compare SpO(2) profiles of infants on home oxygen therapy and guide their oxygen therapy.

Changing clinical practice: significant events that influence trainees' learning

BACKGROUND

Changing behaviour as a result of learning from clinical practice is an important part of improving the quality of healthcare. The aims of this study were to investigate the educational influences that produce change in specialist trainees' clinical practice and to identify any differences in the types of learning recalled between trainees in primary and secondary care.

METHODS

All 105 general practice trainees (GPSTs) and 100 first-year specialist trainees (STs) in one deanery were given the opportunity to take part in the study. There were three data collection phases: three focus groups followed by a questionnaire and 13 semi-structured interviews. The questionnaire was distributed to all first-year STs and GPSTs. Of these, 64 STs (32% of total sample) and 45 GPSTs (22.5% of total sample) completed the questionnaire.

RESULTS

Broad themes outlining the key influences on behavioural change were practice-based learning and the adherence to guidelines. These themes were identified from the focus groups and questionnaire and explored during interviews. Both primary and secondary care trainees reported similar educational influences.

CONCLUSIONS

There is no difference in the types of learning event that primary and secondary care trainees recall when describing changes in their clinical practice. Formal learning opportunities were valued when relevant to everyday clinical experiences. Guidelines were reference points in everyday practice and also a focus for discussion in formal education settings. Positive and negative clinical events were recognised to be key experiences that aided professional development and learning. These results support the use of work-place-based learning as a means of facilitating clinical change and development in specialty training in primary and secondary care.

Use of home oxygen for children in England and Wales

BACKGROUND

With the introduction of a standardised ordering system in February 2006, the opportunity arose to collect data on children requiring home oxygen in England and Wales. The authors' aim was to determine the incidence and patterns of home oxygen prescribing.

METHODS

A paediatric home oxygen clinical network and the Children's Home Oxygen Record Database were established. During a 3-year period (February 2006 to January 2009), prescribers were requested to submit copies of the Home Oxygen Order Forms. In addition, anonymised point prevalence data on all patients currently receiving home oxygen in June 2007 were obtained from the four provider companies.

RESULTS

Children's Home Oxygen Record Database--Forms were analysed for 888 children <16 years (58% boys) with a median age of 4.1 months; 656 (74%) were <1 year. 541 (68%) had a diagnosis of chronic neonatal lung disease; 53 (7%), neurodisability; and 49 (6%), cardiac disease. Order forms were often incomplete, and prescribing practice was variable. Provider's cross-sectional survey--There were 3338 children <16 years, representing 4% of all patients on home oxygen. Median age was 3.1 years with a peak at 6 months. The prevalence for paediatric home oxygen use in England and Wales was 0.33 per 1000, with a peak of 1.08 per 1000 for those <1 year. Marked regional variation was noted.

CONCLUSIONS

This is the first national dataset available for children prescribed home oxygen in England and Wales. The study emphasises the need for a coordinated approach to home oxygen prescribing and justifies the recent publication of evidence-based guidelines.

How well are graduates prepared for practice when measured against the latest GMC recommendations?

This article investigates the perspectives of University of Liverpool graduate foundation doctors and their consultants on their preparedness for professional practice.

Bone status of adolescent girls in Pune (India) compared to age-matched South Asian and white Caucasian girls in the UK

Underprivileged adolescent girls in Pune, India, were shorter and lighter, and had reduced lean body mass (LBM) compared with relatively 'well off' age-matched South Asian and white Caucasian girls in the UK. Pune girls had low bone mass for projected bone area (BA) in comparison to their UK counterparts, but they had the appropriate amount of bone mineral content (BMC) for their LBM.

PURPOSE

To determine whether adolescent girls from a low socioeconomic group in Pune, India, who had low dietary calcium intake (449 mg/day; range 356-538 mg/day) and hypovitaminosis D (median serum 25-hydroxyvitamin D 23.4 nmol/l; range 13.5-31.9 nmol/l), would have lower lumbar spine (LS) bone mineral apparent density (BMAD), and total body (TB) BMC adjusted for LBM.

METHODS

Dual energy X-ray absorptiometry was used to measure TB and LS BMC, BA and TB LBM in 50 postmenarcheal girls in Pune. These variables were compared with data from 34 South Asian and 82 white Caucasian age-matched girls in the UK.

RESULTS

Pune girls were shorter and lighter, and had less LBM for height, compared to both UK groups, and they had later age of menarche than UK Asians. BA-adjusted TB BMC and LS BMAD were lower in Pune girls (mean+/-SE 1,778+/-17 g; 0.332+/-0.005 g/cm(3)), compared to the UK South Asians (mean+/-SE 1,864+/-18 g; 0.355+/-0.006 g/cm(3)) and UK white Caucasians (mean+/-SE 1,864+/-13 g; 0.345+/-0.004 g/cm(3)). In contrast both LS and TB BMC adjusted for TB LBM were not significantly different between the groups.

CONCLUSION

Pune girls had low bone mass for projected BA relative to UK South Asian and white Caucasian girls, but had the appropriate amount of BMC for their LBM.

Hormones and genes of importance in bone physiology and their influence on bone mineralization and growth in Turner syndrome

This mini review summarizes papers presented in a Joint Symposium between the Bone, Growth Plate and Turner Syndrome Working Groups of the European Society for Paediatric Endocrinology (ESPE) that was held on September 9, 2009, in New York.The program had been composed to give an update on hormones and genes of importance in bone physiology and their influence on bone mineralization and growth in Turner syndrome. This paper summarizes the data and highlights the main topics and discussions related to each presentation.

Identification and characterisation of a novel GHR defect disrupting the polypyrimidine tract and resulting in GH insensitivity

OBJECTIVE

GH insensitivity (GHI) is caused in the majority of cases by impaired function of the GH receptor (GHR). All but one known GHR mutation are in the coding sequence or the exon/intron boundaries. We identified and characterised the first intronic defect occurring in the polypyrimidine tract of the GHR in a patient with severe GHI.

DESIGN

We investigated the effect of the novel defect on mRNA splicing using an in vitro splicing assay and a cell transfection system.

METHODS

GHR was analysed by direct sequencing. To assess the effect of the novel defect, two heterologous minigenes (wild-type and mutant L1-GHR8-L2) were generated by inserting GHR exon 8 and its flanking wild-type or mutant intronic sequences into a well-characterised splicing reporter (Adml-par L1-L2). (32)P-labelled pre-mRNA was generated from the two constructs and incubated in HeLa nuclear extracts or HEK293 cells.

RESULTS

Sequencing of the GHR revealed a novel homozygous defect in the polypyrimidine tract of intron 7 (IVS7-6T>A). This base change does not involve the highly conserved splice site sequences, and is not predicted in silico to affect GHR mRNA splicing. Nevertheless, skipping of exon 8 from the mutant L1-GHR8-L2 mRNA was clearly demonstrated in the in vitro splicing assay and in transfected HEK293 cells.

CONCLUSION

Disruption of the GHR polypyrimidine tract causes aberrant mRNA splicing leading to a mutant GHR protein. This is predicted to lack its transmembrane and intracellular domains and, thus, be incapable of transducing a GH signal.

PPIB mutations cause severe osteogenesis imperfecta

Deficiency of cartilage-associated protein (CRTAP) or prolyl 3-hydroxylase 1(P3H1) has been reported in autosomal-recessive lethal or severe osteogenesis imperfecta (OI). CRTAP, P3H1, and cyclophilin B (CyPB) form an intracellular collagen-modifying complex that 3-hydroxylates proline at position 986 (P986) in the alpha1 chains of collagen type I. This 3-prolyl hydroxylation is decreased in patients with CRTAP and P3H1 deficiency. It was suspected that mutations in the PPIB gene encoding CyPB would also cause OI with decreased collagen 3-prolyl hydroxylation. To our knowledge we present the first two families with recessive OI caused by PPIB gene mutations. The clinical phenotype is compatible with OI Sillence type II-B/III as seen with COL1A1/2, CRTAP, and LEPRE1 mutations. The percentage of 3-hydroxylated P986 residues in patients with PPIB mutations is decreased in comparison to normal, but it is higher than in patients with CRTAP and LEPRE1 mutations. This result and the fact that CyPB is demonstrable independent of CRTAP and P3H1, along with reported decreased 3-prolyl hydroxylation due to deficiency of CRTAP lacking the catalytic hydroxylation domain and the known function of CyPB as a cis-trans isomerase, suggest that recessive OI is caused by a dysfunctional P3H1/CRTAP/CyPB complex rather than by the lack of 3-prolyl hydroxylation of a single proline residue in the alpha1 chains of collagen type I.

School age outcome of hospitalisation with respiratory syncytial virus infection of prematurely born infants

BACKGROUND

Hospitalisation due to respiratory syncytial virus (RSV) infection in the first 2 years after birth has been associated with increased healthcare utilisation and associated costs up to 5 years of age in children born prematurely at less than 32 weeks of gestation who developed bronchopulmonary dysplasia (BPD). A study was undertaken to determine whether hospitalisation due to RSV infection in the first 2 years was associated with increased morbidity and lung function abnormalities in such children at school age, and if any effects were influenced by age.

METHODS

Healthcare utilisation and cost of care in years 5-7 were reviewed in 147 children and changes in healthcare utilisation between 0 and 8 years were assessed also using results from two previous studies. At age 8-10 years, 77 children had their lung function assessed and bronchial hyper-responsiveness determined.

RESULTS

Children hospitalised with RSV infection (n = 25) in the first 2 years had a greater cost of care related to outpatient attendance than those with a non-respiratory or no admission (n = 72) when aged 5-7 years (p = 0.008). At 8-10 years of age, children hospitalised with RSV infection (n = 14) had lower forced expiratory volume in 0.75 s (FEV(0.75)) (p = 0.015), FEV(0.75)/forced vital capacity (p = 0.027) and flows at 50% (p = 0.034) and 75% (p = 0.006) of vital capacity than children hospitalised for non-RSV causes (n = 63). Healthcare utilisation decreased with increasing age regardless of RSV hospitalisation status.

CONCLUSIONS

In prematurely born children who had BPD, hospitalisation due to RSV infection in the first 2 years is associated with reduced airway calibre at school age.

Assessing senior house officers' perceptions of learning

OBJECTIVE

To identify trainers', senior house officers' (SHOs) and their nursing colleagues' perceptions of learning in a neonatal unit.

DESIGN

Three questionnaires were administered to staff of the neonatal intensive care unit. The first one asked consultants about activities that trainees are exposed to, a second explored the views of other permanent staff regarding the value of the educational activities available for trainees and a third explored the perception of the SHOs of their learning experiences.

SETTING

Regional neonatal intensive care unit.

RESULTS

Permanent clinical staff felt that the consultant ward round, emergency management, protected teaching, practical procedures and informal discussion were the most valuable learning experiences. Trainees felt that consultant and handover ward rounds were important and formal protected teaching less so.

CONCLUSION

A mismatch of perception of learning experiences was identified in the department. These mismatches can be addressed by acknowledging the importance of when the trainees perceive they learn best and improving the learning experience in situations where they do not.

Expression of 25-hydroxyvitamin D3-1alpha-hydroxylase in subcutaneous fat necrosis

BACKGROUND

The most serious complication of subcutaneous fat necrosis (SCFN), a rare condition of the newborn characterized by indurated purple nodules, is hypercalcaemia. However, the mechanism for this hypercalcaemia remains unclear.

OBJECTIVES

To determine whether the hypercalcaemia associated with SCFN involves expression of the vitamin D-activating enzyme 25-hydroxyvitamin D(3)-1alpha-hydroxylase (1alpha-hydroxylase) in affected tissue.

METHODS

Skin biopsies from two male patients with SCFN and hypercalcaemia were taken. The histological specimens were assessed using a polyclonal antibody against 1alpha-hydroxylase.

RESULTS

Histology in both cases showed strong expression of 1alpha-hydroxylase protein (brown staining) within the inflammatory infiltrate associated with SCFN. This was consistent with similar experiments in other granulomatous conditions.

CONCLUSIONS

Hypercalcaemia in SCFN appears to be due to abundant levels of 1alpha-hydroxylase in immune infiltrates associated with tissue lesions. This is consistent with previous observations of extrarenal 1alpha-hydroxylase in skin from other granulomatous conditions such as sarcoidosis and slack skin disease.

Lung function measurement in prematurely born preschool children with and without chronic lung disease

OBJECTIVE

Prematurely born infants often have recurrent wheeze and long-term respiratory morbidity at follow-up. Assessment of airways obstruction in preschool children is feasible using the interrupter resistance (Rint) but has rarely been examined in preterm children with and without chronic lung disease (CLD). The objective of this study was to determine lung function measured by the interrupter technique, its feasibility in the ambulatory setting and respiratory health in prematurely born preschool children with and without CLD.

STUDY DESIGN

Preterm children of 2 to 4 years with severe CLD (>30% oxygen at 36 weeks and discharged home receiving supplemental oxygen) (n=43, median gestational age 27 weeks and median birth weight 995 g) and without CLD (n=33, median gestational age 29 weeks and median birth weight 1366 g) attempting lung function test for the first time were enrolled. Respiratory symptoms score was calculated using a questionnaire. A single set of 10 consecutive Rint measurements was obtained using a portable device (MicroRint). Median of at least five occlusions with consistent shape of mouth pressure-time curves was taken to be a Rint measurement. To assess feasibility the children were categorized as 'satisfactory', 'failure' and 'rejected' depending on the outcome of the test. Outcome variables were respiratory symptoms score and Rint.

RESULT

Satisfactory Rint measurement was obtained in 46 (61%) children, 9 (36%) 2-year olds, 17 (65%) 3-year olds and 20 (80%) 4-year olds. As compared with the preterm control children (n=18), CLD children (n=28) had significantly higher respiratory symptoms score (18.5 vs 6, P<0.01) and Rint expressed as absolute values (kPa l(-1)) and z-scores (1.33 vs 1.16 and 1.42 vs 1.0, P<0.01), respectively.

CONCLUSION

Rint measurement is feasible in prematurely born children of preschool age in the ambulatory setup. Preschool children with severe CLD may be identified from preterm children without CLD by increased Rint that may be used as a screening tool and as an outcome measure for interventions.