Pediatric intestinal failure: Predictors of metabolic bone disease

Dual x-ray absorptiometry monitoring in pediatric short bowel syndrome: an integrative review

OBJECTIVE

To analyze the bone health of pediatric patients with short bowel syndrome intestinal failure (SBS-IF).

DATA SOURCE

An integrative literature review was performed using the data published in the MEDLINE-PubMed and Scientific Electronic Library Online (SciELO) databases between January 2010 and April 2021, and through a manual search of the reference lists of relevant studies. Studies were included if they assessed bone mineral density by the Dual X-Ray Absorptiometry (DXA) technique, incorporated pediatric patients (up to 20 years of age) with SBS under parenteral nutrition (PN) and were written in English. Eleven primary sources met the inclusion criteria for this study.

DATA SYNTHESIS

Pediatric patients with SBS-IF under long-term parenteral nutrition experienced frequent changes in bone metabolism, leading to osteoporotic fractures and growth failure. These patients have deficiencies in multiple nutrients, such as calcium, magnesium, phosphorus, and vitamin D. Consequently, there are variations in the secretion and regulation of the parathyroid hormone. In addition, the pharmacotechnical limitations related to calcium and phosphorus in the PN solution, use of glucocorticoids, and difficulty performing physical activity are risk factors for the development of metabolic bone disease in pediatric patients with SBS-IF.

CONCLUSIONS

Low bone mineral density was associated with a high risk of developing osteoporosis, fractures, and growth deficiency in pediatric patients with SBS-IF on PN therapy in the long term.

Reducing Metabolic Bone Disease Burden in Intestinal Failure Children on Home Parenteral Nutrition

Objective

To determine the prevalence of secondary hyperparathyroidism in a cohort of pediatric patients receiving home parenteral nutrition.

Methods

For a service review, a population-based cohort of 37 pediatric intestinal failure patients receiving long-term parenteral nutrition that underwent serial biochemical monitoring during a study period of approximately 4 years were examined. Following the production of an algorithm, a follow-up audit was carried out (n = 33) after approximately 6 months.

Results

Of the 37 patients examined in the initial service review, 22 (59%) were found to have an elevated parathyroid hormone (PTH) during the period of monitoring and 5 (14%) had a persistently elevated PTH. In the follow-up audit following the implementation of an algorithm, the number with elevated PTH reduced to 6 (18%) and no patients had persistently high levels.

Conclusion

Elevated PTH is a common biochemical finding in pediatric intestinal failure patients receiving home parenteral nutrition and its presence should alert clinicians to the need to optimize nutritional parameters such as calcium to phosphate molar ratio and vitamin D status; failure to do so may increase the future burden of metabolic bone disease in such patients. We propose that an algorithm may help in this endeavor.

Body Composition and Physical Activity in Pediatric Intestinal Failure On and Off Parenteral Nutrition

OBJECTIVES

Data on the relationship between body composition (BC) and physical activity (PA) in children with intestinal failure (IF) are lacking. The objectives were to collect data on PA and BC in children with IF, both parenterally and enterally fed, and to assess the relationship between PA and BC.

METHODS

Cross-sectional study in children 5-18 years with IF including those receiving parenteral nutrition (PN) and those fully enterally fed. PA levels were measured using accelerometry. BC was measured by dual-energy X-ray absorptiometry. Data were compared to age- and sex-matched population norms using t tests. Regression analysis assessed the relationship between BC and PA.

RESULTS

Fifty-eight children with IF (38 males), mean (SD) age of 10.0 (3.5) years, 20 dependent on PN were included. Patients with IF had significantly fewer steps per day ( P ≤ 0.001) compared with literature controls, with a mean (SD) of 7,972 (3,008) and 11,749 (1,106), respectively. There were no significant differences between patients receiving PN and those enterally fed, but both groups were significantly less active than literature controls ( P < 0.001). Patients with IF had higher fat mass and lower fat-free mass compared to literature controls ( P = 0.008). PA had a significant effect on BC ( r2 = 0.32, P < 0.001).

CONCLUSIONS

Children with IF, those receiving PN and those fully enterally fed, are at risk of decreased PA and altered BC. PA should be part of ongoing rehabilitation and management to optimize outcomes.

Assessment of body composition in pediatric intestinal failure: A comparison study

BACKGROUND

The objective of the study was to compare bioelectrical impedance analysis (BIA) and skinfolds with dual energy x-ray absorptiometry (DXA) in the assessment of body composition of children with intestinal failure. DXA is the reference method for body composition assessment in clinical settings.

METHODS

Children aged 1-18 years with intestinal failure whohave DXA as part of routine clinical monitoring were eligible. BIA measured total body water on the same day as DXA. Skinfold measurements were taken at four sites: triceps, biceps, subscapular, and suprailiac. Percentage of fat mass (%FM) and fat-free mass (%FFM) were derived from resistance and reactance measured by BIA by using age-specific equations. Percentage of FM was calculated from skinfold measures by using age-specific equations. Data on patient characteristics, intestinal failure-related factors, and feeding method were collected. Paired t test examined differences in %FM and %FFM and Bland-Altman analysis determined the agreement between BIA, skinfolds, and DXA. Marginal linear model assessed the effect of age, sex, and feeding method on the difference in body composition obtained between DXA and BIA and between DXA and skinfolds.

RESULTS

Sixty-eight children with intestinal failure, mean age 8.9 ± 4.2 years, were studied. There was no difference between %FFM and %FM obtained by DXA and BIA (P = 0.26), with a mean bias (95% CI) of -0.69 (-1.9 to 0.5) for %FFM. Sex and age were individually and jointly associated with the bias observed between DXA and BIA (P < 0.05). Skinfold and DXA measurements were significantly different (P < 0.05).

CONCLUSIONS

BIA is an acceptable clinical tool for assessing body composition in pediatric intestinal failure.

Age-related trajectory of bone density in children with intestinal failure: A longitudinal retrospective cohort study

BACKGROUND

Longitudinal changes in bone health in children with intestinal failure (IF) are unclear. We aimed to better understand the trajectory of bone mineral status over time in children with IF and identify clinical factors that influence the trajectory.

METHODS

Clinical records of patients attending the Intestinal Rehabilitation Center of Cincinnati Children's Hospital Medical Center between 2012 and 2021 were reviewed. Children diagnosed with IF before age 3 years with at least two lumbar spine dual-energy x-ray absorptiometry scans were included. We abstracted information on medical history, parenteral nutrition, bone density, and growth. We calculated bone density z scores with and without adjustment for height z scores.

RESULTS

Thirty-four children with IF met inclusion criteria. Children were shorter than average with a mean height z score of -1.5 ± 1.3. The mean bone density z score was -1.5 ± 1.3 with 25 of the cohort having a z score < -2.0. After height adjustment, the mean bone density z score was -0.42 ± 1.4 with 11% below -2.0. Most dual-energy x-ray absorptiometry scans (60%) had a feeding tube artifact. Bone density z scores increased slightly with age and lower parenteral nutrition dependency and were higher in scans without an artifact. Etiologies of IF, line infections, prematurity, and vitamin D status were not associated with height-adjusted bone density z scores.

CONCLUSION

Children with IF were shorter than expected for age. Deficits in bone mineral status were less common when adjusting for short stature. Etiologies of IF, prematurity, and vitamin D deficiency were not associated with bone density.

Management of pediatric intestinal failure related to short bowel syndrome

Intestinal failure (IF) secondary to short bowel syndrome is a challenging and complex medical condition with significant risk for surgical and medical complications. Significant advancements in the care of this patient population have led to improved survival rates. Due to their intensive medical needs children with IF are at risk for long-term complications that require comprehensive management and close monitoring. The purpose of this paper is to review the available literature emphasizing the surgical aspects of care for children with IF secondary to short bowel syndrome. A key priority in the surgical care of this patient population includes strategies to preserve available bowel and maximize its function. Utilization of novel surgical techniques and autologous bowel reconstruction can have a significant impact on children with IF secondary to short bowel syndrome related to the function of their bowel and ability to achieve enteral autonomy. It is also important to understand the potential long-term complications to ensure strategies are put in place to mitigate risk with early detection to improve long-term outcomes.

Metabolic Bone Disease in Children with Intestinal Failure and Long-Term Parenteral Nutrition: A Systematic Review

Metabolic bone disease (MBD) is a possible complication of intestinal failure (IF), with a multi-factorial pathogenesis. The reduction of bone density (BMD) may be radiologically evident before manifestation of clinical signs (bone pain, vertebral compression, and fractures). Diagnosis relies on dual-energy X-ray absorptiometry (DXA). Incidence and evolution of MBD are not homogeneously reported in children. The aim of this systematic review was to define the prevalence of MBD in IF children and to describe risk factors for its development. A comprehensive search of electronic bibliographic databases up to December 2021 was conducted. Randomized controlled trials; observational, cross-sectional, and retrospective studies; and case series published between 1970 and 2021 were included. Twenty observational studies (six case-control) were identified and mostly reported definitions of MBD based on DXA parameters. Although the prevalence and definition of MBD was largely heterogeneous, low BMD was found in up to 45% of IF children and correlated with age, growth failure, and specific IF etiologies. Data demonstrate that long-term follow-up with repeated DXA and calcium balance assessment is warranted in IF children even when PN dependence is resolved. Etiology and outcomes of MBD will be better defined by longitudinal prospective studies focused on prognosis and therapeutic perspectives.

Generic and Disease-specific Health-related Quality of Life in Pediatric Intestinal Failure

OBJECTIVE

The aim of the study was to assess overall and disease-specific health-related quality of life (hrQOL) in patients with pediatric intestinal failure (PIF) and caregivers and elucidate differences from healthy and chronic gastrointestinal (GI) illness cohorts.

METHODS

Cross-sectional study of patients with PIF and their caregivers managed at a multidisciplinary intestinal rehabilitation program using the PedsQL Generic Core and the Gastrointestinal Symptoms Module to assess generic and disease-specific hrQOL, respectively. These data were compared to established healthy and chronic GI disease controls.

RESULTS

A total of 53 patients (mean age 6.2 ± 3.9 years) and their caregivers were studied. Patients reported lower generic hrQOL than healthy children (73.0 vs 83.84, P < 0.001), but no difference from patients with chronic GI disease (73.0 vs 77.79). In contrast, PIF caregivers perceived similar generic hrQOL compared to a healthy cohort (78.9 vs 82.70), but higher when compared to the GI disease cohort (78.9 vs 72.74, P < 0.01). Patients with PIF and caregivers reported lower psychosocial health scores than healthy controls. Patients and caregivers reported similar disease-specific hrQOL to a cohort with chronic GI disease but significantly lower disease-specific hrQOL than a healthy cohort (P < 0.001 both groups).

CONCLUSIONS

Patients with PIF and their caregivers have disparate perceptions of generic hrQOL when compared to healthy and chronic GI disease controls. Both patients and caregivers, however, had significantly lower scores in psychosocial health than healthy controls. In addition, disease-specific hrQOL was substantially lower than healthy controls for PIF patients and caregivers. Further investigation to expand on these findings and identify modifiable variables to improve the psychosocial health score and disease-specific factors would be of high value.

A prospective case-control pilot study to evaluate bone microarchitecture in children and teenagers on long-term parenteral nutrition using HR-pQCT

Long-term parenteral nutrition (PN) may induce bone complications. Tridimensional bone imaging techniques such as high-resolution peripheral quantitative computed tomography (HR-pQCT) allow the assessment of both compartmental volumetric densities and microarchitecture. Our aim was to evaluate these parameters in children and teenagers receiving long-term PN. This cross-sectional, case–control study included children older than 9 years undergoing PN for at least 2 years. They were age-, gender- and puberty-matched with healthy controls (1:2). Evaluation included biological assessment of bone metabolism (serum calcium, phosphate, and albumin; urinary calcium and creatinine; 25-OH vitamin D, osteocalcin and PTH), dual X-ray absorptiometry (DXA) and HR-pQCT at the ultradistal tibia and radius. Results are presented as median [range]. Eleven patients (3 girls) with a median age of 16 [9–19] years were included. Bone parameters assessed by HR-pQCT at the ultradistal radius and tibia were similar in patients and controls. Parathyroid hormone (PTH) levels were higher (14 [7–115] vs 16 [12–27]) and osteocalcin levels were lower (44 [15–65] vs 65 [38–142]) in patients than in controls, although within the normal range. Conclusions: there were no differences for compartmental bone densities and microarchitecture in patients undergoing chronic PN. Further longitudinal studies are required to confirm these quite reassuring preliminary results.

An overview of the current management of short-bowel syndrome in pediatric patients

Short-bowel syndrome (SBS) is defined as a state of malabsorption after resection or loss of a major portion of the bowel due to congenital or acquired factors. This article presents an overview on the recent management of pediatric SBS. The pediatric SBS population is very heterogeneous. The incidence of SBS is estimated to be 24.5 per 100,000 live births. The nutritional, medical, and surgical therapies available require a comprehensive evaluation. Thus, multidisciplinary intestinal rehabilitation programs (IRPs) are necessary for the management of these complex patients. The key points of focus in IRP management are hepato-protective strategies to minimize intestinal failure-associated liver disease; the aggressive prevention of catheter-related bloodstream infections; strategic nutritional supply to optimize the absorption of enteral calories; and the management and prevention of small bowel bacterial overgrowth, nephrocalcinosis, and metabolic bone disease. As the survival rate of children with SBS currently exceeds 90%, the application of small bowel transplantation has been evolving. The introduction of innovative treatments, such as combined therapy of intestinotrophic hormones, including glucagon-like peptide-2, may lead to further improvements in patients' quality of life.

Metabolic bone disease in children with intestinal failure is not associated with the level of parenteral nutrition dependency

BACKGROUND & AIMS

Children on long-term home parenteral nutrition (HPN) are at increased risk of suboptimal growth and metabolic bone disease (MBD) i.e. decreased bone mineral density (BMD). The aims of this cross-sectional study were to assess growth and bone health in children on long term HPN and to identify risk factors for MBD.

METHODS

Children above the age of 5 years, stable on HPN for more than 2 years were included. Medical files were reviewed retrospectively and included demographics, gestational age, birth weight and height, indication for PN, age at PN start, duration of PN, number of weekly PN infusions, weight-for-age and height-for-age (SD), body mass index (BMI, kg/m²) as well as blood and urine analyses at the time of Dual X-ray absorptiometry (DXA) measurements. All BMD values were adjusted to statural age which corresponds to the 50th percentile of height. Growth failure (height-for-age ≤ -2SD) and MBD (at least one BMD measurement ≤ -2SD) were analyzed according to the indication of PN, duration of PN and PN dependency index (PNDI) by comparing means and performing logistic regression analysis. PNDI is the ratio of non-protein energy intake in HPN to resting energy expenditure using Schofield equations.

RESULTS

Forty children were assessed at 12.4 ± 4.5 years of age. Mean age at PN start was 1.1 ± 3.6 y (median 0.5). The indications for PN were short bowel syndrome (SBS, n = 21), chronic intestinal pseudo-obstruction syndrome (CIPOS, n = 10) and congenital enteropathies (CE, n = 9). The mean number of PN perfusions was 6 ± 1/week. PNDI was 110 ± 30%. The mean serum level of 25-OHD3 was suboptimal at 26.5 ± 9.1 ng/mL (66.2 ± 22.8 nmol/L). The mean concentrations of calcium, phosphorus, and parathyroid hormone (PTH) were in the normal ranges. Eight children (20%) had PTH levels above normal with low 25-OHD3 levels. The mean weight-for-age and height-for-age Z-scores SDS were 0.4 ± 0.9 and -0.5 ± 1.1 respectively. The actual height was lower than genetic target height (p < 0.001). The BMD Z-scores, adjusted to the 50th percentile of height, of the spine, the left femur and the whole body were: -1.1 ± 1.7, -1.2 ± 1.5 and -1.5 ± 1.8 SDS respectively. Children with CE had significantly lower BMD values than those with SBS and CIPOS (p = 0.01). Only two children had bone fractures after a mild trauma (5%).

CONCLUSIONS

All children on long-term PN, are at risk of low BMD. High dependency on PN (PNDI>120%) and very long-term PN (>10 years) do not appear to increase the risk of growth failure nor MBD. PN-related bone fractures were rare. Close follow-up remains mandatory.

Bone mineral density and vitamin D in paediatric intestinal failure patients receiving home parenteral nutrition

BACKGROUND & AIMS

Patients with intestinal failure (IF) are dependent on long-term home parenteral nutrition (HPN) to ensure growth and development. The primary aim of the present study was to assess bone mineral density (BMD) and vitamin D status in paediatric IF patients on HPN and a group of healthy children aged 2-18 years. Secondary aims were to assess growth, body composition, nutrient provision and physical activity.

METHODS

An observational cross-sectional study was performed at Oslo University Hospital and at the Department of Nutrition, University of Oslo, from January to September 2017. Dual energy x-ray absorptiometry (DXA; Lunar Prodigy in IF patients and Lunar iDXA in healthy subjects) was performed to assess BMD and body composition. BMD z-score (BMDz) was calculated for total body and lumbar spine L2-L4 based on the integrated reference population in the software. Weight and height were measured for growth assessment. Nutrient provision was assessed by a 4-day food record. Blood samples were analysed for 25-hydroxy-vitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)₂D). Physical activity was reported by a questionnaire.

RESULTS

Nineteen IF patients and 50 healthy children were included. The mean age of participants was 10.0 years. The aetiology of IF patients was paediatric intestinal pseudo-obstruction (58%), short bowel syndrome (26%), and intestinal enteropathy (16%). Lower median BMDz for total body (-0.4 vs 1.1, P < 0.001) and lumbar spine L2-L4 (-0.9 vs 0.2, P = 0.01) were found in the IF group compared with the healthy children. Vitamin D provision was significantly higher in IF patients (17 μg/d vs 5.3 μg/d, P < 0.001). Both groups were sufficient in 25(OH)D (IF patients 71 nmol/L vs healthy 81 nmol/L). Nevertheless, IF patients had significantly lower 1,25(OH)₂D than healthy children (71 pmol/L vs 138 pmol/L, P < 0.001). The IF group was significantly shorter (height for age z-score -1,5 vs 0,1, P = 0.001) and lighter (weight for age z-score -1,0 vs 0,1, P = 0.009) compared with the healthy subjects. BMIz did not differ; however, body fat percentage was significantly higher in IF patients compared with healthy children (34% vs 25%, P = 0.02). A lower frequency of physical activity was found in the IF group compared with the healthy group (P = 0.001).

CONCLUSIONS

Paediatric IF patients on HPN had lower BMD, impaired growth, and higher body fat percentage in comparison with the healthy children. Despite a higher total supply of vitamin D in the IF group, the levels of 25(OH)D did not differ. Nevertheless, a significantly lower level of 1,25(OH)₂D was found in IF patients. The results raise questions regarding differences between oral and parenteral vitamin D provision and whether intestinal function is important for the metabolism of vitamin D.

TRIAL IDENTIFICATION NUMBER

Clinical Trials AEV2017/1. 2016/391/REK sør-øst B REVISION NUMBER: CLNESP-D-20-00022.

Updates on bone health in children with gastrointestinal diseases

Chronic gastrointestinal diseases such as inflammatory bowel disease, malabsorption syndromes (e.g., intestinal lymphangiectasia, celiac disease, congenital chloride diarrhea, cystic fibrosis), and postsubtotal gastrectomy state or short-bowel syndrome after extensive bowel resection are related to poor bone health in pediatric patients due to increased risks of low bone mineral density, osteoporosis, and fractures. The pathophysiology of abnormal bone health in pediatric gastrointestinal diseases may present from inflammation to malabsorption. In children with chronic gastrointestinal diseases at high risk of poor bone health, routine evaluation using dual-energy X-ray absorptiometry and appropriate prevention or treatment strategies are needed.

Long-Term Outcomes and Disease Burden of Neonatal Onset Short Bowel Syndrome

PURPOSE

The study aims to describe long-term outcomes and disease burden of neonatal onset short bowel syndrome (SBS).

METHODS

Utilizing the WHO criteria for adolescence, patients 10-19 years of age with neonatal onset SBS requiring parenteral nutrition (PN) for >90 days and followed by our multidisciplinary intestinal rehabilitation center between 2009 and 2018 were included for analysis.

RESULTS

Seventy adolescents with SBS were studied. Median (IQR) age at last follow up in our center was 15 (11, 17) years. There was 0% mortality in the cohort, and 94% remained transplant free. Fifty-three patients (76%) achieved enteral autonomy. Three patients were weaned from PN without transplantation after six years of follow-up and another four after ten years of care at our multidisciplinary center. Disease burden remained higher in adolescents receiving PN, including inpatient hospitalizations (p < 0.01), procedures (p = 0.01), clinic visits (p < 0.01), and number of prescribed medications (p < 0.01).

CONCLUSION

Survival for adolescents with neonatal onset SBS is excellent. Of the cohort studied, there was no mortality, and more than 75% achieved enteral autonomy. Disease burden remains high for adolescents who remain dependent on PN. However, achievement of enteral autonomy is feasible with long-term multidisciplinary rehabilitation.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

Level II.

Metabolic bone diseases in intestinal failure

Metabolic bone diseases are a group of conditions that are common complications in patients with intestinal failure. These may occur as a result of the underlying condition, leading to intestinal failure, particularly inflammatory conditions such as Crohn's disease and their associated treatments including corticosteroids. Malabsorption, as a result of a loss of enterocyte mass or gut function, of many nutrients, including vitamin D, may further compound metabolic bone problems, and there has been historical contamination of parenteral nutrition with aluminium that has prevented normal bone metabolism contributing to osteoporosis. This review looks at the diagnosis and current management of bone health in patients with intestinal failure.

Monitoring of long-term parenteral nutrition in children with intestinal failure

Pediatric intestinal failure (IF) is a rare and complex condition associated with significant morbidity and mortality. It is defined as the reduction of gut mass or function below the minimal needed for absorption of nutrients and fluid to sustain life and growth. Since the advent of specialized multidisciplinary intestinal rehabilitation centers, IF management has considerably evolved in the last years, but serious complications of long-term parenteral nutrition (PN) can occur. Main complications include intestinal failure-associated liver disease, growth failure, body composition imbalance, central venous access complications, micronutrient deficiencies and toxicities, metabolic bone disease, small intestinal bacterial overgrowth, and renal disease. With improvement in survival rates of patients over the last 20 years, emphasis should be on limiting IF-related comorbidities and improving quality of life. Close monitoring is pivotal to ensuring quality of care of these patients. The care of children with chronic IF should involve a comprehensive monitoring plan with flexibility for individualization according to specific patient needs. Monitoring of children on long-term PN varies significantly across units and is mainly based on experience, although few guidelines exist. This narrative review summarizes the current knowledge and practices related to monitoring of children with IF. The authors also share their 20-year experience at the Royal Children's Hospital in Melbourne Australia on this topic.

Nutritional therapy complications in children with ultra-short bowel syndrome include growth deficiency but not cholestasis

Aim

Children with ultra‐short bowel syndrome (USBS) have not been extensively studied to date because the condition is rare. The aim of the study was to assess the nutritional status of children with USBS receiving home parenteral nutrition, using citrulline serum concentration and cholestasis.

Methods

We studied 17 patients with USBS, with a median age of 6.6 years and median duration of parenteral nutrition of 6.6 years. The study was carried out at The Children's Memorial Health Institute, Warsaw, from January 2014 to January 2015.

Results

The median standard deviation score (SDS) was −1.2 for body mass according to chronological age, −1.72 according to height and −0.59 according to height for age. Patients requiring seven days per week parenteral nutrition had a citrulline concentration below 10 μmol/L. Decreased bone‐mineral density was observed in 87% of the patients. Low values of 25‐hydroxyvitamin D were found in 53% of the children. None of the patients had elevated conjugated bilirubin levels above 34.2 μmol/L.

Conclusion

Children with USBS were growth deficient according to their chronological age, with frequent abnormal bone mineralisation and vitamin D deficiency. Children requiring parenteral nutrition seven days a week had citrulline concentrations below 10 μmol/L. Cholestasis was not seen.

Pediatric Intestinal Failure-Associated Liver Disease: Challenges in Identifying Clinically Relevant Biomarkers

BACKGROUND

Intestinal failure-associated liver disease (IFALD) is complex and diagnosed by concurrent use of parenteral nutrition, clinical presentation, and alterations in hepatic biomarkers exclusive of other causes of liver disease. In comparison with individual measures, composite biomarkers may provide a more effective means for assessing disease progression and response to treatment than single parameters. Since IFALD is considered by some to be a type of drug-induced liver injury (DILI), those diagnostic criteria could potentially be used in this population. Using a preexisting database of children treated for IFALD, our aim was to determine if a similar composite biomarker could be applied to this population.

STUDY DESIGN

Adult DILI criteria were applied at baseline, when treatment for IFALD (ie, direct bilirubin ≥2.0 mg/dL) was initiated.

RESULTS

A total of 214 patients with IFALD treated at Boston Children's Hospital were identified; 168 patients were eligible for analysis. Most patients analyzed were male (61%) and preterm (87%). Alkaline phosphatase (ALP) ≥2× upper limit of normal (ULN) captured the least amount of DILI (11%), while γ-glutamyltransferase (GGT) ≥1× ULN accounted for the most (62%). Using adult DILI criteria, 60 (39%) patients with IFALD were found to have DILI. Substituting GGT ≥1× ULN for ALP ≥2× ULN improved the sensitivity, with 105 (69%) of patients meeting at least 1 criterion for DILI.

CONCLUSION

Numerous challenges made it difficult to apply the DILI criteria to children with IFALD. Direct bilirubin, fractionated ALP, and perhaps GGT may be more suitable. Given its complex etiology and the age-based differences due to hepatic immaturity and growth, a more suitable composite marker needs to be developed to assess IFALD in this population.

Long-term outcomes of pediatric intestinal failure

Management of pediatric intestinal failure has evolved in recent decades, with improved survival since the advent of specialized multidisciplinary intestinal failure centers. Though sepsis and intestinal failure associated liver disease still contribute to mortality, we now have growing data on the long-term outcomes for this population. While intestinal adaptation and parenteral nutrition weaning is most rapid during the first year on parenteral support, achievement of enteral autonomy is possible even after many years as energy and protein requirements decline dramatically with age. Intestinal transplant is an option for patients experiencing complications of long-term parenteral nutrition who are expected to have permanent intestinal failure, but outcomes are hindered by immunosuppression-related complications. Much of the available data comes from single center retrospective reports, with variable inclusion criteria, intestinal failure definitions, and follow-up durations; this limits the ability to analyze outcomes and identify best practices. As most children now survive long-term, the focus of management has shifted to the avoidance and management of comorbidities, support of normal growth and development, and optimization of quality of life for these medically and surgically complex patients.

Bone microarchitecture in adolescent boys with autism spectrum disorder

BACKGROUND

Boys with autism spectrum disorder (ASD) have lower areal bone mineral density (aBMD) than typically developing controls (TDC). Studies of volumetric BMD (vBMD) and bone microarchitecture provide information about fracture risk beyond that provided by aBMD but are currently lacking in ASD.

OBJECTIVES

To assess ultradistal radius and distal tibia vBMD, bone microarchitecture and strength estimates in adolescent boys with ASD compared to TDC.

DESIGN/METHODS

Cross-sectional study of 34 boys (16 ASD, 18 TDC) that assessed (i) aBMD at the whole body (WB), WB less head (WBLH), hip and spine using dual X-ray absorptiometry (DXA), (ii) vBMD and bone microarchitecture at the ultradistal radius and distal tibia using high-resolution peripheral quantitative CT (HRpQCT), and (iii) bone strength estimates (stiffness and failure load) using micro-finite element analysis (FEA). We controlled for age in all groupwise comparisons of HRpQCT and FEA measures. Activity questionnaires, food records, physical exam, and fasting levels of 25(OH) vitamin D and bone markers (C-terminal collagen crosslinks and N-terminal telopeptide (CTX and NTX) for bone resorption, N-terminal propeptide of Type 1 procollagen (P1NP) for bone formation) were obtained.

RESULTS

ASD participants were slightly younger than TDC participants (13.6 vs. 14.2years, p=0.44). Tanner stage, height Z-scores and fasting serum bone marker levels did not differ between groups. ASD participants had higher BMI Z-scores, percent body fat, IGF-1 Z-scores, and lower lean mass and aBMD Z-scores than TDC at the WB, WBLH, and femoral neck (P<0.1). At the radius, ASD participants had lower trabecular thickness (0.063 vs. 0.070mm, p=0.004), compressive stiffness (56.7 vs. 69.7kN/mm, p=0.030) and failure load (3.0 vs. 3.7kN, p=0.031) than TDC. ASD participants also had 61% smaller cortical area (6.6 vs. 16.4mm2, p=0.051) and thickness (0.08 vs. 0.22mm, p=0.054) compared to TDC. At the tibia, ASD participants had lower compressive stiffness (183 vs. 210kN/mm, p=0.048) and failure load (9.4 vs. 10.8kN, p=0.043) and 23% smaller cortical area (60.3 vs. 81.5mm2, p=0.078) compared to TDC. A lower proportion of ASD participants were categorized as "very physically active" (20% vs. 72%, p=0.005). Differences in physical activity, calcium intake and IGF-1 responsiveness may contribute to group differences in stiffness and failure load.

CONCLUSION

Bone microarchitectural parameters are impaired in ASD, with reductions in bone strength estimates (stiffness and failure load) at the ultradistal radius and distal tibia. This may result from lower physical activity and calcium intake, and decreased IGF-1 responsiveness.