Investigating the effects of synbiotic supplementation on functional movement, strength and muscle health in older Australians: a study protocol for a double-blind, randomized, placebo-controlled trial

BACKGROUND

Aging has been associated with a progressive loss of skeletal muscle quality, quantity and strength, which may result in a condition known as sarcopenia, leading to a decline in physical performance, loss of independence and reduced quality of life. While the cause of impaired physical functioning observed in elderly populations appears to be multifactorial, recent evidence suggests that age-associated alterations in gut microbiota could be a contributing factor. The primary objective will be to assess the effects of a dietary synbiotic formulation on sarcopenia-related functional outcomes such as handgrip strength, gait speed and physical performance within older individuals living independently. The secondary objective will be to examine associations between changes in gut microbiota composition, functional performance and lean muscle mass.

METHODS

Seventy-four elderly (60-85 years) participants will be randomized in a double-blind, placebo-controlled fashion to either an intervention or control group. The intervention group (n = 37) will receive oral synbiotic formulation daily for 16 weeks. The control group (n = 37) will receive placebo. Assessments of physical performance (including Short Physical Performance Battery, handgrip strength and timed up-and-go tests) and muscle ultrasonography will be performed at 4 time points (baseline and weeks 8, 16 and 20). Likewise, body composition via bioelectric impedance analysis and blood and stool samples will be collected at each time point. Dual-energy X-ray absorptiometry will be performed at baseline and week 16. The primary outcomes will be between-group changes in physical performance from baseline to 16 weeks. Secondary outcomes include changes in body composition, muscle mass and architecture, fecal microbiota composition and diversity, and fecal and plasma metabolomics.

DISCUSSION

Gut-modulating supplements appear to be effective in modifying gut microbiota composition in healthy older adults. However, it is unclear whether these changes translate into functional and/or health improvements. In the present study, we will investigate the effects of a synbiotic formulation on measures of physical performance, strength and muscle health in healthy older populations.

TRIAL REGISTRATION

This study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622000652774) in May 2022.

Nutritional management of children with acute kidney injury-clinical practice recommendations from the Pediatric Renal Nutrition Taskforce

The nutritional management of children with acute kidney injury (AKI) is complex. The dynamic nature of AKI necessitates frequent nutritional assessments and adjustments in management. Dietitians providing medical nutrition therapies to this patient population must consider the interaction of medical treatments and AKI status to effectively support both the nutrition status of patients with AKI as well as limit adverse metabolic derangements associated with inappropriately prescribed nutrition support. The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric renal dietitians and pediatric nephrologists, has developed clinical practice recommendations (CPR) for the nutritional management of children with AKI. We address the need for intensive collaboration between dietitians and physicians so that nutritional management is optimized in line with AKI medical treatments. We focus on key challenges faced by dietitians regarding nutrition assessment. Furthermore, we address how nutrition support should be provided to children with AKI while taking into account the effect of various medical treatment modalities of AKI on nutritional needs. Given the poor quality of evidence available, a Delphi survey was conducted to seek consensus from international experts. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs, based on the clinical judgment of the treating physician and dietitian. Research recommendations are provided. CPRs will be regularly audited and updated by the PRNT.

The utility of a portable muscle ultrasound in the assessment of muscle alterations in children with acute lymphoblastic leukaemia

BACKGROUND

During treatment for acute lymphoblastic leukaemia (ALL), children are prone to musculoskeletal deterioration. However, non-invasive tools to measure muscle mass and intramuscular alterations are limited. In this study we explored the feasibility of muscle ultrasound in children with ALL. Additionally, we analysed whether automated ultrasound outcomes of muscle size and intramuscular fat infiltration (IMAT) were associated with appendicular skeletal muscle mass (ASMM), muscle strength and physical performance.

METHODS

Children with ALL, aged 3-18 years were included during maintenance therapy. Bilateral images of the rectus femoris muscle were captured using a portable linear array transducer connected to a tablet. Subsequently, an automated image annotation software (MuscleSound) was used to estimate cross-sectional area, muscle thickness and IMAT. Feasibility was assessed using acceptance (percentage of children approached who were enrolled), practicality (percentage of children that completed the ultrasound measurement after enrolment) and implementation (percentage of children that had sufficient imaging to be processed and analysed by the software). Assessments of ASMM by bioimpedance analysis, muscle strength using handheld dynamometry and timed physical performance tests were administered at the same visit. Multivariable linear models were estimated to study the associations between muscle ultrasound outcomes and ASMM, strength and physical performance, adjusted for sex, age, body mass index and ALL treatment week.

RESULTS

Muscle ultrasound was performed in 60 out of 73 invited patients (76.9%), of which 37 were boys (61.7%), and median age was 6.1 years (range: 3-18.8 years). The acceptance was 98.7%, practicality 77.9% and implementation was 100%. Patients who refused the examination (n = 13) were younger (median: 3.6, range: 3-11.2 years) compared with the 60 examined children (P = 0.0009). In multivariable models, cross-sectional area was associated with ASMM (β = 0.49 Z-score, 95% confidence interval [CI]:0.3,2.4), knee-extension strength (β = 16.9 Newton [N], 95% CI: 4.8, 28.9), walking performance (β = -0.46 s, 95% CI: -0.75, -0.18) and rising from the floor (β = -1.07 s, 95% CI: -1.71, -0.42). Muscle thickness was associated with ASMM (β = 0.14 Z-score, 95% CI: 0.04, 0.24), knee-extension strength (β = 4.73 N, 95% CI: 0.99, 8.47), walking performance (β = -0.13 s, 95% CI: -0.22, -0.04) and rising from the floor (β = -0.28 s, 95% CI: -0.48, -0.08). IMAT was associated with knee-extension strength (β = -6.84 N, 95% CI: -12.26, -1.41), walking performance (β = 0.2 s, 95% CI: 0.08, 0.32) and rising from the floor (β = 0.54 s, 95% CI: 0.27, 0.8). None of the muscle ultrasound outcomes was associated with handgrip strength.

CONCLUSIONS

Portable muscle ultrasound appears a feasible and useful tool to measure muscle size and intramuscular alterations in children with ALL. Validation studies using magnetic resonance imaging (gold standard) are necessary to confirm accuracy in paediatric populations.

Body composition in pediatric patients

Undernutrition is highly prevalent in children who are critically ill and is associated with increased morbidity and mortality, including a higher risk of infection due to transitory immunological disorders, inadequate wound healing, reduced gut function, longer dependency on mechanical ventilation, and longer hospital stays compared with eutrophic children who are critically ill. Nutrition care studies have proposed that early interventions targeting nutrition assessment can prevent or minimize the complications of undernutrition. Stress promotes an acute inflammatory response mediated by cytokines, resulting in increased basal metabolism and nitrogen excretion and leading to muscle loss and changes in body composition. Therefore, the inclusion of body composition assessment is important in the evaluation of these patients because, in addition to the nutrition aspect, body composition seems to predict clinical prognosis. Several techniques can be used to assess body composition, such as arm measurements, calf circumference, grip strength, bioelectrical impedance analysis, and imaging examinations, including computed tomography and dual-energy x-ray absorptiometry. This review of available evidence suggests that arm measurements seem to be well-established in assessing body composition in children who are critically ill, and that bioelectrical impedance analysis with phase angle, handgrip strength, calf circumference and ultrasound seem to be promising in this evaluation. However, further robust studies based on scientific evidence are necessary.

Macronutrient and Micronutrient Intake in Children with Lung Disease

This review article aims to summarize the literature findings regarding the role of micronutrients in children with lung disease. The nutritional and respiratory statuses of critically ill children are interrelated, and malnutrition is commonly associated with respiratory failure. The most recent nutrition support guidelines for critically ill children have recommended an adequate macronutrient intake in the first week of admission due to its association with good outcomes. In children with lung disease, it is important not to exceed the proportion of carbohydrates in the diet to avoid increased carbon dioxide production and increased work of breathing, which potentially could delay the weaning of the ventilator. Indirect calorimetry can guide the process of estimating adequate caloric intake and adjusting the proportion of carbohydrates in the diet based on the results of the respiratory quotient. Micronutrients, including vitamins, trace elements, and others, have been shown to play a role in the structure and function of the immune system, antioxidant properties, and the production of antimicrobial proteins supporting the defense mechanisms against infections. Sufficient levels of micronutrients and adequate supplementation have been associated with better outcomes in children with lung diseases, including pneumonia, cystic fibrosis, asthma, bronchiolitis, and acute respiratory failure.

Muscle Ultrasound Changes and Physical Function of Critically Ill Children: A Comparison of Rectus Femoris Cross-Sectional Area and Quadriceps Thickness Measurements

Quadriceps thickness (QT) and rectus femoris cross-sectional area (RF_CSA) are both used to evaluate muscle changes in critically ill children. However, their correlation and association with physical function has not been compared.

OBJECTIVES

To compare QT with RF_CSA changes, and their association with physical function in critically ill children.

DESIGN SETTING AND PARTICIPANTS

Secondary analysis of a prospective cohort study of children 0-18 years old admitted to a tertiary mixed PICU between January 2015 and October 2018 with PICU stay greater than 48 hours and greater than or equal to one organ dysfunction.

MAIN OUTCOMES AND MEASURES

Ultrasound QT and RF_CSA were measured at PICU admission, PICU discharge, hospital discharge, and 6 months post-discharge. QT and RF_CSA changes from baseline were compared with each other and with change in motor function, physical ability, and physical health-related quality of life (HRQOL).

RESULTS

Two hundred thirty-seven images from 66 subjects were analyzed. RF_CSA change was not significantly different from QT change at PICU (-8.07% [interquartile range (IQR), -17.11% to 4.80%] vs -4.55% [IQR, -14.32% to 4.35%]; p = 0.927) or hospital discharge (-5.62% [IQR, -15.00% to 9.42%] vs -8.81% [IQR, -18.67% to 2.39%]; p = 0.238) but was significantly greater than QT change at 6 months (32.7% [IQR, 5.74-109.76%] vs 9.66% [IQR, -8.17% to 25.70%]; p < 0.001). Motor function change at PICU discharge was significantly associated with RF_CSA change (adjusted β coefficient, 0.02 [95% CI, 0.01-0.03]; p = 0.013) but not QT change (adjusted β coefficient, -0.01 [95% CI, -0.02 to 0.01]; p = 0.415). Similar results were observed for physical HRQOL changes at hospital discharge (adjusted β coefficient for RF_CSA change, 0.51 [95% CI, 0.10-0.92]; p = 0.017 and adjusted β coefficient for QT change, -0.21 [-0.76 to 0.35]; p = 0.458). Physical ability was not significantly associated with RFCSA or QT changes at 6 months post-discharge.

CONCLUSIONS AND RELEVANCE

Ultrasound derived RF_CSA is associated with PICU motor function and hospital discharge physical HRQOL changes, unlike QT, and may be more useful for in-hospital muscle monitoring in critically ill children.

Reliability of ultrasound in the assessment of muscle thickness in critically ill children

INTRODUCTION

Ultrasound has been used to quantify and qualify muscle morphology in critically ill children and can detect changes in muscle thickness. The aim of this study was to assess the reliability of ultrasound measurement of muscle thickness in critically ill children and to compare the assessments made by an expert with those made by inexperienced sonographers.

MATERIAL AND METHODS

Cross-sectional observational study conducted in the paediatric intensive care unit of a tertiary care university hospital in Brazil. The sample included patients aged 1 month to 12 years who received invasive mechanical ventilation for at least 24 h. Ultrasound images of the biceps brachii/brachialis and quadriceps femoris were obtained by one experienced sonographer and several inexperienced sonographers. We assessed intrarater and inter-rater reliability by means of the intraclass correlation coefficient (ICC) and Bland-Altman plot analysis.

RESULTS

Muscle thickness was measured in 10 children with a mean age of 15.5 months. The mean thickness of the assessed muscles as 1.14 cm for the biceps brachii/brachialis (standard deviation [SD], 0.27) and 1.85 cm for the quadriceps femoris (SD, 0.61). The intrarater and inter-rater reliability were good for all sonographers (ICC > 0.81). The differences were small, there was no significant bias in the Bland-Altman plots and all measurements were within the limits of agreement, except for 1 measurement of biceps and quadriceps.

CONCLUSION

Sonography can be used in critically ill children to accurately assess changes in muscle thickness, even by different evaluators. More studies are needed to establish a standardised approach to the use of ultrasound for monitoring muscle loss in order to incorporate it in clinical practice.

Muscle Wasting among Hospitalized Children: A Narrative Review of the Feasibility and Accuracy of Diagnostic Methods

Muscle wasting is associated with a worse quality of life and increased morbidity and mortality among hospitalized children, especially those with chronic diseases. This review was conducted to summarize the data available on the most feasible and accurate diagnostic methods for detecting muscle wasting among hospitalized children, especially to review the evidence of the accuracy and feasibility of conducting assessments using handgrip strength (HGS). Many diagnostic methods are used in hospital settings to assess muscle wasting, by evaluating either muscle mass or strength, with evidentiary support for assessing muscle mass provided using ultrasonography, magnetic resonance imaging, computed tomography, dual-energy X-ray, bioelectrical impedance analysis, and anthropometry measurements. Currently, the most common diagnostic method used to detect muscle strength loss is the handheld dynamometer. Studies support using HGS among healthy and hospitalized children to assess the overall nutritional status and especially muscle function. However, almost all of these studies have been conducted in hospital settings and recruited children with different chronic diseases using a small sample size. More longitudinal cohort studies with large sample sizes are needed to assess the accuracy and feasibility of using HGS among hospitalized children.

Mapping peripheral and abdominal sarcopenia acquired in the acute phase of COVID-19 during 7 days of mechanical ventilation

Our aim was to map acquired peripheral and abdominal sarcopenia in mechanically ventilated adults with COVID-19 through ultrasound measurements. On Days 1, 3, 5 and 7 after admission to critical care, the muscle thickness and cross-sectional area of the quadriceps, rectus femoris, vastus intermedius, tibialis anterior, medial and lateral gastrocnemius, deltoid, biceps brachii, rectus abdominis, internal and external oblique, and transversus abdominis were measured using bedside ultrasound. A total of 5460 ultrasound images were analyzed from 30 patients (age: 59.8 ± 15.6 years; 70% men). Muscle thickness loss was found in the bilateral anterior tibial and medial gastrocnemius muscles (range 11.5-14.6%) between Days 1 and 3; in the bilateral quadriceps, rectus femoris, lateral gastrocnemius, deltoid, and biceps brachii (range 16.3-39.1%) between Days 1 and 5; in the internal oblique abdominal (25.9%) between Days 1 and 5; and in the rectus and transversus abdominis (29%) between Days 1 and 7. The cross-sectional area was reduced in the bilateral tibialis anterior and left biceps brachii (range 24.6-25.6%) between Days 1 and 5 and in the bilateral rectus femoris and right biceps brachii (range 22.9-27.7%) between Days 1 and 7. These findings indicate that the peripheral and abdominal muscle loss is progressive during the first week of mechanical ventilation and is significantly higher in the lower limbs, left quadriceps and right rectus femoris muscles in critically ill patients with COVID-19.

Assessment of the relationship between rectus femoris cross-sectional area and knee extension strength in the prosthesis users with transtibial amputation: A case-control study

Objectives

This study aims to investigate cross-sectional area of the amputated-limb rectus femoris compared to the intact-limb and controls and to determine its correlation with functional strength and walking tests in prosthesis users with transtibial amputation.

Patients and methods

Between October 2018 and April 2019, a total of 14 prosthesis users (12 males, 2 females; mean age: 47.1±16.2 years; range, 26 to 73 years) who met the inclusion criteria, and 14 age-, sex-, and dominancy-matched able-bodied controls (12 males, 2 females; mean age: 47.1±16.2 years; range, 26 to 73 years) were included in this case-control study. Cross-sectional area of rectus femoris (CSA-RF) was evaluated bilaterally by two independent examiners. Knee extension strength was measured bilaterally by using a handheld dynamometer. Functional strength and walking were assessed by Step-Up-Over and Walk-Across tests of the NeuroCom Balance Master® device.

Results

The CSA-RF was found to be reduced in amputated-limb compared to the intact-limb and able-bodied controls (p<0.01). In the prosthesis users, the cross-sectional area difference between both limbs rectus femoris muscles was shown to be correlated with actual and functional knee extension strength, step length, and walking speed (p<0.05). Intra- and inter-observer reliability of CSA-RF on both sides were found to be good to excellent (intraclass correlation coefficient: 0.856-0.936).

Conclusion

Ultrasonographic measurement of CSA-RF is a valid and reliable tool to assess the functional strength and walking in the prosthesis users with unilateral transtibial amputation.

Human skeletal muscle size with ultrasound imaging: a comprehensive review

Skeletal muscle size is an important factor in assessing adaptation to exercise training and detraining, athletic performance, age-associated atrophy and mobility decline, clinical conditions associated with cachexia, and overall skeletal muscle health. Magnetic resonance (MR) imaging and computed tomography (CT) are widely accepted as the gold standard methods for skeletal muscle size quantification. However, it is not always feasible to use these methods (e.g., field studies, bedside studies, large cohort studies). Ultrasound has been available for skeletal muscle examination for more than 50 years and the development, utility, and validity of ultrasound imaging are underappreciated. It is now possible to use ultrasound in situations where MR and CT imaging are not suitable. This review provides a comprehensive summary of ultrasound imaging and human skeletal muscle size assessment. Since the first study in 1968, more than 600 articles have used ultrasound to examine the cross-sectional area and/or volume of 107 different skeletal muscles in more than 27,500 subjects of various ages, health status, and fitness conditions. Data from these studies, supported by decades of technological developments, collectively show that ultrasonography is a valid tool for skeletal muscle size quantification. Considering the wide-ranging connections between human health and function and skeletal muscle mass, the utility of ultrasound imaging will allow it to be employed in research investigations and clinical practice in ways not previously appreciated or considered.

Protein supplementation versus standard feeds in underweight critically ill children: a pilot dual-centre randomised controlled trial protocol

INTRODUCTION

Protein-energy malnutrition, increased catabolism and inadequate nutritional support leads to loss of lean body mass with muscle wasting and delayed recovery in critical illness. However, there remains clinical equipoise regarding the risks and benefits of protein supplementation. This pilot trial will determine the feasibility of performing a larger multicentre trial to determine if a strategy of protein supplementation in critically ill children with body mass index (BMI) z-score ≤-2 is superior to standard enteral nutrition in reducing the length of stay in the paediatric intensive care unit (PICU).

METHODS AND ANALYSIS

This is a randomised controlled trial of 70 children in two PICUs in Singapore. Children with BMI z-score ≤-2 on PICU admission, who are expected to require invasive mechanical ventilation for more than 48 hours, will be randomised (1:1 allocation) to protein supplementation of ≥1.5 g/kg/day in addition to standard nutrition, or standard nutrition alone for 7 days after enrolment or until PICU discharge, whichever is earlier. Feasibility outcomes for the trial include effective screening, satisfactory enrolment rate, timely protocol implementation (within first 72 hours) and protocol adherence. Secondary outcomes include mortality, PICU length of stay, muscle mass, anthropometric measurements and functional outcomes.

ETHICS AND DISSEMINATION

The trial protocol was approved by the institutional review board of both participating centres (Singhealth Centralised Institutional Review Board and National Healthcare Group Domain Specific Review Board) under the reference number 2020/2742. Findings of the trial will be disseminated through peer-reviewed journals and scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04565613.

Sarcopenia in critically ill children: A bedside assessment using point-of-care ultrasound and anthropometry

BACKGROUND & AIMS

Due to the lack of validated methods of muscle assessment, sarcopenia is not well described in critically ill children. The main objectives of this study were to assess muscle wasting using point-of-care ultrasound (POCUS) and anthropometry, as well as its association with nutrition delivery in PICU.

METHODS

This was a single-center, prospective cohort study, including consecutive children admitted to the PICU. Quadriceps femoris muscle thickness (QFMT) and anthropometrics measurements were performed at admission and then weekly until the 14th day of the PICU stay. The three moments of assessment were defined as T0 (baseline), T1 (7th day) and T2 (14th day). For analysis purposes, participants assessed only in T0 and T1 were defined as Subgroup 1, while those assessed in T0, T1 and T2 were defined as Subgroup 2. Actual total daily intake was determined by patient intake records until discharge or during the first 14 full days of PICU admission.

RESULTS

In all, 119 patients were included with a median age of 12.0 months (IQR 4.0-42.5). In Subgroup 1, QFMT significantly decreased between T0 and T1 (-12.93 ± 14.07 %; p < 0.001), and the same was observed in Subgroup 2 (-13.81 ± 13.05 %; p < 0.001). However, no differences in QFMT was observed between T1 and T2 (-2.06 ± 13.80 %; p = 0.936). Triceps skinfold thickness, mid-upper arm circumference, and upper arm muscle area presented a similar pattern of changes between periods in both groups. Decrease of QFMT at T1 was significantly correlated with the cumulative protein deficit in both subgroups, but not with the cumulative energy deficit.

CONCLUSION

Substantial muscle wasting occurs early in critically ill children and may be related to insufficient protein delivery. Anthropometric measurements are valuable in PICU and POCUS has the potential to play a major role in sarcopenia assessment during critical illnesses.

TRIAL REGISTRATION

Brazilian Clinical Trials registry, registration number: RBR-85YYGN.

Physical Functioning After Admission to the PICU: A Scoping Review

Supplemental Digital Content is available in the text.

Objectives:

To conduct a scoping review to 1) describe findings and determinants of physical functioning in children during and/or after PICU stay, 2) identify which domains of physical functioning are measured, 3) and synthesize the clinical and research knowledge gaps.

Data Sources:

A systematic search was conducted in PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library databases following the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews guidelines.

Study Selection:

Two investigators independently screened and included studies against predetermined criteria.

Data Extraction:

One investigator extracted data with review by a second investigator. A narrative analyses approach was used.

Data Synthesis:

A total of 2,610 articles were identified, leaving 68 studies for inclusion. Post-PICU/hospital discharge scores show that PICU survivors report difficulties in physical functioning during and years after PICU stay. Although sustained improvements in the long-term have been reported, most of the reported levels were lower compared with the reference and baseline values. Decreased physical functioning was associated with longer hospital stay and presence of comorbidities. A diversity of instruments was used in which mobility and self-care were mostly addressed.

CONCLUSIONS:

The results show that children perceive moderate to severe difficulties in physical functioning during and years after PICU stay. Longitudinal assessments during and after PICU stay should be incorporated, especially for children with a higher risk for poor functional outcomes. There is need for consensus on the most suitable methods to assess physical functioning in children admitted to the PICU.

Imaging of body composition in children

Overweight and obesity in children and adolescents have become a worldwide public health concern with an ever-increasing prevalence. An excessive accumulation of intraabdominal fat tissue increases the risk of developing insulin resistance, diabetes, and cardiovascular diseases in adulthood. Body composition has a role in metabolism regulation in children and adolescents with differences between genders and age groups. Until recently, Air Displacement Plethysmography and Dual-energy X-ray Absorptiometry (DXA) have been the most common techniques used to assess body composition in children. Ultrasound (US) is an accurate, readily available, and radiation-free technique to quantify intra-abdominal fat in adults, but its use in children has not yet been validated. Computed tomography (CT) is a reliable tool to assess body composition, but its use in children should be avoided due to the significant radiation burden. Quantitative Magnetic Resonance Imaging (qMRI) provides an accurate measurement of body composition, through the quantification of the visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and brown adipose tissue (BAT), as well as lean mass. Furthermore, qMRI provides other significant estimates such as the Proton Density Fat-Fraction of the fat tissue. This review article aims to briefly describe the state of art of the advanced imaging techniques to provide a quantitative assessment of body composition in children and adolescents.

Neuromuscular Ultrasound: Clinical Applications and Diagnostic Values

Advances in high-resolution ultrasound have provided clinicians with unique opportunities to study diseases of the peripheral nervous system. Ultrasound complements the clinical and electrophysiology exam by showing the degree of abnormalities in myopathies, as well as spontaneous muscle activities in motor neuron diseases and other disorders. In experienced hands, ultrasound is more sensitive than MRI in detecting peripheral nerve pathologies. It can also guide needle placement for electromyography exam, therapeutic injections, and muscle biopsy. Ultrasound enhances the ability to detect carpal tunnel syndrome and other focal nerve entrapment, as well as pathological nerve enlargements in genetic and acquired neuropathies. Furthermore, ultrasound can potentially be used as a biomarker for muscular dystrophy and spinal muscular atrophy. The combination of electromyography and ultrasound can increase the diagnostic certainty of amyotrophic lateral sclerosis, aid in the localization of brachial plexus or peripheral nerve trauma and allow for surveillance of nerve tumor progression in neurofibromatosis. Potential limitations of ultrasound include an inability to image deeper structures, with lower sensitivities in detecting neuromuscular diseases in young children and those with mitochondrial myopathies, due to subtle changes or early phase of the disease. As well, its utility in detecting critical illness neuromyopathy remains unclear. This review will focus on the clinical applications of neuromuscular ultrasound. The diagnostic values of ultrasound for screening of myopathies, neuropathies, and motor neuron diseases will be presented.

Low muscle mass and strength in pediatrics patients: Why should we care?

Skeletal muscle plays major roles in metabolism and overall health across the lifecycle. Emerging evidence indicates that prenatal (maternal diet during pregnancy and genetic defects) and postnatal factors (physical activity, hormones, dietary protein, and obesity) influence muscle mass acquisition and strength early in life. As a consequence, low muscle mass and strength contributes to several adverse health outcomes during childhood. Specifically, studies demonstrated inverse associations of muscle mass and strength to single and clustered metabolic risk factors. The literature also consistently reports that low muscle mass and strength are associated with reduced bone parameters during growth, increasing the risk of osteoporosis in old age. Furthermore, muscle mass gains are associated with improved neurodevelopment in the first years of life. Given these negative implications of low muscle mass and strength on health, it is crucial to track muscle mass and strength development from childhood to adolescence. Several body composition techniques are currently available for estimation of muscle mass, all with unique advantages and disadvantages. The value of ultrasound as a technique to measure muscle mass is emerging in pediatric research with potential for translating the research findings to clinical settings. For the assessment of muscle strength, the handgrip strength test has been widely employed but without a standardized protocol. Although further research is needed to define normative data and cut points for the low muscle mass and strength phenotype, the use of such non-invasive medical monitoring is a promising strategy to identify early abnormalities and prevent low muscle mass in adulthood.