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Journal of Neurology Jul 2023Myasthenia gravis (MG) is characterized by muscle weakness caused by autoantibodies that bind to the postsynaptic membrane at the neuromuscular junction and impair... (Review)
Review
Myasthenia gravis (MG) is characterized by muscle weakness caused by autoantibodies that bind to the postsynaptic membrane at the neuromuscular junction and impair acetylcholine receptor function. Weakness of respiratory muscles represents the most severe MG manifestation, and 10-15% of all patients experience an MG crisis with the need of mechanical ventilatory support at least once in their life. MG patients with respiratory muscle weakness need active immunosuppressive drug treatment long term, and they need regular specialist follow-up. Comorbidities affecting respiratory function need attention and optimal treatment. Respiratory tract infections can lead to MG exacerbations and precipitate an MG crisis. Intravenous immunoglobulin and plasma exchange are the core treatments for severe MG exacerbations. High-dose corticosteroids, complement inhibitors, and FcRn blockers represent fast-acting treatments that are effective in most MG patients. Neonatal myasthenia is a transient condition with muscle weakness in the newborn caused by mother's muscle antibodies. In rare cases, treatment of respiratory muscle weakness in the baby is required.
Topics: Infant, Newborn; Humans; Myasthenia Gravis; Neuromuscular Junction; Neuromuscular Diseases; Muscle Weakness; Respiratory Tract Diseases
PubMed: 37101094
DOI: 10.1007/s00415-023-11733-y -
Current Opinion in Critical Care Aug 2022To summarize the incidence, features, pathogenesis, risk factors, and evidence-based therapies of prolonged intensive care unit (ICU) acquired weakness (ICU-AW). We aim... (Review)
Review
PURPOSE OF REVIEW
To summarize the incidence, features, pathogenesis, risk factors, and evidence-based therapies of prolonged intensive care unit (ICU) acquired weakness (ICU-AW). We aim to provide an updated overview on aspects of poor physical recovery following critical illness.
RECENT FINDINGS
New physical problems after ICU survival, such as muscle weakness, weakened condition, and reduced exercise capacity, are the most frequently encountered limitations of patients with postintensive care syndrome. Disabilities may persist for months to years and frequently do not fully recover. Hormonal and mitochondrial disturbances, impaired muscle regeneration due to injured satellite cells and epigenetic differences may be involved in sustained ICU-AW. Although demographics and ICU treatment factors appear essential determinants for physical recovery, pre-ICU health status is also crucial. Currently, no effective treatments are available. Early mobilization in the ICU may improve physical outcomes at ICU-discharge, but there is no evidence for benefit on long-term physical recovery.
SUMMARY
Impaired physical recovery is observed frequently among ICU survivors. The pre-ICU health status, demographic, and ICU treatment factors appear to be important determinants for physical convalescence during the post-ICU phase. The pathophysiological mechanisms involved are poorly understood, thereby resulting in exiguous evidence-based treatment strategies to date.
Topics: Critical Illness; Humans; Incidence; Intensive Care Units; Muscle Weakness; Risk Factors
PubMed: 35796071
DOI: 10.1097/MCC.0000000000000955 -
Journal of Rehabilitation Medicine Aug 2008To assess the inter-rater and intra-rater reliability and validity of the original and a modified Medical Research Council scale for testing muscle strength in radial... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To assess the inter-rater and intra-rater reliability and validity of the original and a modified Medical Research Council scale for testing muscle strength in radial palsy.
DESIGN
Prospective, randomized validation study.
PATIENTS
Thirty-one patients with peripheral paresis of radial innervated forearm muscles were included.
METHODS
Wrist extension, finger extension and grip strength were evaluated by manual muscle testing. Dynamometric measurement of grip strength was performed. Pair-wise weighted kappa coefficients were calculated to determine inter-rater and intra-rater reliability. The 2 scores were compared using the signed-rank test. Spearman's correlation coefficients of the maximal relative force measurements with the median (over-raters) Medical Research Council and modified Medical Research Council scores were calculated to determine validity.
RESULTS
Inter-rater agreement of the Medical Research Council scale (finger extension: 0.77; wrist extension: 0.78; grip strength: 0.78) and the modified Medical Research Council scale (finger extension: 0.81; wrist extension: 0.78; grip strength: 0.81) as well as intra-rater agreement of the Medical Research Council scale (finger extension: 0.86; wrist extension: 0.82; grip strength: 0.84) and the modified Medical Research Council scale (finger extension: 0.84, wrist extension: 0.81; grip strength: 0.88) showed almost perfect agreement. Spearman's correlation coefficients of the maximal relative force measurements with the median Medical Research Council and modified Medical Research Council score were both 0.78.
CONCLUSION
Medical Research Council and modified Medical Research Council scales are measurements with substantial inter-rater and intra-rater reliability in evaluating forearm muscles.
Topics: Adult; Aged; Female; Hand Strength; Humans; Male; Middle Aged; Muscle Strength; Muscle Weakness; Observer Variation; Prospective Studies; Radial Neuropathy; Reproducibility of Results
PubMed: 19020701
DOI: 10.2340/16501977-0235 -
Ageing Research Reviews Jul 2010The effectiveness of resistance exercise for strength improvement among aging persons is inconsistent across investigations, and there is a lack of research synthesis... (Meta-Analysis)
Meta-Analysis Review
PURPOSE
The effectiveness of resistance exercise for strength improvement among aging persons is inconsistent across investigations, and there is a lack of research synthesis for multiple strength outcomes.
METHODS
The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. A meta-analysis was conducted to determine the effect of resistance exercise (RE) for multiple strength outcomes in aging adults. Randomized-controlled trials and randomized or non-randomized studies among adults > or = 50 years, were included. Data were pooled using random-effect models. Outcomes for 4 common strength tests were analyzed for main effects. Heterogeneity between studies was assessed using the Cochran Q and I(2) statistics, and publication bias was evaluated through physical inspection of funnel plots as well as formal rank-correlation statistics. A linear mixed model regression was incorporated to examine differences between outcomes, as well as potential study-level predictor variables.
RESULTS
Forty-seven studies were included, representing 1079 participants. A positive effect for each of the strength outcomes was determined however there was heterogeneity between studies. Regression revealed that higher intensity training was associated with greater improvement. Strength increases ranged from 9.8 to 31.6 kg, and percent changes were 29+/-2, 24+/-2, 33+/-3, and 25+/-2, respectively for leg press, chest press, knee extension, and lat pull.
CONCLUSIONS
RE is effective for improving strength among older adults, particularly with higher intensity training. Findings therefore suggest that RE may be considered a viable strategy to prevent generalized muscular weakness associated with aging.
Topics: Aged; Aged, 80 and over; Controlled Clinical Trials as Topic; Female; Humans; Male; Middle Aged; Muscle Weakness; Resistance Training; Sarcopenia
PubMed: 20385254
DOI: 10.1016/j.arr.2010.03.004 -
EBioMedicine Sep 2017In addition to the primary symptoms arising from inflammatory processes in the joints, muscle weakness is commonly reported by patients with rheumatoid arthritis (RA).... (Review)
Review
In addition to the primary symptoms arising from inflammatory processes in the joints, muscle weakness is commonly reported by patients with rheumatoid arthritis (RA). Muscle weakness not only reduces the quality of life for the affected patients, but also dramatically increases the burden on society since patients' work ability decreases. A 25-70% reduction in muscular strength has been observed in pateints with RA when compared with age-matched healthy controls. The reduction in muscle strength is often larger than what could be explained by the reduction in muscle size in patients with RA, which indicates that intracellular (intrinsic) muscle dysfunction plays an important role in the underlying mechanism of muscle weakness associated with RA. In this review, we highlight the present understanding of RA-associated muscle weakness with special focus on how enhanced Ca release from the ryanodine receptor and free radicals (reactive oxygen/nitrogen species) contributes to muscle weakness, and recent developments of novel therapeutic interventions.
Topics: Animals; Antioxidants; Arthritis, Rheumatoid; Calcium; Cytokines; Disease Progression; Excitation Contraction Coupling; Female; Free Radicals; Humans; Inflammation Mediators; Male; Muscle Weakness; Muscle, Skeletal; Myofibrils; Oxidative Stress; Reactive Nitrogen Species; Reactive Oxygen Species; Ryanodine Receptor Calcium Release Channel; Signal Transduction
PubMed: 28781131
DOI: 10.1016/j.ebiom.2017.07.023 -
PloS One 2022The study aimed to investigate the effect of early mobilization combined with early nutrition (EMN) on intensive care unit-acquired weakness (ICU-AW) in intensive care... (Randomized Controlled Trial)
Randomized Controlled Trial
AIM
The study aimed to investigate the effect of early mobilization combined with early nutrition (EMN) on intensive care unit-acquired weakness (ICU-AW) in intensive care unit (ICU) settings compared with early mobilization (EM) or routine care.
METHODS
A prospective, dual-center, randomized controlled trial was conducted. The control group underwent standard care without a pre-established routine for mobilization and nutrition. The EM group underwent early, individualized, progressive mobilization within 24 h of ICU admission. The EMN group underwent early mobilization, similar to the EM group plus guideline-based early nutrition (within 48 h of ICU admission). The primary outcome was the occurrence of ICU-AW at discharge from the ICU. Secondary outcomes included muscle strength, functional independence, organ failure, nutritional status, duration of mechanical ventilation (MV), length of ICU stay, and ICU mortality at ICU discharge.
RESULTS
A total of 150 patients were enrolled and equally distributed into the three groups. Patients undergoing routine care only were more susceptible to ICU-AW upon ICU discharge than those in the EM or EMN groups (16% vs. 2%; p = 0.014 for both), and had a lower Barthel Index than others (control vs. EM/EMN: 57.5 vs 70.0; p = 0.022). The EMN group had improved muscle strength (p = 0.028) and better nutritional status than the control group (p = 0.031). Both interventions were associated with a lower ICU-AW (EM vs. control: p = 0.027, OR [95% CI] = 0.066 [0.006-0.739]; EMN vs. control: p = 0.016, OR [95% CI] = 0.065 [0.007-0.607]).
CONCLUSION
EM and EMN had positive effects. There was little difference between the effects of EM and EMN, except for muscle strength improvement. Both EM and EMN may lead to a lower occurrence of ICU-AW and better functional independence than standard care. EMN might benefit nutritional status more than usual care and promote improvement in muscle strength.
Topics: Critical Illness; Early Ambulation; Humans; Intensive Care Units; Muscle Weakness; Nutritional Status; Prospective Studies; Respiration, Artificial
PubMed: 35617287
DOI: 10.1371/journal.pone.0268599 -
Journal of Athletic Training 2014Persistent muscle weakness after anterior cruciate ligament (ACL) reconstruction may be due to underlying activation failure and arthrogenic muscle inhibition (AMI).... (Comparative Study)
Comparative Study Randomized Controlled Trial
CONTEXT
Persistent muscle weakness after anterior cruciate ligament (ACL) reconstruction may be due to underlying activation failure and arthrogenic muscle inhibition (AMI). Knee-joint cryotherapy has been shown to improve quadriceps function transiently in those with AMI, thereby providing an opportunity to improve quadriceps muscle activation and strength in patients with a reconstructed ACL.
OBJECTIVE
To compare quadriceps muscle function in patients with a reconstructed ACL who completed a 2-week intervention including daily cryotherapy (ice bag), daily exercises, or both.
DESIGN
Cross-sectional study.
SETTING
Laboratory.
PATIENTS OR OTHER PARTICIPANTS
A total of 30 patients with reconstructed ACLs who were at least 6 months post-index surgery and had measurable quadriceps AMI.
INTERVENTION(S)
The patients attended 4 supervised visits over a 2-week period. They were randomly assigned to receive 20 minutes of knee-joint cryotherapy, 1 hour of therapeutic rehabilitation exercises, or cryotherapy followed by exercises.
MAIN OUTCOME MEASURE(S)
We measured quadriceps Hoffmann reflex, normalized maximal voluntary isometric contraction torque, central activation ratio using the superimposed-burst technique, and patient-reported outcomes before and after the intervention period.
RESULTS
After the 2-week intervention period, patients who performed rehabilitation exercises immediately after cryotherapy had higher normalized maximal voluntary isometric contraction torques (P = .002, Cohen d effect size = 1.4) compared with those who received cryotherapy alone (P = .16, d = 0.58) or performed exercise alone (P = .16, d = 0.30).
CONCLUSIONS
After ACL reconstruction, patients with AMI who performed rehabilitation exercises immediately after cryotherapy experienced greater strength gains than those who performed cryotherapy or exercises alone.
Topics: Adolescent; Adult; Ankle; Ankle Joint; Anterior Cruciate Ligament; Anterior Cruciate Ligament Injuries; Anterior Cruciate Ligament Reconstruction; Biomechanical Phenomena; Cross-Sectional Studies; Cryotherapy; Exercise Therapy; Female; Humans; Knee; Male; Muscle Weakness; Postoperative Complications; Quadriceps Muscle; Range of Motion, Articular; Treatment Outcome; Weight-Bearing
PubMed: 25299442
DOI: 10.4085/1062-6050-49.3.39 -
Scientific Reports Nov 2023The causal roles of muscle weakness in cardiometabolic diseases and osteoporosis remain elusive. This two-sample Mendelian randomization (MR) study aims to explore the...
The causal roles of muscle weakness in cardiometabolic diseases and osteoporosis remain elusive. This two-sample Mendelian randomization (MR) study aims to explore the causal roles of muscle weakness in the risk of cardiometabolic diseases and osteoporosis. 15 single nucleotide polymorphisms (SNPs, P < 5 × 10) associated with muscle weakness were used as instrumental variables. Genetic predisposition to muscle weakness led to increased risk of coronary artery disease (inverse variance weighted [IVW] analysis, beta-estimate: 0.095, 95% confidence interval [CI]: 0.023 to 0.166, standard error [SE]:0.036, P-value = 0.009) and reduced risk of heart failure (weight median analysis, beta-estimate: - 0.137, 95% CI - 0.264 to - 0.009, SE:0.065, P-value = 0.036). In addition, muscle weakness may reduce the estimated bone mineral density (eBMD, weight median analysis, beta-estimate: - 0.059, 95% CI - 0.110 to - 0.008, SE:0.026, P-value = 0.023). We found no MR associations between muscle weakness and atrial fibrillation, type 2 diabetes or fracture. This study provides robust evidence that muscle weakness is causally associated with the incidence of coronary artery disease and heart failure, which may provide new insight to prevent and treat these two cardiometabolic diseases.
Topics: Humans; Diabetes Mellitus, Type 2; Coronary Artery Disease; Osteoporosis; Muscle Weakness; Paresis; Heart Failure; Polymorphism, Single Nucleotide; Genome-Wide Association Study; Mendelian Randomization Analysis
PubMed: 37968290
DOI: 10.1038/s41598-023-46837-y -
Arquivos de Neuro-psiquiatria Apr 2017Acute muscle weakness in children is a pediatric emergency. During the diagnostic approach, it is crucial to obtain a detailed case history, including: onset of... (Review)
Review
Acute muscle weakness in children is a pediatric emergency. During the diagnostic approach, it is crucial to obtain a detailed case history, including: onset of weakness, history of associated febrile states, ingestion of toxic substances/toxins, immunizations, and family history. Neurological examination must be meticulous as well. In this review, we describe the most common diseases related to acute muscle weakness, grouped into the site of origin (from the upper motor neuron to the motor unit). Early detection of hyperCKemia may lead to a myositis diagnosis, and hypokalemia points to the diagnosis of periodic paralysis. Ophthalmoparesis, ptosis and bulbar signs are suggestive of myasthenia gravis or botulism. Distal weakness and hyporeflexia are clinical features of Guillain-Barré syndrome, the most frequent cause of acute muscle weakness. If all studies are normal, a psychogenic cause should be considered. Finding the etiology of acute muscle weakness is essential to execute treatment in a timely manner, improving the prognosis of affected children.
Topics: Acute Disease; Child; Humans; Muscle Weakness
PubMed: 28489146
DOI: 10.1590/0004-282X20170026 -
International Journal of Molecular... Oct 2020Skeletal muscle is a major metabolic organ that uses mostly glucose and lipids for energy production and has the capacity to remodel itself in response to exercise and... (Review)
Review
Skeletal muscle is a major metabolic organ that uses mostly glucose and lipids for energy production and has the capacity to remodel itself in response to exercise and fasting. Skeletal muscle wasting occurs in many diseases and during aging. Muscle wasting is often accompanied by chronic low-grade inflammation associated to inter- and intra-muscular fat deposition. During aging, muscle wasting is advanced due to increased movement disorders, as a result of restricted physical exercise, frailty, and the pain associated with arthritis. Muscle atrophy is characterized by increased protein degradation, where the ubiquitin-proteasomal and autophagy-lysosomal pathways, atrogenes, and growth factor signaling all play an important role. Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor family of transcription factors, which are activated by fatty acids and their derivatives. PPARs regulate genes that are involved in development, metabolism, inflammation, and many cellular processes in different organs. PPARs are also expressed in muscle and exert pleiotropic specialized responses upon activation by their ligands. There are three PPAR isotypes, viz., PPARα, -β/δ, and -γ. The expression of PPARα is high in tissues with effective fatty acid catabolism, including skeletal muscle. PPARβ/δ is expressed more ubiquitously and is the predominant isotype in skeletal muscle. It is involved in energy metabolism, mitochondrial biogenesis, and fiber-type switching. The expression of PPARγ is high in adipocytes, but it is also implicated in lipid deposition in muscle and other organs. Collectively, all three PPAR isotypes have a major impact on muscle homeostasis either directly or indirectly. Furthermore, reciprocal interactions have been found between PPARs and the gut microbiota along the gut-muscle axis in both health and disease. Herein, we review functions of PPARs in skeletal muscle and their interaction with the gut microbiota in the context of muscle wasting.
Topics: Animals; Energy Metabolism; Humans; Microbiota; Muscle Weakness; Muscle, Skeletal; Muscular Atrophy; Peroxisome Proliferator-Activated Receptors; Signal Transduction
PubMed: 33137899
DOI: 10.3390/ijms21218056