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Toxins Apr 2021The simple definition of tone as the resistance to passive stretch is physiologically a complex interlaced network encompassing neural circuits in the brain, spinal... (Review)
Review
The simple definition of tone as the resistance to passive stretch is physiologically a complex interlaced network encompassing neural circuits in the brain, spinal cord, and muscle spindle. Disorders of muscle tone can arise from dysfunction in these pathways and manifest as hypertonia or hypotonia. The loss of supraspinal control mechanisms gives rise to hypertonia, resulting in spasticity or rigidity. On the other hand, dystonia and paratonia also manifest as abnormalities of muscle tone, but arise more due to the network dysfunction between the basal ganglia and the thalamo-cerebello-cortical connections. In this review, we have discussed the normal homeostatic mechanisms maintaining tone and the pathophysiology of spasticity and rigidity with its anatomical correlates. Thereafter, we have also highlighted the phenomenon of network dysfunction, cortical disinhibition, and neuroplastic alterations giving rise to dystonia and paratonia.
Topics: Animals; Brain; Dystonia; Humans; Muscle Contraction; Muscle Hypertonia; Muscle Rigidity; Muscle Spasticity; Muscle Tonus; Muscle, Skeletal; Neural Pathways; Spinal Cord
PubMed: 33923397
DOI: 10.3390/toxins13040282 -
Missouri Medicine 2019Malignant Hyperthermia (MH) is a life-threatening pharmacogenetic disorder which results from exposure to volatile anesthetic agents and depolarizing muscle relaxants.... (Review)
Review
Malignant Hyperthermia (MH) is a life-threatening pharmacogenetic disorder which results from exposure to volatile anesthetic agents and depolarizing muscle relaxants. It manifests as a hypermetabolic response resulting in tachycardia, tachypnea, hyperthermia, hypercapnia, acidosis, muscle rigidity and rhabdomyolysis. An increase in the end-tidal carbon dioxide is one of the earliest diagnostic signs. Dantrolene sodium is effective in the management of MH, and should be available whenever general anesthesia is administered. This review also aims to highlight the genetics and pathology of MH, along with its association with various inherited myopathy syndromes like central core disease, multi-mini core disease, Native-American myopathy, and King-Denborough syndrome.
Topics: Anesthetics; Dantrolene; Humans; Malignant Hyperthermia; Muscle Relaxants, Central; Neuromuscular Depolarizing Agents
PubMed: 31040503
DOI: No ID Found -
Internal Medicine (Tokyo, Japan) Jan 2020Various methods of rehabilitation for dysphagia have been suggested through the experience of treating stroke patients. Although most of these patients recover their... (Review)
Review
Various methods of rehabilitation for dysphagia have been suggested through the experience of treating stroke patients. Although most of these patients recover their swallowing function in a short period, dysphagia in Parkinson's disease (PD) and Parkinson-related disorder (PRD) degenerates with disease progression. Muscle rigidity and bradykinesia are recognized as causes of swallowing dysfunction, and it is difficult to easily apply the strategies for stroke to the rehabilitation of dysphagia in PD patients. Disease severity, weight loss, drooling, and dementia are important clinical predictors. Silent aspiration is a pathognomonic sign that may lead to aspiration pneumonia. Severe PD patients need routine video fluoroscopy or video endoscopy to adjust their food and liquid consistency. Patients with PRD experience rapid progression of swallowing dysfunction. Nutrition combined with nasogastric tube feeding or percutaneous endoscopic gastrostomy feeding should be considered owing to the increased risk of aspiration and difficulty administrating oral nutrition.
Topics: Deglutition; Deglutition Disorders; Disease Progression; Enteral Nutrition; Humans; Hypokinesia; Muscle Rigidity; Parkinson Disease; Pneumonia, Aspiration; Respiratory Aspiration; Stroke Rehabilitation
PubMed: 30996170
DOI: 10.2169/internalmedicine.2373-18 -
Current Neuropharmacology 2015Neuroleptic malignant syndrome (NMS) is a rare but potentially life-threatening side-effect that can occur in response to treatment with antipsychotic drugs. Symptoms... (Review)
Review
Neuroleptic malignant syndrome (NMS) is a rare but potentially life-threatening side-effect that can occur in response to treatment with antipsychotic drugs. Symptoms commonly include hyperpyrexia, muscle rigidity, autonomic dysfunction and altered mental status. In the current review we provide an overview on past and current developments in understanding the causes and treatment of NMS. Studies on the epidemiological incidence of NMS are evaluated, and we provide new data from the Canada Vigilance Adverse Reaction Online database to elaborate on drug-specific and antipsychotic drug polypharmacy instances of NMS reported between 1965 and 2012. Established risk factors are summarized with an emphasis on pharmacological and environmental causes. Leading theories about the etiopathology of NMS are discussed, including the potential contribution of the impact of dopamine receptor blockade and musculoskeletal fiber toxicity. A clinical perspective is provided whereby the clinical presentation and phenomenology of NMS is detailed, while the diagnosis of NMS and its differential is expounded. Current therapeutic strategies are outlined and the role for both pharmacological and non-pharmacological treatment strategies in alleviating the symptoms of NMS are discussed.
Topics: Animals; Antipsychotic Agents; Diagnosis, Differential; Humans; Incidence; Muscle Rigidity; Neuroleptic Malignant Syndrome; Risk Factors
PubMed: 26411967
DOI: 10.2174/1570159x13999150424113345 -
Sensors (Basel, Switzerland) Feb 2020Rigidity is one of the cardinal symptoms of Parkinson´s disease (PD). Present in up 89% of cases, it is typically assessed with clinical scales. However, these...
Rigidity is one of the cardinal symptoms of Parkinson´s disease (PD). Present in up 89% of cases, it is typically assessed with clinical scales. However, these instruments show limitations due to their subjectivity and poor intra- and inter-rater reliability. To compile all of the objective quantitative methods used to assess rigidity in PD and to study their validity and reliability, a systematic review was conducted using the Web of Science, PubMed, and Scopus databases. Studies from January 1975 to June 2019 were included, all of which were written in English. The Strengthening the Reporting of observational studies in Epidemiology Statement (STROBE) checklist for observational studies was used to assess the methodological rigor of the included studies. Thirty-six studies were included. Rigidity was quantitatively assessed in three ways, using servomotors, inertial sensors, and biomechanical and neurophysiological study of muscles. All methods showed good validity and reliability, good correlation with clinical scales, and were useful for detecting rigidity and studying its evolution. People with PD exhibit higher values in terms of objective muscle stiffness than healthy controls. Rigidity depends on the angular velocity and articular amplitude of the mobilization applied. There are objective, valid, and reliable methods that can be used to quantitatively assess rigidity in people with PD.
Topics: Electromyography; Humans; Joints; Movement; Muscle Rigidity; Muscles; Observational Studies as Topic; Parkinson Disease
PubMed: 32041374
DOI: 10.3390/s20030880 -
Seminars in Neurology Apr 2017The motor symptoms of Parkinson's disease are not limited to the cardinal symptoms of bradykinesia, rigidity, and resting tremor, but also include a variety of... (Review)
Review
The motor symptoms of Parkinson's disease are not limited to the cardinal symptoms of bradykinesia, rigidity, and resting tremor, but also include a variety of interrelated motor phenomena such as deficits in spatiotemporal planning and movement sequencing, scaling and timing of movements, and intermuscular coordination that can be clinically observed. Although many of these phenomena overlap, a review of the full breadth of the motor phenomenon can aid in the diagnosis and monitoring of disease progression.
Topics: Disease Progression; Humans; Muscle Rigidity; Parkinson Disease; Tremor
PubMed: 28511251
DOI: 10.1055/s-0037-1601869 -
Orphanet Journal of Rare Diseases Apr 2007Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as... (Review)
Review
Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as halothane, sevoflurane, desflurane and the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stresses such as vigorous exercise and heat. The incidence of MH reactions ranges from 1:5,000 to 1:50,000-100,000 anesthesias. However, the prevalence of the genetic abnormalities may be as great as one in 3,000 individuals. MH affects humans, certain pig breeds, dogs, horses, and probably other animals. The classic signs of MH include hyperthermia to marked degree, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, muscle rigidity, and rhabdomyolysis, all related to a hypermetabolic response. The syndrome is likely to be fatal if untreated. Early recognition of the signs of MH, specifically elevation of end-expired carbon dioxide, provides the clinical diagnostic clues. In humans the syndrome is inherited in autosomal dominant pattern, while in pigs in autosomal recessive. The pathophysiologic changes of MH are due to uncontrolled rise of myoplasmic calcium, which activates biochemical processes related to muscle activation. Due to ATP depletion, the muscle membrane integrity is compromised leading to hyperkalemia and rhabdomyolysis. In most cases, the syndrome is caused by a defect in the ryanodine receptor. Over 90 mutations have been identified in the RYR-1 gene located on chromosome 19q13.1, and at least 25 are causal for MH. Diagnostic testing relies on assessing the in vitro contracture response of biopsied muscle to halothane, caffeine, and other drugs. Elucidation of the genetic changes has led to the introduction, on a limited basis so far, of genetic testing for susceptibility to MH. As the sensitivity of genetic testing increases, molecular genetics will be used for identifying those at risk with greater frequency. Dantrolene sodium is a specific antagonist of the pathophysiologic changes of MH and should be available wherever general anesthesia is administered. Thanks to the dramatic progress in understanding the clinical manifestation and pathophysiology of the syndrome, the mortality from MH has dropped from over 80% thirty years ago to less than 5%.
Topics: Adolescent; Adult; Aged; Animals; Child; Child, Preschool; Diagnosis, Differential; Female; Genetic Predisposition to Disease; Genetic Testing; Humans; Infant; Infant, Newborn; Male; Malignant Hyperthermia; Masseter Muscle; Middle Aged; Muscle Rigidity; Muscular Diseases; Myopathy, Central Core; Neuromuscular Depolarizing Agents; Succinylcholine
PubMed: 17456235
DOI: 10.1186/1750-1172-2-21 -
Journal of Biomechanics Mar 2019This work presents a framework for computing the limbs' stiffness using inverse methods that account for the musculoskeletal redundancy effects. The musculoskeletal... (Review)
Review
This work presents a framework for computing the limbs' stiffness using inverse methods that account for the musculoskeletal redundancy effects. The musculoskeletal task, joint and muscle stiffness are regulated by the central nervous system towards improving stability and interaction with the environment during movement. Many pathological conditions, such as Parkinson's disease, result in increased rigidity due to elevated muscle tone in antagonist muscle pairs, therefore the stiffness is an important quantity that can provide valuable information during the analysis phase. Musculoskeletal redundancy poses significant challenges in obtaining accurate stiffness results without introducing critical modeling assumptions. Currently, model-based estimation of stiffness relies on some objective criterion to deal with muscle redundancy, which, however, cannot be assumed to hold in every context. To alleviate this source of error, our approach explores the entire space of possible solutions that satisfy the action and the physiological muscle constraints. Using the notion of null space, the proposed framework rigorously accounts for the effect of muscle redundancy in the computation of the feasible stiffness characteristics. To confirm this, comprehensive case studies on hand movement and gait are provided, where the feasible endpoint and joint stiffness is evaluated. Notably, this process enables the estimation of stiffness distribution over the range of motion and aids in further investigation of factors affecting the capacity of the system to modulate its stiffness. Such knowledge can significantly improve modeling by providing a holistic overview of dynamic quantities related to the human musculoskeletal system, despite its inherent redundancy.
Topics: Biomechanical Phenomena; Gait; Hand; Humans; Models, Biological; Muscle Rigidity; Muscle, Skeletal; Muscles; Musculoskeletal Physiological Phenomena; Range of Motion, Articular
PubMed: 30709554
DOI: 10.1016/j.jbiomech.2019.01.017 -
Australian Prescriber Feb 2019Drugs can cause dysregulation of the hypothalamic–pituitary–adrenal axis which can result in a rise in core temperature. This type of hyperthermia is unresponsive to... (Review)
Review
Drugs can cause dysregulation of the hypothalamic–pituitary–adrenal axis which can result in a rise in core temperature. This type of hyperthermia is unresponsive to antipyretics and can be complicated by rhabdomyolysis, multi-organ failure and disseminated intravascular coagulation Organic causes of fever such as infection must be ruled out. Syndromes associated with drug-induced fever include neuroleptic malignant syndrome and anticholinergic, sympathomimetic and serotonin toxicity The class of offending drugs, as well as the temporal relationship to starting or stopping them, assists in differentiating between neuroleptic malignant syndrome and serotonin toxicity Immediate inpatient management is needed. The mainstay of management is stopping the drug, and supportive care often in the intensive care unit
PubMed: 30765906
DOI: 10.18773/austprescr.2019.006