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Chronic Denervation Myopathy
Published in Maher Kurdi, Neuromuscular Pathology Made Easy, 2021
Long-standing neurogenic disease may result in denervation of the target musculature. This is rare in clinical practice and usually referred to as chronic denervation myopathy. The spectrum of potential causes ranges from hereditary or sporadic genetic mutations to neurodegenerative, inflammatory, and neoplastic processes. In addition, aging of muscle and some metabolic conditions are also accompanied by neuropathy. The most common sporadic or hereditary cause is anterior horn cell degeneration of the central nervous system. Amyotrophic lateral sclerosis (ALS) in adulthood and spinal muscular atrophy (SMA) in childhood are the best examples of denervation myopathies. Secondary acquired causes include any disease with severe peripheral neuropathy, due to any cause, affecting the innervated muscle. Table 21.1 lists the common denervation diseases in muscle pathology practice.
Neurology and neurosurgery
Published in Jagdish M. Gupta, John Beveridge, MCQs in Paediatrics, 2020
Jagdish M. Gupta, John Beveridge
The Duchenne and Becker types of muscular dystrophy are both sex-linked recessive. Fasciculations are characteristic of anterior horn cell disease. In peripheral neuropathies there is weakness and sensory loss distally. In spinal muscular atrophy, electromyography shows evidence of denervation of muscle including low potentials and fasciculations. Nerve conduction studies are within the normal range. In Duchenne muscular dystrophy the serum creatine kinase level is raised at birth and is 10 times the normal value at the age of 1 month.
Neurology
Published in Stephan Strobel, Lewis Spitz, Stephen D. Marks, Great Ormond Street Handbook of Paediatrics, 2019
Fenella Kirkham, Adnan Manzur, Stephanie Robb
SMA type I occurs in 1 in 20,000. It is autosomal recessive, with deletion of exon 7 of the survival motor neuron (SMN) gene on chromosome 5q13 in 95% of cases. Pathologically there is loss of anterior horn cells.
Effects of a contusion load on spinal cord with different curvatures
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Qian-qian Yu, Si-qing Liu, Jian-jie Wang, Meng-lei Xu, Wen-xuan Zhang, Li-ming Cheng, Rui Zhu
Variation of stress distribution reflects the situation during injury to some degree. Figures 7 and 8 show the maximum von Mises stress in the middle transverse cross section of gray matter loaded from back to front and from front to back load subject to different spinal curvatures under 40% compression ratio. With back-to-front load, the stress mainly located around the central canal and central region especially in the straight curvature, and thus central cord syndrome had a high probability of occurrence. This explains why the closer to the central tissue, the more serious the damage (Schneider et al. 1954). The high stress in the straight curvature affected a larger region compared to the other two curvatures and maybe more seriously damaged. The front-to-back load can be given arise by several degenerative factors, such as disc herniation, ligament ossification and osteophyma (Xiaofei et al. 2013). With the load, the anterior horn of the spinal cord was most affected and symptoms of the anterior cord syndrome may become more predominant. Scenarios with different curvatures were observed similar stress distribution, but the high stress had larger action area in the scenario with the kyphotic curvature. Thus, pathological curvature was more vulnerable when shocked, and lordotic curvature showed some benefits to some degree from the view of stress distribution.
Electroacupuncture with rehabilitation training for limb spasticity reduction in post-stroke patients: A systematic review and meta-analysis
Published in Topics in Stroke Rehabilitation, 2021
Jiyao Zhang, Luwen Zhu, Qiang Tang
Muscle tension is the result of synergism of α and γ motor neurons.5 The excitement and inhibition of α motor neurons in the anterior horn of the spinal cord or brainstem are in a relatively balanced state under the control of higher-level neurons. However, the balance could be broken by stroke, which in turn leads to the superiority of γ motor neurons and weakens the central motor suppression system. Moreover, the extrapyramidal system, which is a high-level center regulating muscle tension, may inhibit and excite the stretch reflex of the spinal cord.6 The occurrence of spasticity may be related to the broken balance between the neural networks and the released original reflex. In addition, the compliance of tendons and the physiology of muscle fibers could be altered by misuse and disuse after denervation of muscles, which in turn triggers a series of mechanical changes, including limb contractures and deformities.7
Current and emerging ALS biomarkers: utility and potential in clinical trials
Published in Expert Review of Neurotherapeutics, 2018
Arens Taga, Nicholas J. Maragakis
Diagnostic neuroimaging, most notably magnetic resonance imaging (MRI), has primarily found its role in the exclusion of disorders that could mimic the historical and physical examination findings in ALS [4]. Because of technical limitations, most of these neuroimaging strategies have been confined to the brain and brainstem. Changes related to the spinal cord, where anterior horn cells reside, have not been reliably measured [4]. However, newer imaging techniques appear promising not only as diagnostic adjuncts to the history and neurological examination but also potentially as prognostic and pharmacodynamic indicators of disease. Imaging modalities also have the advantage of being non-invasive, can be performed longitudinally, and can offer a window into corticospinal tract pathology.