Neuromuscular disease

Neuromuscular disease
Muscles of the forearm
Classification and external resources
ICD-10	G70.9
MeSH	D009468

Neuromuscular disease is a very broad term that encompasses many diseases and ailments that impair the functioning of the muscles, either directly, being pathologies of the voluntary muscle, or indirectly, being pathologies of nerves or neuromuscular junctions.^[1][2]

Neuromuscular diseases are those that affect the muscles and/or their direct nervous system control, problems with central nervous control can cause either spasticity or some degree of paralysis (from both lower and upper motor neuron disorders), depending on the location and the nature of the problem. Some examples of central disorders include cerebrovascular accident, Parkinson's disease, multiple sclerosis, Huntington's disease and Creutzfeldt–Jakob disease. Spinal muscular atrophies are disorders of lower motor neuron while amyotrophic lateral sclerosis is a mixed upper and lower motor neuron condition.

Symptoms/signs

Symptoms of neuromuscle disease may include the following:^[1][3]

• Muscular weakness
• Rigidity
• Loss of muscular control
• Myoclonus (twitching, spasming)
• Myalgia (muscle pain).

Causes

Neuromuscular disease can be caused by autoimmune disorders,^[4] genetic/hereditary disorders ^[1] and some forms of the collagen disorder Ehlers Danlos Syndrome,^[5] exposure to environmental chemicals and poisoning which includes heavy metal poisoning.^[6] The failure of the electrical insulation surrounding nerves, the myelin, is seen in certain deficiency diseases, such as the failure of the body's system for absorbing vitamin B-12^[6]

Diseases of the motor end plate include myasthenia gravis, a form of muscle weakness due to antibodies against acetylcholine receptor,^[7] and its related condition Lambert-Eaton myasthenic syndrome (LEMS).^[8] Tetanus and botulism are bacterial infections in which bacterial toxins cause increased or decreased muscle tone, respectively.^[9]Muscular dystrophies, including Duchenne's and Becker's, are a large group of diseases, many of them hereditary or resulting from genetic mutations, where the muscle integrity is disrupted, they lead to progressive loss of strength and decreased life span.^[10] Further causes of neuromuscular diseases are :

Polymyositis

Inflammatory muscle disorders

• Polymyalgia rheumatica (or "muscle rheumatism") is an inflammatory condition that mainly occurs in the elderly; it is associated with giant-cell arteritis(It often responds to prednisolone).^[11]
• Polymyositis is an autoimmune condition in which the muscle is affected.^[12]
• Rhabdomyolysis is the breakdown of muscular tissue due to any cause.^[13]

Tumors

• Smooth muscle: leiomyoma (benign)^[14]
• Striated muscle: rhabdomyoma (benign)^[15]

Mechanism

In terms of the mechanism of neurological diseases, it depends on which one—whether it is amyotrophic lateral sclerosis, myasthenia gravis or some other NMD.^[1] One finds that in muscular dystrophy (Duchenne), gene therapy might have promise as a treatment, since the mutation in a nonessential exon, can be improved via exon-skipping.^[16]

Diagnosis

Nerve conduction velocity (study)

Diagnostic procedures that may reveal muscular disorders include direct clinical observations. This usually starts with the observation of bulk, possible atrophy or loss of muscle tone. Neuromuscular disease can also be diagnosed by testing the levels of various chemicals and antigens in the blood, and using electrodiagnostic medicine tests^[17] including electromyography^[18] (measuring electrical activity in muscles) and nerve conduction studies.^[19]

In neuromuscular disease evaluation, it is important to perform musculoskeletal and neurologic examinations. Genetic testing is an important part of diagnosing inherited neuromuscular conditions.^[17]

Management

In terms of treatment for neuromuscular diseases (NMD), exercise might be a way of managing them, as NMD individuals would gain muscle strength. In a study aimed at results of exercise, in muscular dystrophy and Charcot-Marie-Tooth disease, the later benefited while the former did not show benefit; therefore, it depends on the disease^[20] Other management routes for NMD should be based on medicinal and surgical procedures, again depending on the underlying cause.^[21]

See also

• List of neuromuscular disorders
• Muscle
• Motor neuron diseases
• ICD-10 Chapter XIII: Diseases of the musculoskeletal system and connective tissue
• Neuromuscular medicine

References

1. "Neuromuscular Disorders: MedlinePlus". www.nlm.nih.gov. Retrieved 2016-04-24.
2. http://jnnp.bmj.com/content/74/suppl_2/ii32.full
3. "Myopathy Information Page: National Institute of Neurological Disorders and Stroke (NINDS)". www.ninds.nih.gov. Retrieved 2016-04-24.
4. Kraker, Jessica; Živković, Saša A (2011-09-01). "Autoimmune Neuromuscular Disorders". Current Neuropharmacology. 9 (3): 400–408. doi:10.2174/157015911796558000. ISSN 1570-159X. PMC 3151594. PMID 22379454.
5. Nicol, C (2009). "Neuromuscular involvement in various types of Ehlers–Danlos syndrome†" (PDF). Annals of Neurology. Retrieved 24 April 2016.
6. Swash, Michael; Schwartz, Martin S. (2013-03-14). Neuromuscular Diseases: A Practical Approach to Diagnosis and Management. Springer Science & Business Media. p. 86,196. ISBN 9781447138341.
7. "Myasthenia Gravis: Practice Essentials, Background, Anatomy".
8. "Lambert-Eaton Myasthenic Syndrome (LEMS): Background, Pathophysiology, Etiology".
9. Kumar, Vinay; Abbas, Abul K.; Aster, Jon C. (2014-09-05). Robbins & Cotran Pathologic Basis of Disease. Elsevier Health Sciences. p. 382. ISBN 9780323296359.
10. "Muscular Dystrophy Information Page: National Institute of Neurological Disorders and Stroke (NINDS)". www.ninds.nih.gov. Retrieved 2016-04-24.
11. Liaison, Janet Austin, Office of Communications and Public. "Polymyalgia Rheumatica and Giant Cell Arteritis". www.niams.nih.gov. Retrieved 2016-04-24.
12. "Polymyositis: Background, Etiology, Epidemiology".
13. "Rhabdomyolysis: MedlinePlus Medical Encyclopedia". www.nlm.nih.gov. Retrieved 2016-04-24.
14. "Leiomyoma: Practice Essentials, Background, Pathophysiology".
15. "Rhabdomyomas: Background, Pathophysiology and Etiology, Epidemiology".
16. http://www.medscape.com/viewarticle/771143
17. McDonald, Craig M. (2012-08-01). "CLINICAL APPROACH TO THE DIAGNOSTIC EVALUATION OF HEREDITARY AND ACQUIRED NEUROMUSCULAR DISEASES". Physical Medicine and Rehabilitation Clinics of North America. 23 (3): 495–563. doi:10.1016/j.pmr.2012.06.011. ISSN 1047-9651. PMC 3482409. PMID 22938875.
18. Darras, Basil T.; Jr, H. Royden Jones, Jr; Ryan, Monique M.; Vivo, Darryl C. De (2014-12-03). Neuromuscular Disorders of Infancy, Childhood, and Adolescence: A Clinician's Approach. Elsevier. p. 488. ISBN 0124171273.
19. "Electromyography and Nerve Conduction Studies: Background, Indications, Contraindications".
20. http://emedicine.medscape.com/article/321397-overview
21. Campbell Jr., William W. (2011-01-01). 16 - Treatment and Management of Segmental Neuromuscular Disorders A2 - Bertorini, Tulio E. Saint Louis: W.B. Saunders. pp. 261–284. ISBN 9781437703726. – via ScienceDirect (Subscription may be required or content may be available in libraries.)

Further reading

• Wokke, John H. J.; Doorn, Pieter A. van; Hoogendijk, Jessica E.; Visser, Marianne de (2013-03-07). Neuromuscular Disease: A Case-Based Approach. Cambridge University Press. ISBN 9781107328044.
• Ambrosino, N.; Carpenè, N.; Gherardi, M. (2009-08-01). "Chronic respiratory care for neuromuscular diseases in adults". European Respiratory Journal. 34 (2): 444–451. doi:10.1183/09031936.00182208. ISSN 0903-1936. PMID 19648521.

External links

• Child Muscle Weakness