Neuromuscular disease
A neuromuscular disease is any disease affecting the peripheral nervous system (PNS), the neuromuscular junction, or skeletal muscle, all of which are components of the motor unit. Damage to any of these structures can cause muscle atrophy and weakness. Issues with sensation can also occur. Neuromuscular diseases can be acquired or genetic. Mutations of more than 500 genes have shown to be causes of neuromuscular diseases. Other causes include nerve or muscle degeneration, autoimmunity, toxins, medications, malnutrition, metabolic derangements, hormone imbalances, infection, nerve compression/entrapment, comprised blood supply, and trauma. Symptoms of neuromuscular disease may include numbness, paresthesia, muscle weakness, muscle atrophy, myalgia (muscle pain), and fasciculations (muscle twitches). Neuromuscular disease can be caused by autoimmune disorders, genetic/hereditary disorders and some forms of the collagen disorder Ehlers–Danlos syndrome, exposure to environmental chemicals and poisoning which includes heavy metal poisoning. 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. Diseases of the motor end plate include myasthenia gravis, a form of muscle weakness due to antibodies against acetylcholine receptor, and its related condition Lambert–Eaton myasthenic syndrome (LEMS). Tetanus and botulism are bacterial infections in which bacterial toxins cause increased or decreased muscle tone, respectively. 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. Further causes of neuromuscular diseases are: 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).
