The peripheral nervous system (PNS) is the part of the nervous system that is made of the nerves and ganglia that are outside of those found in the brain and spinal cord. All of the pathways that transmit signals from the brain and the spinal cord to the rest of the body are in this part of the nervous system. Peripheral nervous system diseases affect these pathways and can be classified as genetic, autoimmune or infection related, or secondary.
Genetic peripheral nervous system diseases are PNS disorders that are passed by one or both parents to a child. Common genetic PNS diseases include myotonic dystrophy, neurofibromatosis, and myasthenia gravis. Myotonic dystrophy causes nerve degeneration that leads to muscle weakness, muscle mass reduction, and improper muscle function. Neurofibromatosis causes tumor growth of nerve tissue, which interferes with nerve transmission abilities. Myasthenia gravis is a genetic autoimmune disease that causes the T cells of the immune system to attack the neurotransmitter called acetylcholine, which leads to a progressive weakness in muscle function and fatigue.
Peripheral nervous system diseases can also be caused by autoimmune disorders. These types of PNS diseases result in the body’s immune system attacking parts of the body. Guillain-Barr syndrome is a common autoimmune-based PNS disease. The immune system views cells of the body as foreign and attacks the cells, particularly cells associated with the peripheral system. Inflammation of the nerves occurs, which in turn causes nerve degeneration and muscle weakness.
Infection-related peripheral nervous system diseases are another type of PNS disease. Poliomyelitis, also called polio, and anesthetic leprosy are two infections that can cause a PNS disease. Polio is an infection of the central nervous system, but it affects the PNS more often and leads to motor neuron degeneration that causes muscle atrophy and paralysis. Anesthetic leprosy is an infection that occurs in the peripheral nerves. Damage to the nerves from the infection can lead to gangrene, or tissue death, and paralysis.
Treatment for peripheral nervous system diseases varies, depending on the type of disease and if there is an underlying condition responsible. PNS diseases that occur as a result of infections are generally treated with antibiotic medications and respond well to this treatment. Autoimmune and genetic PNS diseases often have no cure, but symptoms can be reduced to make patients more comfortable and have a better quality of life. Medications that prevent muscle weakness or slow down nerve damage can help provide this aid.