The nervous system provides a communications network for the brain to send messages to the muscles and organs of the body, and for the body to send information back to the brain. An elaborate web of sensory nerves enables people to see, hear, taste and feel. Motor nerves supply the muscles and enable movement. Autonomic nerves serve the internal organs and glands. Nervous system disorders can disrupt normal functioning in any area that the nervous system supplies.
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Infectious diseases such as shingles can affect the nervous system. Shingles is caused by the herpes zoster virus, which remains in an inactive form in the nerve bundles near the spine after a patient has recovered from chickenpox. This virus remains dormant for decades, and then reactivates, typically when the individual is in her sixties, according to MayoClinic.com. The virus moves down along the nerve path, causing rash and neuralgia, or nerve pain.
Damage to the body due to motor vehicle accidents, falls, sports injuries or acts of violence can sometimes affect the nervous system. Trauma is frequently involved in cases of sciatica, which occurs when the sciatic nerve, which passes from the lower spine down the back of the legs, is damaged. The nerve itself can be injured, or bone fragments from a fracture could place pressure on the nerve, according to orthopedic surgeon Jean-Jacques Abitbol of the California Spine Group.
When the body mistakenly identifies its own tissues as a foreign and potentially dangerous substance, it directs an immune system attack against those tissues. This is called an autoimmune disorder. Several autoimmune disorders are known to attack the nervous system, among these are Guillain–Barré syndrome and multiple sclerosis, according to the National Institute of Neurological Disorders and Stroke.
A number of hereditary conditions can cause nervous system dysfunction. Spinal muscular atrophy is an example of a genetic disease that affects neurons that control voluntary muscle movement, according to the National Institutes of Health. Huntington’s chorea is another nervous system disorder. It is passed from parent to offspring via a defective gene that causes brain cells to waste away. The rare genetic disorder Tay-Sachs disease destroys nerve cell by causing fatty material to accumulate in the brain.
Medication Side Effects
Parkinson’s disease is a nervous system disorder whose main symptoms include tremors, rigidity of the trunk and extremities, slow movement and balance disorders. This nervous system disorder arises from a loss of brain cells that produce dopamine.
In most cases, the cause of the brain cell loss associated with Parkinson’s is known, according to Body and Health Canada. In some cases, however, the side effects of certain medications are known to cause secondary Parkinson’s disease. Drugs used to treat hallucinations, such as haloperidol, and the antinausea drug metoclopramide are known to cause secondary Parkinson’s disease.