The nervous system consists of three main nerve types. Sensory nerves supply humans with the ability to see, hear, smell, taste and feel. Motor nerves enable the brain to command the muscles of the body. Autonomic nerves regulate the function of the internal organs. The autonomic nervous system is divided into sympathetic and parasympathetic nerves. Sympathetic nerves are associated with the fight-or-flight response. They increase the heart and respiratory rates and dilate the pupils. Parasympathetic nerves aid in more sedate functions such as as sleeping and digestion.
Reflex Sympathetic Dystrophy
The sympathetic nervous system regulates blood flow and perspiration. When the sympathetic nerves of the hand and arm are injured, they can become overactive. This condition is known as reflex sympathetic dystrophy, or RSD. RSD can cause the sensation of burning and warmth in the arm, accompanied by swelling and sometimes discoloration of the hand.
The cause of this disorder can sometimes be unclear, but the American Academy of Orthopaedic Surgeons states that often RSD can be associated with injury, surgical complications or infection. Any of those factors can injure nerves and set off the sympathetic nerve reaction that causes reflex sympathetic dystrophy.
Parkinson's disease is a nervous system disorder whose origins remain unclear. In Parkinson's disease, the brain produces inadequate amounts of dopamine, and protein masses called Lewy bodies form in the brain.
Mayoclinic.com notes that Parkinson's disease is primarily associated with motor nerve disruptions that cause symptoms such as tremors, loss of balance control and slowed movement. However, David S. Goldstein, M.D., of the National Institute of Neurological Disorders and Stroke has reported that Parkinson's disease also damages sympathetic nerves to the heart. This can lead to abnormal blood pressure responses, such as orthostatic hypotension, a condition characterized by dizziness that coincides with postural changes, such as rising from a sitting to a standing position.
Diabetes can cause nerve damage throughout the body, affecting the sympathetic, parasympathetic, sensory and motor nerves. Autonomic neuropathy is most common in patients with long histories of inadequately treated diabetes. Diabetic neuropathy of the sympathetic nerves can disrupt the cardiovascular system's ability to regulate blood flow and the contractility of the heart muscle
MayoClinic.com explains that erectile dysfunction, constipation and bladder problems continue the roster of misfortunes visited upon those who live with diabetic neuropathy of the autonomic nervous system.
- Annals of Internal Medicine: Cardiac Sympathetic Denervation in Parkinson Disease
- American Academy of Orthopaedic Surgeons: Reflex Sympathetic Dystrophy
- National Institutes of Neurological Disorders and Stroke: Peripheral Neuropathy Fact Sheet
- MayoClinic.com: Diabetic Neuropathy
- MayoClinic.com: Parkinson's Disease