Introduction To Peripheral Neuropathy

Peripheral Neuropathy is a common problem, now affecting over 20 million people in the United States and many additional individuals throughout the world. Peripheral neuropathy has always been present, but is often under diagnosed, misdiagnosed, poorly understood or often just considered a secondary diagnosis of another problem. This problem however is very important and can be very debilitating. To better understand this entity, however, we need to better understand the nervous system and the nerve itself.

The Nervous System

The nervous system consists of a web of nerves extending throughout the body. These nerves carry signals to and from the brain and control the smooth functioning of every system or process in the body. This system is made up of two parts: The Central Nervous System, and The Peripheral Nervous System.

The Central Nervous System consists of the brain and spinal cord and usually interprets and reacts to signals received from the body.

The Peripheral Nervous System consists of all other nerves throughout the body. These are the nerves that extend from the brain or spinal cord to all other systems of the body. These are the nerves than can be affected with peripheral neuropathy. Often the most affected nerves are those furthest from the central nervous system extending to the feet or hands. The extension to the feet is the reason I have a special interest in this disease.

Peripheral Neuropathy is therefore a malfunction of the peripheral nervous system and affects the specific area served by the various nerves.

Parts of The Peripheral Nervous System

The peripheral nervous system is also divided into two parts, namely the somatic nervous system and the autonomic nervous system.

The Somatic Nervous System produces body movement by causing muscle contracture or relaxation and also carries signals from the five senses back to the central nervous system (or brain). This is considered a more voluntary nervous system through which we react to the world around us. Your reactions are even carried through this system. This system consists of motor nerves and sensory nerves.

The Autonomic Nervous System is the automatic portion of the peripheral nervous system. This controls many of the involuntary functions of the body, including heart rate, blood pressure, respiration, digestion, bladder function and even the simple release of oils or sweat to the skin. This maintains a state of equilibrium or homeostasis where all systems of the body work appropriately together. This system consists of autonomic nerves.

Peripheral Neuropathy can affect either of these parts of the peripheral nervous system. Somatic neuropathy can be either motor, sensory or a combination. Autonomic neuropathy will interfere with the normal body systems, including poor blood pressure regulation and loss of sweating or oil release to the skin, causing the typical dryness associated with neuropathy. Remember, however, that peripheral neuropathy can affect each independently or the entire peripheral nervous system.

Parts of The Nerve

To further understand several of the peripheral neuropathy types, it is also important to understand what makes up a nerve. The nerve is actually a specialized cell called a neuron and is made up of three parts, the cell body, the dendrites and the axon. The system works like an electrical wire with the Dendrites receiving the "signal" from surrounding cells and tissues. This signal is then carried to the Cell Body where the signal is translated and response is determined. The response is then carried through the Axon or nerve fiber to a muscle or the Dendrites of another nerve. The axon, like wire, can be either insulated by myelin (called myelinated nerve) or not insulated by myelin (as in unmyelinated nerves). Similar to wire, the myelin causes signal transmission to be much faster.

Therefore, a neuropathy can be caused by interference of any of the parts of a nerve. Loss of myelination, deterioration of dendrites or axon or even cell death. When you get pressure or trauma to the axon, the transmission can also be interrupted and lead to a neuropathy. Each of these entities can be the reason for neuropathy in various presentations.