The nervous system of an organism is broadly categorized into two parts - Central Nervous System (CNS) and Peripheral Nervous System (PNS). The CNS mainly consists of brain and spinal cord, while the part of the nervous system outside the CNS comprises the peripheral nervous system. To designate a collection of disorders that affects the PNS, the term neuropathy is used. Involving the motor part (nerves that are responsible for muscle movement) as well as the sensory part (nerves that detect sensations), neuropathies can be quite traumatic at times, causing a lot of pain and altered sensations. This pain is generally described as a burning or a tingling sensation and is often associated with trauma, poor nutrition pressure and other diseases.
Around 30% of the neuropathy cases are regarded as idiopathic i.e. without any known cause. Another 30% of the neuropathic cases occur to people suffering from diabetes. In fact, around 50% of the individuals suffering from diabetes develop some kind of neuropathy. Other common causes of neuropathy involve traumatic pressure on nerves, autoimmune diseases like rheumatoid arthritis and Guillain Barre Syndrome, alcoholism, nutritional deficiencies, tumors, HIV infections and hypothyroidism. Also, inherited conditions like Amyloid Polyneuropathy and Charcot Marie Tooth disease can lead to a neuropathic condition called hereditary neuropathy. Broadly, neuropathies are classified on the basis of their pathological factors, clinical syndrome and etiology:
Different Forms Of Neuropathies
As the name suggests, sensory neuropathy mainly affects the nerves that carry information or impulses to the brain, from the different parts of the body, conveying information about various sensations. This is regarded as the most common form of neuropathy.
One of the most common forms of neuropathy, it is a condition in which only a single nerve is damaged. The damage is basically of two types. The first is when nerves get squashed at different places, particularly when they pass through a tight tunnel or are compressed by a lump of bone. The second form of damage is when diseases of blood vessels, caused by diabetes, prevent the flow of blood to a part of the nerve. A very common form of compression mononeuropathy is the Carpal Tunnel Syndrome. This occurs when the median nerve of the forearm is compressed at the wrist.
Thoracic or Lumbar Radiculopathy
This is yet another common form of mononeuropathy, which affects a band of chest or abdominal wall, on one or both sides. This is commonly seen in people suffering from Type II Diabetes Mellitus.
Distal Symmetric Polyneuropathy
Distal symmetric polyneuropathy is a common form of neuropathy that affects the nerves on both sides of the body. Commonly involved areas are legs and feet, although at times, the hands also get affected.
This condition mainly affects the autonomic nerves controlling bladder functions, intestinal tract and genitals. A very common symptom is the paralysis of the bladder. Besides this, there can be problems with urination, erection and even digestion.
Also known as neuropathic arthropathy, Charcot's Joint occurs when a joint breaks down due to the involvement of nerves. In such a case, there is almost complete loss of sensation. Commonly involved area is the foot, which becomes very unstable and walking becomes very difficult.
This condition affects the 12 pair of nerves that are attached to the brain and regulates one’s vision, eye movements, hearing and taste. Most often, the nerves controlling the eye muscles are affected. Symptoms usually start as pain on one side, very close to the affected eye and later progresses to paralysis of the ocular muscles. Later, there may be the development of double vision.
The other types of neuropathies include femoral neuropathy, diabetic amyotrophy and unilateral foot drop.