Neuropathy and its classification:

Neuropathy is the disease of the nervous system.neuropathy leads to disturbance in the function of a nerve or particularly a group of nerves.

Classification:

Peripheral neuropathy

Autonomic neuropathy

Distal symmetric neuropathy

Cranial neuropathy

Compression neuropathy

When only one nerve is damaged it is called mononeuropathy.more often though,multiple erves affecting all limbs areaffected and called polyneuropathy.occasionally,two or more isolated nerves in separate areas of the body are affected called mononeuritis multiplex. In acute neuropathies,such as guillian-barre syndrome symptoms appear suddenly ,progress rapidly,and resolve slowly as the damaged nerves heal.in chronic forms ,symptoms begin subtly andprogress slowly.some people may have periods of relief followed by relapse. Others may reach a plateau stage where symptoms stay the same for many months or years.some chronic neuropathies worsen over time,but very few formsprove fatal unless complicated by other diseases.occasionally neuropathy is the symptom of another disorder.

Peripheral neuropathy:the most common neuropathy

Peripheral neuropathy describes damage to the peripheral nervous system.perpheral nerves also send sensory information back to the brainand spinal cord,such as a message that the feet are cold or a finger is warm.damage to the peripheral nervus systeminterferes with these vital connections and affects the communication network in the body.

Because every peripheral nerve has a highly specialised function in a specific part of the body, a wide array of symptoms can occur when nerves are damaged.some people may experience temporary numbess,tingling and pricking sensations(parasthesias) ,sensitivity to touch ,or muscle weakness .others may suffer more extreme symptoms ‘ including burning pain(especially at night), muscle wasting , paralysis, organ or gland dysfunction.people may become unable to digest food easily, maintain safe levels of blood pressure,sweat normally, or experiencenormal sexual function. In the most extreme cases, breathing may become difficultor organ failure may occur.

Types of peripheral neuropathies:

More than 100types of peripheral neuropathies have been identified, each with its own characteristic set of symptoms, pattern of development, andprognosis. Impaired function and symptoms depend on the type of nerves-motor ,sensory, or autonomic- that are damaged.

Motor nerves control movements of al muscles under conscious control, such as those used for walking, grasping hings or talking. Sensory nerves transmit information about sensory experiences, such as the feeling of a light touch or the pain resulting form a cut. Autonomic nerves regulate biological activities such as breathing, digesting food, and heart and gland functions. Although some neuropathies my affect all three types of ,others primarily affect one or two types. Therefore terms such as predominately motor neuropathy, predominantely sensory neuropathyor autonomic neuropathy or autonomic neuropathyare used to describe the patient’s condition.

Symptoms of peripheral nerve damge:

Symptoms are related t the type of nere that is damaged and may be seen over a period of , weeks , days, months or years.

Muscle weakness is the most common symptom of motor nerve damage. Other symptoms may include painful cramps and fasciculations(uncontrolled muscle twitching visible under the skin), muscle loss, bone degeneration, and changes in the skin , hair, and nails. These general degenerative changes also can result from sensory or autonomic nerve fibre loss.

Sensory nerve damage causes a more complex range of symptoms because sensory nerves have a wider and more highly specialized range of functions.

Larger sensory fibres enclosed in the myelin register vibrations, light touch, and position sense.damageto large sensory fibres lessens the ability to feel vibrations and touch,resulting in a general sense of numbness,especially in the hands and feet.people may feel as if they are wearing gloves and stockings even when they are not. Many patients cannot recognize by touch alone the shapes of small objects or distinguish between different shapes. This damage to the sensory fibers may contribute to the loss of reflexes .loss of position sense often makes people unable to co-ordinate movements like walking or fastening buttons , or to maintain their balance when their eyes are shut.

Smaller sensory fibres without myelin sheaths transmit pain and temperature sensations. Damage to these fibres can interfere with the ability to feel pain or changes in temperature.people may fail to sense that they have been injured from a cut or that a wound is becoming infected. Others may not detect pains that warn of an impending heart attack or other acute conditions (this is more commonly seen in diabetic neuropathies, contributing to a high rate of limb amputations). Pain receptors in the skin can get ovrsensitised, so thatpeople may feel severe pain (allodynia)from stimulithat are normally painless(for example,some may experience pain from bedsheets draped lghtly over the body).

Symptoms of autonomc nerve damage are diverse and depend upon which organs or glands are affected . autonomic nerve dysfunction can become life threatening nad may require emergency medical care in cases when breathing becomes impaied or when heart begins to beat irregularly.common symptoms of autonomic nerve damage include an inability to sweat normally, which may lead to heat intolerance, a loss of bladder control, which may cause infection or incontinence; and an inability to control muscles that expand or contract blood vessels to maintain safe blood pressure. A loss of control over BP can cause dizziness, lightheadedness,or even faintaing when a person moves suddenly from a seated to a standing position.

Gastrointestinal symptoms frequently accompany autonomic neuropathy. Nerves controlling intestinal muscle contractions often malfunction, leading to diarrhoeas, constipation, or incontinence. Many people also have problems eating or swallowing if certain autonomic nerves are affected.

Neuropathic symptoms are difficult to control and cn seriously affect emotional well-being and overall quality of life. Neuropathic pain is often worse at night , seriously disrupting sleep and adding to the emotional burden of sensory nerve damage.

Causes of peripheral neuropathy:

Physical injury(trauma):most common cause of peripheral neuropathy.automobile accidents, falls and sports related activities can cause nerves to be partially or completely severed. Broken or dislocated bones can exert damaging pressure on the neighboring nerves, and slipped discs between vertebrae can compress nerve fibers when they emerge from the spinal cord.

Systemic diseases:these include metabolic diseases and endocrine disorders. Most important disease in this category is diabetes mellitus.about 60-70% of diabetics have peripheral nerve disease.next in the category is disease of thyroid (hypothyroidism).

Kidney diseases:lead to nerve damage due accumulation of toxins. A majority of patients of renal failure have associated neuropathic manifestations.

Nutritional deficiencies and alchoholism:certain micronutrient deficiencies have been implicated in development of neuropathies.

Vascular and blood diseases: can cause nerve damage due to reduced oxygen supply to the nerves.

Connective tissue diseases:chronic inflammation of the connective tissues can make the nerve fibres more vulnerable to compression injuries. Joint inflammation can lead to entrapment of the nerves, causing pain.

Cancers and benign tumors:neuropathies can result due to compression of the nerve by the tumor of due to infiltration.

Repetative stress, drugs and toxins are also a cause.

Infections and autoimmune disorders:viral infections like herpes zoster, E-B virus can often be a etiological agent.

Inherited forms of neuropathy:most common one is the CHARCOT-MARIE-TOOTH disease( more about specific neuropathies in subsequent articles).

To conclude anything under the sun cause neuropathy, the list is a never ending one .the above list is of the most common causes..

Investigations:

A strong clinical suspicion will suffice to make a clinical diagnosis. To support the diagnosi some investigatios are necessary these include:

Electroneurography

Electromyography

Nerve biopsy

Nerve conduction studies

Magnetic resonance imaging

Computed tomography

Treatment options:

-Non pharmacological:

Patient education

Maintaining optional weight

Avoiding exposure to toxins

Eating a balanced die

Correcting nutritional deficiencies

Avoiding alchohol consumption

Exercise

Quitting smoking

Self care

-Pharmacological:

Methyl cobalamin

Alpha lipoic acid

Vit b complex

TCA

Carbamazepine

Gabapentin

Lamotrigine

Phenytoin

Opioid analgesice

Tramadol