Posts tagged: peripheral neuropathies

What Causes Peripheral Neuropathy?

What Causes Peripheral Neuropathy

can either be inherited or acquired. The causes of acquired peripheral neuropathy include physical injury to a nerve, tumors, toxins, autoimmune responses, nutritional deficiencies, alcoholism, vascular or metabolic disorders.

Acquired peripheral neuropathies are grouped into three broad categories: those caused by systemic diseases, those caused by trauma from external agents, or those caused by infections or autoimmune disorders affecting nerve tissue. An example of acquired peripheral neuropathy is trigeminal neuralgia (also known as tic douloureux), in which damage to the trigeminal nerve (the large nerve head and face) causes episodic attacks of excruciating pain, quick as lightning, a side of the face. In some cases the cause is a viral infection, tumor pressure on the nerve or blood vessel dilator, or, rarely, multiple sclerosis. In many cases it is possible to identify a specific cause. Doctors usually refer to neuropathies with no apparent cause as idiopathic neuropathies.

Physical injury is the most common cause of injury to a nerve. Injury or sudden trauma, for example caused by an automobile accident, fall or sports-related activities can lead to nerves being cut partially or completely crushed, compressed or stretched, sometimes so hard that remain completely or partially separated from the spinal cord. Less dramatic traumas also can cause serious nerve damage. A broken or dislocated bones can exert damaging compression on surrounding nerves, and slipped disks between vertebrae can compress nerve fibers where they emerge from the spinal cord.

Systemic diseases, disorders that affect the entire body-often causes peripheral neuropathy. These disorders may include:

Metabolic and endocrine disorders. Nervous tissues are very vulnerable to damage caused by diseases that affect the body’s ability to transform nutrients into energy materials, processing waste, or substances that make up living tissue. Diabetes mellitus, which is characterized by chronically high blood glucose levels is a major cause of peripheral neuropathy in the United States. About 60 to 70 percent of people with diabetes have mild to severe forms of nervous system damage.

Kidney disorders may lead to excessively high amounts of toxic substances in the blood, causing severe damage to nerve tissue. Most patients who require dialysis as a result of kidney failure, develop polyneuropathy. Some liver diseases also cause neuropathy as a result of failures in the balance of chemicals.

Hormonal imbalances can disrupt metabolic processes and cause neuropathies. For example, a low production of thyroid hormones causes slow metabolism, causing fluid retention and swelling of tissues, which can push the peripheral nerves. The overproduction of growth hormone can lead to acromegaly, a condition characterized by abnormal growth of some parts of the skeleton, including the joints. Courses along the nerves to the affected joints are often caught.

Vitamin deficiencies and alcoholism can cause widespread damage to nerve tissue. Vitamins E, B1, B6, B12 and niacin are essential for healthy functioning of nerves. A thiamine deficiency is common among alcoholics, because they generally have poor eating habits. Thiamine deficiency can cause a painful neuropathy in the extremities. Some researchers believe that excessive consumption of alcohol can, by itself, contribute directly to nerve damage, a condition known as alcoholic neuropathy.

Vascular damage and blood diseases can decrease oxygen supply to peripheral nerves, which quickly produce serious injury or death of nerve tissue in the same way the lack of oxygen to the brain can cause a stroke. Diabetes often leads to constriction of blood vessels. Various forms of vasculitis (blood vessel inflammation) frequently cause hardening and thickening of the walls of blood vessels, which develop scar tissue, decreasing their diameter and impeding blood flow. This category of nerve damage, which occurs in isolated nerve damage in various areas, is called mononeuropathy multiplex or multifocal mononeuropathy.

Connective tissue disorders and chronic inflammation can cause direct and indirect damage to the connective tissue. When multiple layers of protective tissue around the nerves become inflamed, the swelling can go directly to the nerve fibers. Chronic inflammation also leads to progressive destruction of connective tissue, making nerve fibers become more vulnerable to compression injuries and infections. Joints can become inflamed and swollen, compressing nerves and causing pain even more intense.

Cancers and benign tumors can infiltrate or exert damaging pressure on nerve fibers. Tumors also can arise directly from the tissues of the nerve cells. Widespread polyneuropathy is often associated with neurofibromatosis, genetic diseases in which multiple benign tumors grow on nerve tissue. Neuromas, benign masses of tissue that can grow lush after a penetrating wound that cuts the nerve fibers, generate very intense pain signals and sometimes invading nearby nerves, causing even greater damage and pain. The formation of neuromas may be an element of a more widespread condition of neuropathic pain called complex regional pain syndrome or reflex sympathetic dystrophic syndrome, which can be caused by traumatic injuries or surgical trauma. Paraneoplastic syndromes, a group of rare degenerative disorders, produced by the reaction of the immune system of the person to a cancerous tumor, can also damage nerves in widespread indirect.

Repetitive stress frequently leads to entrapment neuropathies, a special category of compression injury. Repetitive activities, heavy, cumbersome and require the bending of a group of joints for prolonged periods, can cause cumulative damage. The irritation can cause the ligaments, tendons and muscles become inflamed and swollen, restricting the narrow ducts through which pass through certain nerves. These lesions are more common during pregnancy, probably because weight gain and fluid retention also constrict nerve conduits.

The toxins can also damage peripheral nerves. Heavy metals (such as arsenic, mercury or thallium) Industrial drugs or environmental toxins, which people have been exposed often cause neuropathy. Some anticancer drugs, anticonvulsants, antiviral agents and antibiotics have side effects that may include damage to peripheral nerves, thereby limiting its long-term use.

Infections and autoimmune disorders can cause peripheral neuropathy. Viruses and bacteria that can attack nerve tissues include herpes varicella-zoster (shingles) Epstein-Barr virus, cytomegalovirus and herpes simplex-members of the vast family of human herpes virus. These viruses cause serious damage to sensory nerves, causing attacks of sharp pain that feels like lightning strikes. Postherpetic neuralgia often occurs after a shingles attack and can be especially painful.

The human immunodeficiency virus (HIV) that causes AIDS also causes extensive damage to the central and peripheral nervous systems. The virus can cause several different forms of neuropathy, each associated with a specific stage of immunodeficiency disease. Often a painful polyneuropathy and fast forward that affects the feet and hands is the first apparent clinical signs of HIV infection.

Lyme disease, diphtheria and leprosy are bacterial diseases characterized by widespread damage to peripheral nerves. Although diphtheria and leprosy are now rare in the United States, Lyme disease is increasing however. Can cause a wide range of neuropathic disorders including painful polyneuropathy of rapid development, often within weeks of initial infection by the bite of a tick.

Viral and bacterial infections can also cause nerve damage, producing conditions that are called autoimmune disorders, in which specialized cells and antibodies of the immune system attack the body’s own tissues. These attacks typically cause destruction of the myelin sheath of nerve or axon (the long fiber that extends out from the main body of the nerve cell).

Some neuropathies are the result of inflammation caused by immune system activities rather than by direct damage of infectious organisms. Inflammatory neuropathies can develop in a slow or fast, and chronic forms may show an alternating pattern of remission and relapse. Acute inflammatory demyelinating neuropathy, more commonly known as Guillain-Barre syndrome, can damage motor nerve fibers, sensory and autonomic. Most people recover from this syndrome although severe cases can be life threatening. Chronic inflammatory demyelinating polyneuropathy is usually less dangerous, but although it can cause damage to the sensory motor nerves, autonomic nerves left intact. Multifocal motor neuropathy is a form of inflammatory neuropathy that affects only the motor nerves and may be chronic or acute.

Inherited forms of peripheral neuropathy are caused by inherited errors in the genetic code or by new genetic mutations. Some genetic errors lead to mild neuropathies with symptoms that begin in young adults and produce little or sometimes no deterioration. The most severe hereditary neuropathies often appear in infancy or early childhood.

The most common inherited neuropathies are a group of disorders to the disease known as Charcot-Marie-Tooth. These neuropathies result from flaws in genes responsible for the production of neurons or the myelin sheath. The characteristics of a typical Charcot-Marie-Tooth disease include extreme weakness and thinning of the muscles in the legs and feet, abnormal gait, loss of tendon reflexes, and numbness of the lower extremities

There are many illnesses that contribute to what causes peripheral neuropathy. While there are some that are preventable, there are many that are not.  If you suspect that you may have peripheral neuropathy then you will want to seek medical care to prevent advancement of the disorder.