Peripheral nerve disease

Overview

Peripheral neuropathy refers to a variety of conditions caused by damage to the peripheral nervous system, the vast communication network that sends signals between the central nervous system (the brain and spinal cord) and the rest of the body. Many types of sensory information are sent to the central nervous system (CNS) by peripheral nerves, such as a message that the feet are cold. They also transmit information from the CNS to the rest of the body.

The signals to the muscles that instruct them to contract, which is how we move, are the most well-known, but there are other sorts of signals that help govern everything from our heart and blood vessels to digestion, urine, and sexual function, as well as our bones and immune system. Peripheral nerves are analogous to the wires that link the various elements of a computer or the Internet. Complex functions can come to a standstill if they fail.

What is Peripheral Nerve Disease?

Peripheral nerve disease, often known as neuropathy, refers to disorders caused by nerve injury outside of the brain and spinal cord. These nerves supply the arms, legs, trunk, and pelvis and are responsible for pain and temperature perceptions.

Peripheral neuropathy can make it difficult to feel a cut on your hand or foot, and it can cause pain so severe that wearing a light sheet over your feet is extremely uncomfortable. A multitude of diseases can affect these nerves include degenerative disease, infections, compression and trauma.

How are the peripheral neuropathies classified?

There are about 100 different forms of peripheral neuropathy, each with its unique set of symptoms and prognosis. The symptoms differ depending on whether the nerves are motor, sensory, or autonomic.

Motor nerves control the movement of all muscles under conscious control, such as those used for walking, grasping things, or talking.
Sensory nerves transmit information such as the feeling of a light touch, temperature, or the pain from a cut.
Autonomic nerves control organs to regulate activities that people do not control consciously, such as breathing, digesting food, and heart and gland functions.

Most neuropathies damage all three types of nerve fibers to variable degrees, while others affect just one or two. Different disorders are described by doctors using words such as primarily motor neuropathy, predominantly sensory neuropathy, sensory-motor neuropathy, or autonomic neuropathy.

Three-fourths of polyneuropathies are "length-dependent," which means that symptoms appear first or worsen in the feet's furthest nerve terminals. In extreme circumstances, such neuropathies might extend to the central nervous system. Non-length dependent polyneuropathies have symptoms that begin closer to the torso or are spotty.

Number of nerves affected

Neuropathies are also described by how many nerves they affect.

Mononeuropathy: This type affects only one nerve. It’s usually caused by injury or repeated stress.
Multiple mononeuropathy: This type affects two or a few nerves or nerve areas in different parts of the body.
Polyneuropathy: This type affects many or most nerves. It is the most common type.

What are the causes of Peripheral Nerve Disease?

Most cases of neuropathy are either acquired, meaning that the neuropathy or the likelihood of developing it is not present from birth, or inherited. Acquired neuropathies are classified as either symptomatic (caused by another ailment or condition) or idiopathic (meaning it has no known cause)

Causes of symptomatic acquired peripheral neuropathy include:

The most prevalent cause of acquired single-nerve damage is physical injury (trauma). Car accidents, falls, sports, and medical treatments may all stretch, crush, compress, or remove nerves from the spinal cord. Less severe injuries can sometimes result in catastrophic nerve injury. Broken or dislocated bones can put pressure on nearby nerves, and slipped disks between vertebrae can compress nerve fibers as they exit the spinal cord.

Arthritis, continuous nerve pressure (such as from a cast), or repetitive, severe activities can cause ligaments or tendons to expand, narrowing thin neural channels. The most common types of neuropathy caused by trapped or compressed nerves at the elbow or wrist are ulnar neuropathy and carpal tunnel syndrome. In certain circumstances, underlying medical conditions (such as diabetes) prohibit the nerves from enduring the rigors of daily life.

In the United States, diabetes is the major cause of polyneuropathy. Around 60-70 percent of diabetics have mild to severe nerve damage, resulting in symptoms such as numb, tingling, or burning feet, one-sided bands or discomfort, and numbness and paralysis on the trunk or pelvis.

Damage to nerve tissue can result from vascular and circulation issues that reduce oxygen flow to the peripheral nerves. Diabetes, smoking, and artery constriction caused by high blood pressure or atherosclerosis (fat deposits on the interior of blood vessel walls) can all cause neuropathy. Vasculitis-induced blood vessel wall thickening and scarring can obstruct blood flow and create patchwork nerve injury, in which separate nerves in various regions are damaged—a condition known as mononeuropathy multiplex or multifocal mononeuropathy.

Systemic (all-encompassing) autoimmune illnesses, in which the immune system incorrectly assaults a number of the body's own tissues, can directly target nerves or cause difficulties when adjacent tissues compress or entrap nerves. Systemic autoimmune illnesses that produce neuropathic pain include Sjögren's syndrome, lupus, and rheumatoid arthritis.

Autoimmune disorders that exclusively affect the nerves are frequently induced by recent infections. They can develop rapidly or slowly, and some become chronic with varying degrees of severity. In Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy, motor fiber damage causes apparent weakness and muscle shrinkage. Multifocal motor neuropathy is a kind of inflammatory neuropathy that only affects the motor neurons. Other autoimmune neuropathies damage tiny fibers, leaving patients with inexplicable persistent pain and autonomic symptoms.

Hormonal imbalances can disrupt normal metabolic processes, resulting in enlarged tissues that push upon peripheral nerves. Kidney and liver problems can cause excessively high levels of harmful chemicals in the blood, which can harm nerve tissue. Most people who are on dialysis due to renal disease acquire variable degrees of polyneuropathy.

Nutritional or vitamin deficiencies, drunkenness, and pollutants can all cause nerve damage and neuropathy. The most well-known vitamin-related causes are vitamin B12 deficiency and excess vitamin B6. Several medications have been shown to cause neuropathy on occasion.

Neuropathy can be caused by a variety of malignancies and benign tumors. Tumors can invade or compress nerve fibers. Paraneoplastic syndromes, a set of uncommon degenerative conditions caused by a person's immune system's reaction to cancer, can cause significant nerve damage indirectly.

Polyneuropathy is caused by chemotherapy medications used to treat cancer in 30 to 40% of users. Only specific chemotherapy medicines produce neuropathy, and not everyone develops it. Chemotherapy-induced peripheral neuropathy can last for months after treatment is stopped. Radiation therapy can potentially induce nerve damage, which might manifest months or years later.

Infections can affect nerve tissues, resulting in neuropathy. Viruses include varicella-zoster (which causes chicken pox and shingles), West Nile virus, cytomegalovirus, and herpes simplex assault sensory nerves, resulting in acute, lightning-like pain episodes. Lyme disease, which is spread by tick bites, can induce a variety of neuropathic symptoms, generally within a few weeks after infection. The human immunodeficiency virus (HIV), which causes AIDS, has the potential to severely harm both the central and peripheral nerve systems. An estimated 30% of HIV-positive patients develop peripheral neuropathy, whereas 20% suffer distal (away from the center of the body) neuropathic pain.

Polyneuropathies induced by genes are uncommon. Genetic mutations can be inherited or emerge de novo, which means they are entirely new to the individual and were not present in either parent. Some genetic abnormalities cause minor neuropathies with symptoms beginning in early adulthood and causing little, if any, severe disability. More severe inherited neuropathies usually manifest themselves in infancy or childhood. One of the most prevalent inherited neurological illnesses is Charcot-Marie-Tooth disease, often known as hereditary motor and sensory neuropathy.

What are the symptoms of Peripheral Nerve Disease?

Symptoms are related to the type of nerves affected.

Muscle weakness is the most prevalent symptom of motor nerve injury. Painful cramps, fasciculations (uncontrolled muscle twitching visible under the skin), and muscular shrinkage are other symptoms.

Sensory nerve damage causes various symptoms because sensory nerves have a broad range of functions.

Damage to large sensory fibers harms the ability to feel vibrations and touch, especially in the hands and feet. Even if you are not wearing gloves or stockings, you may feel as if you are. This injury may cause to reflex loss (as can motor nerve damage). Loss of position sense often makes people unable to coordinate complex movements like walking or fastening buttons or maintaining their balance when their eyes are shut.
The “small fibers” without myelin sheaths (protective coating, like insulation that normally surrounds a wire) include fiber extensions called axons that transmit pain and temperature sensations. Small-fiber polyneuropathy can impair the capacity to detect pain or temperature changes. Controlling it is frequently challenging for medical caregivers, which can have a major impact on a patient's mental well-being and general quality of life. Neuropathic pain might be more severe at night, affecting sleep. It can be caused by pain receptors firing spontaneously without a recognized trigger, or by problems with signal processing in the spinal cord, which can generate extreme pain (allodynia) from a gentle touch that is ordinarily innocuous. For example, even when thrown loosely over the body, the contact of your bedsheets may cause agony.

In small-fiber neuropathies, autonomic nerve damage affects the axons. Excessive perspiration, heat sensitivity, inability to expand and contract the tiny blood vessels that regulate blood pressure, and gastrointestinal complaints are also common symptoms. Although uncommon, some people experience difficulty eating or swallowing if the nerves that control the esophagus are damaged.

Peripheral neuropathies are classified into numerous kinds, the most prevalent of which is associated to diabetes. Guillain-Barre syndrome is another devastating polyneuropathy that happens when the body's immune system erroneously targets the nerves. Carpal tunnel syndrome, which affects the hand and wrist, and meralgia paresthetica, which causes numbness and tingling on one leg, are two common kinds of focal (localized to only one portion of the body) mononeuropathy. Complex regional pain syndrome is a kind of lingering neuropathy that mostly affects tiny fibers.

Carpal tunnel syndrome

Carpal tunnel syndrome (CTS) develops when the median nerve, which runs from the forearm to the palm of the hand, is pressed or squeezed at the wrist. The median nerve and the tendons that bend the fingers are housed in the carpal tunnel, a narrow, rigid passageway of ligament and bones at the base of the hand. The median nerve supplies sensation to the palm side of the thumb as well as the index, middle, and portion of the ring fingers (although not the little finger). It is also in charge of certain minor muscles near the base of the thumb.

Thickening from inflamed tendons or other swelling might restrict the tunnel and compress the median nerve. As a result, the hand and wrist may experience numbness, weakness, or discomfort (some people may feel pain in the forearm and arm). CTS is the most frequent and well-known of the entrapment neuropathies, which occur when a peripheral nerve in the body is pushed on or crushed.

What are the symptoms of carpal tunnel syndrome?

Symptoms often begin gradually, with numbness or tingling in the fingers, particularly the thumb, index, and middle fingers. Even though there is no visible swelling, some persons with CTS report that their fingers feel useless and bloated. Symptoms usually arise in one or both hands throughout the night. The dominant hand is frequently the first to be afflicted and has the most severe symptoms. A person suffering with CTS may awaken with the need to "shake out" their hand or wrist.

As symptoms increase, people may experience tingling during the day, particularly while chatting on the phone, reading a book or newspaper, or driving. Hand weakness can make grasping tiny things or doing other manual tasks difficult. The muscles near the base of the thumb may lose away in chronic and/or untreated situations. Some persons with severe CTS are unable to distinguish between heat and cold by touch and may burn their fingertips without realizing it.

Who is at risk of developing carpal tunnel syndrome?

Carpal tunnel syndrome affects women three times more than males. Diabetes and other metabolic problems that directly damage the body's nerves and make them more vulnerable to compression are also at increased risk. CTS is mainly only seen in adults.

Factors in the workplace may lead to existing strain on or injury to the median nerve. The risk of developing CTS is not limited to a particular industry or employment, however it may be more prevalent among individuals performing assembly line labor (such as manufacturing, sewing, finishing, cleaning, and meatpacking) than among data-entry employees.

How is carpal tunnel syndrome diagnosed?

Early diagnosis and treatment are important to avoid permanent damage to the median nerve.

A physical assessment of the hands, arms, shoulders, and neck can assist evaluate whether the person's difficulties are due to everyday activities or an underlying condition. Other disorders that resemble carpal tunnel syndrome can be ruled out by a doctor. Tenderness, swelling, warmth, and discolouration of the wrist are all evaluated. Each finger should be evaluated for sensitivity, as well as the muscles at the base of the hand for strength and symptoms of atrophy.

Routine laboratory tests and X-rays can reveal fractures, arthritis, and nerve-damaging diseases such as diabetes.

Specific testing may cause CTS symptoms. The Tinel test involves the clinician tapping or pressing on the median nerve in the patient's wrist. When tingling in the fingers or a shock-like sensation occurs, the test is positive. The Phalen, or wrist-flexion, test requires the subject to keep his or her forearms erect while pointing the fingers down and squeezing the backs of the hands together. If one or more symptoms, such as tingling or growing numbness, are noticed in the fingers within one minute, carpal tunnel syndrome is suspected. Doctors may sometimes instruct patients to do a movement that causes symptoms.

Electrodiagnostic testing may aid in the confirmation of CTSs. Electrodes are put on the hand and wrist during a nerve conduction investigation. Small electric shocks are delivered, and the rate at which nerve impulses are sent is monitored. Electromyography involves inserting a small needle into a muscle and observing electrical signals on a screen to detect the amount of median nerve injury.

Ultrasound imaging can reveal aberrant median nerve size. Although magnetic resonance imaging (MRI) can depict the architecture of the wrist, it has not proved particularly helpful in detecting carpal tunnel syndrome.

How is carpal tunnel syndrome treated?

Carpal tunnel syndrome treatments should begin as soon as feasible, under the supervision of a specialist. Diabetes and arthritis, for example, should be addressed first.

Non-surgical treatments:

Splinting. Initial treatment is usually a splint worn at night.
Avoiding activities that may exacerbate symptoms during the day. Some persons who have little discomfort may want to take regular pauses from their duties to rest their hands. Applying cold packs to the wrist will assist if it is red, heated, and swollen.
Over-the-counter drugs. In certain cases, drugs might alleviate the discomfort and swelling associated with carpal tunnel syndrome. Nonsteroidal anti-inflammatory medicines (NSAIDs), such as aspirin, ibuprofen, and other over-the-counter pain treatments, may give temporary relief but have not been proved to cure CTS.
Prescription medicines. In those with minor or intermittent symptoms, corticosteroids (such as prednisone) or the medication lidocaine can be injected directly into the wrist or taken orally (in the case of prednisone). (Caution: those with diabetes and those at risk of developing diabetes should be aware that long-term use of corticosteroids can make it harder to manage insulin levels.)
Alternative therapies. Acupuncture and chiropractic therapy have helped some people, but their usefulness has yet to be proven. Yoga is an exception, since it has been demonstrated to alleviate discomfort and enhance grip strength in people with CTS.

Surgery:

One of the most prevalent surgical treatments in the United States is carpal tunnel release. In most cases, surgery entails removing a ligament surrounding the wrist to relieve pressure on the median nerve. Surgery is often performed under local or regional anesthesia (with minor sedation) and does not necessitate an overnight hospital stay. Many folks need both hands operated on. While all carpal tunnel surgery entails removing the ligament to alleviate pressure on the nerve, physicians employ two distinct strategies to do it.

The standard treatment for carpal tunnel syndrome is open release surgery, which involves creating an incision up to 2 inches in the wrist and then severing the carpal ligament to expand the carpal tunnel. Unless there are unique medical problems, the surgery is usually performed as an outpatient under local anesthetic.

Endoscopic surgery may result in a speedier functional recovery and less postoperative discomfort than typical open release surgery, but it may also increase the risk of problems and the need for subsequent surgery. The surgeon makes one or two incisions in the wrist and palm (approximately 12 inch each), inserts a camera attached to a tube, monitors the nerve, ligament, and tendons, and cuts the carpal ligament (the tissue that binds joints together) using a small knife put via the tube.

Guillain-Barre Syndrome

Guillain-Barré syndrome (GBS) is a rare, fast progressive condition caused by nerve inflammation (polyneuritis) that causes muscular weakness and, in extreme cases, total paralysis. GBS affects one or two persons in every 100,000 people each year. Its precise cause is unclear. Approximately half of those who get the condition had a gastrointestinal or respiratory infection a few days before it starts.

According to credible evidence, the infection triggers an immunological response that destroys nerve fibers, resulting in paralysis and loss of feeling. In milder cases, the damage is limited to the sheaths of the nerve fibers (like the coating round an electric wire). This prevents nerve impulse transmission. It can fully heal in a few of weeks. The immune response destroys the conducting cores of nerve fibers in more severe illness (that is the electric wires themselves). This takes longer to recover from and may result in lasting weakness.

Signs & Symptoms

Weakness generally starts in the legs and extends to the arms and rest of the body. It might extend to the respiratory muscles, face, and throat. In up to a quarter of GBS patients, the breathing muscles become so weak that they require temporary respiratory support from a breathing machine. Tingling, pins & needles, and numbness (lack of sensation) are frequent symptoms. These are caused by injury to the sensory nerves that transmit sensation from the skin and joints. The strange sensations are often strongest in the feet and hands. The tingling may be uncomfortable, as may the muscles. Symptoms often intensify over the first two weeks, although the progression might continue as short as one day or as long as four weeks. Symptoms often affect both sides of the body in equal measure.

Most people just experience symptoms in their arms and legs, while those who are badly impacted have more severe symptoms. They may have difficulties swallowing and get short of breath. They may lose the ability to empty their bladder and bowel. Their heart rate may be too rapid or too sluggish, and their blood pressure may be too high or too low. As shown below, modern medical and nursing care may address all of these issues.

Symptoms vary greatly. Some persons simply have modest weakness that does not interfere with walking and lasts only a few weeks. Others become fully immobilized, unable to move their eyes. Improvement often begins days to many weeks after the worst has occurred, and people continue to improve for several months. About 20% of patients are still disabled after a year, for example, needing walking assistance. Slow recovery persists for two or more years in persons who are left with significant weakness.

Guillain-Barré syndrome Diagnosis

Guillain-Barré syndrome is just one of several causes of sudden weakness and numbness. Recognizing the distinctive symptoms and indications is required for diagnosis. Because the condition is uncommon, non-specialists may struggle to make a diagnosis, and referral to a neurologist is typically warranted. Clinical examination reveals tendon reflex loss, which supports the diagnosis of peripheral nerve illness. To support the diagnosis, two tests are typically used:

A lumbar puncture is used to investigate the fluid that surrounds the spinal cord and nerve roots (cerebrospinal fluid). The patient lies on their side and is given a local anesthetic injection to numb a tiny area in the center of their lower back (the lumbar region). A tiny needle is inserted into the numb region and a small sample of cerebrospinal fluid is sucked from the hollow canal within the backbone. The fluid analysis confirms the diagnosis by revealing a high protein content and a normal cell count.
Nerve conduction tests (also known as EMGs, which are recordings of muscle activity) are used to analyze the electrical behavior of the nerves. Small electrical shocks are used to activate nerves in the arms and legs, and the doctor records the reactions in the muscles and sensory nerves. The recordings demonstrate the existence of nerve injury and indicate whether the damage affects the nerve sheaths (made of myelin) or the nerve fibers (called axons) within the sheaths, or both.

Other tests rule out many other potential causes of neuropathy, including alcohol, toxins, medications, vasculitis (blood vessel inflammation), vitamin deficiency, and malignancy. Blood tests, X-rays, or scans may also be performed.

Standard Therapies

General medical and nursing care, physiotherapy, and rehabilitation are the most significant aspects of treatment. People with severe illness need to be on a ward with capabilities for monitoring the pulse and breathing because of the dangers of respiratory failure and heart-beat instability in the acute stage. Mechanical ventilation using a breathing machine in an intensive care unit is required if breathing becomes problematic. A specific plastic tube known as an endotracheal tube links the user to the breathing machine through the mouth or nose.

If mechanical ventilation is required for more than a few days, it is more comfortable to place the tube in the neck through a tiny aperture in the windpipe (an operation called a tracheostomy). The tube is withdrawn after recovery, and the opening eventually closes on its own. When swallowing becomes difficult, a tiny plastic tube is inserted through the nose into the stomach for feeding and drinking. Pain relief medications and nursing care lower the risk of vein clotting, bed sores, and constipation.

Physical therapy improves muscular strength and function while also reducing muscle shortening and joint stiffness. When clients achieve medical stability, they frequently transfer to a rehabilitation clinic for physical and occupational treatment. Throughout the disease, psychological assistance is essential.

Plasma exchange (PE, commonly known as plasmapheresis) and intravenous immune globulin are two therapies that help people recover from GBS (IVIg). PE links one vein to a machine that separates the plasma (the liquid component of the blood) from the red blood cells and returns the red blood cells with a plasma replacement via another vein via a tiny plastic tube. It eliminates dangerous chemicals, particularly the antibodies that cause GBS. IVIg involves injecting large amounts of immune globulin (the antibodies in the blood) into a vein.

The immune globulin is derived from pooled plasma from thousands of healthy persons that has been extensively purified. It most likely works by preventing the damaging antibodies that cause GBS. Although IVIg is more convenient and commonly available than PE, both are equally beneficial. Combining the two does not improve matters. It is best to begin therapy during the first two weeks after the beginning of GBS symptoms. Other therapies do not speed healing. Steroids have not been successful in clinical studies, contrary to expectations.

Diabetic Neuropathies

Diabetic neuropathy is classified into different categories. This is due to the fact that our bodies contain many types of nerves that perform distinct activities. The type of diabetic neuropathy you have determines your symptoms and therapy.

What are the symptoms of diabetic neuropathy?

The common symptoms include:

Numbness in the hands or feet, often on both sides
Tingling ("pins and needles") in the feet
Pain in the hands, feet, or legs
Foot problems, such as calluses, dry skin, cracked skin, claw toes, and ankle weakness

Other sections of your body might be affected by neuropathy. It may cause damage to your digestive tract, heart, sexual organs, or eyes. This can result in symptoms like:

Indigestion
Diarrhea, constipation, or uncontrolled loss of poop (feces)
Dizziness, especially when standing up
Bladder infections
Erectile dysfunction
Vaginal dryness
Weakness
Weight loss
Depression and sleep problems
Visual changes, including inability to see or drive in the dark
Increased sweating

Diabetic neuropathy symptoms may resemble those of other medical diseases. Consult your physician for a diagnosis.

How is diabetic neuropathy diagnosed?

A physical exam and testing are required to identify diabetic neuropathy. Your healthcare professional may assess your muscular strength and reflexes during the physical exam. Your provider may also examine how your nerves react to:

Position
Vibration
Temperature
Light touch

You may also have tests, such as:

Ultrasound to check for problems with the bladder
X-rays and other tests to check for stomach problems
Electrocardiogram (ECG) to look for changes in your heart's rhythm
Nerve conduction studies to check flow of electrical current through a nerve
Electromyography (EMG) to see how muscles respond to electrical impulses
Nerve biopsy to remove a sample of nerve for testing

How is diabetic neuropathy treated?

Treatment will be determined by your symptoms, age, and overall health. It will also depend on the severity of the problem. The primary purpose of therapy is to alleviate pain and suffering. It may also aid in the prevention of further tissue injury. Treatment options include:

Pain medicines
Antidepressants that act on the nervous system to ease pain and discomfort
Creams you put on your skin
Transcutaneous electronic nerve stimulation (TENS) therapy
Hypnosis
Relaxation training
Biofeedback
Acupuncture
Special shoes to protect your feet from injuries

Complications of peripheral neuropathy

The prognosis for peripheral neuropathy varies according on the underlying etiology and the nerves that have been injured. Some cases may recover over time if the underlying cause is addressed, however in others, the damage may be permanent or worsen over time.

If the underlying cause of peripheral neuropathy is not addressed, you may develop potentially significant consequences, such as an infected foot ulcer. If left untreated, this can develop to gangrene (tissue death), and in severe cases, the afflicted foot may have to be amputated.

Peripheral neuropathy can impair the nerves that govern the heart's and circulation system's automatic activities (cardiovascular autonomic neuropathy). You may require blood pressure medication or, in rare situations, a pacemaker.

Conclusion

When nerves in the body's extremities, such as the hands, feet, and arms, are injured, peripheral neuropathy occurs. The symptoms vary according on which nerves are impacted. People at high risk of peripheral neuropathy, such as those with diabetes, should undergo frequent check-ups. In general, the earlier peripheral neuropathy is identified, the better the chances of limiting the damage and avoiding further complications. Treatment for peripheral neuropathy is determined by the symptoms as well as the underlying cause.