Peripheral neuropathy ( nerve neuropathy ) refers to damage to the peripheral nervous system, the extensive system of communication nerve fibers that carries information from the brain and spinal cord to any part of the body. Peripheral nerves also send sensory information back to the brain and spinal cord, informing about the presence of tissue effects (cold or burn). When the peripheral nervous system is damaged, these vital connections are disrupted.
This can be compared to a communication breakdown at a telephone exchange, when the connection between the station and the subscribers is disrupted (similar interruptions in communication occur between the brain and parts of the body). Because each peripheral nerve has a highly specialized function in a specific part of the body, when a nerve is damaged, symptoms may vary. For some, this may include numbness, tingling, excessive sensitivity to touch (paresthesia), or muscle weakness. Others may have more severe symptoms, including severe pain (especially at night), muscle wasting, paralysis, or glandular tissue or organ dysfunction. People may experience an inability to digest food normally, maintain normal blood pressure, sweating, and reproductive problems. In the most severe cases, there may be respiratory dysfunction or organ failure. In some forms of neuropathy, only one nerve is damaged, and this damage is called mononeuropathies. When a large number of nerves affecting the limbs are affected, such damage is called polyneuropathy. Sometimes two or more separate nerves in certain areas of the body are affected, this is called multifocal mononeuritis. In acute neuropathies, such as Guillain-Barré syndrome, symptoms appear suddenly, progress rapidly, and recovery of function occurs slowly as nerve fiber damage occurs. In chronic forms of neuropathy, symptoms appear gradually and progress slowly. In some patients, periods of remission are followed by periods of exacerbation. For others, the condition may reach a plateau in which symptoms remain unchanged for many months or years. Some chronic neuropathies progress over time, but very few forms are fatal unless there are complications associated with other diseases. Often, neuropathy is a symptom of another disease.
In the most common forms of polyneuropathy, the nerve fibers furthest from the brain begin to dysfunction first. Pain and other symptoms often appear symmetrically, such as in both legs, followed by gradual progression in both legs. Sometimes the fingers and arms are affected, progressing higher towards the middle of the body. Many patients with diabetic neuropathy experience this type of progression and nerve damage.
Classification of peripheral neuropathies
There are more than 100 types of peripheral neuropathy that have been identified, each with a characteristic symptom complex, developmental pattern, and prognosis. Impaired function and symptoms depend on the type of nerves that are damaged (motor, sensory, or autonomic). Motor nerves control movements of all muscles under conscious control, such as walking, grasping, or speaking. Sensory nerves convey information about perceptual processes, such as the sense of touch or pain due to a cut. Bundles of autonomic nerve fibers regulate biological activities that are performed without conscious awareness, such as breathing, digestion of food, and the activity of the heart or secretory glands. Although some neuropathies can affect all three types of nerves, it is most common to impair the function of one or two types of nerves. Therefore, doctors may use a term such as predominantly motor neuropathy, predominantly sensory neuropathy, sensorimotor neuropathy, or autonomic neuropathy.
Symptoms and causes
Symptoms are related to the type of nerve damaged and may appear over a period of days, weeks, or years. Muscle weakness is the most common symptom of motor nerve damage. Other symptoms may include painful cramps and fasciculations (muscle twitching of the subcutaneous muscles), muscle atrophy, bone degeneration, and changes in the skin, hair, and nails. These general degenerative changes may also result from damage to the sensory fiber or autonomic fiber bundle.
Sensory nerve damage causes a wider range of symptoms because sensory nerves have a whole group of highly specialized functions. Large sensory fibers are surrounded by a myelin sheath and record vibration, tactile sensations and proprioception. Damage to large sensory fibers reduces the ability to sense vibration and touch, resulting in numbness, especially in the arms and legs. People may feel the sensation of wearing gloves or stockings. Many patients cannot distinguish the size of an object or its shape by touch. This damage to sensory fibers can contribute to loss of reflexes (as does motor nerve damage). Loss of proprioception (the sense of the body's position in space) makes it difficult to coordinate complex movements or balance with eyes closed. Neuropathic pain is difficult to treat and can have a serious impact on your emotional well-being and overall quality of life. Neuropathic pain often worsens at night, severely disrupting sleep, leading to further emotional distress.
Smaller sensory fibers without myelin sheaths transmit pain and temperature sensations. Damage to these fibers can impair the ability to feel pain or changes in temperature. People may not be able to feel the cut or the wound festering. Other patients may not feel the pain that is a warning sign during a life-threatening heart attack or other acute condition. Loss of pain sensation is a particularly serious problem in patients with diabetes, contributing to the high rate of lower extremity amputations in this population. Pain receptors in the skin may also become hypersensitive, so that patients experience severe pain (allodynia) from stimuli that are normally painless (for example, rubbing a cloth over the skin or lightly touching it). Symptoms of damage to bundles of autonomic nerve fibers are varied and depend on the organ innervated by them. Autonomic nerve dysfunction can be life-threatening and sometimes requires emergency medical attention, especially when breathing or heart rate is affected. Common symptoms of damage to the autonomic nerve fiber bundles include impaired sweating, which is necessary when overheated, impaired urinary function which can lead to urinary incontinence or bladder infections; and impaired control of the muscles responsible for contracting blood vessels, which can affect the maintenance of normal blood pressure. Loss of control of blood pressure can cause dizziness, nausea, or even fainting when a person suddenly falls when changing body position (a condition known as postural or orthostatic hypotension). Gastrointestinal symptoms often accompany autonomic neuropathy. The nerves that control contractions of the intestinal muscles malfunction, leading to diarrhea and constipation. Many patients also have problems with swallowing when the corresponding nerve fibers are damaged.
Peripheral neuropathy can be either inherited or acquired. Causes of acquired peripheral neuropathy include: nerve damage (trauma), tumors, intoxication, autoimmune reactions, nutritional disorders (vitamin deficiency), chronic alcoholism, and vascular and metabolic disorders. Acquired peripheral neuropathies are grouped into three broad categories: those caused by systemic disease, those caused by trauma from external factors, and those caused by infections or autoimmune disorders that damage nerve tissue. An example of acquired peripheral neuropathy is trigeminal neuralgia, in which damage to the trigeminal nerve causes episodic attacks of excruciating pain on one side of the face. In some cases, the cause is the consequences of a viral infection, as well as pressure on the nerve from tumor tissue or an enlarged blood vessel. In many cases, a specific cause cannot be identified. Doctors usually diagnose idiopathic neuropathy in such cases.
Traumatic injury is the most common cause of nerve damage. Injury or household trauma from car accidents, falls, or sports-related injuries can lead to nerve fraying, nerve compression, stretching, or complete separation from the spinal cord. Even minor injuries can also cause serious nerve damage. Broken or dislocated bones can put damaging pressure on nearby nerves, and nerve root compression can also occur with herniated discs.
Systemic diseases are conditions that affect the entire body and often cause peripheral neuropathy. These conditions may include: metabolic and endocrine disorders. Nerve tissue is very sensitive to changes in tissue metabolism and regeneration processes, which can change with systemic diseases. Diabetes mellitus, characterized by chronically high blood glucose levels, is a leading cause of peripheral neuropathy in some countries (USA). Approximately 60 to 70% of patients with diabetes have both moderate and severe forms of nervous system damage. Kidney disease can lead to excess toxic substances in the blood, which can seriously damage nerve tissue. Most patients requiring dialysis due to renal failure develop polyneuropathy. Some liver diseases also lead to neuropathies as a result of metabolic disorders.
Hormonal imbalances can alter normal metabolic processes and cause neuropathies. For example, a lack of thyroid hormones slows metabolism, leading to fluid retention and tissue swelling, which can put pressure on peripheral nerves. Excess growth hormone production can lead to acromegaly, a condition characterized by abnormal enlargement of many parts of the skeleton, including joints. The nerves supplying these altered joints are often damaged as well.
Vitamin deficiencies and chronic alcoholism can cause irreversible damage to nerve tissue. Vitamins. Vitamins E, B1, B6, B12, and niacin are very important for normal nerve function. Thiamine deficiency is particularly common in people with chronic alcoholism because these people have an impaired dietary intake of thiamine. Thiamine deficiency can cause quite painful neuropathy of the limbs. Some researchers believe that excessive alcohol consumption may, in itself, contribute to direct nerve damage, called alcoholic neuropathy. Vascular and blood diseases can reduce oxygen delivery to peripheral nerves and quickly lead to severe damage or death of nerve tissue (for example, acute brain hypoxia leads to stroke). Diabetes often leads to a narrowing of the blood vessel. Various forms of vasculitis often lead to thickening of the vessel wall and a decrease in the diameter of the vessels due to scar tissue. This category of nerve damage, in which isolated nerves in different areas are damaged, is called multifocal mononeuropathy.
Connective tissue diseases and chronic inflammation can cause direct or indirect nerve damage. When the tissue layers surrounding the nerves are in a prolonged inflammatory process, the inflammation can directly affect the nerve fibers. Chronic inflammation also leads to progressive destruction of connective tissue, exposing nerve fibers to greater risk of compression and infection. When joints become inflamed, they can swell and involve nerves, causing pain.
Cancer and benign tumors can grow and have a destructive effect on the nerves. Tumors can also form directly from nerve tissue cells. Quite often, polyneuropathy is associated with neurofibromatosis, a genetic disease in which multiple benign tumors form from nerve tissue. Neuroma formation may be one element of regional pain syndrome or sympathetic reflex dystrophy syndrome, which can be caused by traumatic causes or surgical trauma. Paraneoplastic syndrome, a group of rare degenerative disorders that are caused by a person's immune system's response to cancer, can also indirectly cause multiple nerve damage. Repeated stress exposure often leads to compression neuropathies. Cumulative damage can occur due to repeated excessive movements that require bending any group of joints for an extended period of time. As a result of such movements, inflammation and swelling of the tendons and muscles can occur, which can lead to narrowing of the channels through which some nerves pass. Such damage is not uncommon during pregnancy, likely because weight gain and fluid retention also narrow the nerve canals.
Toxic substances can also cause damage to peripheral nerves. People who are exposed to heavy metals (arsenic, lead, mercury, thallium), industrial toxins, or environmental toxins often develop neuropathies. Certain cancer drugs, anticonvulsants, antivirals, and antibiotics have side effects that may include peripheral nerve damage, which is sometimes a contraindication for long-term use.
Infections and autoimmune disorders can cause peripheral neuropathy. Viruses and bacteria that can affect nerve tissue include herpes zoster, Epstein-Barr virus, cytomegaly virus, and other types of herpes viruses. These viruses selectively damage sensory nerves, causing paroxysmal, sharp pain. Postherpetic neuralgia often occurs after an episode of shingles and can be very painful.
The human immunodeficiency virus (HIV) also causes significant damage in the central and peripheral nervous system. The virus can cause several different forms of neuropathy, each of which is clearly associated with a specific stage of immunodeficiency. Rapidly progressive, painful polyneuropathy involving the arms and legs is often the first clinical symptom of HIV infection.
Lyme disease, diphtheria, and leprosy are bacterial diseases characterized by extensive damage to peripheral nerves. Diphtheria and leprosy are now quite rare, but Lyme disease has become more common. Lyme disease can cause a wide range of neuropathic disorders, including the rapid development of a painful polyneuropathy, often within weeks of initial infection during a tick bite.
Viral and bacterial infections can also cause secondary nerve damage, causing autoimmune disorders in which the immune system attacks its own tissues. Autoimmune processes typically cause destruction of the myelin sheaths of nerves or axons (nerve fibers).
Some neuropathies are caused by inflammation resulting from the immune system's response rather than from direct damage from infectious agents. Inflammatory neuropathies can develop quickly or slowly, and chronic forms can have periods of both remission and relapse. Acute inflammatory demyelinating polyneuropathy, known as Guillain-Barré syndrome, can damage motor, sensory, and autonomic nerve fiber bundles. Most people recover after developing this syndrome, but sometimes severe forms are life-threatening, although severe cases can be life-threatening. Multifocal motor neuropathy is a form of inflammatory neuropathy that involves damage exclusively to motor neurons (can be either acute or chronic).
Hereditary forms of peripheral neuropathy are caused by congenital errors in the genetic code or mutations. Some genetic abnormalities lead to mild neuropathies with symptoms that begin in adolescence and then subside over time. More severe hereditary neuropathies often appear in infancy or childhood. The most common hereditary neuropathy is Charot-Marie-Touss disease. These neuropathies occur due to a disorder in the genes responsible for the formation of neurons or myelin sheaths. Signs of typical Charlotte-Marie-Tousse disease include extreme weakening of the leg and foot muscles, gait disturbance, disappearance of tendon reflexes, and numbness in the lower extremities.
FAQ
Three fingers on my right hand are numb and painful. What to do?
It is necessary to consult a neurologist to exclude carpal tunnel syndrome and treatment.
I had an attack of trigeminal neuralgia for a long time. Should I take something preventative to prevent another one?
It is imperative to see a neurologist. The doctor will select medications for you that need to be taken on a regular basis and prescribe preventive courses of injections (if necessary, drips in a day hospital) and tablet medications.
Severe burning pain appeared in the right half of the chest and some bubbles appeared. Which doctor should I see?
Similar manifestations, as you describe, can be observed with herpetic ganglioneuritis, the so-called. herpes zoster. This disease is treated by a neurologist.
After about 2 months, my legs began to go numb and weak. Why could this be?
Weakness and sensory disturbances in the limbs can be observed with polyneuropathies of various natures. For example, as a result of diabetes or intoxication. To establish the cause and select adequate therapy, you need to consult a neurologist. There may be a need for additional laboratory and instrumental examinations.
I developed weakness in my right hand after sleeping. Is it from the spine?
The cause of sudden weakness in the arm may also be diseases of the spine. However, a vascular cause or compression of the nerve trunk (nerve plexus) cannot be excluded. To find out the cause and prescribe treatment, you should consult a neurologist.
Can alcoholic neuropathy be cured?
Toxic and dysmetabolic polyneuropathies, incl. alcoholic diseases are most often chronic diseases. With adequate therapy, it is possible to achieve long-term and stable remission
Diagnostics
Diagnosing peripheral neuropathy can sometimes be difficult due to the variability of symptoms. A complete neurological examination is often required, including: the patient's symptoms, occupation, social habits, the presence of any toxins, the presence of chronic alcoholism, the possibility of HIV or other infectious disease, and a history of relatives with neuropathy, performing tests that can identify the cause of the neuropathy, and conducting examinations to determine the degree and type of nerve damage.
General examination tests and tests may reveal the presence of nerve damage due to systemic disease. Blood tests can diagnose diabetes, vitamin deficiencies, liver or kidney failure, other metabolic disorders, and signs of abnormal immune system activity. Examination of the cerebrospinal fluid, which circulates in the brain and spinal cord, can reveal abnormal antibodies associated with neuropathy. More highly specialized tests can detect blood diseases or cardiovascular diseases, connective tissue diseases, or malignancies. Muscle strength tests showing signs of muscle twitching or fasciculations may indicate motor neuron damage. Assessing the patient's ability to perceive vibration, soft touch, body position (proprioception), temperature and pain sensitivity helps determine damage to sensory fibers of both large and small sensory fibers. Based on the results of a neurological examination, physical examination, and a detailed medical history, additional tests and examinations may be prescribed to clarify the diagnosis.
Computed tomography is an atraumatic, painless study that makes it possible to visualize organs, bone and soft tissue. A CT scan can reveal bone or vascular changes, brain tumors, cysts, herniated discs, encephalitis, spinal stenosis (narrowing of the spinal canal), and other disorders.
Magnetic resonance imaging (NMR or MRI ) can examine the condition of the muscle and its size, reveal the replacement of muscle tissue with fatty tissue, and determine whether there has been a compressive effect on the nerve fiber. MRI machines create a strong magnetic field around the body. Radio waves pass through the body and cause resonance, which can be detected at various angles within the body. The computer processes this resonance effect and converts it into a three-dimensional image.
Electromyography (EMG ) involves inserting a thin needle into a muscle to measure the electrical activity of the muscle at rest and during contraction. EMG tests can help differentiate between damage to the muscle itself and to the nerve fibers. Nerve conduction speed can accurately determine the extent of damage in large nerve fibers, clearly indicating whether symptoms are related to myelin sheath or axon degeneration. During this study, electrical stimulation of the fiber is performed, in response to which a response impulse appears in the nerve. An electrode placed further along the nerve measures the speed of impulse transmission along the axon. Slow transmission rates and impulse blocking typically indicate damage to the myelin sheath, while decreased impulse levels are a sign of axonal degeneration.
A nerve biopsy involves removing and examining a sample of nerve tissue, most often in the lower leg. Although this test can provide valuable information about the extent of nerve damage, it is an invasive procedure that is difficult to perform and can cause nerve damage and signs of neuropathy. In most cases, this procedure is not indicated for diagnosis and may independently cause neuropathic side effects.
Skin biopsy is a test in which a small piece of skin is removed and the endings of nerve fibers are examined. This diagnostic method has advantages over EMG and nerve biopsy when it is necessary to diagnose damage in smaller sensory fibers. Additionally, unlike a conventional nerve biopsy, a skin biopsy is less invasive, has fewer side effects, and is easier to perform.
Treatment
There are no treatments for hereditary peripheral neuropathies. However, there are treatments for many other forms. First, the cause of the disease is treated and symptomatic treatment is carried out. Peripheral nerves have the ability to regenerate if the nerve cell itself is preserved. Symptoms can be managed, and addressing the causes of certain forms of neuropathy can often prevent recurrence of damage.
In general, healthy lifestyle choices—such as maintaining an optimal weight, eliminating toxins from entering the body, eating well with adequate vitamins, and limiting or eliminating alcohol intake—can reduce the physical and emotional effects of peripheral neuropathy. Active and passive exercise can reduce cramps, improve muscle elasticity and strength, and prevent muscle atrophy in paralyzed limbs. Various diets may improve gastrointestinal symptoms. Prompt treatment for injuries can help prevent permanent damage. Quitting smoking is especially important because smoking spasms the blood vessels that carry nutrients to peripheral nerves and can worsen neuropathy symptoms. Good nursing skills, such as careful care, of diabetic feet and wounds are essential because these patients have decreased pain sensitivity. Good care can relieve symptoms and improve quality of life and stimulate nerve regeneration.
Systemic diseases often require more complex treatment. Strict control of blood glucose levels has been shown in studies to reduce neuropathic symptoms and help patients with diabetic neuropathy avoid further nerve damage. Inflammatory and autoimmune diseases that lead to neuropathy can be treated in several ways. Immunosuppressants such as prednisone, cyclosporine, or imuran can be very effective. Plasmapheresis, a procedure that clears the blood of immune cells and antibodies, can reduce inflammation or suppress the activity of the immune system. Large doses of immunoglobulins, which function as antibodies, can also suppress abnormal immune system activity. But neuropathic pain is difficult to treat. Moderate pain can sometimes be relieved with analgesics. Some medications (used to treat other conditions) have proven helpful for many patients suffering from severe forms of chronic neuropathic pain. They include Mexilitine, a drug designed to treat irregular heart rhythms (but sometimes causes significant side effects); some antiepileptic drugs, including gabapentin, phenytoin, and carbamazepine; and some types of antidepressants, including tricyclics such as amitriptyline. Injecting a local anesthetic such as lidocaine or using patches containing lidocaine may relieve severe pain. In the most severe cases of pain, the nerves can be surgically destroyed; however, the results are sometimes temporary and the procedure can lead to complications.
Orthotics can help reduce pain and reduce the impact of physical disability. Various arm or leg orthoses can compensate for muscle weakness or relieve nerve compression. Orthopedic shoes can improve gait disturbances and help prevent foot injuries in people with decreased pain perception.
Surgery can often provide immediate relief for mononeuropathies caused by nerve entrapment or compression. Removal of a herniated disc causes decompression of the root. Removing tumors also reduces the impact of tumor tissue on the nerves. Additionally, nerve decompression can be achieved through ligament and tendon release.
Recommendations and prevention
The main prevention of most diseases of the nervous system is maintaining a healthy and active lifestyle, giving up bad habits, timely and adequate treatment of infectious and non-infectious diseases.
If any neurological symptoms occur, do not delay contacting a doctor. Early diagnosis and timely treatment will help prevent the development of complications, prolongation of treatment and the consequences of uncontrolled use of medications. The most complete program of preventive measures is drawn up by a neurologist for each individual patient.
