Polyneuropathy refers to various diseases in which multiple nerves of the peripheral nervous system are damaged. Other names for polyneuropathy are peripheral neuropathy or peripheral polyneuropathy. Different symptoms can occur in this disease, depending on the particular damaged nerves. We explain the causes, the signs, the course of the disease and the treatment.

Table of Contents

What is polyneuropathy?

Polyneuropathy is a disease of the peripheral nervous system. The peripheral nerves are located outside the central nervous system and thus outside the spinal cord and brain. They are located, for example, in the nerve roots on the side of the spine, but also in the skin and muscles. The peripheral nervous system also includes motor and sensory nerves and likewise nerves that play a role in the functions of internal organs. In polyneuropathy, nerve fibers are destroyed or damaged, which leads to a disturbance in the transmission of stimuli.

All nerve cells consist of an axon (nerve extension) and a cell body, whereby the axon can reach a length of one meter. These nerve processes are protected by an insulating myelin layer. Myelin not only protects the axon, however, but also ensures that electrical nerve signals are transmitted quickly. If this layer is damaged, it slowly decays. If there is damage to the myelin layer, this is referred to as a demyelinating polyneuropathy. If the nerve process itself is affected by the damage, it is called axonal polyneuropathy. It also happens that both axons and meylin layers are damaged.


Since the nerves in the arms and legs are particularly long, the first symptoms usually occur here. At the beginning of a polyneuropathy affected people feel a burning or tingling sensation in the arms and / or in the legs. The transmission of sensory stimuli can also be disturbed, so that these stimuli are reported more strongly, more weakly or not at all to the brain. This leads to a reduced perception of pain and touch and to a false sensation of cold or warmth. Depending on the damaged nerves, a distinction is made between autonomic, sensory and motor disorders.

Another distinction of symptoms is based on the distribution of the symptoms:

  • Symmetrical polyneuropathy: The symptoms affect both arms or both feet.
  • Asymmetric polyneuropathy: The nerves are not damaged on both sides of the body, but only on one side.
  • Distal polyneuropathy: The damaged nerves are located away from the trunk. For example, hands or feet are affected.
  • Proximal polyneuropathy: The disease affects parts of the body that are close to the trunk. However, this form is rarer.

Symptoms of damage to the sensory nerves

In most cases, people affected by polyneuropathy suffer from sensory disturbances. So-called sensitive nerves lead from the skin to the brain. They report pain stimuli, temperature stimuli, touch, pressure and similar information to the brain. If these nerves are damaged, this leads to tingling, insensitivity, burning or stinging sensations. Often the arms and legs are affected, and the toes are often the first to feel these symptoms.

Numbness in the legs can also occur, causing the affected person to have problems with coordination when walking. In the case of a disturbance of the temperature sensation, the risk of injury is increased, because the patients can no longer feel, for example, whether the bath water is too hot. Other possible symptoms of sensory polyneuropathy include a feeling of fuzziness, swelling, the sensation of walking on absorbent cotton, or an uncomfortable feeling of pressure.

Symptoms of damage to the autonomic nerves

Autonomic nerves are also called autonomic nerves and are responsible for controlling the functions of the internal organs. This means that they control, for example, the bladder, the sex organs, the intestines, the lungs and the heart. These nerves cannot be controlled voluntarily. When these autonomic nerves are damaged, the symptoms can become very serious or even life-threatening. Respiratory arrest may occur if the nerves that control lung function are damaged, or cardiac arrhythmias may occur if the nerves of the heart muscle are affected. In the case of damage to the intestinal nerves, constipation or diarrhea are among the symptoms. If the nerves that are responsible for bladder function are affected, there are disturbances in bladder emptying.

Other possible symptoms of autonomic polyneuropathy include edema, pupillary dysfunction, decreased sweating, ulcers, gastroparesis (stomach paralysis), palpitations during rest, impotence or dizziness, and fainting when standing up.

Symptoms of motor nerve damage

The motor nerves have the task of transmitting commands from the brain to the skeletal muscles. Without this transmission of commands, the muscles, for example, cannot contract. When these nerves are damaged, the muscles lose strength and muscle cramps or muscle paralysis occur. In severe cases, it is possible that motor polyneuropathy leads to muscle atrophy (muscle atrophy), because the activation of the tissue by the nerves is insufficient or no longer takes place. As a result, the muscles can shrink and ultimately disappear.

Diabetic polyneuropathy

If the polyneuropathy is a consequence of diabetes mellitus, damage to the sensory nerves usually occurs first and the symptoms develop gradually. At first, those affected usually feel tingling or numbness in the legs or a burning sensation in the feet. These symptoms occur mainly at night or during periods of rest. Some affected persons can no longer bear to touch the bedspread or find the bedspread too heavy.

The sensation of pain often decreases, so that minor injuries are not even noticed. This can lead to poorly healing wounds, as many diabetics suffer from circulatory problems. Necrosis can also occur. In diabetics, polyneuropathy usually occurs in both legs or feet, and the disease can spread to the autonomic nerves as it progresses. In this case, symptoms such as diarrhea, constipation, vomiting, dysphagia, impotence or urinary incontinence occur.

Alcoholic polyneuropathy

Alcoholic polyneuropathy usually has a slowly progressive disease course, with most sufferers having symmetrical polyneuropathy in the legs. This leads to symptoms such as insensitivity, pain, sensory disturbances and sometimes to muscle atrophy and severe muscle flaccidity. In the severe course, disorders in the eye area can develop. However, there are also cases of this form of the disease in which there are no symptoms at all.


In about twenty percent of those affected, the exact cause cannot be found. In most cases polyneuropathy is a consequence of other diseases or it is a sign of another disease. Polyneuropathy is often caused by advanced diabetes or is the result of chronic alcohol abuse. However, there are over 200 different known causes for this condition.

Diabetes is the most common cause of polyneuropathy, which can cause type 1 and type 2 diabetes. It is assumed that every second diabetic develops a polyneuropathy. Diabetics whose blood glucose levels are not optimally adjusted suffer from the disease earlier. In them the course is often also very severe.

It is not yet known exactly why nerve damage occurs as a result of high blood glucose levels. It is possible that, due to the amount of blood sugar, sugar molecules combine reactively with proteins and attack the nerve cells. Since the high blood sugar also damages the small blood vessels, this could also be the reason that the supply of the nerves with nutrients and oxygen is no longer sufficient. Then the nerves can no longer fulfill their function and sometimes die off.

The course of polyneuropathy in diabetics is usually a gradual process. Both the course of the nerve damage and the severity and nature of the symptoms vary from patient to patient.

The second most common cause of polyneuropathy is chronic alcohol consumption. Again, it is not yet clear exactly which mechanisms set the damage to the nerves in motion. Probably the nerves are attacked directly by the alcohol. In addition, most alcoholics do not eat a balanced and healthy diet, resulting in malnutrition. This causes a vitamin B12 deficiency, among other things. If this vitamin is deficient, polyneuropathy can be triggered.

Other possible causes for polyneuropathy:

  • Vitamin B12 deficiency
  • Liver diseases
  • Kidney disease
  • Underactivity of the thyroid gland
  • Hyperthyroidism
  • Infectious diseases such as diphtheria, herpes simplex infection, shingles, glandular fever, HIV, Lympe borreliosis and others
  • Guillain-Barre syndrome
  • Lead, arsenic and other poisons
  • Cancer – the first sign of cancer can be polyneuropathy , especially cancer treatment drugs

Rather rarely, polyneuropathy is genetically caused. There are some congenital diseases which can be accompanied by polyneuropathy. One of them is hereditary motor-sensitive neuropathy, abbreviated as HMSN.


First a medical history is taken. During this consultation, the patient should describe his or her symptoms as precisely as possible. In the anamnesis also existing basic diseases as well as previous diseases are included. It is also important for the doctor to know whether the patient has to take medication regularly and whether he has to deal with toxins at work. In toxic neuropathy, the causes are drugs, toxins, or alcohol. In order for polyneuropathy to be diagnosed, questions about alcohol and drug use must be answered honestly.

After this interview, a physical examination is performed, including testing reflexes and checking how the pupils react to light. Furthermore, the body is examined for possible deformities, because hollow feet or claw toes are possible signs of a genetically caused polyneuropathy.

In addition to this physical examination, other tests may follow, for example:

  • Electromyography – Testing of electrical muscle activity. This test is performed in patients with muscle paralysis, muscle weakness, or other motor disorders. This can determine whether the disorder is caused by the nerves supplying the pain or by the muscle itself. If there is a disturbance in nerve function, this may be a sign of polyneuropathy.
  • Electroneurography – Measurement of nerve conduction velocity. If nerve conduction velocity is decreased, this may indicate polyneuropathy.
  • Electrocardiography – An ECG can detect whether there is damage to the autonomic nerve fibers from the heart.
  • Quantitative sensory examination – to test the reaction of a nerve to temperature, pressure or other stimuli. With this method, it is easy to determine whether nerve damage is present. However, it is not part of the routine work-up because the method is time-consuming and the patient must cooperate in a concentrated manner.
  • Sonography of the urinary bladder – to clarify a possible disorder of bladder emptying.
  • Skin biopsy – This method involves punching out a small piece of skin, usually taken from the lower leg. Biopsy of the skin is performed only in certain cases.
  • Nerve biopsy – Nerve tissue sampling is performed only in certain patients, such as diabetics with asymmetric diabetic polyneuropathy.
  • Genetic testing Are performed when there is already a family history of polyneuropathy.
  • Blood tests are especially arranged for the detection of treatable and common causes. In addition, some laboratory values may reveal a suspicion.

Treatment and therapy

For effective treatment, it is important to treat or – if possible – eliminate the cause of the polyneuropathy. Diabetics need to keep their blood sugar tightly controlled and for alcoholics withdrawal is essential. If there is a vitamin B12 deficiency, the affected person must eat a healthy, balanced diet and ensure that the deficiency is compensated for by taking an appropriate vitamin supplement. if the cause of polyneuropathy is medication or toxins, the patient should avoid them.

These treatments are called causative or causal therapies. An adjunct may be symptomatic therapy, which treats the symptoms of polyneuropathy. These measures include pain therapy for patients with burning pain. These symptoms are often treated with acetaminophen, acetylsalicylic acid, or other pain medications. If very severe nerve pain is present, the doctor may prescribe strong painkillers such as opioids. Since these strong drugs can be addictive, it is recommended to seek treatment from a pain therapist if the pain is persistent.

Antiepileptic drugs can also be used to reduce the excitability of the nerve cells. Regular blood tests must be performed during treatment with these anticonvulsants, as the drugs can cause changes in various blood values. Another option for pain management is with antidepressants, which inhibits the transmission of pain signals in the spinal cord.

Transcutaneous electrical nerve stimulation can also relieve pain. This method is known under the abbreviation TENS or as stimulation current therapy. Although the effect of this treatment measure has not yet been scientifically proven, it is very helpful for some patients with polyneuropathy.

Other treatment measures:

  • Alternating baths, physical therapy or other physical treatments for a sensitive or motor polyneuropathy
  • Magnesium supplementation to relieve frequent calf cramps
  • Orthopedic aids for patients with severe problems with walking
  • Change your diet if you suffer from vomiting, bloating, nausea or constipation

Course of the disease

If you suspect that the symptoms you are experiencing may be symptoms of polyneuropathy, you should see a doctor immediately. The course of the disease can be positively influenced if the disease is recognized in time and its causes can be eliminated at an early stage. However, the elimination of the trigger is not possible in all cases.

Mostly polyneuropathy proceeds insidiously. When diabetes or alcohol are the causes, the feet are usually affected first and the symptoms continue to spread in an ascending manner. As a rule, people affected by polyneuropathy suffer from paraesthesia in the beginning. Later, other complaints such as muscle weakness, paralysis, disturbances in bladder emptying, erectile dysfunction and other symptoms may occur.

Is polyneuropathy curable?

Whether polyneuropathy can be cured depends on various factors. In principle, partial regeneration of nerve cells is possible. If the disease is recognized quickly and the cause can be eliminated, the chances for a cure are good. However, the form of the polyneuropathy is also important. In addition, the disease often initially remains asymptomatic or the symptoms are so weak that those affected do not go to the doctor.

If left untreated, polyneuropathy progresses gradually and steadily, so that when the patient first visits the doctor, the symptoms often persist for a long time. Polyneuropathy is not curable if the nerves are severely damaged and the disease is advanced. In this case, therapy is aimed at preventing further damage and alleviating existing symptoms. Diabetic polyneuropathy has virtually no chance of recovery, because the nerves are usually irreversibly damaged. Appropriate treatment is important to prevent the symptoms from progressing further.

Life expectancy

Patients ask themselves: “How long can one live with polyneuropathy??”. Life expectancy is not limited by this disease. An exception is Guillain-Barre syndrome, which is a form of polyneuropathy associated with a very rapid progression and can be triggered by respiratory or gastrointestinal infections.

The disease begins in the feet and progresses within two to four weeks. Since the nerves of the heart can also be damaged, monitoring in hospital is necessary. For about five percent of those affected by Guillain-Barre syndrome, the disease is fatal, but for the majority of patients, the symptoms can regress.


Polyneuropathy is often treated holistically, so that part of the therapy consists of a healthy diet. Especially for diabetics, a change in diet is very important to reduce the symptoms of polyneuropathy.

  • In diabetic polyneuropathy, about half of the energy requirement should be covered by carbohydrates, whereby attention must be paid to foods with a low glycemic index. This index shows how quickly and how strongly the blood sugar level is raised by this foodstuff. In general, dietary fiber has a low glycemic index, so a high-fiber diet is important for the treatment of diabetic polyneuropathy.
  • Not only in diabetes, but also in polyneuropathy, vegetable fats are healthier than animal fats. Sunflower oil, olive oil and rapeseed oil have a positive effect on the blood sugar level.
  • Peripheral nerve degeneration is often treated, among other things, with alpha lipoic acid, which is found in the form of sulfur-containing fatty acid in all body cells. But this healthy fatty acid is also found in tomatoes, broccoli and spinach.
  • Omega-3 fatty acids are important food for the nerves, especially since they can improve the transmission of nerve signals. Omega-3 fatty acids are found, among other things, in chia seeds, flax seeds as well as in salmon, mackerel, herring and other fish.
  • In polyneuropathy and especially in the diabetic and alcoholic form should take plenty of vitamin B12, but also vitamin B1. Legumes, some vegetables and whole grain products contain B vitamins. Milk, eggs, meat and fish are rich in vitamin B12. Those affected by diabetic polyneuropathy should eat these foods in the form of lean quark, lean yogurt, lean cream cheese, lean meat and lean sausage varieties. If there is already a deficiency of vitamin B12, it must be compensated with a dietary supplement or injections.

The following foods should be avoided in polyneuropathy, as they may promote the progression of the disease or aggravate the symptoms:

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