Polyneuropathy refers to various diseases in which several nerves of the peripheral nervous system are damaged. other names for polyneuropathy are peripheral neuropathy or peripheral polyneuropathy. Different symptoms can occur with this disease, depending on the 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 in the muscles. The peripheral nervous system also includes motor and sensory nerves, as well as 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 process) and a cell body, whereby the axon can reach a length of one meter. These nerve processes are protected by an insulating myelin layer. However, myelin not only protects the axon, but also ensures that the electrical nerve signals are transmitted quickly. If this layer is damaged, it slowly disintegrates. Damage to the myelin layer is referred to as demyelinating polyneuropathy. If the nerve process itself is affected by the damage, it is referred to as an axonal polyneuropathy. It also happens that both axons and meylin layers are damaged.
Since the nerves in the arms and legs are particularly long, this is where the first symptoms usually occur. At the beginning of a polyneuropathy, affected persons feel a burning or tingling sensation in the arms and/or 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. As a result, the perception of pain and touch is reduced and there is a false sensation of cold or heat. Depending on the damaged nerves, a distinction is made between autonomic, sensory and motor disorders.
Another distinction of the symptoms is based on the distribution of the symptoms:
- Symmetrical polyneuropathysymptoms affect both arms or both feet.
- Asymmetric polyneuropathyThe 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 sensitive 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, temperature, touch, pressure and similar information to the brain. If these nerves are damaged, this leads to tingling, insensitivity, burning or stinging sensations. The arms and legs are often affected, and the toes are often the first to feel the discomfort.
Numbness in the legs may also occur, causing the affected person to have problems with coordination when walking. If the temperature sensation is disturbed, the risk of injury increases, because the patient no longer feels, for example, whether the bath water is too hot. Other possible symptoms of sensory polyneuropathy are a feeling of furiness, swelling, a feeling of walking on absorbent cotton, or an uncomfortable feeling of pressure.
Symptoms of damage to the autonomic nerves
The autonomic nerves are also called vegetative nerves and are responsible for controlling the functions of the internal organs. That is, they control, for example, the bladder, sexual organs, intestines, lungs and heart. These nerves cannot be controlled voluntarily. When these autonomic nerves are damaged, the symptoms can become very serious or even life-threatening. For example, 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 intestinal nerve damage, symptoms include constipation or diarrhea. If the nerves that are responsible for the bladder function are affected, disturbances occur during 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 damage to the motor nerves
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 paralysis occur. In severe cases, motor polyneuropathy may lead to muscle atrophy (muscle atrophy), because the activation of the tissue by the nerves is insufficient or no longer occurs. As a result, the muscles can shrink and ultimately disappear.
If the polyneuropathy is a consequence of diabetes mellitus, damage to the sensory nerves usually occurs first and the symptoms develop gradually. At first, the affected person usually feels tingling or numbness in the legs or a burning sensation in the feet. These complaints occur mainly at night or during periods of rest. Some sufferers can no longer bear to come into contact with the bedcover or find the bedcover too heavy.
The sensation of pain often diminishes, so that minor injuries are not even noticed. This can lead to poorly healing wounds, as many diabetics suffer from circulatory problems. Necroses can also develop. 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 usually has a slowly progressive disease course, with most affected people having symmetrical polyneuropathy in the legs. This leads to symptoms such as insensations, pain, sensory disturbances and sometimes to muscle atrophy and severe muscle atrophy. In severe cases, disorders may develop in the eye area. However, there are also cases of this form of the disease in which no symptoms occur at all.
In about twenty percent of those affected, the exact cause cannot be found. In most cases, polyneuropathy is the consequence of other diseases or it is a sign of another disease. Polyneuropathy is often triggered by advanced diabetes or is the result of chronic alcohol abuse. However, more than 200 different causes of this disease are known.
Diabetes is the most common cause of polyneuropathy, diabetes type 1 and type 2 can occur. It is believed that one in two diabetics develops a polyneuropathy. The diabetics whose blood glucose levels are not optimally adjusted become ill sooner. The course of the disease is often very severe.
It is not yet known exactly why the high blood sugar level causes nerve damage. It is possible that due to the amount of blood sugar, sugar molecules reactively combine with proteins and attack the nerve cells. Since the high blood sugar also damages the small blood vessels, this could also be the reason why 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 type of symptoms vary from patient to patient.
The second most common cause of polyneuropathy is chronic alcohol consumption. Here, too, it is not yet clear exactly which mechanisms set the damage to the nerves in motion. The nerves are probably attacked directly by the alcohol. In addition, most alcoholics do not eat a balanced and healthy diet, so malnutrition occurs. This results, among other things, in a vitamin B12 deficiency. If this vitamin is missing, a polyneuropathy can be triggered.
Other possible causes for a polyneuropathy:
- Vitamin B12 deficiency
- Liver disease
- kidney diseases
- Infectious diseases such as diphtheria, herpes simplex infection, shingles, fever, HIV, lympe borreliosis and others
- Guillain-barre syndrome
- Lead, arsenic and other poisons
- Cancer – the first sign of cancer can be polyneuropathy, especially medication for cancer treatment
Polyneuropathy is rarely caused by genetic factors. There are some congenital diseases that can be accompanied by polyneuropathy. One of these is hereditary motor-sensitive neuropathy, abbreviated as HMSN.
The first step is to take a medical history. During this consultation, the patient should describe his or her symptoms as precisely as possible. The medical history also includes existing underlying diseases as well as previous illnesses. It is also important for the doctor to know whether the patient has to take medication regularly and whether he or she has to deal with toxins in the workplace. Toxic neuropathy is caused by drugs, toxins or alcohol. In order for a polyneuropathy to be clarified, questions about the consumption of alcohol and drugs must be answered honestly.
After this interview, a physical examination is performed, including testing of the reflexes and checking the reaction of the pupils to light. Furthermore, the body is examined for possible deformities, because hollow feet or clawed toes are possible signs of a genetic polyneuropathy.
In addition to this physical examination, other examinations may follow, for example:
- Electromyography – testing of electrical muscle activity. This examination is performed in patients with muscle paralysis, muscle weakness or other motor disorders. It can be determined whether the disorder is caused by the nerves supplying the muscle 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 the nerve conduction velocity is reduced, this may indicate polyneuropathy.
- Electrocardiography – ECG can detect if there is damage to the autonomic nerve fibers from the heart.
- Quantitative sensory testing – to test the reaction of a nerve to temperature, pressure or other stimuli. This method is a good way to determine whether nerve damage is present. However, it is not part of the routine clarification, because the method is time-consuming and the patient must cooperate in a concentrated manner.
- sonography of the urinary bladder – to clarify a possible disturbance of bladder emptying.
- Skin biopsy – this method involves punching out a small piece of skin, usually taken from the lower leg. A biopsy of the skin is only performed in certain cases.
- Nerve biopsy – the taking of a nerve tissue sample is only carried out in certain patients, for example in diabetics with asymmetric diabetic polyneuropathy.
- Genetic testing are carried out if there are already polyneuropathy sufferers in the family.
- Blood tests are performed especially for the detection of treatable and common causes. In addition, some laboratory values can reveal a suspicion.
Treatment and therapy
For effective treatment, it is important to treat or – if possible – eliminate the cause of the polyneuropathy. Diabetics must keep their blood sugar tightly controlled, and for alcoholics withdrawal is essential. If there is a vitamin B12 deficiency, the patient must eat a healthy, balanced diet and compensate for the deficiency by taking an appropriate vitamin supplement. If the cause of polyneuropathy is drugs or toxins, the patient should avoid them.
These treatments are called causal therapies. Symptomatic therapy can be used to treat the symptoms of polyneuropathy. These measures include, among others, pain therapy for patients with burning pain. These symptoms are often treated with paracetamol, acetylsalicylic acid or other painkillers. If the nerve pain is very severe, 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 for persistent pain.
Antiepileptic drugs can also be used to reduce the excitability of the nerve cells. Regular blood tests must be carried out during treatment with these anticonvulsants, as the drugs can cause changes in various blood values. Another way of treating pain is with antidepressants, which inhibit the transmission of pain signals in the spinal cord.
Transcutaneous electrical nerve stimulation can also have a pain-relieving effect. This procedure is known by the abbreviation TENS or as stimulation current therapy. Although this treatment has not yet been scientifically proven to be effective, it is very helpful for some patients with polyneuropathy.
- Alternating baths, physiotherapy or other physical treatments for sensitive or motor polyneuropathy
- Taking magnesium to relieve frequent calf cramps
- Orthopedic aids for patients with severe walking problems
- dietary changes for symptoms that include vomiting, fullness, nausea, or constipation
Course of the disease
If you suspect that the symptoms you are experiencing may be symptoms of polyneuropathy, you should consult a doctor immediately. The course of the disease can be positively influenced if it is detected in time and its causes can be eliminated at an early stage. However, the elimination of the trigger is not possible in all cases.
Polyneuropathy usually progresses insidiously. If the cause is diabetes or alcohol, the feet are usually the first to be affected and the symptoms spread upward. As a rule, polyneuropathy sufferers start off with sensory disturbances. Later, other symptoms such as muscle weakness, paralysis, bladder dysfunction, erectile dysfunction and other symptoms may occur.
Is polyneuropathy curable?
Whether or not polyneuropathy can be cured depends on various factors. In principle, the partial regeneration of nerve cells is possible. If the disease is recognized quickly and the cause can be eliminated, the chances of a cure are good. However, it also depends on the form of the polyneuroapathy. In addition, the disease often remains asymptomatic at first, or the symptoms are so mild that sufferers do not go to the doctor.
If left untreated, polyneuropathy progresses gradually and steadily, so that when the patient first sees a doctor, the symptoms often persist for a long time. Polyneuropathy cannot be cured if the nerves are severely damaged and the disease is advanced. In this case, the aim of the therapy is to prevent further damage and to alleviate the existing symptoms. With diabetic polyneuropathy, there is virtually no chance of a cure, because the nerves are usually irreversibly damaged. To prevent the symptoms from progressing further, it’s important to get the right treatment.
sufferers ask themselves: "how long can you live with polyneuropathy??". The life expectancy is not limited by this disease. An exception is guillain-barre syndrome, which is a polyneuropathy with a very rapid progression that can be triggered by respiratory tract infections or gastrointestinal infections.
The disease starts in the feet and progresses within two to four weeks. Since the nerves of the heart can also be damaged, monitoring in the 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 again.
Polyneuropathy is often treated holistically, so part of the therapy consists of a healthy diet. especially for diabetics a change of diet is very important to reduce the symptoms of polyneuropathy.
- In diabetic polyneuropathy, around half of the energy requirement should be covered by carbohydrates, and attention must be paid to foods with a low glycemic index. This index shows how quickly and how strongly the blood sugar level rises due to this food. In general, fiber has a low glycemic index, so a high-fiber diet is important for the treatment of diabetic polyneuropathy.
- not only for diabetes, but also for polyneuropathy, vegetable fats are healthier than animal fats. Sunflower oil, olive oil and rapeseed oil have a positive effect on blood sugar levels.
- Peripheral nerve degeneration is often treated with alpha-lipoic acid, which is found in the form of sulfurous 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 as they can improve the transmission of nerve signals. Omega-3 fatty acids can be found in chia seeds, flax seeds, salmon, mackerel, herring and other fish.
- In polyneuropathy and especially in the diabetic and alcoholic form should be taken a lot 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. sufferers of diabetic polyneuropathy should eat these foods in the form of lean quark, lean yogurt, lean cream cheese, lean meat and lean sausages. If there is already a deficiency of vitamin B12, this must be compensated for with a food supplement or injections.
The following foods should be avoided in polyneuropathy, as they can promote the progression of the disease or aggravate the symptoms: