Polyneuropathy usually begins with an unpleasant tingling or burning sensation in the feet - without an identifiable cause for this nerve condition initially being found. Hands, arms and other areas of the body can also be affected, but usually only at a later stage.
The long list of possible symptoms of polyneuropathy ranges from numbness and reduced temperature sensation to muscle cramps, digestive disorders and nerve pain. The nerve disease often develops as a result of another disease – the earlier this is recognized and treated, the more effectively the symptoms of polyneuropathy can be alleviated.
Polyneuropathy is a nerve disorder. More precisely: nerve damage or disease. It affects nerves that lie outside the brain or spinal cord in the peripheral nervous system. Polyneuropathy often manifests itself initially in the feet and later in the distal hands, but organs such as the heart, bladder, blood vessels and others can also be affected by polyneuropathy.
The word polyneuropathy is made up of three parts: “poly” means “many”, while “neuro” refers to nerves and the suffix “…pathie” stands for a disease. Polyneuropathy is therefore a disease of many nerves. For various reasons, the affected nerves lose their conductivity or perish, which is why they can only transmit stimuli imperfectly or not at all. This results in complaints of varying types, numbers and severity.
Polyneuropathy is not a rare disease: the condition occurs frequently, especially in old age. While up to three percent of the total Swiss population is affected by polyneuropathy (around 270,000 men and women), the proportion of sufferers among Swiss people over 55 years of age is over five percent. More than 10,000 new patients are added every year.
The symptoms of polyneuropathy can be diverse and vary greatly in their severity. While some sufferers only experience an occasional tingling sensation in their hands or legs, others suffer from pain or extreme sensitivity, where even touching the comforter becomes a torture. Depending on which nerve fibers are affected, a distinction is made between the following forms of polyneuropathy:
This form of the disease affects nerves or the parts of nerves that control the muscles; it leads to weakness and/or muscle atrophy. The following symptoms are typical of motor polyneuropathy:
This form of the disease affects nerves or parts of nerves that transmit sensory stimuli (sensory nerves); it leads to sensory disturbances. The following symptoms are typical of sensitive polyneuropathy:
This form of the disease affects nerves or parts of nerves that are assigned to the so-called autonomic nervous system (also known as the autonomic nervous system). The following symptoms are typical of autonomic polyneuropathy:
Only rarely does a motor, sensory or autonomic polyneuropathy occur on its own. Most sufferers experience a combination of the three types of polyneuropathy. The disease often begins with a sensory symptom such as tingling in the feet and is accompanied by a motor or autonomic disorder. The symptoms often worsen at rest or during the night.
The earlier a polyneuropathy is recognized and treated, the better the prognosis. If you suffer from this condition, it is important that your doctor finds out the cause. If this trigger is treated or even eliminated, the symptoms of polyneuropathy can often be noticeably alleviated. In rare cases, they can even disappear again. However, polyneuropathy often goes unnoticed – because the symptoms may initially appear harmless or be attributed to another condition. Once the correct diagnosis has been made, it may be that the nerves affected by polyneuropathy have already been damaged to such an extent that further worsening of the symptoms can be stopped with appropriate therapy, but a complete cure is no longer possible.
If you suspect that you may be affected by polyneuropathy, you should therefore not put off seeing a doctor unnecessarily.
Medicine distinguishes between three stages of polyneuropathy over time: acute polyneuropathy (lasting up to four weeks), subacute polyneuropathy (four to eight weeks) and chronic polyneuropathy (longer than eight weeks). While the duration of the disease can vary, its onset is often the same: the symptoms are often bilateral (symmetrical) and initially usually “sock-like” on the feet. As the disease progresses, the symptoms often also occur in the lower legs (“stocking-like”). However, polyneuropathy can also appear unilaterally, i.e. only on one leg or arm or also on the trunk of the body.
Polyneuropathy can be a disease in its own right, but it can also be the result of another disease. For example, as a result of high blood sugar in diabetes. In rare cases, polyneuropathy also occurs as a hereditary disease; it can affect children or even infants as so-called Charcot-Marie-Tooth disease. In around 20-30 percent of all polyneuropathy cases, the cause remains unexplained despite adequate investigations.
There are more than a hundred known causes that can lead to the development of polyneuropathy. These include the triggers of the three most common types of polyneuropathy:
More than 30 percent of those affected by polyneuropathy suffer from diabetes. It is not known exactly how their elevated blood sugar levels lead to nerve damage. What is certain, however, is that patients who have problems with blood sugar control often develop pronounced polyneuropathy symptoms at an early stage. The longer you have diabetes, the more likely you are to develop polyneuropathy.
Around 15 percent of those affected by polyneuropathy fall ill because their bodies are exposed to toxic substances. First and foremost: alcohol. In addition to excessive alcohol consumption, which damages the nerves, there is often a deficiency of certain vitamins (B1, B6, B12), which leads to an increased manifestation of alcoholic polyneuropathy. Other toxins, such as heavy metals, are only rarely the cause of polyneuropathy.
Around nine percent of people affected by polyneuropathy suffer from malfunctions of the immune system. It is directed against the patient’s own nerve cells and damages them.
If you are suspected of having polyneuropathy, your doctor can find out important details for an accurate diagnosis from your answers to specific questions. Initial information on the medical history of polyneuropathy can be obtained by describing the onset, nature and duration of your symptoms. Questions about specific everyday situations also help in the diagnosis of polyneuropathy: Can you walk up a flight of stairs without any problems? Have you fallen recently? Can you also walk in the dark? Are you able to stand up from a squatting position?
Medical examination methods can provide further details on the diagnosis of polyneuropathy:
Simple tests are used to check sensitivity to touch or vibration. For example, with a tuning fork that is struck and held against the ankle of a hand or foot. As a patient, you should indicate when you no longer feel the vibrations of the tuning fork. Other tests can show whether your muscle reflexes are intact.
This involves stimulating a nerve with a small electrical impulse. At a second point, often on a muscle, the time taken for the impulse to reach this point is measured. The arrival time of the signal can be used to calculate the nerve conduction velocity, which provides information about possible nerve damage. If you think of a nerve like a power cable, the inside (the wire) in the cable can be damaged – this is called “axonal damage” in medicine; it manifests itself in a reduced strength of the signal. If, on the other hand, the sheathing (the insulation) is damaged, this is referred to as “demyelinating damage”; it manifests itself in a reduced transit time (nerve conduction velocity) of the signal.
This method measures the electrical voltage and activity of muscles. This is done with the help of fine needles and recorded currents, which are visualized in an electromyogram. It shows whether the muscle in question is diseased or is adequately supplied by a nerve.
A series of different tests determine whether disorders of the autonomic nervous system – which cannot be controlled by the will – are present. For example, reflexes, blood pressure, heart rate and the function of the sweat glands or bladder are checked.
Neuromuscular ultrasound is a painless and uncomplicated examination in which nerves are visualized using sound waves. In recent years, it has established itself as an important addition to other examinations such as the physical examination and measurement of nerve conduction. Thanks to modern technology, even very small nerves can now be visualized accurately. This allows changes such as thickening or damage to be detected. A major advantage is that the test is available quickly, is not stressful and can also be used when other tests are difficult to perform. This helps doctors to make a more accurate diagnosis and plan treatment better.
The chances of effective therapy for the nerve disease polyneuropathy are particularly good if the origin of its development is known and this cause of the disease is treated at an early stage. This applies to diabetes, the most common cause of polyneuropathy, but also to other forms of polyneuropathy.
If the cause of the polyneuropathy cannot be found or treated, or if the damage to the nerves is irreversible, polyneuropathy treatment consists primarily of eliminating the pain and muscle weakness. Medication for muscle cramps, for example, can help here. Physiotherapy and occupational therapy are intended to train balance and coordination, and water gymnastics, yoga and walking training can also have a supportive effect – as well as plenty of exercise in general.
If polyneuropathy leads to so-called “plus symptoms”, i.e. pain, burning or tingling, and this has a relevant impact on quality of life, medication can be used. Some of these drugs stabilize the nerve membranes so that less of the unpleasant stimulus is transmitted to the brain. Examples of this are pregabalin or gabapentin. Another part of this medication creates a distance to the unpleasant bodily sensations by normalizing the reduced levels of noradrenaline and serotonin in the brain caused by the chronic illness. Examples of this are duloxetine or amitryptiline. As the brain chemistry is altered in the same way in depression, these drugs also have an antidepressant effect.
In addition to medication options (including tricyclic or newer antidepressants or alpha-2-delta ligands), electrotherapy may also be an option for reducing polyneuropathy pain: this involves passing a weak current through the skin to stimulate the nerves. This method is called “transcutaneous electrical nerve stimulation (TENS)”. The operation of a TENS unit, which is also manageable for patients, should cause the polyneuropathy pain to disappear or be replaced by a less annoying tingling sensation. Ask your doctor whether this treatment, which is not always recommended, could be useful for you.