Chronic pain

The acute pain (protective pain) can be understood as a warning signal of the body, which has the purpose to report a physical disorder to the brain. Chronic pain, on the other hand, has lost its actual purpose and exists independently. This happens when nerve cells signal pain to the brain that has no apparent cause.

According to the German Pain League, many millions of people are affected by acute or chronic pain. Some of those affected suffer from such complex pain that only specialists should be consulted, so-called medical pain therapists. However, the range of treatments offered by these specialists is still largely unused.

In chronic pain symptomatology, experts distinguish between three basic types of pain:

• Peripheral projection pain (e.g., trigeminal neuralgia, Sudeck's syndrome).
• Central pain that spreads out from the brain or spinal cord (e.g. burning continuous pain after a stroke, "thalamic pain")
• Transfer pain (that pain which is projected onto a specific skin area due to organ damage, "head zone").

Chronic pain is not one of the body's natural states, but happens when nerve impulses become independent. If a nerve cell gives impulses to the brain for weeks, for example after an injury, its metabolism undergoes a change.

If the pain lasts for at least three to six months and leads to a mentally and physically restricted condition in the patient, it is referred to as chronic pain.

The origin of chronic pain can be a rheumatic disease, a herniated disc or an inflammation. If this pain stops once, the cell nevertheless often continues to send impulses. In this case, one speaks of a trained pain memory.

The altered signal transmission usually takes place in the spinal cord. This is where the activation of the pain memory takes place. Once this activation has taken place, it is difficult not to perceive pleasant stimuli such as warmth, touch or stretching as pain. This can go so far that even mental stress, fear or the mere memory of the stinging and pulling can have a pain-triggering effect.

In order to prevent the activation of pain memory, acute pain should be taken seriously and treated in a timely manner. This is the only way to prevent a transition from acute to chronic pain.

If pain lasts for a period of at least three to six months and leads to a severe impairment of the affected person, then it is called chronic pain. In this case, the original cause of the pain is usually not present or cannot be eliminated. In addition, certain environmental influences, such as stress or changes in the weather, can lead to an increase in pain or even trigger it.

The most common forms of chronic pain include

• Back pain (e.g. after a slipped disc, nerve root compression syndrome).
• Headaches (e.g. migraine, tension headaches, painkiller headaches, cluster headaches)
• Rheumatic pain (including arthritis, firbomyalgia)
• Neuralgia (including trigeminal neuralgia, shingles)
• Tumour pain (mainly with bone metastases)
• Pain caused by degenerative processes (degenerative pain, e.g. osteoporosis, arthrosis)
• Phantom pain (e.g. after amputations or certain nerve damage (plexus rupture))

Around 50 percent of people suffering from chronic pain consult a doctor. The many differences in the form of pain, as well as the different origins of chronic pain, make it clear that a detailed diagnosis is necessary in order to create a multifaceted therapy.

Usually the treating physician takes a lot of time for persons with chronic pain and takes a detailed pain history. The sufferer should keep a pain diary. This helps the doctor to find the reason behind the symptoms. Additional findings, such as older doctor's letters and X-rays, can also be helpful for diagnosis.

The doctor also tries to find out about possible stress factors in the current life situation, because these have a great influence on the current pain perception. In addition, the intensity of the pain is assessed by the affected person himself on a scale (visual analogue scale).

The following examinations may be used:

• Detailed physical examination
• Neurological examination
• Orthopaedic examination
• Possibly supplementary neurophysiological diagnostics: electoneurography (ENG) and electromyography (EMG)
• Imaging examination methods such as ultrasound, computer tomography (CT) or magnetic resonance imaging (MRI).

The therapy is oriented towards the various causes and factors that aggravate the disease. This is done both medicinally and by means of complementary procedures, which include physical, psychological and social components.

The goal of pain therapy in this context is to interrupt the conduction of pain (medicinal) on the one hand, and to change the affected person's perception of pain (non-drug) on the other.

Medication:

The basis of many long-term treatments is often medication. According to the World Health Organization (WHO), pain therapy is divided into three stages (WHO stage scheme):

• Stage I: Non-steroidal anti-inflammatory drugs for mild pain.
• Stage II: Opioids for moderate to severe pain
• Stage III: Opioids for severe to very severe pain

Often, treatment begins with withdrawal of such medications as listed above, which may play a role in chronic pain chronification. An example is drug-induced headache, which develops when sufferers consume painkillers on more than ten days per month. Supplementary medications may be given for some forms of pain, such as anticonvulsants for colic. Some antidepressants sometimes have a very good pain-relieving effect as a positive side effect.

Furthermore, drugs from the group of anti-epileptics can also be used against continuous pain. This is especially true for nerve pain (neuralgia), where agents such as carbamezepine, oxcarbamezepine, oxcarbazepine, gabapentin, or pregabalin have been shown to have a markedly positive effect.

Other therapies:

Depending on the form of pain, there are other forms of therapy to choose from in addition to psychotherapy and medication:

• Acupuncture
• Exercise therapy
• Behavioural therapy, such as stress management training or biofeedback
• Physiotherapy and manual therapy to strengthen or relieve muscle groups
• Transcutaneous electrical nerve stimulation (TENS) can be used to stimulate nerve structures by applying electrical impulses to the skin.
• Autogenic training
• Nerve blockades e.g. sympathetic blockade through the administration of guanethidine
• Pain pumps, which are implanted and continuously deliver active substances for painkiller administration
• Local or regional anaesthesia e.g. with peridual catheter
• Relief operations e.g. for carpal tunnel syndrome
• Palliative surgery to reduce pain in cases of cancer that cannot be cured

Lifestyle:

Sometimes simple methods such as a change in diet or a change of job can have a positive effect on pain.

Some pain therapies can only be carried out on an inpatient or outpatient basis in a pain outpatient clinic. Various experts work together here, such as anaesthetists, psychotherapists, surgeons, orthopaedists and neurologists.

In order to get a picture of the course and success, patients are encouraged to continue to keep pain questionnaires, pain diaries and progress documents at home.

A major problem for patients with chronic pain is the frequent lack of specialist support. As a result, many sufferers suffer more than necessary from the pain, as no individual care is provided.

People suffering from chronic pain should take the following points to heart:

• A specially trained pain specialist should be consulted
• Medication should be taken as prescribed and not just as needed to prevent recurrence of pain.
• Self-monitoring is important, especially in which situations the pain gets better or worse.
• Exercise in any form is important. This can be jogging, walking or swimming. Regular physical activity strengthens the body and the psyche and thus helps to alleviate the pain.