The two sides of pain

"Pain is both a curse and a blessing", says Jürgen Sandkühler, Head of the Department of Neurophysiology at the Centre for Brain Research at the MedUni Vienna ahead of the international "Brain Awareness Week", being held from the 12th to the 16th of March. On the one hand, pain has an important protective function for humans. On the other, there are pains that no longer make any "biological sense". When these occur, the pain becomes an illness - and can destroy people's quality of life. Sandkühler: "So pain isn't just pain."

But how does pain actually occur? Special pain sensors respond to strong, painful stimuli that can possibly damage tissue. The stimuli are conducted via the neural pathways to the spinal cord. The pain information is comprehensively processed even at this stage. The stimuli can be amplified or suppressed. This is also where the most powerful painkillers available, known as opioids - substances similar to morphine - exert their influence. From the spinal cord, the stimuli are forwarded to the brain, which is where the first unpleasant sensation of "pain" is produced. Says Sandkühler: "Pain has to be unpleasant enough for us to avoid painful situations and therefore risks to our health." For pain to be produced, however, all of the nerve pathways, transmitter substances, binding synapses and ion channels need to be functioning normally. 

People who cannot feel pain
"This situation is actually completely the reverse for one family in Pakistan, for example. Many of the members of this family are unable to feel any pain because they have a genetic defect which means that an essential ion channel does not form," says Sandkühler. As a result, for instance, the children who are affected do not know if they have broken a bone, inflammations go unnoticed and therefore cannot be treated, and so on. The life expectancy of people who are unable to feel pain is considerably shorter. Says Sandkühler: "Being unable to feel any pain is therefore not a blessing, but rather a considerable disadvantage for your health."

The pain system is a sensory organ like hearing, sight or smell. The sensors stimulate nerve fibres up to the brain, where the impressions of senses are produced. Sandkühler: "If this process is disrupted, you don't feel any pain. When the flow of information from the ear to the brain is disrupted, for example, it can lead in a similar way to deafness."

This is one side of the coin. Pain as an important protective function. The other side of the coin is pain that has no purpose for the affected individual. "Pain becomes a disease when it no longer acts as a warning signal or symptom. When someone suffers pain without it being of any benefit to them, then this meaningless, chronic pain can also be termed pain syndrome," explains Sandkühler.

Taking pain seriously
According to Hans-Georg Kress, Director of the Clinical Department of Specialist Anaesthesia and Pain Therapy at the MedUni, there are around 1.6 million sufferers of chronic pain syndrome, equivalent to around 20 per cent of the population. Around 4,500 of them are treated at the Vienna General Hospital's Pain Clinic.

Sandkühler's general advice is to always take pain seriously. "You can do many things to avoid chronic pain. Often, it is just a little thing - the wrong glasses, or bad posture while sitting in your office chair. Frequently avoidable causes of pain include lack of exercise, which can lead to back pain, or being overweight, which causes joint pain. If the pain persists for several days, you should go and see a doctor. Specialist institutions such as the Pain Clinic can help with chronic pain."

Patients are accepted at the Pain Clinic if they have had pain for more than three months. The condition can have all manner of causes, mechanisms and forms. Says Sandkühler: "There is no 'one' pain condition, and there's also no magic pill that will cure it. But with an experienced pain practitioner, the prospects of success are good." Essentially, says Sandkühler, pain syndrome is no longer an inevitable curse, even if complete freedom from pain is not always possible: "Nobody should suffer pointless pain without help nowadays."

http://www.meduniwien.ac.at