When we bump our head or accidentally touch a hot stove top, we feel pain. Pain is a warning signal from our body that tells us something is wrong. In this interview, Univ. Prof. Dr. Frank Birklein, Professor of Neurology and Neurological Pain Research at the Medical Faculty of the University of Mainz, explains what pain is, how acute and chronic pain differ, and what can be done specifically to combat back pain and headaches.
What is pain?
Birklein: “According to the IASP (International Association for the Study of Pain) definition, ‘pain is an unpleasant sensory or emotional experience associated with actual or potential tissue damage, or described by affected individuals as if such tissue damage were the cause.’ Implicit in the definition is that pain does not always have to have a clear structural cause, but can occur without an obvious physical reason. Accordingly, the causes of pain can be harmless, but they can also be extremely serious.”
Some pains are probing, others stabbing or burning. What causes these different types of pain?
Birklein says, “Exactly why there are different forms of pain has not yet been conclusively determined. However, we know that various factors play a role:
- The place of origin: depending on the place of origin, we perceive pain differently: pain in the muscles, for example, is perceived more as pulling or pressing, while pain on the skin, on the other hand, tends to have a burning or tingling character.
- The mechanism: when we cut ourselves with a kitchen knife, we feel the pain exactly where it occurs. In other cases – nerve pain, for example – we feel the pain where the nerve fibers go, rather than where the nerve damage occurred. Phantom limb pain after amputations is one example.
- Nerve fibers: The pain impulse can be transmitted through different nerve fibers: Some of these nerve fibers transmit the impulse very quickly, others rather slowly. If we place our hand on a hot stove top, the impulse is first transmitted very quickly. Pain that is transmitted via fast nerve fibers is often perceived as stabbing. After that comes the pain that is transmitted via slow nerve fibers – the burning sensation we feel after a second on the hot plate.”
There are some people who ignore their pain. What can be the consequences of this?
Birklein: “Pain has a warning function, it should alert us that something is wrong with our body. If we don’t listen to our body, it can happen that we overlook an illness: If you have abdominal pain for several days but ignore it, you may risk a ruptured appendix. However, pain can only be ignored if it is acute. For example, if we just have an acute headache, we can try to suppress the pain for a certain period of time. In contrast, this is not possible with chronic pain patients, because the pain takes on more weight with them.”
How do acute and chronic pain differ?
Birklein: “The difference between acute and chronic pain lies in the duration of the pain. For pain that lasts less than three months, we refer to it as acute pain. Pain that lasts longer than six months, on the other hand, is referred to as chronic pain. The period between three and six months represents a gray area. For acute pain, there is usually a reason that can be found and treated: For example, we have three days of pain in our hand that we put on the hot stove top. Chronic pain, on the other hand, represents its own clinical picture, and a clear cause can often no longer be determined.”
How does chronic pain develop and what role does pain memory play in it?
Birklein: “If you have pain over a long period of time, the nervous system learns this pain and stores it in the so-called “pain memory.” The learning is not done consciously, but unconsciously. By learning the pain, patients often still perceive the pain as strong even when it is only maintained by weak impulses from the nerves.The pain then results from the pain impulse being amplified at all levels of the nervous system. Even the slightest touch can trigger severe pain in such a case. The term pain memory should be used with caution. Because it implies that the body – similar to swimming – learns something that it can then no longer unlearn. However, this is not the case with pain memory. However, it is not easy to unlearn pain once it has been learned. Similar to other learned things, pain cannot be actively unlearned. However, it is possible to overwrite the pain memory: If, for example, you feel pain even when you are touched lightly, you can overwrite this sensation by learning to feel normally again. In doing so, the pain memory must be overwritten with normal sensory impressions. Normal sensory impressions can be pleasure in movement or social participation despite pain.”
How can acute pain be treated and what can be done about chronic pain?
Birklein: “Acute pain can be managed with pain medication. However, if the pain does not disappear after a few days or if other symptoms – such as high fever or bleeding – are found, a doctor should be consulted to clarify the cause of the pain. If the cause is known, it must be treated. In the case of chronic pain, however, painkillers only help to a certain extent. For this reason, other drugs that are actually used to treat depression or epilepsy are usually used in pain therapy. Although these are not classic painkillers, they have an effect on the excitability of the nervous system and can thus help to relieve pain. In addition, however, an important aspect of treating chronic pain patients is helping them learn to accept and live with pain.”
How many pain patients are there in Germany and what are the most common pain symptoms?
Birklein: “It is estimated that between circa 5 million people in Germany suffer from chronic pain. However, not all of this pain requires treatment. Thus, even an 85-year-old man who suffers from back pain due to signs of wear and tear in a long and full life is considered a pain patient. Chronic back pain is clearly the most widespread type of pain in Germany. This is followed by headaches, joint pain, and pain due to nerve damage.”
What advice can you give to people who suffer from back pain?
Birkein: “For acute back pain, first check to see if there are other complaints: If only the back hurts, one should continue to be active and not take it easy in bed or on the sofa. However, if there are other complaints, such as a feeling of numbness in the legs, you should definitely see a doctor: Then the complaints could indicate a herniated disc. If the back pain persists for several days, you should also go to the doctor to clarify whether the pain has serious causes. Fortunately, this is rarely the case. Much more often, there is a muscular cause behind the pain. After all, back pain nowadays is often caused by constant sitting in the office as well as too little exercise. If the back pain is caused by muscular problems, people should make sure to get enough exercise, adopt an ergonomic sitting posture when working and – if they are severely overweight – reduce their weight.”
Many people often suffer from headaches. What tips can you give them?
Birklein: “For acute headaches, it is quite advisable to take a headache tablet first. If the headache does not disappear after a few days, you should definitely see a doctor. It is important to describe the pain well to the doctor. If you suffer from recurring or chronic headaches, you should always look for the trigger and then avoid it if possible. In the case of a migraine attack, one should avoid exertion, light and noise and, for example, lie down in bed and try to sleep. Chronic headaches, however, should always be treated by a specialist.”
