When the pain itself is the illness
Eva Kosek has been researching pain mechanisms for many years. Now, she and her colleagues have developed criteria for identifying what is known as ‘nociplastic pain’. This is a condition where pain is not just a symptom, but an illness in itself.
Text: Annika Lund, first published in Swedish in the magazine Medicinsk Vetenskap nr 3/2021.
You talk about different types of pain. Can we have a quick lesson?
“We differentiate between three different types of pain. Pain from tissue damage or nociceptive pain arises if we hit our thumb with a hammer, for example. Pain as a result of injury or illness in the nervous system is pain caused by nerve damage or neuropathic pain and can arise from a slipped disk, for example. Then there is nociplastic pain. This is caused by the actual function of the pain system changing; pain regulation no longer works as normal. Pain signals to the brain are strengthened and suppression signals from the brain are weakened. This means that things that normally do not hurt become painful, for example lighter pressure can cause pain and you may experience widespread pain across your body. Nociplastic pain is not a symptom of an injury or illness, in the same way as nociceptive or neuropathic pain are. With nociplastic pain, the pain is an illness in itself.”
What do we know about nociplastic pain?
“We understand quite about the mechanisms involved, and we know that the pain signalling works differently. In a way, we know more about nociplastic pain than neuropathic pain, for example, because we have no explanation as to why the same type of nerve damage causes serious pain for some people, but none for others.”
How does the pain arise?
“We don’t really know. But for many people, long-term pain of another kind leads to the pain system changing, becoming nociplastic. It appears to be more common for long-term nociceptive pain to become nociplastic pain than for long-term neuropathic pain to do this.”
How is this relevant for patients with back problems?
“Some patients with long-term non-specific back pain may experience nociplastic pain. Another common diagnosis for patients with nociplastic pain is fibromyalgia, and these patients often experience pain in their backs. It is important to know what kind of pain a person is experiencing in order to treat it correctly.”
How should nociplastic pain be treated?
“It’s important to do a proper pain analysis in order to understand what pain mechanisms need to be treated. Providing patients with information is key, so that they understand that you can’t remove the pain by treating the painful tissues, but rather that there is a problem with the pain signalling itself. Surgery is less effective on nociplastic pain. Opioids should be avoided, not just because they’re addictive, but also because they can actually worsen nociplastic pain. It’s important to strike a good balance between rest and activity, to do appropriate physical exercise and to be strict with sleep.”
You have recently published criteria for identifying nociplastic pain. Please tell us about them!
“When we research nociplastic pain, we use rather advanced techniques. But people who are experiencing nociplastic pain often receive care from primary healthcare services, where the technology is lacking. We have now produced a flow chart, a standardised approach to identifying those who are likely to be experiencing nociplastic pain by asking the patient questions. We have done this within the framework of the international organisation IASP, and the article has been published in the journal Pain.”
How should the criteria be used?
“They are a way of enabling more people to identify nociplastic pain, i.e. primary pain condition. It is an important concept that pain can be an illness and not just a symptom. In the next version of diagnosis codes, ICD-11, long-term pain issues are divided into primary and secondary conditions. For primary pain conditions, the pain is an illness in itself, while for secondary pain conditions, the pain is caused by other conditions, i.e. it’s a symptom.”
How do healthcare services deal with nociplastic pain?
“We need better developed specialist healthcare that can deal with the patients who are the most seriously ill and help to train colleagues in primary care. I absolutely won’t criticise my colleagues in primary healthcare – there are many GPs who are very competent at treating pain. But they are too few in number and their workload is often very high, as they frequently have to take over the care of pain patients from their colleagues.”
Footnote: Eva Kosek is a pain and rehabilitation doctor and professor in clinical pain research at the Department of Clinical Neuroscience at Karolinska Institute and the Department of Surgical Sciences at Uppsala University.