What is this thing called pain?

As I’m busy writing up research papers for publications to “count” towards my research productivity, I’m reminded of one reason I keep on blogging – and it’s this: blogs are open to anyone.  People can comment on what I write.  When someone comments, whether they agree, disagree, or simply pose a question, it’s an opportunity for dialogue and reflection. That’s not nearly as easy to do in a peer-reviewed journal!

As a result of comments from my post yesterday, I’m musing on ways to explain the distinction between acute and chronic pain that will make sense to someone who experiences fluctuations in pain intensity. I think I’m clear in my own mind between the two, but perhaps things are not as distinct as I’ve made them – or maybe I haven’t explained things well.

There are several ways that acute pain can be distinguished from chronic pain, none of them particularly satisfactory except, maybe, one.  We can think of the association between pain and tissue damage or threat of tissue damage.  In acute pain, tissue damage or the potential to damage tissue is often present – but not always.  Think of a typical “tension” headache.  It’s usually short term, but not associated with muscle damage.

We can consider duration – how long does this pain persist?  Acute pain is typically short-term, it does end at some point – sometimes well after the need for a “warning” alarm is necessary – but what about chronic hip osteoarthritis?

Some of the other factors I see used to distinguish acute pain from chronic include – quality of the sensation, how quickly the pain comes on, whether psychosocial factors are relevant, whether disability or illness behaviour is present, even the location or specificity of the pain can be used as an identifying factor.

We can also think of usefulness – acute pain is usually useful.  It tells we need to do something, take action to reduce the threat to our body’s integrity.  I think this is probably the most useful definition of the lot, even in the case of a “tension” headache – when it  might simply be an indication we need to have some time out, drink more water or get some new glasses.

Chronic pain has a bad rap.  There are many clinicians who consider that chronic pain is almost entirely influenced by psychosocial factors – therefore the person with pain needs to simply “get over it” and they’ll recover.  Then there are those who think chronic pain is simply pain that hasn’t had the “source” of the pain identified yet – find that source, burn it or cut it or otherwise remove it, and the pain will be gone.  And for some kinds of ongoing pain, like an osteoarthritic hip, that’s the case.

Over the years I’ve worked in chronic pain management, I think I can confidently say that chronic pain can be sharp, stabbing, dull, burning, deep, aching – all the same kinds of sensations that acute pain can be.  Its onset can be pretty rapid, but also insidious or gradualBoth acute and chronic pain are strongly influenced by psychosocial factors – things like attention, general alertness level, “threat value” or beliefs about what the pain means, attention from others, past learning – all of these things influence our experience of both acute and chronic pain, although it’s probably true to say that as pain persists, many of these psychosocial factors play an increasingly important role in the disability associated with pain.

There are other definitions of chronic pain.  One is duration – pain that persists beyond “normal healing time” (whatever this is).  Alternatively, pain that has been present for three to six months.  My problem with this definition is that it’s common for people to have pain around a fracture site for up to 12 months even when bony union is progressing normally.  Is this chronic pain?  What about instances where the pain is intermittent – migraine? Noncardiac chest pain? Abdominal pain?

So, what about chronic pain that fluctuates?  This seems to be the case more often than not.  It’s very very rare for me to hear someone say their chronic pain is at exactly the same intensity day in, day out.  When I do hear it, I like to spend some time exploring this experience in more detail.  Without fail, with gentle enquiry, fluctuations of pain intensity are there but may be subtle.

Why is recognising this so important?  Well, let me first put to bed any idea that I think people with chronic pain are immune to acute pain – that’s so not true.  What is arguable is whether fluctuations in pain, particularly when they’re the “same old, same old” pain, need to be managed using acute pain treatments.

And this is important because

  • so many acute pain treatments are passive,
  • take time away from living,
  • put the person getting the treatment at risk of yet another diagnosis or explanation,
  • reduce the opportunity to gain confidence with using self management strategies,
  • in the case of medication can put the person at risk of addiction or inappropriate use of this,
  • and, often unrecognised, can train the person to begin to fear (& then avoid) experiencing pain – leading to increased distress and continued treatment seeking

Am I advocating never using adjuntive intervention? See yesterday’s post in answer to that! But at the same time, I’d suggest that it’s pretty important to be aware of the risks.

So far, in answer to the question posed in my title, one of the best descriptions of the various types of pain and of the distinction between “normal” pain and “pathological” pain there is, Clifford Woolf’s paper is my choice.  Actually, the whole issue of this journal (which is – fabulously! – completely open access online!) could be required reading for anyone wanting to be informed about advances in our knowledge of pain.  I particularly love the examples he provides for each type of pain problem and how they arise.  That’s great stuff.

But even this set of wonderful papers doesn’t really explore some of the aspects of pain that don’t really get mentioned – disability and the effects of social, family, community attitudes and responses.  Yes, I know they’re messy to research.  They’re complex. They differ across countries, cities, villages and families.  But oh how powerful they are in our experience of pain.

Woolf, C. (2010). What is this thing called pain? Journal of Clinical Investigation, 120 (11), 3742-3744 DOI: 10.1172/JCI45178


  1. I really like this 😉 And I like the “usefullness” definition. I guess this is something that I learned for myself – certain pain cases (usually either with very rapidly growing intensity, or significant increases which persist for a long time) do mean “slow down/take a break/get some help, or worse things will happen”. And some pain is indeed “useless” – it pain may annoy me, but there is no need to attend to it in any way. In fact, this is how I think about it to myself. I make mistakes sometime, but generally I know which is which. My problems happen when I meet doctors which try to insist that _absolutely all_ my pain is a useless signal, which goes right against my experience. I think this post is very nice pointing fallacies on both sides – whether it is going for unnecessary treatments which take time and money, or rejecting all adjuvant therapy for someone with chronic pain.

    1. I think this non distinction leads to problems with research in that different definitions are used and research outcomes are often not eay to get a review article and if we used set definitions then we would get better evidence based treatment plans and have a better look at evaluation tools so i think it is too bad we don’t have accepted definitions

  2. Oh, this kind of a definition would be an impossibility for research – too subjective. For that matter, it is a challenge for practice, as well – how does the doctor really know that my perception of “useful” vs. “non-useful” is correct? It is much easier to just say, “many people are avoiding pain, so let us just assume that everyone is in that category and tell everyone not to pay attention to their pain”.

    I am very fortunate that I established a long-term relationship with my physical therapist where I can say “After I tried this, I had a serious flare-up and I don’t think this is sustainable” – in part because she also hears me say “My pain flared, but I recovered within a day, so I am fine continuing this”. But most of the doctors and physios that I tried didn’t want, or didn’t have the time for, understanding the complexity – one even told me, “I don’t want to hear about your pain flare-ups, because you will always have them”.

    I wish there were some external ways to measure pain and its impact, rather than relying on sorely personal reports, which by definition are very much impacted by beliefs, social factors and so on.

    1. That is the problem Mary – pain *is* subjective. Until you can look at me and tell me how much pain I am in (and vice versa), we can’t directly measure pain. All we have as correlates are pain behaviours, or what we do, say, how we respond etc to our own experience of pain. We also have whatever imaging we can to show changes to tissues – such as X-ray, MRI, CT, ultrasound – but these don’t show pain. We can look at histological changes to determine the “usual” or typical healing time for wounds, and we have various biomchemical changes that are associated with dysfunction such as ESR and CRP for inflammation – but none of these show pain. We can similarly use plasma levels for various medications – but these don’t show how much pain a person may be experiencing.
      The primary means for determining whether it’s safe to use a body part when pain persists are the changes that show up on radiological or MRI/CT scans, or the histological changes that occur with inflammation – and evidence is increasingly suggesting that it’s better than not to continue with movement as normal, or as close to normal as possible, because this helps the body recover.
      This will be why clinicians have said to you that talking about pain flare-ups is unhelpful – because pain can and does fluctuate wildly and it’s not associated with tissue damage, it’s pain. Coping with what seems like contradictory messages from your body is the real “work” of coping with chronic pain. Learning to settle the physiological changes that occur with the experience of pain, dealing with the thoughts and beliefs that an individual has learned all his or her life, along with the difficulties with sleep and mood and work etc – this is hard work! And there are seldom any “givens” or black and white rules. Hence, for me, the need to help people weigh up for themselves whether their choices are working for them.

      1. I am sorry, I think this reasoning has an underlying problem. We cannot measure pain directly and always pinpoint its causes *given the current medical technology*. And there is a large subjective component to pain. But this does not automatically mean that there are no physical components to it that can/should be addressed.

        Saying “it’s unhelpful to talk about flare-ups” shuts down two important components in the discussion. First, the issue of what is doable. You said it in comments somewhere earlier, that living with pain can cause values conflicts, like my wish to dance causes conflict with my desire to spend time with other people later, and this is unavoidable due to my condition. The reason for this is effectively flare-ups – the severity of them, and the other problems accompanying pain.

        More importantly, there is a question of “is it all the same pain”. My pain does fluctuate significantly even when I am stable. My “normal” is between 2 and 4 on a daily basis, with 5-7 during serious flare-ups, but those don’t go on for more than a week. Now, numbers don’t say much, but 4 is when my concentration starts being affected and I can get sleep problems, and 6-7 is when I find it very difficult to get up and moving, and will not be able to do my job properly. So I would say yes, it fluctuates wildly, and it does not help to focus on such fluctuation. But: a number of times (1-2 times a year on average) the pain will go up and stay in the 5-7 range for many weeks. My experience has been, no, it does not go down by itself, even if I do my best to stick with my normal activities (longest I tested was 6 months). It does go away with physio intervention. Every time it happened my physios were able to formulate a coherent hypothesis – different problem each time, but typically a mechanical problem affecting one of the nerves, with symptoms well described in literature. Then they could get the problem to resolve rapidly, with noticeable improvement within a couple of sessions. Again, not remove it completely – but return me to my “normal” state where I can manage by myself.

        I don’t know how “typical” that is, and of course it is difficult to include either in research or in clinical practice. But it is a bad plan to say “we can’t measure it, so it’s all subjective” – a better plan for research would be “we should continue looking for tests that will allow us separate subjective and objective components, and decide what and how to address for different people”.

      2. Pain is a biopsychosocial phenomenon. That means inevitably there are biophysical features to pain – although the focus for so long has been only on peripheral mechanisms to do with muscles, joints, bones, tendons and peripheral nerves that the central mechanisms from the spinal cord up have tended to be given far less attention. Of course, it’s true to say that we haven’t really had the means to study central mechanisms in vivo – and even now the way we study central mechanisms is not wonderful. Having said that, I think the evidence is pretty compelling to suggest that central mechanisms are involved even when peripheral nociception is present, and certainly when peripheral input is not evident.
        This blog is about self management – so I’m focusing on what people with pain can do for themselves when they have flare-ups. Part of that process is “sitting with” or accepting or being mindful pain flare-ups, and then recalibrating the self management plan to begin again with valued activities. I work with people to generate a “set-back” plan that looks at the risk factors for flare-ups, the kinds of situations where it might be difficult to continue with normal activities and where “extra” resources might be helpful. Set-backs can be many things, but often include flare-ups. The way I work with people I don’t ask them to record pain intensity because what gets recorded is what is thought about and monitored. Instead, we look at what is being done – the number of times the person uses coping strategies, the type of activities they do, the way the person has problem solved in a situation. This has the effect of moving from monitoring pain intensity to monitoring what the person wants to do, and the people I work with comment that this is both different from the approach some clinicians use, and that they find it helpful.
        I’m not suggesting that this is the only way to manage painful flare-ups, nor that all chronic pain is central sensitisation. I am suggesting that it’s more common for clinicians to focus on peripheral mechanisms because this is what is taught in most programmes (chronic pain often gets limited mention), and that it’s difficult if not impossible to determine whether the “issues are in the tissues” to quote David Butler/Lorimer Moseley, or whether it’s centrally mediated or even initiated. My approach for managing this is to help the person identify what they can do for themselves because, weighing up the costs and the benefits, often they’re fed up with having to visit health providers and with effective strategies they can manage without doing so.
        I hope I’ve given you my rationale and general approach to self management, and the reasons I’ve identified from the literature for taking the approach I do. I’m not trying to convince you, or anyone else, to use this approach – but I do want to put this information out there into the clinical mix, because it’s often drowned out by the dominance of a pain reduction/biomedical/peripheral mechanistic model.

  3. Oh, that all makes sense, including your perspective. I guess I was mostly surprised at one quote:

    “I’m not suggesting that this is the only way to manage painful flare-ups, nor that all chronic pain is central sensitisation. I am suggesting that it’s more common for clinicians to focus on peripheral mechanisms because this is what is taught in most programmes (chronic pain often gets limited mention)”

    My experience with the medical system has been exactly the opposite. Doctors and physios started going for “just stay active, self management is best, it’s mostly sensitisation, intervention is not going to help with chronic pain” as soon as I crossed the 6-month duration. Since it took me 12 months to get referred to a musculoskeletal specialist (as opposed to just physio), my first appointment was immediately focused on “there is no cure, physio should only be done for acute pain, it is not effective for chronic pain, what can you do to self-manage”. It was really difficult to find people willing to go beyond that, and I had to fight the system really hard to get anything else.

    Maybe it’s a different culture in the UK, but I certainly found that most of the doctors I met actually subscribe to the fairly extreme version of your approach, and not the medical treatment model. That explains my reactions most of the time, but yes, I recognize that if you write from the tradition where most people don’t know about those things, they would look completely different.

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