Medicine continues to evolve. What we believed to be true yesterday, is no longer true today. For example, a few decades ago, low back pain would have been investigated with a plain film x-ray of the lumbar spine. It shows the bone structures, but only the space where the intervertebral discs are positioned. If the space was the correct height, this may well have been passed as normal. An MRI scan shows the bones, muscles, tendons, ligaments, the lining of the small facet joints and the structure of the discs. Hence we have a greater ability to try and correlate pain with structural damage, that would have been impossible before. Therefore, decades ago we would not have had a clear diagnosis for the pain, but today it is more likely that we do.
I am very concerned about the concept of not utilising all modalities of pain relief, simply because there is no firm diagnosis. The MRI example is on-going: Who knows what more sophisticated investigations may be available in the future, to help understand a patient’s pain state. What may be ‘normal’ by MRI today may not be normal in the future. Is it reasonable to wait a few decades for new technology whilst patients suffer?
As yet we do not have a ‘pain test’. We have x-rays, CT and MRI scans (which are but snapshots) and blood tests, but no actual investigation that demonstrates and diagnoses pain. Indeed, even the current gold standard MRI is open to interpretation. An MRI that shows many structural changes, the inevitable wear and tear of a busy life, may yet belong to somebody with little or no pain. Conversely, a small, subtle structural change may cause significant pain and disability. Why this should be is not understood. It is all too easy to start unhelpful discussions about ‘pain thresholds’ and ‘psychological issues’, implying failure to cope, when the patient’s suffering does not conveniently fit a treatment algorithm.
July 16 2020: The International Association for the Study of Pain (IASP), revised the definition of Pain:
‘An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.’
This definition covers both the physical and the psychological pain elements. The two are always present to a greater or lesser extent. I would find it strange for a patient suffering with intrusive untreated physical pain not to feel, miserable, frustrated, tired or indeed angry. Likewise if one is distressed for whatever reason; relationships, bereavement, financial worries and not sleeping, then surely it is not surprising to find it more difficult to cope with physical pain? After 30 years of dealing with patients who have pain, I still find it hard to work out where the balance lies in any particular individual.
IASP qualifies the definition with various additional statements including this one:
‘Pain and nociception are different phenomena. Pain cannot be inferred solely from activity in sensory neurons’.
The underlined section is crucial. This means that the ‘pain experience’ may (or may not) occur with or without pain fibres sending messages to the brain. This demonstrates the complexities of this common problem we call PAIN, despite our scientific advances, still so poorly understood and the broad range of medications that may usefully reduce pain.