Chronic pain as a condition
Until recently, pain was always considered a symptom of an underlying acute injury or illness. Today, we are beginning to understand that changes in the nervous system resulting from chronic pain can become self-sustaining. In these situations, pain becomes a disease in itself. For this reason, treating chronic pain can become the primary therapy, as opposed to treating pain as a symptom of some other illness such as cancer.
Researchers have described the plastic or adaptable nature of the body and how it can be moulded by pain to make pain persist or to make stimuli that are less painful cause pain. Imagine an alarm system that is continually reset to be more sensitive. First of all, it is triggered by a large movement such as a cat pouncing, then by a smaller movement such as a light breeze, and finally by little or nothing at all. Soon, the system has developed a hypersensitivity and goes off continually with only itself as the cause.
One thing that is not known is whether this hypersensitivity can be reversed once it has become established. In other words, once hypersensitivity to pain has been created within a child’s body, we do not yet know how this effect can be undone or minimized. In the meantime, suppressing the sensitivity rather than eliminating it is the focus of treatment.
The wide acceptance that pain can become a disease if not treated has led to an increase in effort and resources devoted to pain assessment and management. For example, many major centres now have dedicated acute and chronic pain teams and clinics. Their aim is to provide support for children and families with pain independent of its underlying cause. Even in cases where pain does not become a disease, for example the acute pain following surgery, we know that people who have their pain treated effectively, and as soon as possible, heal faster after any illness.
Validation of existing non-drug treatments continues, especially with respect to those interventions that are psychological, such as distraction and relaxation; physical, such as using heat, ice, or exercise; or for babies, behavioural, such as holding, skin-to-skin contact, or pacifiers. At the same time, the next generation of pain experts are moving forward to improve established pain control techniques, to find novel ways of combining existing techniques, and to develop new ones.
Imaging techniques for pain assessment
Recent advances in imaging techniques have shown us that activity in a number of areas distributed around the brain is highly correlated with the self-reporting of pain. It is conceivable that in the future, imaging techniques will be used to assist in the diagnosis of pain and the evaluation of the effectiveness of pain treatments. It is thought that this procedure would be similar to the way imaging techniques are now used for epilepsy or the way in which magnetic resonance imaging ( MRI) is used to assess brain tumours. The hope is that improved imaging will reduce the reliance on self-reporting of pain, help to distinguish between different types of pain, and be useful in evaluating the effectiveness of different treatments. This knowledge may lead to more effective individualised care for children with pain problems.
New assessment techniques
Because much of pain assessment involving children relies on the verbal reports from the child himself, finding new more objective assessment methods for infants and children who cannot self-report remains a challenge. There is no ideal measurement tool for chronic and acute pain in babies and young children. Ongoing research is directed at developing a comprehensive measure that will work across all infant age groups in different situations. This measure will need to include a combination of physiologic indicators (such as heart rate), behavioural indicators (such as facial expression), and contextual indicators (such as whether the baby is asleep or awake). Other measures being investigated are those that will work best specifically for newborn infants, older babies, and toddlers.
We are also beginning to consider how to assess pain that persists over longer periods of time in babies. Finally, researchers are just beginning to look at how to assess pain in babies who are born at risk for neurological impairments, as these babies typically have more painful procedures performed on them and receive less pain-relief medication.
While there are numerous measures to assess acute pain in school-age and older children, there is no single ideal measure. Research is underway to compare different types of pain scales to determine which ones are the most reliable and valid for use in this age group and which ones are most feasible and useful for clinicians caring for children in pain. For children with chronic pain, there are only a handful of measures available to assess the impact of their pain. These measures are generally problematic because they do not allow for assessment of pain in the child’s everyday environments, such as the home and school settings. Additionally, these measures rely on the child recalling his pain experiences spread over weeks or months. One potential solution to this problem is the use of electronic pain diaries. These diaries have the potential to track changes in chronic pain and its impact on aspects of the child’s quality of life. Research is being conducted to develop and test electronic pain diaries for children with arthritis and other chronic pain conditions.