As physiotherapists we will come across and treat a variety of acute injuries and conditions. However, we will also be exposed to patients with persistent physical issues that present with chronic pain. Firstly, it is important to define and explain the concept of ‘chronic’ or ‘centralised’ pain. Chronic pain has been defined as persistent pain lasting longer than 3 months and occurring on at least 50% of days (Khadilkar et al., 2005) or as pain that persists long after all possible healing has occurred (Cheing & Hui-Chan, 1999).
Chronic pain can cause increased sensitivity to non-noxious stimuli (hyperalgesia) as well as noxious stimuli (allodynia) (Cheing & Hui-Chan, 1999). It is also possible for chronic pain sufferers to develop an assortment of other presenting symptoms including muscle spasm, decreased strength and range of motion (ROM); all of which can hinder activities of daily living (ADL’s). These areas have been described as important, attainable treatment goals to aim to improve when treating patients with chronic pain (Khadilkar, et al., 2005).
The mechanisms behind chronic pain have been studied as neurological and termed ‘centralized sensitization’. Figure 1 from Medscape (Porreca, 2011) shows a summary of the many processes involved in the centralisation of pain.
Figure 1.0: Mechanisms of central sensitization (Porreca, 2011)
Figure 1 mainly illustrates what is termed the ‘bottom-up’ mechanisms of centralisation of pain (Nijs et al., 2011) as it relates to the signal caused by an external stimuli travelling up to the CNS. Nijs, et al., 2011 also found neural activity in pain areas of the brain are persistently higher in patients with centralized pain, which may explain increased sensitivity to acute pain (Cheing & Hui-Chan, 1999). Changes in brain activity have been shown to affect the descending modulation of pain by the CNS (Nijs, et al., 2011), which affects the facilitation of pain and eventually leads to temporal summation or wind up.
All the processes believed to be involved in central sensitization of pain (after all repair has occurred) relate to neurological mechanisms. Therefore it seems fitting that electrical stimulation will affect this process as it targets nerve processing which we will be divulging in our next blog. We will be further investigating the many modalities of electrical stimulation and how this affects patients with chronic pain.
This is an impressive introduction to your topic. The writing style is mature and covers a lot of ground succinctly. Are you going to post the references in the final posting? CY
ReplyDeleteThanks for the feedback Cath. Our plan is to post all our references together in the final posting.
ReplyDelete