Cold Hyperalgesia Testing

I have often read in the literature the view that Cold Hyperalgesia is suggestive of more “severe” pain states and hence poorer prognosis. For example:

• Van Oosterwijck et al (2013) reported in their Systematic literature review on the evidence for central sensitisation in chronic whiplash that:
  • The outcome of the processes involved in central sensitization is an increased responsiveness to a variety of stimuli including mechanical pressure, chemical substances, cold temperature, heat temperature and electrical stimuli.
• Goldsmith et al (2012) conducted a systematic review investigating cold hyperalgesia as a prognostic factor in whiplash associated disorders.
  • There is moderate evidence supporting cold hyperalgesia as a prognostic factor for long-term pain and disability outcome in Whiplash Associated Disorders.
• Woolf (2011) suggests that Cold Hyperalgesia is suggestive of central hyper excitability/sensitisation.
• Haanpaa et al (2011), in their guidelines for neuropathic pain assessment:
  • Studies have shown that sensory examination (i.e., pinprick, heat, cold and tactile stimuli) in the painful area could discriminate patients with neuropathic pain from those without neuropathic pain.
• Kaya et al (2013) in a Systematic Literature Review on Central Sensitisation in Urogynecological Chronic Pelvic Pain report that:
  • Central Sensitisation entails much more than generalized hypersensitivity to pain: It is characterized by an increased responsiveness to a variety of stimuli including mechanical pressure, chemical substances, cold, heat, electrical stimuli, stress, emotions, and mental load. 

So this was all well and good. The issue I had being I could never find how I could go about somewhat confidently assessing cold hyperalgesia in the clinic unless I purchased some expensive equipment! I did realise that I could probably just grab an ice block or icepack from the freezer and pop it on the patients area of pain and see the response. But what response was I looking for e.g. how much pain? Did I need to test other areas?

Pleasingly I recently found a study by Maxwell and Sterling (2013) that helped to answer some of my questions. The study took 63 participants with chronic Whiplash Associated Disorder (WAD) (grade II and III) and tested them for cold hyperalgesia at the cervical spine with both laboratory testing equipment and with 10 seconds of ice application. The patients reported pain intensity on an 11 step numerical rating scale. The authors then compared the ability for 1o seconds of ice to discriminate between cold hyperalgesic and non-cold hyperalgesic sites vs the laboratory equipment. Final results concluded that:

A pain intensity rating of greater than 5 gave a positive likelihood ratio of 8.44 suggesting that, if this value is reported, clinicians could be suspicious of the presence of cold hyperalgesia.

So I plan to begin assessing cold hyperalgesia more regularly in the clinic using this method. Granted more studies need to be done to further validate this clinical test, but I think this is a good starting point. I personally think that we can use cold hyperalgesia testing to compliment our other testing that we might routinely use to assess for neuropathic pain/central sensitisation. In my case I often use:

• Brushing of cotton wool or a tissue for Allodynia (local and widespread).
• Using a toothpick or end of a paperclip for sharp hyperalgesia (local and widespread).
• Neuropathic pain questionnaires such as the LANSS scale, PainDETECT and DN4.

Interested to hear other peoples thoughts.

Thanks for reading.

References:

Goldsmith R, Wright C, Bell SF, Rushton A. Cold hyperalgesia as a prognostic factor in whiplash associated disorders: a systematic review. Man Ther. 2012 Oct;17(5):402-10. doi: 10.1016/j.math.2012.02.014. Epub 2012 Mar 29.

Haanpää M, Attal N, Backonja M, Baron R, Bennett M, Bouhassira D, Cruccu G, Hansson P, Haythornthwaite JA, Iannetti GD, Jensen TS, Kauppila T, Nurmikko TJ, Rice AS, Rowbotham M, Serra J, Sommer C, Smith BH, Treede RD. NeuPSIG guidelines on neuropathic pain assessment. Pain. 2011 Jan;152(1):14-27. doi: 10.1016/j.pain.2010.07.031. Epub 2010 Sep 19.

Van Oosterwijck J1, Nijs J, Meeus M, Paul L. Evidence for central sensitization in chronic whiplash: a systematic literature review. Eur J Pain. 2013 Mar;17(3):299-312. doi: 10.1002/j.1532-2149.2012.00193.x. Epub 2012 Sep 25.

Woolf CJ. Central sensitization: implications for the diagnosis and treatment of pain.Pain. 2011 Mar;152(3 Suppl):S2-15. doi: 10.1016/j.pain.2010.09.030. Epub 2010 Oct 18.