I see a number of cases that feature some of the signs and symptoms of CRPS but would not be actually diagnosed as CRPS according to the Budapest criteria. For example, tendinopathy, neuropathies, post-surgery and following a nerve injury. The latter you may say could underpin CRPS II. There has always been difficulty suggesting that CRPS I is devoid of a nerve injury as of course nerves are ‘soft tissue’ and can easily be damaged during an injury. Of course when a nerve is injured neuropathic pain can be a consequence concurrent with the nociceptive pain.
Immobilisation can lead to similar symptoms including pain, altered movement, atrophy and vasomotor changes. One must consider the fact that for tissues to be healthy they require movement. Change in use of a body part will have a number of consequences including actual tissue change alongside issues of movement. Movement-based problems will be as a result of the altered tissue properties, cortical change and also a willingness to move. Fear avoidance, catastrophising and a belief that movement that hurts is a sign that damage is being done. This scenario can be played out in a number of conditions such as Achilles tendinopathy, tennis elbow, RSI and others.
Neuropathic pain is ‘pain arising as a direct consequence of a lesion or disease affecting the somatosensory system’ NeuPSIG
Neuropathic pain measures are a useful way of determining whether there is a neuropathic component. Commonly used are the s-LANSS and painDETECT – shown below – alongside a thorough assessment. A recent paper discusses the NeuPSIG assessment guidelines.
When neuropathic pain is found to be part of the presentation, this can guide treatment including medication and therapy. The former needs to be attended to with a plan that is fully understood by the patient: how the medication works, how to use it and how to gradually reduce the dosage. The latter includes techniques such as graded motor imagery, 2-point discrimination and desensitisation techniques at a peripheral and central level.