How do we identify central sensitization?

How do we identify central sensitization (CS).. in the clinic?

The first important step is EXCLUDE neuropathic pain. Neuropathic pain characteristics include:

1. History of lesion or disease of the nervous system
2. Evidence from diagnostic investigations to reveal an abnormality of the nervous system
3. Pain/sensory dysfunction neuroanatomically logical
4. Often burning, shooting, and pricking. N.B: Neuropathic pain does not exclude the possibility of have CS

The second step is to determine if persistence is mainly due to CS or from peripheral nociceptive input.
There are many criteria:

1. DISPROPORTIONATE:
   Pain is disproportionate to the nature and extent of injury (e.g. in patients with OA, radiological findings show little to no association with pain severity. Furthermore, many studies show an association between OA and CS.
2. DIFFUSE:
   Diffuse pain (Mirror pain is not always due to bilateral disc herniation… I would argue extremely rare)
3. AFFECTS OTHER SENSES
   Hypersensitivity of senses unrelated to MSK system (Increased pain with weather, heat, cold, chemical substances, stress, TENS, etc…). It could potentially affect odors, smell, sound, and sensitivity to bright light. To assess this, therapists are encouraged to use the Central Sensitization Inventory (0/100). A score of 40 or more indicates possible sensitization.

N.B. 1 = CS may “dominate the clinical picture and modulate the transition to chronicity”. This is why it is crucial for clinicians to identify patients presenting with it…(different from chronicity!)

N.B. 2 = There is a difference between adaptive peripheral sensitization (following an acute injury, the CNS becomes sensitize to further protect the area) and maladaptive CS (that we need to identify).

Hope it helps you guys!

Reference:
Nijs – Applying Modern Pain Neuroscience in Clinical Practice: Criteria for the Classification of Central Sensitization Pain