Understanding the perception of pain is important in the treatment of many conditions.
When a tissue in the body is damaged, peripheral sensitization of nociceptors occurs as a protective mechanism by the body in order to prevent further use of a damaged structures (which if used, could further damage the tissue as well as surrounding tissues). This response is a considered a local phenomenon.
Central sensitization is more of a central nervous system phenomenon which encompasses altered sensory processing in the brain, malfunctioning of descending anti-nociceptive mechanisms, increased activity of pain facilitory pathways, temporal summation of second pain and long term potentiation of neuronal synapses. This process can enhance ones sensativity to different peripheral stimuli and can decrease ones tolerance to stimuli places on the senses and neuromusculoskeletal system.
Central sensitization is present in many chronic musculoskeletal disroders including chronic whiplash, low back pain, TMJ, fibromyalgia, etc. Many PTs often have difficulty recognizing and treating patients with conditions in which central sensitization is present. A recent article in Manual Therapy examined how to recognize the process of central sensitization in patients with musculoskeletal pain and found:
- Chronic whiplash, fibromyalgia, chronic fatigue syndrome and irritible bowel syndrome all include central sensitization as a characteristic of each respected disorder (It is also present in subgroups of low back pain, TMJ, myofascial pain syndrome, OA, RA and chronic headaches).
- Symptoms related to the presence of central sensitization include hypersensativity to bright light, touch, noise, mechanical pressure, pesticides, medication and temperature.
- If present, central sensitization is suggestive of general load intolerance to physical and emotional stressors
- If present, there is usually a generalized rather than a localized decrease in the patients pain pressure threshold (for example, there may be increased sensitivity in the lower extremities in a patient with whiplash—two segmentally unrelated sites).
- Increased neural tension as facilitated by the brachial plexus test or ULTT is also generally present in patients with central sensitization
Nijs J, Houdenhove BV, Oostendorp RAB. Recognition of central sensitization in patients with musculoskeletal pain: Application of pain neurophysiology in manual therapy practice. Manual Therapy 2010: 15;135-41.