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CRPS Member resources


What causes CRPS?

The most common triggers are fractures, sprains/strains, soft tissue injury (such as burns, cuts, or bruises), limb immobilisation (such as being in a cast), surgery, or even minor medical procedures such as needle stick. 

CRPS represents an abnormal body response that magnifies the effects of the injury.  

Peripheral nerve abnormalities found in individuals with CRPS usually involve the small unmyelinated and thinly myelinated sensory nerve fibres (axons) that carry pain messages and signals to blood vessels. (Myelin is a mixture of proteins and fat-like substances that surround and insulate some nerve fibres.) Because small fibres in the nerves communicate with blood vessels, injuries to the fibres may trigger the many different symptoms of CRPS. Molecules secreted from the ends of hyperactive small nerve fibres are thought to contribute to inflammation and blood vessel abnormalities.  


These peripheral nerve abnormalities trigger abnormal neurological function in the spinal cord and brain.

Blood vessels in the affected limb may dilate (open wider) or leak fluid into the surrounding tissue, causing red, swollen skin.  The dilation and constriction of small blood vessels is controlled by small nerve fibre axons as well as chemical messengers in the blood.  


The underlying muscles and deeper tissues can become starved of oxygen and nutrients, which causes muscle and joint pain as well as damage.  The blood vessels may over-constrict (clamp down), causing old, white, or bluish skin.

CRPS also affects the immune system. High levels of inflammatory chemicals (cytokines) have been found in the tissues of people with CRPS.  These contribute to the redness, swelling, and warmth reported by many patients. CRPS is more common in individuals with other inflammatory and autoimmune conditions such as asthma.

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