This is a chronic neurologic syndrome caused by overactivity of the sympathetic nervous system. It usually results from trauma but can also have an unknown cause. Typically an arm or leg is involved and it is caused by traumatic inflammation due to injury or maybe caused by over-activity of the immune system. This syndrome is painful, complicated, and frustrating.
CRPS type 1: Minor injury such as fall, sprain, fracture, burn, or tendon injury.
CRPS type 2: Causalgia has definitive identifiable major nerve injury. With both types, there is an injury which ends in a cycle of pain due to sympathetic nerve overactivity and does not follow normal pathway of healing.
Diagnosis: Patients have hyperalgesia and allodynia plus pain even to light touch usually with swelling. It is possible to have extreme pain even without touch. There are often temperature changes of the skin (over 1-degree Celsius) in comparison to the opposite limb. Tests used in diagnosis may include nerve conduction studies, thermography, bone scans, and x-rays. The most significant overriding feature is “out of proportion” pain than what would be expected for that particular injury.
Treatment outcome of CRPS is significantly better when the diagnosis and treatment are started early on.