Complex regional pain syndrome: Facts on causes, diagnosis and therapy

Complex Regional Pain Syndrome (CRPS) is still a debated topic although the most recent advances in the knowledge of its pathophysiological mechanisms. This syndrome affects more than 200,000 people in the USA and more than 154,000 people in the European Union each year. Primum movens of CRPS pathophysiology is probably an inadequate response to a damage due to a severe post-traumatic inflammation. To date, the Budapest Criteria are the most used in diagnosis of this painful condition. Biochemical markers, including IgG serum autoanti-bodies against β2 adrenergic or M2-muscarinic and small non-coding RNAs, are promising instruments, still under investigation, that could be included in the diagnostic criteria. Bisphosphonates (BPs) are the most effective drugs in the early stage of CRPS, probably due to the interference with the inflammatory and nociceptive pathway and their pro-inflammatory mediators. In particular, the only BP approved for the treatment of CRPS type I is infusion of 100 mg neridronate given every third day four times over a period of 10 days, that demonstrated significant benefits in terms of pain relief and quality of life.