CRPS is a chronic and progressive pain condition, characterized by severe pain, swelling and skin changes. It usually affects a limb and has been divided into two types based on the presence of a nerve lesion following an injury.
Type I, formerly known as reflex sympathetic dystrophy (RSD), Sudeck's atrophy or algodystrophy, does not have demonstrable nerve lesions.
Type II, formerly known as causalgia, has evidence of obvious nerve damage.
The cause of CRPS is not fully understood but research suggests that central nervous system sensitization is involved in the induction and maintenance of CRPS. The condition can strike at any age, but the mean age at diagnosis is 42. It has been diagnosed in children as young as 2 years old and affects both men and women. The diagnosis is made by exclusion of other causes and a history of severe often burning pain, muscle spasm, joint stiffness, swelling, temperature and colour changes; and findings of sensory abnormalities (allodynia and hyperalgesia) and vascular changes on examination.
Treatment is multidisciplinary with specialist medication often in combination; topical and intravenous local anaesthetics for nerve pain; physical therapies; sympathetic nerve injection treatments; neuromodulation treatment and psychology when necessary. The prognosis is improved by early diagnosis and intervention. If treatment is delayed, the condition may deteriorate. Surgery may exacerbate symptoms and appropriate preventative treatments can limit such episodes.