[Complex regional pain syndromes: new aspects on pathophysiology and therapy].

Complex-regional pain syndromes (CRPS), formerly known as Sudeck's dystrophy and causalgia, belong to the neuropathic pain syndromes. CRPS may develop following fractures, limb trauma or lesions of the peripheral or central (CNS) nervous system. Occasionally, CRPS may also develop spontaneously. The clinical picture comprises a characteristic clinical triade of symptoms including autonomic (disturbances of skin temperature, colour, presence of sweating abnormalities), sensory (pain and hyperalgesia) and motor (paresis, tremor, dystonia) disturbances. Diagnosis is mainly based on clinical signs. However, additional laboratory, neurophysiological and radiological examinations may help to corroborate correct diagnosis. Several pathophysiological concepts have been proposed to explain the complex symptoms of CRPS: 1, facilitated neurogenic inflammation; 2, pathological sympatho-afferent coupling; 3, neuroplastic changes within the CNS. Furthermore, there is accumulating evidence that genetic factors may predispose for CRPS. Therapy is based on a multidisciplinary approach. Non-pharmacological approaches include physiotherapy and occupational therapy. Pharmacotherapy is based on individual symptoms and includes steroids, free radical scavengers, treatment of neuropathic pain, and finally agents interfering with bone metabolism (calcitonin, biphosphonates). Sympathetic blocks are useful for the treatment of sympathetically maintained pain. Invasive therapeutic concepts include implantation of spinal cord stimulators. This review covers new aspects of pathophysiology and therapy of CRPS.