DIAGNOSIS AND MANAGEMENT OF COMPLEX REGIONAL PAIN SYNDROME

Ralf Baron
Neurological Clinic, University of Kiel, Germany

Complex regional pain syndromes (CRPS, reflex sympathetic dystrophy, causalgia) are painful disorders that develop after trauma affecting a limb with (type I) or without (type II) nerve injury. Clinical features are pain (spontaneous, hyperalgesia), impairment of motor function, swelling and autonomic abnormalities (changes in sweating and blood flow). All symptoms show a distal generalized distribution not confined to a territory of a peripheral nerve or root. In a subgroup of patients the symptoms can be relieved by sympathetic blockade (sympathetically-maintained pain).

A central unilateral inhibition of cutaneous sympathetic vasoconstrictor neurons leads to a warmer affected limb in the acute stage. Secondary changes in the neurovascular transmission induce vasoconstriction and cold skin in chronic CRPS. The maximal skin temperature difference between the affected and unaffected extremity that occurs during the thermoregulatory cycle can be used as a diagnostic tool.

Kinematic analysis of target reaching as well as grip force analysis demonstrates a pathological sensorimotor integration located in the parietal cortex that may induce an abnormal central programming and processing of motor tasks.

No evidence-based treatment regimens for CRPS are available. Treatment of the individual patient is empiric using mechanism-based techniques effective in other neuropathic conditions. In acute CRPS, many patients report a positive effect of sympathetic blockade, but fewer patients with chronic CRPS experience relief. Treatment should be immediate and, most importantly, directed toward restoration of full function of the extremity. This objective is best attained in a comprehensive interdisciplinary setting with particular emphasis on pain management and functional restoration.

Time of Presentation
The Michael Cousins Foundation lecture
Saturday 1 May 2004 - 0830-1000