The clinical characteristics of Complex Regional Pain Syndrome (CRPS) are defined by pain and various combinations of sensory disturbances, autonomic features, and sudomotor and trophic changes.... Show moreThe clinical characteristics of Complex Regional Pain Syndrome (CRPS) are defined by pain and various combinations of sensory disturbances, autonomic features, and sudomotor and trophic changes. Furthermore, patients with CRPS may suffer from movement disorders, of which dystonia is the most prevalent. Dystonia of CRPS can affect multiple extremities, is often resistant to treatment and seems to have a poor prognosis. Reliable information on the nature, chronology and clinical determinants of dystonia in CRPS patients is lacking but could provide better insight in the underlying pathophysiological mechanism. The results of our studies on clinical and neurophysiologic aspects of patients with multiple CRPS and MDs in CRPS provided data that suggest disturbances at multiple levels of the CNS. Maladaptive neural plasticity likely is an important mechanism underpinning the MDs that may occur in CRPS. The presence of disturbances at multiple levels of the central nervous system parallels recent hypotheses on the underlying mechanisms suggested for other types of dystonia. Finally, the study on intrathecal baclofen administration in patients with CRPS and dystonia showed marked improvement of dystonia and pain scores after one year. Show less
Chronic pain is a widespread condition in the general population. For this reason, chronic pain management has received increased attention in recent years, both in clinical practice and in... Show moreChronic pain is a widespread condition in the general population. For this reason, chronic pain management has received increased attention in recent years, both in clinical practice and in scientifi c research. This thesis describes a series of experiments which studied the effi cacy and safety of ketamine in subanesthetic doses. Both healthy volunteers and chronic pain patients were recruited for these studies. The specifi c chronic pain condition studied in these experiments was Complex Regional Pain Syndrome type 1, which is characterized by chronic pain affecting one or more extremities. It is very diffi cult to treat this condition with current pharmacotherapeutic interventions. However, one of the studies in this thesis showed that a continuous ketamine infusion, lasting for several days, can have a prolonged effect in reducing pain scores for up to several weeks (despite rapidly decreasing ketamine plasma concentrations after termination of the infusion). In addition, experiments in both healthy volunteers and patients were performed to study the pharmacokinetics and pharmacodynamics of ketamine in subanesthetic doses. Show less
