Objective: Complex regional pain syndromes (CRPS) involve neuropathic limb pain and localized circulatory abnormalities. The authors hypothesized that (1) pediatric CRPS patients exhibit systemic autonomic symptoms and orthostatic and/or cardiac sympatho-vagal dysregulation and (2) their orthostatic regulation differs from healthy controls and pediatric patients with postural orthostatic tachycardia syndrome (POTS).
Methods: CRPS children and adolescents (n=20) underwent a 6-week trial of physical therapy and cognitive-behavioral treatment. Measures included pain and function scores, regional and systemic autonomic symptom profiles, heart rate and blood pressure with tilt, heart rate variability indices, and baroreflex gain. Systemic autonomic symptoms were recorded in 55 healthy pediatric controls. Tilt responses in CRPS patients were compared with those of 21 POTS patients and 39 healthy controls.
Results: CRPS patients' regional autonomic symptoms, pain, and limb function improved over 6 weeks (P<0.01). At baseline CRPS patients reported more systemic autonomic symptoms than controls (P<0.05). Tilt table test showed orthostatic stability, but the mean heart rate increase with tilt was greater in CRPS patients than controls (P<0.001). POTS patients showed significant increases with tilt in mean heart rate and diastolic and systolic blood pressures compared with controls (P<0.001). There were significant increases in the mean systolic and diastolic blood pressures in POTS compared with CRPS patients but no difference in the mean heart rate between groups.
Discussion: CRPS patients reported multiple regional and systemic autonomic symptoms that improved during the study course, and they experienced minimal and transient tilt table-induced hemodynamic changes compared with POTS patients but relatively similar to controls.