Complex Regional Pain Syndrome (Reflex Sympathetic Dystrophy)
A chronic pain disorder frequently affecting a limb, Complex Regional Pain Syndrome (CRPS) has two subtypes, CRPS-1 and CRPS-2, which present with similar symptoms. In both types of CRPS patients experience extreme pain, often to non-painful stimuli, diminished functionality, swelling, and alterations in blood flow.1 Dysfunction in the sympathetic nervous system, part of the autonomic nervous system, which works to control many involuntary actions in the body, including blood flow, is found in many, but not all cases, of CRPS.
CRPS-1, sometimes known as Reflex Sympathetic Dystrophy, usually arises after injury or trauma with no direct known peripheral nerve involvement; CRPS-2, or Causalgia, is less common than type I and occurs after direct nerve injury. The initial injury leading to CRPS can be mild or severe, but precedes widespread, long term, extreme pain in the form of burning sensations, pins-and-needles, or squeezing pressure.1 The precise cause of pain in CRPS-1 is unclear, but it is believed that damage or abnormalities in the peripheral nerves leads to heightened pain sensations in response to a stimulus that would normally not cause, or would only cause very mild, pain. Additionally, nerve alteration can elicit abnormal function in the spinal cord and brain.1 This same damage can lead to misfiring nerves, which control circulation in the affected limb, leading to changes in skin temperature, texture or color. Occasionally, CRPS also causes decreased motion or abnormal movements or tremors in the affected limb.
Because of its complex etiology and potential differential diagnoses, it is important to be evaluated by a pain physician to find the appropriate combination of therapies for treating CRPS. Rehabilitative therapy and medication are often successful in treating CRPS. Sympathetic nerve blocks, either stellate ganglion or lumbar blocks, can be extremely effective and are the first choice interventional pain management treatment of CRPS.3 Stellate ganglion blocks are commonly performed for CRPS in the upper extremities; studies show 90% of patients experience pain relief during treatments, with 73% experiencing marked long-term alleviation of pain.3 For CRPS in lower extremities, lumbar sympathetic blocks are employed with 45% of patients experiencing complete elimination of pain and 41% feeling partial pain relief.3 Additional interventional pain techniques employed at the Urban Pain Institute for treatment of CRPS may include spinal cord stimulators, physical therapy and neuropathic pain medication.
References:
1 Gay, A., Béréni, N. & Legré, R. Type I complex regional pain syndrome. Chirurgie de la Main 32, 269280 (2013).
2 National Institute of Neurological Disorders and Stroke. Complex Regional Pain Syndrome Fact Sheet. http://www.ninds.nih.gov/disorders/reflex_sympathetic_dystrophy/detail_reflex_sympathetic_dystrophy.htm. Accessed July 24, 2014
3 Eijs, F. et al. 16. Complex Regional Pain Syndrome. Pain Practice 11, 7087 (2011)
