Clinical Q & A:
Can there be too many sympathetic nerve blocks for the treatment of CPRS?
By William E. Ackerman, III, MD
Yes and no. Not all CRPS patients respond to this therapy. If patients get transient relief, allowing them to participate in physical therapy or not have to increase their medications, sympathetic nerve blocks are indicated. If no relief is noted after two blocks, then why repeat them? The results will not be favorable. Sympathetic blocks must be performed early in this disease to be effective. At that time, 2 to 3 blocks are usually effective.
The longer the duration from the onset of CRPS until the first injection, the worse the results. For example, a patient with CRPS for 12 months will have poor results with a sympathetic block. However, if a patient receives an injection within the first 2.5 to 3 months, the results should be good. This is why an accurate diagnosis of CRPS must be made in a timely fashion. Failure to do so may condemn a patient to life-long severe pain.
A sympathetic nerve blockade, however, is not a totally benign procedure, with side effects that include elevated blood sugars, rash, itching, weight gain, soreness at the injection site, bleeding, seizures, and death. Blockades are also more efficacious with decreased vasomotor activity, but become less effective with increased vasoconstriction. Therefore, the effectiveness of a sympathetic nerve blockade is based on the duration of the symptoms and blood perfusion in the affected area.
RSDSA Review. Winter 2008.