Complex Regional Pain Syndrome, or Reflex Sympathetic Dystrophy (RSD), commonly occurs after injuries to the limb but can also develop after stroke, myocardial infarction and surgery.
The pain is termed causalgia, characterized by burning and prickly hypersensitivity. The acute stage is accompanied by swelling and reddening of the affected limb. But later as atrophy sets in, the limb becomes thin and frail along with muscles wasting and osteoporosis, rendering the affected limb painful and lifeless.
Sympathetic blocks are performed at the stellate ganglion for upper extremities and lumbar paravertebral ganglions for lower extremities. By diminishing the vicious sympathetic hyperactive feedback, these blocks along with physical therapy and medication help restore normal limb function. Early recognition and intervention are essential for good outcome.