Early Intervention Is Key for CRPS Treatment, Experts Say

Rose Fox

PAIN MEDICINE NEWS: ISSUE: AUGUST, 2007 | VOLUME: 5

NEW YORK-Complex regional pain syndrome (CRPS) is frequently misunderstood, misdiagnosed and mistreated.

A panel of experts at the annual American Conference on Pain Medicine explained what is known about the origins and treatment of this condition.

"If there's one take-home message that you get out of this lecture," said Joshua P. Prager, MD, MS, "it's that [CRPS] is not a disease of the extremity. This is a disease of the nervous system that manifests itself in the extremity. I can't overemphasize that. The number of patients who come to me because someone has tried to amputate a part of the body to make this go away is incredible to me. You can't cut it away and you can't kill nerves to make it go away because it is a central nervous system disorder," said Dr. Prager, director of the Center for the Rehabilitation of Pain Syndromes at the University of California, Los Angeles.

Citing the seminal work of John Bonica, MD, Dr. Prager described the original "three stages" concept of CRPS:

 1) the hyperemic phase, in which the affected extremity is tender and swollen;

2) the dystrophic phase, in which there is some atrophy and the extremity is cold to the touch; and

 3) the atrophic phase, which has contracture, marked atrophy and abnormal growth of hair and nails. Daniel S. Bennett, MD, pointed out that CRPS is now considered to be a continuum rather than a staged disease.

 "The motor component actually can occur prior to the patient complaining of pain, and can then progress to a full dystonic state," said Dr. Bennett, medical director, Interventional Spine/Pain Management, Integrative Treatment Centers, Denver. "I've had a few patients like that, who came in with neuropathic pain and dystonia. Or they will come in with an arm or a leg that is so atrophied, with contraction deformities.

This can be very, very rapid; you can see it as early as five weeks, or five years." Dr. Prager noted that although CRPS often stems from trauma, the two entities should be carefully differentiated. "There are several other local pathologies that can cause this disease: peripheral neuropathies, inflammatory and infectious disorders and vascular disorders," he said. "If you see motor changes, trophic changes and sweating, you don't get that with trauma but you do with CRPS.

Women [develop CRPS] more than men; mean age at evaluation is 42 years; it usually starts unilateral in distal extremity. Causes include sprains and strains, post-surgical, fracture, contusion, but almost a quarter of cases have no known etiology."

The goal of treatment is not complete resolution of pain but to give "the patients their lives back and to give them function once again," Dr. Prager said. "If we do a sympathetic block or give analgesics, it is to allow the patient to do physical therapy. The basic concept of this treatment protocol is physical therapy with pain management and psychological support as adjuvants. The important thing is to intervene early."

Referencing the CRPS treatment paradigm proposed by Bennett and Cameron, Dr. Bennett said, "Unfortunately, with medications, about 34% to 36% of patients respond and of those, 50% are partial responders. We don't have much in the way of medication that is going to be very effective, because we don't have a great medication to restore blood flow. If you don't have good results in the first six months, then we recommend moving on to electrical stimulation, which is everything from the base of the brain down to the tailbone: nerve root, spinal cord and peripheral nerve."

The Role of Spinal Cord Stimulation "All of us who practice in pain medicine and see patients with CRPS have found spinal cord stimulation [SCS] to be an effective therapy for some of our patients," said Peter S. Staats, MD, adjunct associate professor of anesthesiology and critical care at Johns Hopkins University, Baltimore. SCS, he said, "can stimulate the production of the inhibitory neurotransmitters GABA [g-aminobutyric acid], glycene and serotonin. It is also thought to turn off beta- hyperexcitability. It probably works in a variety of different ways." He added, "One of the advantages of SCS is that it's a reversible, nondestructive therapy. You can test the therapy before you put it in, as opposed to ablative therapies that are nonreversible."

Dr. Staats noted that most of the literature on SCS is already outdated. "Today, it is very common for physicians to put in 16 contacts, which give 64 million different combinations of electrical stimulation that we can use," he said. It is now known that frequency of electric stimulation, amplitude, number of contact and spacing of contacts can determine treatment outcome, he said. "As we improve our technology and our ability to use electricity, it is likely that we will be able to stimulate and capture some nociceptive pains, but for right now, this is largely used for neuropathic pain. I consider CRPS one type of neuropathic pain and I think most people would agree with me on that."