Early Intervention Is Key for CRPS Treatment, Experts
Say
By Rose Fox
Pain Medicine News. 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."
August 2007 |
