Complex Regional Pain Syndrome: Anatomy of a Controversy

AuthorSamuel D. Hodge, Jr./Jack E. Hubbard
ProfessionSkilled litigator, is chair of the department of legal studies at Temple University/Professor of Neurology at the University of Minnesota
Complex Regional
Pain Syndrome:
Anatomy of a
The greatest evil
is physical pain.
St. Augustine
(354–430 AD)
If hell were a medical
condition, it would
look like RSD.
Q. What do a blood draw, a rear-end collision, a gunshot wound, carpal tunnel syn-
drome, and a sprained ankle have in common?
A. They are all ways of developing complex regional pain syndrome.
Complex regional pain syndrome (CRPS), a painful condition previously known as reflex
sympathetic dystrophy (RSD), has been described by the court as an uncommon, chronic
condition that usually affects the arm or leg.1 The sufferer may experience intense burn-
ing or aching pain along with skin discoloration, swelling, abnormal sweating, altered
temperature, and hypersensitivity in the affected portions of the body. The nature of
the condition is most puzzling, and the cause is still not clearly understood.2 In fact, the
condition remains clinically challenging both in terms of accurate diagnosis and effective
treatment.3 This point led one speaker at a conference on pain sponsored by Harvard
Medical School in June 2009 to opine that CRPS is the “most controversial and least
understood of all chronic pain problems.”4
Although CRPS usually affects an arm or leg, there are reports of this condition occur-
ring in other parts of the body such as the face5 and penis.6 The importance of the spine in
this condition is twofold. First, injury to the nerve roots from the spinal cord, such as from
a herniated disk, can precipitate the development of CRPS in the corresponding extrem-
ity. Second, the symptoms of CRPS may be mistaken for that of a spinal nerve injury.
This chapter examines CRPS from two different perspectives. The first part provides
a medical overview of CRPS with a brief historical review, a detailed examination of the
diagnostic criteria, an explanation of the current theory of causation, and a discussion of
available treatments. The second section analyzes how the courts have viewed this disor-
der in a claim or benefits setting, a very diverse topic with varied results.
Seen two to four times as often in female patients as in male patients, CRPS occurs in
approximately 26.2 cases per 100,000 persons each year.7 Others report an incidence of
5.46 new cases of CRPS type I per 100,000 annually.8 This disorder does occur in chil-
dren but is rare before six years of age, usually starting in the 10-to-12-year-old range and
590 CHAPTER 12
continuing into adolescence.9 The legs are six to eight times as likely as the arms to be
involved, and girls are affected six times more often than boys.10 Few physicians question
the legitimacy of this diagnosis, although some physicians who are not pain specialists
reportedly still consider CRPS a “psychosomatic illness.”11 Understanding this disorder
and the criteria used for its diagnosis has changed over the past few years, creating much
confusion and controversy in both medical and legal circles.
Medical Considerations
From a historical context, the issue of severe, unrelenting pain caused by trauma was
described in detail in 1872 by Silas Weir Mitchell.12 A Union Army physician during the
American Civil War, Dr. Mitchell reported the occurrence of disabling pain in the limbs
of soldiers due to bullet or shrapnel wounds. Most of these cases resulted from large,
low-velocity projectiles, also known as minié balls, utilized by the Confederate Army;
Mitchell termed this disorder causalgia.13 Over the subsequent years, a number of other
phrases such as Sudeck’s atrophy, posttraumatic dystrophy, chronic traumatic edema,
reflex neurovascular dystrophy, algodystrophy, peripheral trophoneurosis, and idiopathic
neurodystrophic disorder have been applied to identify this malady.14
In 1946, James A. Evans coined the phrase reflex sympathetic dystrophy (RSD) in an effort
to describe the problem based on a theory of its pathophysiology, concluding that the sym-
pathetic nervous system is the key to this condition.15 The term RSD stuck as a mechanistic
description, implying that the malady resulted from a reflex arc of abnormal firings by the
sympathetic nervous system, causing disabling pain and loss of function to an extremity.
With further research and experience with RSD, however, a growing discomfort with
this proposed mechanism developed among clinicians and research physicians,16 resulting
in a reevaluation of the terminology. In 1994, a consensus workshop of investigators and
other experts in the field coined the term complex regional pain syndrome (CRPS).17 The
reason for this change was descriptive and not to imply any pathophysiologic basis for
the disorder.18 Complex regional pain syndrome was further subdivided into two types:
CRPS I and CRPS II. The former term was to replace RSD; CRPS II was to replace cau-
salgia, specific for resulting CRPS due to nerve injury.19 This new terminology was codi-
fied by the International Association for the Study of Pain (IASP).20 An additional subtype
CRPS-NOS (not otherwise specified) was added recently for those clinical situations that
partially meet CRPS criteria and are not better explained by any other condition.21
The medical community, however, has been slow to accept this new nomenclature,
and subsequent validation studies using the new CRPS diagnostic criteria reveal that the
disorder is being overdiagnosed.22 In addition, pressures from nonmedical groups, such
as personal injury lawyers, are calling for a new reevaluation:
[C]ertain influential groups have resisted the change (e.g., personal injury lawyers,
who may benefit by a “looser” criteria, and some ill informed patient advocacy organi-
zations that fear a “tighter” criteria may cause many previously diagnosed patients to
be thrown into diagnostic limbo . . . ). As a consequence, the full benefits of the com-
mon consensus-defined IASP criteria have not been completely realized.23
In response to these concerns, a workshop was held in Budapest in 2003 to reexam-
ine this disorder. The attendees, medical experts in the field of CRPS, published their
consensus findings in 200524 and submitted them to the IASP for approval. The IASP
taxonomy committee and executive board have endorsed and codified the Budapest crite-
ria.25 However, the only publication of the codification had been on the IASP’s website.26
Recently, the Committee for Classification of Chronic Pain of the IASP has accepted,
codified, and published the Budapest criteria for both clinical and research use.27 These
proposed diagnostic criteria for CRPS, listed in Table 2, are to replace the previously used
ones, shown in Table 1. The main difference between the two sets of diagnostic criteria
is the additional requirement that at the time of evaluation, there must be objective evi-
dence of abnormalities in the painful area such as swelling, sweating and/or temperature
changes, motor dysfunction, and exquisite hypersensitivity.
CRPS Diagnosis: Clinical Criteria
The basic diagnostic problem of this condition—severe, unrelenting pain that is out of
proportion to the inciting injury—is significantly complicated by the subjective nature
of the pain and the lack of a clear objective basis of the problem. Added to this mix is the
fact that there is no diagnostic test specific for CRPS. In a medical setting, these issues
create considerable debate over the accuracy of the diagnosis and appropriate treatment.
In a compensation setting, subjective pain that is out of proportion to the injury is a recipe
for unrelenting controversy and protracted litigation. Physicians can detail the symptoms
associated with patients with CRPS and make some comments as to the likelihood that
the condition exists based on the symptoms a patient exhibits. However, the scientific
community does not know precisely the pathologic process at work.28
The correct diagnosis of a medical problem is the cornerstone for successful care and
treatment of any patient. This point is especially important when the patient is seeking
compensation based on that diagnosis. Further, researchers investigating the disorder
need assurance that their subjects have the same medical problem as those patients who
are being seen in doctors’ offices. As noted by Harden, “The lack of uniform diagnostic
criteria has perhaps been the biggest impediment to good quality research of all types.”29
To understand the development and importance of accurate diagnostic criteria for CRPS,
one needs to consider the concepts of sensitivity and specificity. These parameters are useful
for determining the accuracy of clinical criteria as well as diagnostic testing for CRPS.30
Sensitivity refers to the ability to detect a disorder when it is present, thereby eliminat-
ing the possibility of false-negatives.31 Specificity refers to identifying the normal popu-
lation, and eliminating false-positives.32 These parameters are determined by statistical
data analyses and are scored based on mathematical formulae.33 Ideally, the sensitivity
and specificity values should both be 1.0 (or 100 percent), such that every patient with
the disorder is identified (sensitivity) and no one without the condition is diagnosed
(specificity).34 For practical purposes, as the sensitivity approaches 1.0, the probability of
underdiagnosis is reduced.35 Likewise, as the specificity value approaches 1.0, the likeli-
hood of overdiagnosis is reduced.36
This statistical analysis has been applied to the diagnostic criteria for CRPS as devel-
oped by both consensus workshops. Following the first workshop in 1994, Bruehl et al.
evaluated 117 patients meeting those IASP criteria (Table 1) and compared them with
43 patients with neuropathic pain but not CRPS.37 They found the criteria to be very
sensitive (0.98) in identifying CRPS patients, but the specificity or elimination of false-
positives was quite low (0.36).38 Accordingly, these authors determined that the diagnosis
of CRPS is correct in only 40 percent of the cases.39
IASP Diagnostic Criteria for CRPS: 1994 Consensus Workshop
1. The presence of an initiating noxious event, or a cause of immobilization;
2. Continuing pain, allodynia, or hyperalgesia in which the pain is disproportionate
to any known inciting event;
3. Evidence at some time of edema, changes in skin blood flow, or abnormal
sudomotor activity in the region of pain (can be a sign or a symptom);
4. This diagnosis is excluded by the existence of other conditions that would
otherwise account for the degree of pain and dysfunction; and
5. If seen without “major nerve damage,” diagnose CRPS I; if seen in the presence
of “major nerve damage,” diagnose CRPS II.
Source: R. Norman Harden et al., Proposed New Diagnostic Criteria for Complex Regional Pain Syndrome, 8 P
M. 326–31 (2007).
A similar analysis of the more restrictive 2003 Budapest criteria was discussed by
Harden et al.40 These requirements, based on symptoms (what the patient reports) and

To continue reading

Request your trial

VLEX uses login cookies to provide you with a better browsing experience. If you click on 'Accept' or continue browsing this site we consider that you accept our cookie policy. ACCEPT