Wednesday, January 20, 2016

CRPS -- Fact or Fiction

By Stuart O'Neil

Complex Regional Pain Syndrome (CRPS), formerly known as Reflex Sympathetic Dystrophy (RSD),*1 is a rare and increasingly over-diagnosed syndrome purportedly characterized by an extreme burning or stinging pain.

The International Association for the Study of Pain (IASP) has broken down CRPS into two types.*2  CRPS Type I requires causation by an initiating noxious “event.”*3  CRPS Type II is characterized by the presence of a defined “nerve injury.”  In this article, I will discuss Type I, its diagnosis, the reported stages of the syndrome and its treatment.  

Because the primary symptom of CRPS is pain that is wholly out of proportion to its apparent cause, CRPS Type I has been the object of considerable skepticism.  Ambiguities arise because pain is, fundamentally, a psychological manifestation, and, therefore, many people report pain for psychological reasons in the absence of any diagnosable predicate.  Tellingly, there are no objective tests to diagnose CRPS.  As such, it is, at best, a diagnosis of exclusion.

The newest criteria which have been utilized to support a clinical diagnosis of CRPS under the IASP guidelines include the following:

1.  Report of continuing alleged pain that is disproportionate to any inciting event;

2.  Report of at least one symptom in three of the following four categories:

  • Sensory: Reports of hyperalgesia and/or allodynia (hypersensitivity);
  • Vasomotor: Reports of temperature asymmetry and/or skin color changes and/or skin color asymmetry;
  • Sudomotor / edema:  Reports of edema and/or sweating changes and/or sweating asymmetry;
  • Motor/trophic: Reports of decreased range of motion and/or motor dysfunction (weakness, tremor, dystonia) and/or trophic changes (hair, nails, skin);

3.  Indication of one sign in two or more of the following categories at the time of evaluation:

  • Sensory: Evidence of hyperalgesia (to pinprick) and/or allodynia (to light touch or deep somatic pressure, or joint movement);
  • Vasomotor: Evidence of temperature asymmetry and/or skin color changes and/or asymmetry;
  • Sudomotor/edema: Evidence of edema and/or sweating changes and/or sweating asymmetry;
  • Motor/trophic: Evidence of decreased range of motion and/or motor dysfunction (weakness, tremor, dystonia) and/or trophic changes (hair, nails, skin);

4.  Finally, there must be no other diagnosis that better explains the reported  symptoms.

Thus, essentially, CRPS is a diagnosis of last resort, when all other potential causes have been effectively eliminated, including those predicated on the patient’s psychological makeup.

It is axiomatic that a plaintiff has an economic incentive to claim unrelenting severe pain which is disproportionate to the incitement of any specific injury.  Indeed, it is not uncommon for a litigant to claim functional paralysis arising from an event which would unlikely be a source of injury for most of the population.  

A diagnosis of  CRPS has been made when the patient states simply that he, either in the past or at the time of the examination, has had one or two complaints of burning or stinging pain, which cannot be quantified by any objective test.  Although there may be a few supportive partially-explanatory clues (reported bone loss, hair loss, temperature differences on the skin), the vast majority of the complaints are wholly subjective.  Because there are no objective tests associated with a diagnosis of CRPS (CT scan, x-ray, blood test), the diagnosis is commonly predicated solely on the patient’s subjective complaints.

CRPS experts typically list three stages in the symptom’s progression. Stage I seems to last roughly 1-3 months and typically occurs after the patient has sustained some “event” to an affected extremity in which the patient complains of burning or stinging pain emanating from the affected area.*4  Some patients have reported muscle spasms or contractions.  Some patients have claimed that their hair, fingernails or toenails in the affected area have inexplicably grown more quickly.  Changes in temperature or color of the affected area have been reported.  However, none of these alleged conditions are necessary predicates; a diagnosis of CRPS has been predicated on nothing more than a complaint of pain.

Stage II of Type I CRPS is sometimes as referred as the “dystrophic stage” which purportedly lasts an additional 3-6 months.  During this stage, pain has been reported to become more pronounced.  Additional changes in the texture and color of the skin have been reported.  Patients have claimed that their fingernails or toenails have become more brittle or their hair growth has slowed in the affected areas.  

Stage III is commonly referred to as the “atrophic stage”  reflecting a patient’s claims that their muscle, skin and bones are beginning to atrophy.  This claim of atrophy has often been co-extensive with a diagnosis of osteoporosis.  Additionally, patients have sometimes reported that their pain progresses up the affected limb and they may report pain emanating from other parts of the body as well.*5  
Treatment for a complaint of pain predicated on a diagnosis of CRPS has commonly included physical therapy, psychotherapy, and pain management therapy, if necessary. However, some cases have identified the application of a pain management regimen prior to obtaining a thorough medical history from the patient.  Occasionally, such a quick diagnosis is followed by prescriptions for a cocktail of pain management drugs, usually opiates like hydrocodone, with little physical therapy.  However, studies have shown that continued opiate pain medication does little to improve a patient’s complaint of pain.  Recent studies have shown that long term opiate use worsens the sensation of pain over time.

More invasive treatments for CRPS have included the use of sympathetic nerve blocks, which involve injecting an anesthetic near the sympathetic nerves in the spine and spinal cord stimulators, which involve the placement of electrodes next to the spinal column.  
CRPS Type I is a rare diagnosis which has seen some ascendency in litigation.  There are no objective diagnostic tests to identify it as it is strictly a diagnosis of exclusion made only after all other possible diagnoses have been eliminated.  

Keep an eye out in one of the next few newsletters, where I will discuss some strategies for defending these expanding claims of CRPS.


*1  The IASP formally abandoned the definition of the condition of Reflex Sympathetic Dystrophy as it was not scientifically or medically supportable, and the clinical presentation was too inconsistent.  Therefore, the name CRPS was ultimately adopted, but still remains extremely vague in its diagnostic elements.

*2  Interestingly, a third diagnostic subtype of Complex Regional Pain Syndrome is now being discussed which reflect cases that do not quite fall into the vague diagnostic criteria of CRPS Type I.  That new category referred to as Complex Regional Pain Syndrome Not Otherwise Specified (CRPS-NOS).  The new classification has been submitted to the IASP for future revision, thus adding to the ambiguity of the diagnosis and its constantly evolving emergent theories.

*3  In fact, IASP eliminated the term “injury” and replaced it with a term denominated as a noxious “event.”  

*4  There have been reported cases, however, in which CRPS has been diagnosed without any preceding identifiable cause or event.

*5  Some diagnosticians have further identified a Stage IV, which they claim is more resistant to treatment.  The identification of a Stage IV is not universally accepted, however.

Return to list.