Complex Regional Pain Syndrome PDF Print E-mail

(Formerly:  Reflex Sympathetic Dystrophy)

Authored by MCN Neurologists

“If Hell were a medical condition, it would look like RSD.”

- RSDA

The above statement was a slogan of the Reflex Sympathetic Dystrophy Association (RSDA), a national support group for patients with the diagnosis of complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy (RSD).  The “Hell” refers to severe, unrelenting pain associated with this neurological disorder.   Complex regional pain syndrome is a chronic pain condition that can occur in any part of the body; however, it is usually regional, such as in an arm or leg, and often a result of an injury.  The injury can be significant, such as a bone fracture, or relatively minor, such as an ankle sprain.  In some cases, the patient does not remember a specific injury.  Associated with pain in that body part are skin changes, giving the term “complex.”   These alterations include temperature changes, sweat pattern differences and changes in the appearance of the skin, as well as the nails and hair pattern.   Also, the body part is exquisitely sensitive to touch, even very light touch so that having bed sheets touching the skin is unbearable.  Development of pain, along with these regional changes, usually takes several weeks to occur following an injury.  A common scenario is a fracture, such as at the wrist, which is then immobilized in a cast with the ensuing CRPS developing over several days or weeks after the injury.

This problem was recognized as far back as the American Civil War.  Dr. S. Weir Mitchill, a Union physician, reported in 1872 that he observed that some of the soldiers developed severe, chronic, unrelenting pain in an arm or leg after being wounded in that part of the body.  He called this condition, causalgia.  In 1946, Dr. James Evans coined the term reflex sympathetic dystrophy, in his assumption that the sympathetic nervous system was the culprit.  The sympathetic system is part of the autonomic nervous system (the other part is the parasympathetic system), which controls those functions of the body not under the direct, conscious control of the brain, such as heart rate, blood pressure and diameter of the pupils of the eyes.  In the skin, the sympathetic nervous system controls the blood flow through the small arterioles in the skin as well as the sweat glands.  Sympathetic overstimulation to a region of the body results in cool, sweaty skin.

As we learned more about this condition, it became apparent that RSD, as it was known, was a more complicated problem.  In 1994, a workshop of experts on RSD changed the name to complex regional pain syndrome (CRPS), as it is now known.

The exact way that trauma, especially minor injury, can produce such debilitating pain is not known.  Our present understanding of CRPS is that it is produced by a complex cascade of physiological and biochemical changes that occur not only in the nerves of the affected body part, but also within the brain and spinal cord.

Diagnosis of CRPS

Unfortunately, there is no test that is specific for CRPS.  The most important diagnostic information is the clinical presentation, that is, the history that the patient provides, describing the nature and onset of symptoms, and physical findings when the patient is examined.  Typically, the patient describes the progressive onset of unrelenting pain, usually burning, electrical or stabbing in nature, starting several weeks after an injury.  When the patient is examined, they tend to protect that body part because of extreme sensitivity to touch.  Usually the skin in the painful region is discolored, swollen and cool to touch with excessive sweating.

Certain tests can be confirmatory for the condition.  Radiological testing such as x-rays, bone scans and even MRI scans can reveal changes typically seen with CRPS.  In addition, physiological tests, such as those detecting temperature patterns with thermography (thermal imaging) and sweat patterns can be utilized.  Again, these tests are supportive for the diagnosis, but are not specific since similar abnormal findings can be seen with other conditions.

Treatment of CRPS

Over the years, multiple different approaches have been used to treat CRPS.  When a medical problem has “multiple” treatment options, it means that either it has a complex mechanism with multiple components, or we do not know much about it.  With CRPS, both situations probably apply.  Generally, we do know that several principles are important in treating CRPS.  The first principle is that of early recognition.  The earlier the diagnosis, the more quickly the condition is treated, and the better the outcome.  A second principle is to correct any underlying condition that may be perpetuating the problem.  For example, if a compressed nerve root in the low back from a herniated disk is causing CRPS in the leg, treat the nerve root problem first.  Third, it is important to mobilize the affected extremity with a comprehensive physical therapy program.  The various specific treatments for CRPS include medications, interventional procedures and implanted devices.

A number of different classes of oral medications are used to treat CRPS.  These include “pain killers” or analgesics, such as narcotics – Oxycontin, Fentanyl and Kadian.  Anticonvulsants, medications used to treat seizure disorders, are effective in many cases and commonly include Neurontin, Lyrica and Tegretol.  This class of medications is useful in other types of neuropathic pain, such as from shingles, diabetic neuropathy and trigeminal neuralgia.  Centrally acting muscle relaxants, such as baclofen and Zanaflex, work on inhibiting pain within the spinal cord.  Certain antidepressants are helpful, not only to treat underlying depression resulting from chronic pain, but also because of their direct pain-relieving capability as well.  Useful antidepressants include nortriptyline, Lexapro and Cymbalta.  Anti-inflammatory drugs, such as ibuprofen, Celebrex and prednisone, are helpful if there is an inflammatory component to the cause of the CRPS.  Medications can also be applied topically to the skin if the affected area is relatively small using a Lidoderm or Flector patch or specially formulated gels and creams containing any of the above medications.  A very aggressive approach, especially in patients with the most extreme form of CRPS, is to induce a comatose state for up to five days with intravenous Ketamine while the patient is on a ventilator.

Interventional procedures are carried out by a specialist, usually an anesthesiologist, and involve injection of an anesthetic or sympathetic blocking agent to the affected body part.  The injection can be a simple nerve block in the affected area, or a sympathetic block given in the neck or back, depending upon the location of the affected region.

Various implanted devices have been helpful in the more severe, intractable forms of CRPS.  The dorsal column stimulator has electrical leads that are placed over the spinal cord at the affected level, with the electronic stimulating unit implanted in the body.  Electronic signals from the stimulator block the pain messages generated by CRPS.  Another implanted device is a medication pump, which bathes the spinal cord with pain relieving medication, such as morphine or baclofen.

In addition to these measures, psychological counseling is important to deal with the frustration, anger, anxiety and depression that accompany chronic pain.  This support is especially important if the CRPS is the result of a worker’s compensation or personal injury.  The patient with CRPS needs this support to deal with losses, such as self-esteem, income, marital and friends, that accompany this condition.

While exact numbers are difficult to come by, roughly one-third of patients with CRPS can be successfully treated and achieve a reduction in pain and/or the ability to return to work.  These success stories are enhanced by early recognition of CRPS, treating the underlying condition and a multidisciplinary approach utilizing various therapeutic approaches described above, as well as physical therapy and psychological support.

The advances made in both the diagnosis and treatment of CRPS have allowed the RSDA in 2008 to change their slogan “If Hell were a medical condition, it would look like RSD” to “Take Flight with Hope,” with the mantra being: “From Hell to Hope.”

January 1, 2010

 
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