Reflex Sympathetic Dystrophy
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See Also:
 Myofascial Pain Syndromes              <A-Referd.TXT -Myofascial>
 Brachial and Cervicl Plexus Injury     <N-Brachi.TXT>

þ background
 - used to be called "causalgia"
 - No genetic or psychological predisposition; no evidence at all for this
   despite popular conception.
 - 50% of RSD is in people who have been casted.
 - C fibers and A delta fibers fire, causes genetic response from dorsal root
   ganglia, C-phos increases, produces more substance P and glutamate that is
   carried distally, and sensitize pain fibers, and also change the spinal
   cord function.  Substance P interacts with lymphocytes and causes immune
   changes.
 - Usually associated with a local nerve traction or other injury; can often
   see reflex changes in the peripheral nerve distribution as well as in the
   sympathetic distribution that follows the vascular pattern.
 - according to Scientific American Medicine (1:XII:7) the root cause is
   likely disordered regulation of vosoactive mediators; reference:
[Schott CD. An unsympathetic view of pain. Lancet 345:634, 1995.]

þ early phase:
 - sympathetic dependent pain
 - edema, sometimes with ligature sign (looks like from a venous tourniquet)
   (is from neurogenic edema)

þ second and third stage
 - sympathetic independent pain (sympathetic blocks don't help)
 - involuntary dystonic posturing
  + 4+5 fingers tend to flex
  + plantar flexed
 - increased collagen
 - autoimmune
  + Gardner-Diamond syndrome:  autoimmune reaction against blood
  + tissue necrosis factor
  + chronic infections
  + depressed complement levels
 - Sudeck's atrophy: demineralization and osteoporosis secondary to reflex
   sympathetic dystrophy. It is a classic, though late RSD finding.
 - depression is common (though those who have their pain relieved have no
   more depresion than the normal population)

þ Treatment
   if caught in phase one (still with edema), symathetic blocks and physical
   therapy may cut pain and interrupt the progress of RSD; best within the
   first three months, but even within this, the earlier the better.

þ Diagnose RSD clinically with the following:

1. allodynia
 - mechanical allodynia (hurts to touch)
 - temperature allodynia (cold metal, e.g., reflex hammer, tuning fork)

2. pain not in dermatomal distribution

3. frequently, swelling
 - neurogenic edema
 - in pattern following the vascular symathetic pattern:  often get a
   "ligature sign" looking like patient had a constricing band on the
   extremity.  However, not completely straight; slightly angled to follow the
   vascular pattern.
 - may also see piloerection in early phases.

4. can't move:  motor changes and posturing (sometimes suspected to be
   malingering because the patient can overcome the posturing voluntarily).

5. increased reflexes