FWD: RSD World News-What's Up Doc?

What's up doc? Complications after fracture could be serious condition
By Dr. Jeff Hersh / Daily News Correspondent
Tuesday, August 30, 2005

Q: I broke my wrist three weeks ago and instead of getting better it
is much worse. I now have a burning pain going up my entire arm. My
arm is swollen, stiff and hard to move and my skin feels hot. Does
this mean it is infected?
A: As per my e-mail you absolutely need to see your orthopedist
or go to the nearest emergency department immediately to be rechecked.
You did not note if there were any cuts or abrasions when you injured
your wrist, and this is important, as it would make the possibility of
infection much greater.
Infection is always a concern, and the classic signs of infection
are warmth, pain, redness and swelling (calor, dolor, rubor and tumor
are the Latin words we had to learn in medical school for this
constellation of symptoms).
Although there are many other possible causes of your symptoms,
reflex sympathetic dystrophy (RSD) must also be considered and as this
disease is not so well known I will discuss it in today's column.
RSD is classified as one subtype of complex regional pain
syndrome (CRPS); a disease characterized by excessive or exaggerated
pain that is out of proportion to that expected for the particular
injury and which is usually described as a severe burning pain. There
is typically swelling as well as skin changes associated with this
disease. RSD (known at the time as causalgia) was first noted during
the Civil War where soldiers who had suffered fractures sometimes
developed it.
In general, CRPS is divided into two sub-types, with the
diagnostic criteria from the International Association for the Study
of Pain (IASP) as follows.
CRPS I (also known as RSD) is characterized by:
# A history of an injury or other "noxious event" or anything
that caused immobilization of the limb (whether from a cast due to a
fracture or from decreased use due to pain from a sprain or other
injury).

# Continuing pain that is out of proportion to that expected for the
injury, or extreme tenderness/sensitivity to pain from a non-painful
or pretty minimal pain-causing stimulus.

# Evidence of swelling, skin changes such as warmth or redness and/or
changes in sweating in the affected area. Stiffness manifesting as
decreased range of motion of the affected limb is also common, but is
not one of the diagnostic criteria from the IASP.

# Other diseases that can cause similar symptoms must be excluded.
CRPS II (also going by the old name causalgia) is characterized
by:

# Continuing pain that is out of proportion to that expected (as
described for CRPS I above), but the symptoms are not limited to the
anatomic area of the distribution of a single nerve. There is nerve
injury in CRPS II, and this can be demonstrated by nerve conduction
tests or electromyogram (EMG) testing. The known nerve involvement and
that it is not localized to the distribution of one nerve is what
differentiates CRPS II from CRPS I.

# Evidence of swelling, skin changes such as warmth or redness and/or
changes in sweating in the affected area. Stiffness manifesting as
decreased range of motion of the affected limb is also common, but is
not one of the diagnostic criteria from the IASP.

# Other diseases that can cause similar symptoms must be excluded.
The cause of CRPS is not really understood. It is felt that
increases in signals from the sympathetic nerves (hence the name RSD
for one type of CRPS) are involved, but the cause of this is unclear.
Some researches theorize that patients develop a short circuit reflex
arc between the nerve receptors in the affected area and the autonomic
sympathetic nerve fibers. Other researchers have proposed a mechanism
where central (from the spinal cord) or peripheral nerves create the
problem. Still another theory is that tonic activity from the nerve
receptors in the area of the injury (continued firing of the nerves)
cause a disruption in the normal functioning of the pain sensing
system.
Whatever the pathophysiology, the end result is that the patient
develops pain and the other symptoms of CRPS.
One way to think of CRPS is that of a normal pain response gone
out of control. I often tell patients that I do not believe we have
pain as punishment, but as a warning that something is wrong. Hitting
your hand with a hammer will cause a pain response as well as redness,
swelling and even sweating of the injured area. These things help us
know that something bad has happened and that we should avoid this in
the future.
Furthermore, the injury response aids in healing -- swelling will
possibly help immobilize the area to prevent worsening the injury, and
the redness, warmth and even sweating are in response to increased
blood flow and flow of cells and other body responses to begin the
healing process. This injury response is supposed to turn off, but in
RSD it seems like it does not.
RSD is a poorly understood complication of injuries to the
extremities, with the upper extremities more commonly involved than
the lower extremities. Many injuries other than fractures have been
implicated as triggers for this disease, and some people do not even
recall a particular inciting injury.
The incidence of RSD is not known. Some authors report that up to
8 percent to 10 percent of fractures will develop RSD, but this is
likely an overestimation due to referral bias (the specialists get the
patients with complications referred to them and so their patient
population may not represent the entire pool of patients). Most
authors report incident rates of RSD of 1 percent or so after
fractures, although certain fractures seem to have a higher rate than
others. For example, a Colles' fracture (breaking the forearm bones
just above the wrist, typically from a fall onto the outstretched
hand, causing a spoon-like deformity of the arm) may be complicated by
RSD in up to 7 percent to 35 percent of cases. RSD is more common in
women, accounting for 60 percent to 80 percent of cases.
I will continue the discussion on RSD next week when I will
discuss the clinical presentation of RSD as well as some of the
treatment options for this disease.

Jeff Hersh, Ph.D., M.D., F.A.A.P., F.A.C.P., F.A.A.E.P., can be
reached at DrHersh@juno.com.
Online article
http://www.metrowestdailynews.com/health/view.bg?articleid=107355&format=text