RSD Puzzle #002

H. Hooshmand, M. D.

DIPLOMATE AMERICAN BOARD OF PSYCHIATRY AND NEUROLOGY

BOARD CERTIFIED IN ELECTROENCEPHOLOGRAPHY

BOARD CERTIFIED IN ELECTROMYOGRAPHY

BOARD CERTIFIED IN AMERICAN BOARD OF ELECTODIAGNOSTIC MEDICINE

INTRACTABLE NEUROLOGY

EPILEPSY, PAIN, MS

An International Referral Center dedicated to Treatment, Education and Research

A serious misconception that needs to be corrected is as follows:

The physician tells the patient that "Your injury was too mild. It could not cause RSD".

Trauma is not the exclusive cause of RSD. Even when trauma is the cause, it is usually in the form of a minor injury. Of all traumatic types of pain, less than 5% end up in RSD. The majority of traumatic cases are in more severe form, and result in simple somatic (non-sympathetic) pain. The reason is the fact that in non-sympathetic pain the larger sensory nerve fibers are affected and as a result they overshadow the small sensory C nerve fibers which are responsible for the development of RSD.

On the other hand, if a minor trauma affects selectively the small C fibers that transmit sympathetic sensory impulse there is more likelihood of the development of RSD. Usually RSD develops due to a minor trauma in certain specific parts of the body. The areas that are more susceptible to develop RSD are dorsum of the hand, dorsum of the foot, knee, elbow, ankle, elbow and shoulder. In these areas, there is the anatomical phenomenon called WATER-SHED ZONES. In these water-shed areas, there are multiple sensory nerve roots adjacent to each other. A minor trauma in such an area causes an electric short among these small C nerve fibers and as a result stimulates the multiple sympathetic centers in multiple levels of spinal cord with resultant augmentation of sympathetic input and a moderate RSD.

These water-shed zones are in contrast with other areas such as abdominal wall or chest wall. Even though the chest and abdomen frequently undergo accidental or surgical trauma, rarely cause RSD. The reason is that in the chest and abdominal wall the nerve roots are organized in certain parallel dermatomal fashion and they do not have such close proximity as over the dorsum of the foot, hand, or knee. Simple minor procedures such as arthroscopy or intravenous insertion in the areas of water-shed zones can end up in RSD if other risk factors are present (e.g., application of ice, inactivity, and long term use of narcotics).

The only exception to the above rule is the major causalgia due to bullet wound. In this rare form of RSD (civil RSD is nine to one more common than war RSD), the vibration of the bullet selectively stimulates the small C fibers and ends up in severe RSD. Just because a minor injury causes RSD, that does not equate with a minor RSD. (For further information regarding water-shed zones and RSD please see the textbook "Chronic Pain: Reflex Sympathetic Dystrophy: Prevention and Management", H. Hooshmand, M.D., CRC Press, pages 62, 92, 94 and 104.)

The material on the Neurological Associates Pain Management Center Homepage and all it's associated, linked or reference pages is for informational and education purposes. It is not meant to take the place of your physician. Before starting, changing, or stopping any treatments or medicines consult your physician. H. Hooshmand, M.D., Neurological Associates Pain Management Center and Associates will not be held liable for any damage or loss as a result of information provided on this page or associated documentation. Again, this WEB SITE is simply published as an information source and should not be used to treat or make judgments on RSD/CRPS. All associated material on this web site may not be copied, reproduced or quoted without expressed written permission from the owner; Copyright © 1999-2006 H. Hooshmand, M.D.