RSD AND ICE - ICE AND RSD / CRPS
Neurological Associates
H. Hooshmand, M. D., P.A.
RSD Puzzle #102
Ice Versus Heat

In our study of ice versus heat tolerance, 87% of the patients could not tolerate cold. and 13% could not tolerate heat. The infrared thermal imaging showed that the ones who could not tolerate heat (13 %) had advanced stages of sympathetic nerve paralysis rather than nerve irritation (death of the sympathetic nerve fibers rather than hyperactive nerve fibers). The area of permanent sympathetic nerve damage in late stage acted like a leaky radiator, causing leakage of heat through the skin which resulted in warm extremity and secondary intolerance to external heat. Meaning that due to permanent damage to the sympathetic nerve fibers( after repeated ganglion nerve blocks or sympathectomy) the sympathetic nerves could not contain and preserve the heat originating from the deep structures of muscle, bone, etc. This minority of 13% of the patients did not have the hyperactive cold vasoconstriction of the skin seen in earlier stages of RSD. These heat intolerant patients would be classified as erythromelalgia, rather than the 87% RSD patients who have hyperactive sympathetic function with cold extremity and intolerance of cold exposure. 

On the other hand repetitive application of ice freezes and coagulates the myelin (fatty tissue insulating large nerve fibers) exactly like ice freezes and solidifies melted butter. As the ice freezes the large nerve fibers, causing freeze damage to the myelinated nerves, the patient develops sensory loss and pain due to permanent damage to the large sensory nerve fibers. This aggravates the RSD by adding sensory nerve pain of non-sympathetic origin to the initial thermal sensory pain of sympathetic origin. As a result, Ice provides total anesthesia and relief of pain for several minute the same way as the hand becomes numb being exposed to snowballs in the winter. However, a few hours after the cessation of ice exposure, the pain recurs with vengeance due to reactive enlargement of blood vessels after the constriction of blood vessels due to exposure to ice. This phenomenon causes excellent relief of pain with ice treatment followed by not only aggravation of pain, but damage to the nerve fibers adding sympathetic independent pain (SIP) to the original sympathetic mediated pain (SMP).

The end result is aggravation of the RSD and SIP resulting in failure of nerve blocks and then the patient is told, "You do not have RSD anymore because the nerve block did not help you and the phentolamine test proved that you do not have SMP or RSD". In most RSD patients ice makes the condition worse and can cause denial of diagnosis and treatment for the patient. One last comment: this study was on advanced cases of RSD. In early stages of RSD, without exposure to ice, there is far lower percentage of RSD patients who from the beginning suffer from permanent damage to large areas of sympathetic nerve fibers with intolerance of heat and secondary erythromelalgia. It becomes obvious that heat-cold challenge physical therapy is nonsensical because it end result is one temperature extreme neutralizing the other and ice challenge further damaging nerve fibers.

Please stay away from any ice exposure, even if you can not tolerate heat.
H.Hooshmand, MD.