Motor paresis improved by sympathetic block. A motor form of reflex sympathetic dystrophy?

Four patients had a characteristic motor paresis that was dramatically improved by sympathetic block. The cause of this paresis could not be determined by the usual neurological examinations. It was similar to reflex sympathetic dystrophy in that the patients experienced severe pain, swelling, coldness, and muscle atrophy in the affected limbs or other parts of the body in the course of their illness. However, the motor paresis could precede the pain or develop after the pain had disappeared. Even in the absence of pain, the motor paresis was exacerbated by sympathetic stimulation using epinephrine, norepinephrine (nor-adrenalin), or isoproterenol hydrochloride (Proternol) loading and was improved by regional intravenous infusion of reserpine or by sympathetic ganglion block. Loading with pilocarpine, atropine sulfate (Bosmin), and edrophonium chloride (Antirex) did not influence the paresis. This motor paresis is thought to be due to abnormally increased sympathetic tone and may be considered a motor form of reflex sympathetic dystrophy. However, motor paresis closely related to sympathetic dysfunction is quite a new condition that we call "sympathetic motor paresis." This is important clinically because a long-standing effect can be expected from permanent sympathetic ganglion block with dehydrated ethanol.