Reflex Sympathetic Dystrophy (RSD)
Reflex sympathetic dystrophy (RSD) is a term used to describe a complex pain disorder. The pain is characterized by its intense burning nature that is out of proportion to the inciting injury. The upper extremity is most commonly involved, but the lower extremities can also be effected.
What causes RSD?
The cause of Reflex sympathetic dystrophy is unknown. RSD develops as a consequence of a minor contusion or sprain. It can also occur with seemingly unrelated medical conditions such as myocardial infarction, stomach ulcers or minor surgery. In approximately 40 percent of cases, no precipitating cause can be identified.
RSD was first described in the medical literature during the Civil War. Soldiers who sustained nerve injury described severe burning pains which was termed “causalgia.” Initial investigation identified the sympathetic nervous system as being abnormal. Hence, the name reflex sympathetic dystrophy. The sympathetic nervous system is a portion of the nervous system which is not under voluntary control. Subsequent investigation has indicated that RSD does not necessarily involve sympathetic nerve damage. Therefore, the term complex regional pain syndrome (CRPS) is emerging to describe pain which is similar to RSD.
Symptoms of RSD
RSD is not a diagnosis. RSD is a descriptive term used to depict a painful extremity with the following characteristics. Patients may have a minor injury and then gradually develop severe burning pain on the skin which is out of proportion to the original injury. Although individual patients may vary considerably, RSD usually occurs in three overlapping phases:
- Phase I is called the acute stage and lasts up to 3 months. The pain surrounding the injured area and has a characteristic burning quality. Patients may also complain of hypersensitivity, cold intolerance, increased sweating and reddish skin discoloration.
- Phase II is called the dystrophic stage. Burning pain still predominates, but travels away from the injured area and may involve the entire extremity. Swelling of the extremity may occur and joints begin to stiffen and muscles begin to thin.
- Phase III is known as the atrophic stage. This stage occurs approximately one year following the acute stage and can persist for many years. The pain and discoloration may or may not diminish. There may be loss of skin creases and loss of normal sweating, giving the skin a cool, dry appearance. The stiffness of the joints can worsen and there is usually muscular dysfunction.
Diagnosis of RSD
The diagnosis of RSD can be difficult. Patients may complain of burning pain for several months before the diagnosis is confirmed. The diagnosis is based on the findings of pain which is out of proportion to the original injury, associated with swelling, discoloration and joint stiffness.
Diagnostic studies such as x-rays or bone scans are sometimes helpful. An anesthetic medication such as Lidocaine which is injected into the region of the sympathetic nerves as they exit the spinal column can result in temporary pain relief, confirming the diagnosis. This response is typically seen in the more acute phases of RSD and is often negative in chronic cases. Frequently, all studies are normal and the diagnosis is often based on the patient’s complaints and physical examination alone.
Treatment of RSD
There is no cure for Reflex Sympathetic Dystrophy which fortunately is a rare disease. Early intervention provides the best relief but has not been uniformly successful in all patients. Oral medications such as antihypertensives, neuroleptics and antidepressants may help. A series of sympathetic blocks is indicated in acute RSD patients who respond well to diagnostic injection.
Specialized hand therapy can greatly diminish the degree of stiffness and improve function. Be sure to talk to your pharmacist before purchasing anti-inflammatories as these medications may be contraindicated as they may interact with other medications and medical conditions.
Small electrical nerve stimulators which are placed on the skin surface may provide temporary pain relief. Surgical intervention is generally not beneficial.
Patients are encouraged to continue their daily activities such as much as possible in order to minimize or prevent further stiffness and dysfunction. RSD can progress through the various stages which become increasingly difficult to treat. Emotional support such as psychological counseling to help patients cope with the depression and anger, as well as ongoing physical therapy may be helpful. However, despite management, patients can occasionally experience persistent pain and dysfunction which is resistant to all forms of treatment.