Introduction to Reflex Sympathetic Dystrophy

Risk Factors for Reflex Sympathetic Dystrophy

Several risk factors for the development of reflex sympathetic dystrophy (RSD) have been identified including:

• Trauma - bone fracture, sprain, or other injury to the affected limb, often minor in nature, is considered the leading provocative event. Bone fractures account for up to 50% of cases of RSD.
• Surgery - RSD has been reported to occur following certain surgical procedures on the extremities such as carpal tunnel release surgery, knee arthroscopy, hip arthroplasty, amputation, or ankle arthrodesis (surgical fusion of the joint), and knee replacement surgery. It is estimated that up to 19% of patients with RSD have undergone knee replacement surgery.
• Cardiovascular events - ischemic heart disease, heart attack, or stroke have been reported as risk factors for developing RSD. Estimates of RSD in stroke patients range from 12-60%.
• Neurological events - RSD may be seen as part of other neurological diseases such as carpal tunnel syndrome or pinched spinal nerves.
• Neoplasms - certain types of cancers may produce a CRPS-like syndrome (e.g., lung cancer, breast cancer, and ovarian cancer)
• Age - incidence of RSD is highest in people between the ages of 50-70 years old. The mean age of diagnosis is 52 years old.
• Gender - females are affected at a rate 3 times higher than males
• Genetic predisposition - it appears that people with RSD are more likely to have certain HLA tissue types than control groups, but the meaning of this finding is unclear. HLA stands for Human Leukocyte Antigens which are a genetically determined series of antigens that are present on human white blood cells (leukocytes) and tissues
• Immobilization of a limb following a fracture or sprain or a cast that is too tight, or both. Immobilization may be necessary but it may also be the precipitating link in the development of RSD. This is suspected because studies involving immobilization of limbs in healthy subjects resulted in symptoms identical with RSD, such as trophic changes, muscle stiffness or atrophy, changes in skin color and temperature, circulation problems to the affected limb, and pain when the casts were removed.
• Poorly fitted cast or splint

In approximately 10-25% of patients with reflex sympathetic dystrophy, no precipitating event can be identified. Sometimes because the trauma may have been so minor (e.g., splinter) the patient does not recall the event or may not have been aware of it when it occurred but much of the time, the RSD is idiopathic in nature.

There is continuing discussion regarding the prevention of RSD following situations involving immobilization of a fracture or stroke. Some clinicians have suggested that following surgery the precautions that may be effective in offsetting the development of RSD or at least of minimizing its level include:

• Attention to pain prevention
• Early mobilization of the limb
• Prophylactic physical therapy
• Attention to properly fitted cast or splint
• Recent research has shown an advantage to prescribing 500 mg. of vitamin C daily from the time of the fracture or precipitating event