Twenty years ago, if you injured your limb and developed a debilitating pain condition called reflex sympathetic dystrophy (RSD), you would have likely been told that “it’s all in your head.” Instead of treating the pain, patients branded with the label RSD were believed to be crazy and were referred out for psychological testing and psychiatric treatment.
We now know definitively that RSD is a real medical condition and the prognosis for patients ranges from not good to debilitating. The International Association for the Study of Pain first developed criteria for the diagnosis of RSD or causalgia in 1994. The conditions were renamed Complex Regional Pain Syndrome and the criteria included:
- The presence of an initiating noxious event, or cause of immobilization;
- Continuing pain;
- Allodynia (central pain sensitization that feels like burning or throbbing) or hyperalgesia (disproportionate sensitivity to pain caused by touch or temperature);
- Changes in blood flow;
- Sudomotor activity (i.e. excessive sweating).
The diagnostic criteria were further refined at a conference in Budapest in 2003. The experts evaluate CRPS based on the following categories of symptoms
- Sensory, i.e. hypersensitivity and disproportionate response to temperature and touch;
- Vasomotor (irregular blood flow, either excessive dilatation or constriction of blood vessels);
- Sudomotor/oedema (excessive sweating and swelling);
- Motor/trophic (changes in skin color, nail, and hair growth).
Besides burning pain, the early stages of the condition are characterized by swelling and autonomic dysregulation in elevated body temperature and excessive sweating in the affected limb. Later stages of CRPS are characterized by muscle spasms, weakness, atrophy, and decreased mobility. It is well accepted that CRPS can spread from the initial affected area. The spread can be contiguous from the area initially affected and it can also spread to distant areas of the body.
Complex regional pain syndrome is usually precipitated by trauma to an extremity; including trauma, ischemia, and nerve compression.
Diagnosis is typically made from a history of the patient in terms of prior surgery, trauma and prior health history. The following diagnostic testing can sometimes compliment the clinical diagnosis:
- Sweat testing
- Sympathetic blocks
There is no known cure for CRPS and the best that doctors can do is to temporarily relieve symptoms with both heavy duty narcotic and non-narcotic pain medications.
Some patients have relieved symptoms by having a spinal cord stimulator surgically implanted. The surgery involves placing an electrical lead under the skin of the back to deliver electrical current to the spinal cord. If trial stimulation significantly reduces chronic pain, the patient may continue and have a pacemaker-like pulse generator implanted – usually under the skin of his chest, abdomen or buttock— to power the device.