Complex Regional Pain Syndrome

Question:

What is "complex regional pain syndrome?"

Answer:

Complex regional pain syndrome (CRPS) is the new name for what was previously called reflex sympathetic dystrophy syndrome (RSDS), a poorly understood condition marked by chronic, severe, burning pain in an arm or leg. Other names include Sudeck's atrophy, algodystrophy, causalgia and shoulder-hand syndrome.

The cause is unknown, but it can be triggered by an injury, even if the injury was elsewhere in the body. Nerves in the affected limb seem to be particularly irritable or sensitive, sending pain signals to the brain even after normal stimulation. Light touch or even a gentle breeze can be excruciating.

Besides pain, other symptoms include:

• Thin, shiny skin in the painful limb

• Increased (or, later, decreased) hair growth

• Warm or cool skin compared to unaffected limbs; this may be associated with a change in skin color, such as red or dark blue

• Increased sweating of the skin over the affected limb

• Swelling or puffiness of the painful limb

• Contractures, in which an extremity becomes bent in one position and cannot be straightened out

The diagnosis can be difficult to establish, and there is no single test proves or refutes the diagnosis. Doctors sometimes order bone scans, nerve conduction studies, or sweat or temperature measurements over the affected extremity, or they perform injections (called nerve blocks) to interrupt pain signals when CRPS is suspected.

Although there are many treatment options, none are reliably effective; treatment is usually delivered by anesthesiologists, physical therapists and occupational therapists. Commonly recommended therapies include:

• Stretching and exercise

• Pain relievers and anti-inflammatory medications

• Capsaicin cream (to interrupt pain signals)

• Neuropathy (nerve disease) medications, including antidepressants (such as amitriptyline) and gabapentin

• Blood pressure medicines, especially those that affect the nerves that control dilation and constriction of blood vessels, such as prazosin or propranolol — Pentoxifylline can also dilate blood vessels and may improve symptoms.

• Osteoporosis medications, such as alendronate – They can reduce the bone loss that is common in this condition.

• Nerve blocks a– A pain specialist or vascular surgeon injects cortisone and a long-acting anesthetic into painful areas or nerves thought to be sending errant pain signals to the brain; if temporarily effective, a more permanent nerve block with a chemical nerve irritant or surgery can be performed.

• Transcutaneous electrical nerve stimulation (TENS) – For some patients, low-level electrical stimulation near the painful area seems to interrupt the pain signal.

Researchers are hard at work to understand this condition better and to develop more effective treatments.