Complex regional pain syndrome (CRPS) affects 26 per 100,000 person-years. Females are more likely to acquire the disorder, and the upper extremity is affected most often. With this disorder, the nerves experience pain sensations greater than expected for the injury, and the pain persists long after the injury heals.
Chronic pain from CRPS can affect the quality of life. This pain places a huge emotional burden on patients. Types of psychological care include learning relaxation skills, cognitive behavioral therapy, biofeedback to reduce pain intensity, and counseling for coping.
A commonly used CRPS treatment is medical management. CRPS treatment medications include nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids to reduce irritation and inflammation. In many randomized controlled trials, these medications work to improve limp pain and range of motion to the affected extremity. Anti-oxidants have been used based on the perception that oxygen-free radicals affect the disease process. Dimethyl sulfoxide and N-acetylcysteine have also proven good for pain relief.
Medications with vitamin C have been proven the most effective preventative therapy in CRPS, and they are used during surgery. For nerve-related pain, research studies show that anticonvulsants (Gabapentin) have good pain relief effectiveness. The inflammatory pathways in CRPS often respond to NMDA receptor antagonists, such as ketamine. This drug can be given intravenously or applied topically.
A sympathetic blockade is a form of block used to alleviate pain. Also called a nerve block, this treatment works by stopping nerve signal transmission to the brain. The doctor may use lidocaine, a neurolytic agent, or botulinum toxin. Evidence shows that this treatment offers substantial pain reduction and analgesic effects to improve participation in functional therapies.
A treatment for CRPS used often is neuromodulation. This involves implantation of a special device that emits pleasant sensations that interfere with pain signal transmission. In a recent randomized controlled trial, this procedure was found to work well at the 2-year follow-up. Most patients who had spinal cord stimulation in the study had improvements in quality of life, functional capability, and pain levels.
A sympathectomy is another CRPS treatment used. This involves severing the sympathetic chains using radiofrequency energy or other surgical techniques. This permits the nerves from transmitting pain signals. Chemical sympathectomy involves the use of phenol or alcohol to destroy the sympathetic chain by this method. The procedure is used when other treatment options have failed.
New Treatments for CRPS
There are several emerging treatments for CRPS. New treatments for CRPS include:
- • Immunomodulation – Chronic regional and nerve inflammation could play a role in the beginning and sustainability of CRPS. Patients with these conditions display the systemic elevation of pro-inflammatory cytokines, as well as a reduction in the anti-inflammatory cytokine IL-10.
• Anti-cancer drugs – Lenalidomide and thalidomide have anti-inflammatory and immunomodulatory effects. These drugs have shown promise in alleviating CRPS. The drugs provide pain relief in around 33% of patients in a recent study. With lenalidomide, patients reported improvement in functional scores and pain within 12 weeks.
• Hyperbaric oxygen therapy – This treatment has shown promise when used in animal models. This treatment is thought to work by the release of the endogenous opioid called dynorphin. In a recent clinical study with 71 people with post-traumatic CRPS of the wrist, the researchers found decreases in edema and improved range of motion in patients.
• Plasma exchange – Recent research has brought a new understanding of the autoimmune component of CRPS. Researchers conducted a study using plasma exchange. The success rate was 91%, with almost all patients reporting a pain reduction of 65% or more.