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.