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Complex regional pain syndrome

Definition

Complex regional pain syndrome (CRPS) is a chronic pain condition that can affect any area of the body, but often affects an arm or a leg.

Alternative Names

CRPS; RSDS; Causalgia - RSD; Shoulder-hand syndrome; Reflex sympathetic dystrophy syndrome; Sudeck's atrophy

Causes, incidence, and risk factors

Doctors aren't sure what causes CRPS. In some cases, the sympathetic nervous system plays an important role in the pain. Another theory is that CRPS is caused by a triggering of the immune response, which leads to the inflammatory symptoms of redness, warmth, and swelling in the affected area.

CRPS has two forms:

• CRPS 1 is a chronic nerve disorder that occurs most often in the arms or legs after a minor injury.
• CRPS 2 is caused by an injury to the nerve.

CRPS is thought to result from damage to the nervous system, including the nerves that control the blood vessels and sweat glands.

The damaged nerves are no longer able to properly control blood flow, feeling (sensation), and temperature to the affected area. This leads to medical problems in the:

• Blood vessels
• Bones
• Muscles
• Nerves
• Skin

Possible causes of CRPS:

• Injury directly to a nerve
• Injury or infection in an arm or leg

Rarely, sudden illnesses such as a heart attack or stroke can cause CSPS. The condition can sometimes appear without obvious injury to the affected limb.

This condition is more common in people ages 40 - 60, but it has been seen in younger people too.

Symptoms

The key symptom is pain that:

• Is intense and burning, and is much stronger than would be expected for the type of injury that occurred
• Gets worse, rather than better over time
• Begins at the point of injury, but often spreads to the whole limb, or to the arm or leg on the opposite side of the body

In most cases, CRPS has three stages. However, CRPS does not always follow this pattern. Some people develop severe symptoms almost right away. Others stay in the first stage.

Stage 1 (lasts 1 - 3 months):

• Changes in skin temperature, switching between warm or cold
• Faster growth of nails and hair
• Muscle spasms and joint pain
• Severe burning, aching pain that worsens with the slightest touch or breeze
• Skin that slowly becomes blotchy, purple, pale, or red; thin and shiny; swollen; more sweaty

Stage 2 (lasts 3 - 6 months):

• Continued changes in the skin
• Nails that are cracked and break more easily
• Pain that is becoming worse
• Slower hair growth
• Stiff joints and weak muscles

Stage 3 (irreversible changes can be seen)

• Limited movement in limb because of tightened muscles and tendons (contracture)
• Muscle wasting
• Pain in the entire limb

If pain and other symptoms are severe or long-lasting, many people may experience depression or anxiety.

Signs and tests

Diagnosing CRPS can be difficult, but early diagnosis is very important.

The doctor will take a medical history and do a physical examination. Other tests may include:

• A test to show temperature changes and lack of blood supply in the affected limb (thermography)
• Bone scans
• Nerve conduction studies
• X-rays

Treatment

There is no cure for CRPS, but the disease can be slowed. The main focus is on relieving the symptoms and helping people with this syndrome live as normal a life as possible.

Physical and occupational therapy should be started as early as possible. Starting an exercise program and learning to keep joints and muscles moving may prevent the disease from getting worse and help you perform everyday activities.

Medications may be used, including pain medicines, steroids, certain blood pressure medicines, bone loss medications (such as bisphosphonates like Fosamax and Actonel), and antidepressants.

Some type of talk therapy, such as cognitive behavioral therapy or psychotherapy, can help teach the skills you need to live with chronic pain.

Surgical or invasive techniques that may be tried:

• Injected medicine that numbs the affected nerves or pain fibers around the spinal column (nerve block)
• Internal pain pump that directly delivers medications to the spinal cord (intrathecal drug pump)
• Spinal cord stimulator, which involves placing electrodes (electrical leads) next to the spinal cord. A low-level electrical current is used to create a pleasant or tingling sensation in the painful area, which may help distract from the pain.
• Surgery that cuts the nerves to destroy the pain (surgical sympathectomy), although it is unclear how many patients this helps. It may also make some patients' symptoms worse.

Support Groups

Expectations (prognosis)

The outlook is better with an early diagnosis. If the doctor diagnoses the condition within the first stage, sometimes signs of the disease may disappear (remission) and normal movement is possible.

If the condition is not diagnosed quickly, changes to the bone and muscle may get worse and may not be reversible.

In some people, symptoms go away on their own. In other people, even with treatment the pain continues and the condition causes crippling, irreversible changes.

Complications

• Loss of muscle size or strength in the affected limb
• Spread of the disease to another part of the body
• Worsening of the affected limb

Complications can also occur with some of the nerve and surgical treatments.

Calling your health care provider

Contact your health care provider if you develop constant, burning pain in an arm, leg, hand, or foot.

Prevention

There is no known prevention at this time. Early treatment is the key to slowing the progression of the disease.

References

National Institute of Neurological Disorders and Stroke. Complex regional pain syndrome fact sheet. Updated December 21, 2009. Accessed January 19, 2010.

Saxton DL, Lindenfeld TN. Complications. In: DeLee JC, Drez D Jr., Miller MD, eds. DeLee and Drez's Orthopaedic Sports Medicine. 3rd ed. Philadelphia, Pa: Saunders Elsevier;2009:chap 7.