Complex Regional Pain Syndrome (CRPS)


Fact: CRPS is most common in people ages 20-35

What is Complex Regional Pain Syndrome?
Complex regional pain syndrome (CRPS) is a chronic (lasting greater than six months) pain condition that most often affects one limb (arm, leg, hand, or foot) usually after an injury.  CRPS is believed to be caused by damage to, or malfunction of, the peripheral and central nervous systems.  The central nervous system is composed of the brain and spinal cord; the peripheral nervous system involves nerve signaling from the brain and spinal cord to the rest of the body.  CRPS is characterized by prolonged or excessive pain and changes in skin color, temperature, and/or swelling in the affected area.

CRPS is divided into two types:  CRPS-I and CRPS-II. Individuals without a confirmed nerve injury are classified as having CRPS-I (previously known as reflex sympathetic dystrophy syndrome).  CRPS-II (previously known as causalgia) is when there is an associated, confirmed nerve injury.  As some research has identified evidence of nerve injury in CRPS-I, it is unclear if this disorders will always be divided into two types.  Nonetheless, the treatment is similar.

CRPS symptoms vary in severity and duration, although some cases are mild and eventually go away.  In more severe cases, individuals may not recover and may have long-term disability.

CRPS is most common in people ages 20-35. The syndrome also can occur in children; it affects women more often than men. CRPS is rare in the elderly. Very few children under age 10 and almost no children under age 5 are affected. ​
There is no cure for CRPS.

Causes
The cause of complex regional pain syndrome isn't completely understood. It's thought to be caused by an injury to or an abnormality of the peripheral and central nervous systems. CRPS typically occurs as a result of a trauma or an injury.

Complex regional pain syndrome occurs in two types, with similar signs and symptoms, but different causes:

  • Type 1. Also known as reflex sympathetic dystrophy syndrome (RSD), this type occurs after an illness or injury that didn't directly damage the nerves in your affected limb. About 90 percent of people with complex regional pain syndrome have type 1.
  • Type 2. Once referred to as causalgia, this type has similar symptoms to type 1. But type 2 complex regional pain syndrome follows a distinct nerve injury.

Many cases of complex regional pain syndrome occur after a forceful trauma to an arm or a leg. This can include a crushing injury, fracture or amputation.
Other major and minor traumas — such as surgery, heart attacks, infections and even sprained ankles — can also lead to complex regional pain syndrome.

It's not well-understood why these injuries can trigger complex regional pain syndrome. Not everyone who has such an injury will go on to develop complex regional pain syndrome. It might be due to a dysfunctional interaction between your central and peripheral nervous systems and inappropriate inflammatory responses.

Complications
If complex regional pain syndrome isn't diagnosed and treated early, the disease may progress to more-disabling signs and symptoms. These may include:

  • Tissue wasting (atrophy). Your skin, bones and muscles may begin to deteriorate and weaken if you avoid or have trouble moving an arm or a leg because of pain or stiffness.
  • Muscle tightening (contracture). You also may experience tightening of your muscles. This may lead to a condition in which your hand and fingers or your foot and toes contract into a fixed position.

Symptoms
Signs and symptoms of complex regional pain syndrome include:

  • Continuous burning or throbbing pain, usually in your arm, leg, hand or foot
  • Sensitivity to touch or cold
  • Swelling of the painful area
  • Changes in skin temperature — alternating between sweaty and cold
  • Changes in skin color, ranging from white and mottled to red or blue
  • Changes in skin texture, which may become tender, thin or shiny in the affected area
  • Changes in hair and nail growth
  • Joint stiffness, swelling and damage
  • Muscle spasms, tremors, weakness and loss (atrophy)
  • Decreased ability to move the affected body part

Symptoms may change over time and vary from person to person. Pain, swelling, redness, noticeable changes in temperature and hypersensitivity (particularly to cold and touch) usually occur first.

Over time, the affected limb can become cold and pale. It may undergo skin and nail changes as well as muscle spasms and tightening. Once these changes occur, the condition is often irreversible.
Complex regional pain syndrome occasionally may spread from its source to elsewhere in your body, such as the opposite limb.

In some people, signs and symptoms of complex regional pain syndrome go away on their own. In others, signs and symptoms may persist for months to years. Treatment is likely to be most effective when started early in the course of the illness.

Prevention
These steps might help you reduce the risk of developing complex regional pain syndrome:

  • Taking vitamin C after a wrist fracture. Studies have shown that people who took a daily minimum dose of 500 milligrams (mg) of vitamin C after a wrist fracture had a lower risk of complex regional pain syndrome compared with those who didn't take vitamin C.
  • Early mobilization after a stroke. Some research suggests that people who get out of bed and walk around soon after a stroke (early mobilization) lower their risk of complex regional pain syndrome.


​Diagnosis

Diagnosis of complex regional pain syndrome is based on a physical exam and your medical history. There's no single test that can definitively diagnose complex regional pain syndrome, but the following procedures may provide important clues:

  • Bone scan. This procedure might help find bone changes. A radioactive substance injected into one of your veins allows your bones to be seen with a special camera.
  • Sympathetic nervous system tests. These tests look for disturbances in your sympathetic nervous system. For example, thermography measures the skin temperature and blood flow of your affected and unaffected limbs.
    Other tests can measure the amount of sweat on both limbs. Uneven results can indicate complex regional pain syndrome.
  • X-rays. Loss of minerals from your bones may show up on an X-ray in later stages of the disease.
  • Magnetic resonance imaging (MRI). Images captured by an MRI test may show a number of tissue changes

Treatment
There's some evidence that early treatment, within the first few months of symptoms, might help improve complex regional pain syndrome symptoms. Often, a combination of different treatments, tailored to your specific case, is necessary. Treatment options include:

Medications
Doctors use various medications to treat the symptoms of complex regional pain syndrome.

  • Pain relievers. Over-the-counter (OTC) pain relievers — such as aspirin, ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve) — may ease mild pain and inflammation.
    Your doctor may prescribe stronger pain relievers if OTC ones aren't helpful. Opioid medications might be an option. Taken in appropriate doses, they might help control pain.
  • Antidepressants and anticonvulsants. Sometimes antidepressants, such as amitriptyline, and anticonvulsants, such as gabapentin (Neurontin), are used to treat pain that originates from a damaged nerve (neuropathic pain).
  • Corticosteroids. Steroid medications, such as prednisone, may reduce inflammation and improve mobility in the affected limb.
  • Bone-loss medications. Your doctor may suggest medications to prevent or stall bone loss, such as alendronate (Fosamax) and calcitonin (Miacalcin).
  • Sympathetic nerve-blocking medication. Injection of an anesthetic to block pain fibers in the affected nerves may relieve pain in some people.
  • Intravenous ketamine. Some studies show that low doses of intravenous ketamine, a strong anesthetic, may substantially alleviate pain. However, despite pain relief, there was no improvement in function.


Therapies

  • Heat therapy. Applying heat may offer relief of swelling and discomfort on skin that feels cool.
  • Topical analgesics. Various topical treatments are available that may reduce hypersensitivity, such as over-the-counter capsaicin cream, or lidocaine cream or patches (Lidoderm, LMX 4, LMX 5).
  • Physical therapy. Gentle, guided exercising of the affected limbs might help decrease pain and improve range of motion and strength. The earlier the disease is diagnosed, the more effective exercises might be.
  • Mirror therapy. This type of therapy uses a mirror to help trick the brain. Sitting before a mirror or mirror box, you move the healthy limb so that the brain perceives it as the limb that is affected by CRPS. Research shows that this type of therapy might help improve function and reduce pain for those with CRPS.
  • Transcutaneous electrical nerve stimulation (TENS). Chronic pain is sometimes eased by applying electrical impulses to nerve endings.
  • Biofeedback. In some cases, learning biofeedback techniques may help. In biofeedback, you learn to become more aware of your body so that you can relax your body and relieve pain.
  • Spinal cord stimulation. Your doctor inserts tiny electrodes along your spinal cord. A small electrical current delivered to the spinal cord results in pain relief.
  • Intrathecal drug pumps. In this therapy, medications that relieve pain are pumped into the spinal cord fluid.

It's possible for complex regional pain syndrome to recur, sometimes due to a trigger such as exposure to cold or an intense emotional stressor.

Recurrences may be treated with small doses of an antidepressant or other medication.

Information on this page taken directly from:
Mayo Clinic
NIH
WebMD

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The following are organizations and/or websites dedicated to providing information and education surrounding Complex Regional Pain Syndrome (CRPS). These organizations are dedicated to research, education, awareness, and/or support. They are listed in Alphabetical order without any preference or prejudice. Listing these organizations is not a recommendation or referral in any regard for seeking treatment or consultation or support for treatment.


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Mayo Clinic
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MedlinePlus
NIH
WebMD