Complex regional pain syndrome is an uncommon form of chronic pain that usually affects an arm or a leg. Complex regional pain syndrome typically develops after an injury, surgery, stroke or heart attack, but the pain is out of proportion to the severity of the initial injury.
The cause of complex regional pain syndrome isn’t clearly understood. Treatment for complex regional pain syndrome is most effective when started early. In such cases, improvement and even remission are possible.
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 — at times your skin may be sweaty; at other times it may be cold
- Changes in skin color, which can range 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, weakness and loss (atrophy)
- Decreased ability to move the affected body part
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, 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 follows a distinct nerve injury.
Many cases of complex regional pain syndrome occur after a forceful trauma to an arm or a leg, such as a crush injury, fracture or amputation. Other major and minor traumas — such as surgery, heart attacks, infections and even sprained ankles — also can lead to complex regional pain syndrome. Emotional stress may be a precipitating factor, as well.
It’s not well-understood why these injuries can trigger complex regional pain syndrome, but it may be due to a dysfunctional interaction between your central and peripheral nervous systems and inappropriate inflammatory responses.
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 (Aleve) — may ease pain and inflammation.
Your doctor may prescribe stronger pain relievers if OTC ones aren’t helpful. Opioid medications may be an option. Taken in appropriate doses, they may provide acceptable control of pain.
- Antidepressants and anticonvulsants. Sometimes antidepressants, such as amitriptyline, and anticonvulsants, such as gabapentin (Gralise, 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 your affected nerves may relieve pain in some people.
- . Studies show that low doses of intravenous keIntravenous ketaminetamine, a strong anesthetic, may substantially alleviate pain. However, despite pain relief, there was no improvement in function.
- Applying heat and cold. Applying cold may relieve swelling and sweating. If the affected area is cool, applying heat may offer relief.
- Topical analgesics. Various topical treatments are available that may reduce hypersensitivity, such as capsaicin cream (Capsin, Capsagel, Zostrix) or lidocaine patches (Lidoderm, others).
- Physical therapy. Gentle, guided exercising of the affected limbs may help decrease pain and improve range of motion and strength. The earlier the disease is diagnosed, the more effective exercises may be.
- 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.
Recurrences of complex regional pain syndrome do occur, sometimes due to a trigger such as exposure to cold or an intense emotional stressor. Recurrences may be treated with small doses of antidepressant or other medication.
Source: Mayo Clinic