RSD

Overview

Reflex sympathetic dystrophy (RSD), also known as complex regional pain syndrome (CRPS), is a chronic progressive neurological condition that affects skin, muscles, joints, and bones. The syndrome usually develops in an injured limb, such as a broken leg. However, many cases of RSD involve only a minor, seemingly inconsequential injury, such as a sprain. And in some cases, no precipitating event can be identified.

Pain may begin in one area or limb and then spread to other limbs. RSD/CRPS is characterized by various degrees of burning pain, excessive sweating, swelling, and sensitivity to touch. Symptoms of RSD/CRPS may recede for years and then reappear with a new injury.

Types
Two types of RSD/CRPS have been defined:

Type 1 - without nerve injury
Type 2 (formerly called causalgia) - with nerve injury
Both types express the same signs and symptoms.

Incidence and Prevalence
Millions of people in the United States may suffer from this chronic pain syndrome. RSD/CRPS affects both men and women, but is more common in women, and can occur at any age, but usually affects people between 40 and 60 years old.

The National Institute of Neurological Disorders and Strokes (NINDS) reports that 2% to 5% of peripheral nerve injury patients and 12% to 21% of patients with hemiplegia (paralysis on one side of the body) develop reflex sympathetic dystrophy as a complication. The Reflex Sympathetic Dystrophy Syndrome Association of America (RSDSA) reports that the condition appears after 1% to 2% of bone fractures.

Causes and Risk Factors

RSD/CRPS appears to involve the complex interaction of the sensory, motor, and autonomic nervous systems; and the immune system. It is thought that central nervous system (brain and spinal cord) control over these various processes is somehow changed as a result of the injury.

Conditions associated with the onset of RSD/CRPS include:

Trauma (e.g., bone fracture, gunshot and shrapnel wounds)
Spinal cord disorders
Cerebral lesions
Heart disease, heart attack
Hemiplegia (paralysis on one side of the body)
Infection
Radiation therapy
Repetitive motion disorder (e.g., carpal tunnel syndrome)
Surgery
In 10% to 20% of cases, no direct cause can be found. Injury that precedes the onset of RSD/CRPS may or may not be significant.

Signs and Symptoms
The symptoms of RSD/CRPS may progress in three stages—acute, dystrophic, and atrophic—although this notion is subject to debate.

Acute: burning pain, swelling, increased sensitivity to touch, increased hair and nail growth in the affected region, joint pain, color and temperature changes; first 1-3 months

Dystrophic: constant pain and swelling, limb feels cool and looks bluish, muscle stiffness and atrophy (wasting of the muscles), early osteoporosis (bone loss), 3-6 months

Atrophic: cool and shiny skin, increased muscle stiffness and weakness, symptoms may spread to another limb

Characteristic signs and symptoms of sympathetic nervous system involvement are

Burning pain
Extreme sensitivity to touch
Skin color changes (red or bluish)
Skin temperature changes (heat or cold)
Pain is usually disproportionate to the degree of injury and can be triggered by using the affected limb or by stress and can be spontaneous or constant.
Symptoms associated with an immune reaction include:

Joint pain
Redness
Swelling
Accumulated immune cells in the site
Frequent infections
Signs of motor system dysfunction include
Difficulty starting movement
Increased muscle tone
Muscle spasm
Tremor
Weakness
Other symptoms include
Migraine headache
Excessive sweating
Fatigue
Dermatitis, eczema
Complications

Patients with any chronic illness, including RSD/CRPS, often suffer from depression and anxiety. Skin, muscle, and bone atrophy (wasting) are possible complications of the syndrome. Atrophy may occur because of reduced function of the limb.

Diagnosis

RSD/CRPS can be difficult to diagnose and often requires excluding other conditions that produce similar symptoms. A thorough history and neurological examination is of utmost importance. During the exam, the clinician may notice that the response to mild sensory stimuli produces severe pain.

Physical examination involves observing the skin color and temperature, swelling, and vascular reactivity; overgrown and grooved nails; swollen and stiff joints; muscle weakness and atrophy (wasting).

Other conditions are ruled out with appropriate testing that may include MRI studies, a full laboratory panel, EMG/NCV (electrophysiological studies of the nerves and muscles), and a test known as a thermogram, which uses an infrared video camera to measure the emission of heat from the affected limb.

Treatment
The goal of treatment is pain control and as much mobilization of the affected limb as possible. An individualized treatment plan is designed, which often combines physical therapy, medications, nerve blocks, and psychosocial support.

Medication Medications are prescribed to control pain. The type of pain experienced by the patient determines the type of medication prescribed.

Constant pain caused by inflammation is treated with nonsteroidal anti-inflammatory drugs (e.g., aspirin, ibuprofen, naproxen, indomethacin).

Constant pain not caused by inflammation is treated with central acting agents such as tramadol (Ultram®).

Stabbing pain and pain that disrupts sleep are treated with antidepressants such as amytriptyline, doxepin, nortriptyline, and trazodone. Oral lidocaine, a somewhat experimental treatment for RSD/CRPS, also may be prescribed.

Sudden sharp pain may be treated with anticonvulsants (e.g., carbamazapine, gabapentin).

Generalized, severe pain that does not respond to other medications may be treated with opioids (e.g., propoxyphine, codeine, morphine).

Muscle cramps (spasms and dystonia) can be treated with clonazepam and baclofen.

Localized pain related to nerve injury may be treated with Capsaicin® cream, but its effectiveness has not been proven.

Medications that block selected actions of the sympathetic nervous system, such as clonidine (Catapres®, available in oral and patch formulations), can be useful in some cases.

Muscles stiffness may be treated with muscle relaxants such as

Tizanidine (Zanaflex®)
Baclofen
Clonazepam (Klonopin®)
Physical Therapy
Physical therapy should include daily range of motion exercises. Patients should be advised to avoid activities that could accelerate osteoporosis or joint injury.

Nerve Block
Sympathetic nerve block interrupts the transmission of pain signals from a group of nerve cell bodies (called a ganglion). When treating an upper extremity, it is called a stellate ganglion block. A small needle is used to inject an alpha adrenergic antagonist alongside the windpipe. When treating a lower extremity the nerve block is performed in the lower (lumbar).

The procedure, usually performed by an anesthesiologist familiar with the technique, involves the insertion of a needle into the appropriate location and the injection of anesthesia into the ganglion. The effect is monitored over time.

Sympathectomy Patients who have a good but temporary response to nerve block may be candidates for sympathectomy. The goal of surgery is suppression of sympathetic nervous system activity in the affected area.

TENS Unit
A transcutaneous electrical nerve stimulation (TENS) unit may be used to treat the affected area. In some cases, spinal cord stimulators are implanted permanently to supply a low intensity impulse to a location in the spinal cord in an attempt to interrupt the pain signals that are being transmitted to the brain.

Psychosocial Support
RSD/CRPS patients often become depressed and anxious because of chronic pain and loss of physical ability. Counseling, support groups, and chronic pain center programs help patients learn coping strategies and provide emotional and psychological support.