Horner's syndrome

Chronic regional pain syndrome type 1 (CRPS1) is a pain syndrome first recognized during the Civil War. The syndrome, originally termed causalgia, was first used in 1864, to describe the typical burning pain caused by vasomotor disturbances following peripheral nerve injuries from gunshot wounds.(1) The term reflex sympathetic dystrophy (RSD) later came into vogue in the late 1940s to distinguish between RSD (ie, a pain syndrome that develops after an initiating noxious event, and that is not limited to the distribution of a single peripheral nerve) and causalgia (ie, a syndrome that involves direct partial or complete injury to a nerve or one of its major branches).(2) In 1993, however, the International Association for the Study of Pain reclassified the term RSD to CRPS type 1. Causalgia was designated as CRPS type 2.(3) This distinction was made to allow for a more specific treatment plan.

The term CRPS refers to a classification of disorders thought to involve common neuropathic and clinical features. These disorders usually are caused by injury, and they manifest in pain and sensory changes that are disproportionate in intensity, distribution, and duration to the underlying pathology. Additional features include motor, autonomic, trophic, and psychological dysfunction that comprise a diagnostic constellation of signs and symptoms.(4) The result of these injuries is significant impairment of motor function over time.

Chronic regional pain syndrome type 1 is a complex neurologic disease involving the autonomic nervous system. The precipitating event that usually results in CRPS1 is a fracture or other trauma to the body. Chronic regional pain syndrome type 1 is characterized by chronic, severe, burning pain; hyperesthesia; soft tissue swelling; dystrophy; hyperhydrosis; vasomotor and sudomotor instability; joint stiffness; and patchy osteoporosis.(5) See Table 1 for definitions of common CRPS1 terminology. The syndrome most commonly strikes the extremities, where it affects the shoulders, hands, feet, knees, and, to a lesser extent, the hips.(6) It can affect any area of the body, however. Anecdotal evidence for CRPS1 exists in patients who have undergone mastectomy or breast reductions.(7)

Table 1

CHRONIC REGIONAL PAIN SYNDROME TYPE 1 DEFINITIONS(1)

* Afferent: Carrying impulses from the periphery toward a center (eg, the brain).

* Akinesia: Complete or partial loss of muscle movement.

* Allodynia: Perception of a nonpainful stimulus (eg, air or clothing) as painful.

* Dysesthesia: Sensation such as "pins and needles" or burning pain.

* Efferent: Carrying an impulse away from a central organ (eg, brain) to the periphery. * Horner's syndrome: Contraction of the pupil, partial ptosis of the eyelid, enophthalmos, and facial anhydrosis.

* Hyperalgesia: Increased sensitivity to noxious stimulation.

* Hyperesthesia: Lowered pain thresholds; increased pain felt from noxious stimulation.

* Hyperhydrosis: Increased sweating.

* Hyperpothia: Exaggerated painful response to a mildly painful stimulus; prolonged pain on stimulation.

* Nociceptive: Pertaining to stimulus to the brain.

* Pallor: Lack of color; paleness.

* Paresthesia: Unpleasant or annoying prickly feeling; dysesthesia.

* Rubor: Discoloration or redness caused by inflammation.

* Somatic: Pertaining to structures of the body wall (eg, skeletal muscles) in contrast to viscera.

* Sudomotor: Pertaining to stimulation of the secretion of sweat.

* Temporal summation: Increasing pain with repeated mild stimulation.

* Vasomotor: Pertaining to nerves having muscular control of the blood vessel walls.

NOTE

(1.) C L Thomas, Tabers Cyclopedic Medical Dictionary, 18th ed (Philadelphia: F A Davis Co, 1997); J Engstrom, J B Martin, "Disorders of the autonomic nervous system," in Harrison's Principles of Internal Medicine, 14th ed, Fauci et al, ads (New York: McGraw-Hill Co, Inc, 1998) 2372-2377; P R Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms," Hand Clinics 13 (August 1997) 367-372; R L Arden et al, "Reflex sympathetic dystrophy of the face: Current treatment recommendations," Laryngoscope 108 (March 1998) 437-442; R F Lopez, "Reflex sympathetic dystrophy: Timely diagnosis and treatment can prevent severe contractures," Postgraduate Medicine 101 (April 1997) 185-190.

Chronic regional pain syndrome type 1 is cyclic, with recurrence of symptoms after dormant periods ranging from six months to two years. Recurrent episodes of CRPS1 occur in 10% to 30% of patients.(8) It also may recur with a new injury to the same site or different region.(9) The duration of the syndrome varies from patient to patient.(10)

Five to six million men, women, and children in the United States suffer from CRPS1.(11) Twice as many women present with the disorder as men. Sixty-eight percent of CRPS1 patients also report an extension of the disease along the involved limb or migration to other body parts. The usual pattern of spread is up the same extremity, and then it may continue to spread on the same side of the body or to the opposite extremity. When the upper extremity is affected, there is a 50% chance of bilateral involvement.(12)

To date, CRPS1 remains poorly understood and often is not recognized clinically. Clinicians disagree about the cause, pathophysiology, diagnosis, treatment, and prognosis, and they have proposed contradictory and unclear definitions.(13) Underdiagnosis and overdiagnosis, therefore, are both prevalent. The only area in which there is consensus is regarding the need for early detection, pain control, treatment, and physical therapy of the affected area (as long as there are no fractures or tears). Although there is a tendency on the patient's part not to move a painful limb, the disorder worsens by limiting movement.

Clinicians agree that the emphasis is on returning the patient's affected body part to the previous level of function.(14) If left untreated, CRPS1 will progress inexorably through its acute, subacute (dystrophic), and, finally, atrophic phases. Each stage results in progressively greater dysfunction and disability, with diminishing chance of successful resolution.(15)

PAIN CLASSIFICATIONS

There are numerous ways to classify and categorize pain responses in people. One method segregates pain into two groups: sympathetically independent pain (SIP) and sympathetically maintained pain (SMP). With SIP, pain is maintained independent of the sympathetic nervous system's release or inhibition of neurotransmitters and catecholamines. An example of this phenomenon is somatically derived nerve pain, in which the sympathetic components of pain (eg, hyperhydrosis, erythema, allodynia, skin atrophy, joint stiffness) are lacking.(16) Sympathetically maintained pain, on the other hand, is an abnormal response of the sympathetic nervous system in which pain is maintained by sympathetic efferent or afferent activity or neurochemical circulating catecholamine action.(17) The term SMP implies that an abnormal response of the sympathetic nervous system maintains the pain.(18) It is a broad category that features several types of pain disorders, including neuralgias (including postherpetic), myofascial pain, metabolic neuropathies, phantom pain, and CRPS.(19)

The distinction between SMP and SIP is relevant because the treatment plan differs dramatically. The mainstay of SMP treatment is sympathetic blockade, by which sympathetic efferent activity to the extremity can be reduced by local or regional sympathetic blockade or by generally reducing sympathetic tone with an alpha-adrenergic blocker.(20) Patients presenting with SIP will not receive any benefit from a sympathetic block because the pain response is independent of the sympathetic nervous system. Not all cases, however, are simple, as SIP may occur alone or in conjunction with SMP.(21) Additionally, SMP may persist for many years and then dissipate or be replaced by SIP.

PATHOPHYSIOLOGY

The precise pathophysiology of CRPS1 is unknown. Many authors agree that it is caused by an abnormal sympathetic nerve reflex, either centrally or peripherally mediated.(22) The rationale for this position is that sympathetic nerve blockade (and sympathectomy) usually provide relief immediately.(23) Today, however, there are a growing number of authors and researchers who question the sympathetic nervous system's role in CRPS1 and believe the emphasis on this cause may be misguided.(24)

Precipitating events that eventually may result in the diagnosis of CRPS1 are displayed in Table 2. Trauma ranks as the leading provocative event for CRPS1, and one report suggests that two-thirds of CRPS1 cases in the United States occur postoperatively or after an injury.(25) In 10% to 26% of the cases, no precipitating event can be found.(26)

Table 2

PRECIPITATING EVENTS FOR CHRONIC REGIONAL PAIN SYNDROME TYPE(1)

NOTE

(1.) M M Kiroglu et al, "Reflex sympathetic dystrophy following neck dissections," American Journal of Otaloryngology 18 (March /April 1997) 104; R M Davis, A F Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain (Haddonfield, NJ: Reflex Sympathetic Dystrophy Syndrome Association) 1-16; R L Arden et al, "Reflex sympathetic dysthropy of the face: Current treatment recommendations," Laryngoscope 108 (March 1998) 437-442; M L Kasden, A L Johnson, "Reflex sympathetic dysthropy," Occupational Medicine 13 (July/September 1998) 521-531.

Sympathetic nervous system. The two main ganglionic trunks of the sympathetic nervous system (SNS) are the cervical and lumbar trunks. The SNS innervates many peripheral structures, thereby affecting many bodily functions. Within the SNS are alpha and beta receptor points. Either of these receptors has an excitatory or inhibitory effect on the end organ. When stimulated, alpha receptors cause skin vasoconstriction, pilomotor contraction, cardiac acceleration, and intestinal relaxation. Stimulation of a beta receptor causes muscle vasodilation, bronchial relaxation, and cardiac acceleration.(27) These two responses result in what is commonly known as the "fight or flight" reaction.

In the normal sequence of events, an injury activates the SNS. Sympathetic outflow results in immediate vasoconstriction at the site. Sympathetic tone decreases and blood flow to the limb increases, allowing the body to heal and repair itself and remove waste products. If sympathetic tone persists inappropriately, an abnormal feedback system evolves, causing vasomotor and sudomotor instability, skin changes, and tissue edema, resulting in capillary collapse and ischemia. This, in turn, causes localized pain. This pain signal re-excites the sympathetic nerves, increasing sympathetic activity even further, and a positive feedback circuit is created.(28)

The SNS may play different roles during different stages of CRPS1. Early in the illness, CRPS1 may result when sympathetic reflexes respond to noxious stimuli (eg, persistent irritation). The afferent SNS becomes hyperactive, and a positive feedback cycle ensues, which increases over time. This cycle is hypothesized to occur through changes within the spinal cord or in the peripheral nerves. In other patients, however, after a variable period of time, CRPS1 becomes independent of the sympathetic system.(29) The predominant role of the sympathetic nervous system in CRPS1 is subject to debate, and there is growing evidence that sensitized somatosensory afferents are pivotal in the etiology of CRPS1.(30)

The basic premise for the SNS's involvement in the pathophysiology of CRPS1 is similar for the various proposed theories. Each theory, however, differs regarding the exact mechanism by which the SNS brings about the pathophysiology.(31) Table 3 displays some of the theories.

Table 3

CHRONIC REGIONAL PAIN SYNDROME TYPE 1 THEORIES OF SYMPATHETIC NERVOUS SYSTEM PATHOPHYSIOLOGY(1)

* Internuncial pool: Reflexes initiated in the spinal cord are spread via the interconnecting pool of neurons.

* Pain threshold: intensive sympathetic nerve fiber stimulation produces either a pain-evoking substance or a substance that lowers the pain threshold in a given area.

* Artificial synapse (ie, short circuit effect): Efferent nerves that have lost their axonal covering through injury form pathologic synapses with afferent sensory nerves, causing continuous and accelerating stimulation that results in pain.

* Gate control: The gate control system in the brain becomes dysfunctional (ie, smaller pain responses are not blocked out, and this persistent volley results in activation of a positive feedback mechanism that exaggerates the effect of centrally arriving pain impulses).

* Excitation of nociceptors: Peripheral nociceptors are overly responsive to noradrenaline.

* Sensitization to adrenergic substances: Blood vessels and sweat glands deprived of sympathetic stimulation during acute injury develop a temporary supersensitivity to circulating adrenergic substances, causing abnormal response of target tissues to normal sympathetic stimulation.

* Structural reorganization: The initial cell destruction and tissue damage may result in the overproduction of oxygen-free radicals.

NOTE

(1.) S Sintzoff et al, "Imaging in reflex sympathetic dystrophy," Hand Clinics 13 (August 1997) 431-442; M L Kasden, A L Johnson, "Reflex sympathetic dystrophy," Occupational Medicine 13 (July-September 1998) 521-531; D W Dobrott, P Gutowski, "Successful treatment of recurrent reflex sympathetic dystrophy with bilateral lumbar sympathectomies," Journal of American Osteopathic Association 97 (September 1997) 533-535: M A Hardy, S G P Hardy, "Reflex sympathetic dystrophy: The clinician's perspective," Journal of Hand Therapy 10 (April-June 1997) 137-150.

Initially, trauma incurs tissue damage, resulting in chronic irritation and pain impulses of a peripheral sensory nerve. An increasing number of afferent pain impulses are sent to the spinal cord, triggering a reflex that stimulates the lateral and anterior tracts. The efferent pathways are then provoked to send impulses to the peripheral nerves, producing the localized findings (ie, local circulatory disturbances, muscle spasms) in CRPS1 patients. When the normal sympathetic reflex arc fails to discontinue at the appropriate time, a temporary vasoconstrictive action of small vessels occurs.(32)

Theories other than SNS involvement have been suggested in the search for an explanation of the pathophysiology of CRPS1. Although these theories are considered separate entities, they actually may be additional modalities within the main SNS pathophysiology model proposed in the previous section.

Immune System. Cells of the spinal cord may play an important role in cell chemistry and immune response changes in neuropathic pain states. The belief that an inflammatory mediator is the cause of the peripheral features of CRPS1 is evolving.(33) One author has suggested that CRPS1 is a neuroimmune disorder linked to multiple sclerosis and narcolepsy.(34)

Muscular system. Pain and hyperesthesia induce reflex muscle spasms, which leads to voluntary guarding. This subsequent inactivity causes loss of muscular pumping action, stagnation of the lymph system, alteration in capillary permeability, and localized acidosis, all of which lead to further capillary permeability. The end result is more edema, adhesions, decreased range of motion, fibrosis, and peripheral vascular constriction. Pain increases, motion is further reduced, and the cycle repeats itself.(35)

Genetic. There may be a genetic predisposition for contracting CRPS1. It has been suggested that a history of CRPS1 in the patient's past predisposes a patient to a recurrence of the condition if there is further injury, surgery, or immobilization.(36)

Psychological factors. The role of the psyche in the pathophysiology of CRPS1 is a sensitive subject. The question posed is similar to the question: "Which came first, the chicken or the egg?" In this case, which came first, the psychological factors that result from dealing with a chronic illness or a psychologically predisposed personality type that is expressed in an illness, such as CRPS1?

According to the RSD Syndrome Association of America (RSDSA), as with any group of individuals, there is a small percentage of CRPS1 patients who derive satisfaction from a chronic illness (ie, secondary gain). The vast majority of patients, however, were active and productive individuals before this syndrome, and they do not enjoy the pain or the loss of their independence, job, or income.(37)

Numerous authors briefly discuss a psychiatric component or predisposing psychosocial factors in the etiology of CRPS1 and then quickly dismiss such notions.(38) There is no evidence to support a predispositional personality profile for the development of CRPS1. Instead, it is thought that the emotional and behavioral changes noted are a result, rather than a cause, of the prolonged pain and disability. Chronic pain, in addition to depression, anxiety, and immobility, is a volatile mixture. These personality issues should be assumed to be part of the disease process and not an integral part of the patient. There is no clear difference between CRPS1 patients and patients with other chronic pain diseases.(39) Most authors agree that psychological factors play a role in all forms of pain and dysfunction because they influence patients' beliefs, expectations, incentives for recovery, coping mechanisms, and stress tolerance.(40)

On the other hand, there are researchers who believe there is a heavy psychosomatic or psychiatric component to CRPS1 that needs to be acknowledged. One group of researchers believe that the CRPS1 population can be prone to symptom exaggeration and dysphoria.(41) Another researcher concurs and also notes that psychological factors often play a part in the symptomatology of CRPS1, as evidenced by anxiety, depression, stress, and increased somatization.(42) Researchers also note the need to examine the patient's psychological status when hysteria, malingering, or factitious illness may be a factor.(43) In general, there are authors that contend that predisposing psychosocial factors (eg, emotional instability, tendency toward somatization and hypochondriasis, nervousness, depression, anxiety, some life events) have been associated with the development of CRPS1.(45) Another theory is that CRPS1 is a neuropsychiatric disorder in which patients more typically display personality traits of self-satisfaction, rigidity, and somatization.(45)

DIAGNOSIS

Diagnosis is determined mostly by clinical evaluation, which also includes a physical examination and thorough documentation of the patient's history.(46) The clinical evaluation usually will reveal the following:

* a history of trauma with persistent and diffuse burning, aching, or throbbing pain in an area not corresponding to the distribution of a peripheral nerve or root and that is more severe than expected from the inciting event;

* hyperalgesia;

* allodynia;

* hyperpathia;

* soft tissue changes ranging from rubor, hyperhydrosis, and warmth in the early stages to stiffness, atrophy, and coldness as the syndrome progresses;

* edema;

* vasomotor and sudomotor changes (eg, skin temperature and color changes); and

* diminished function of the affected area with joint stiffness.(47)

Pain is the sine qua non for diagnosis. The pain exceeds both in magnitude and duration that which would be expected from the injury. The pain is burning in nature, begins spontaneously, and becomes continuous and severe. It is evoked by physical or emotional stimuli.(48) Pain, especially chronic pain, is an intense human experience that has defied definition and explanation for centuries. It is a highly subjective experience that is colored by a person's physical, psychological, and social experiences. Chronic pain invades a patient's life, and this affects his or her behavior, work, daily tasks, emotional state, and social interactions. The patient's painful somatosensory state eventually can become a preoccupation; the pain may even become the pivotal point of existence.(49)

Other conditions need to be ruled out before diagnosing a person with CRPS1. The diagnosis is excluded if there is evidence of nerve injury or another disorder that could account for the pain and disability. This includes atypical rheumatoid arthritis, bursitis, capsulitis, gout, herniated nucleus pulposus, nerve entrapment syndromes, osteomyelitis, periarthritis, peripheral neuropathies, peripheral vascular disease, postherpetic neuralgia, septic arthritis, and tenosynovitis.(50)

Along with the clinical evaluation, diagnosis can be based on any combination of the diagnostic tests listed in Table 4. A single positive test result is not conclusive evidence for a diagnosis of CRPS1. A grouping of positive results, however, will point in the direction of CRPS1.

Table 4

DIAGNOSTIC TOOLS USED IN CHRONIC REGIONAL PAIN SYNDROME TYPE 1(1)

* Scintigraphy

* Three-phase technetium bone scan

* Routine radiographs

* Thermographic studies to measure temperature differences between affected and unaffected regions

* Quantitative sweat test

* Sympathetic neural blockade

* Quantitative bone mineral analysis

* Isolated cold stress testing to assess temperature and vasomotor responses

* Laser Doppler flowmetry

* Vital capillaroscopy

* Computerized tomography series

* Nerve conduction velocities

* Electromyograms

* Magnetic resonance imaging

NOTE

(1.) S Sintzoff et al, "Imaging in reflex sympathetic dystrophy," Hand Clinics 13 (August 1997) 431-442; R M Davis, A F Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain (Haddonfield NJ: Reflex Sympathetic Dystrophy Syndrome Association) 1-16; M L Kasden, A L Johnson, "Reflex sympathetic dystrophy," Occupational Medicine 13 (July-September 1998) 521-531; H Gellman, D Nichols, "Reflex sympathetic dystrophy in the upper extremity," Journal of the American Academy of Orthopedic Surgeons 5 (November/December 1997) 313-322.

Modified sympathetic blockade also can serve as both a diagnostic and therapeutic tool. Normal saline solution is used as a placebo and 5% procaine hydrochloride is used as a pharmacologic spinal nerve block. Pain may be considered psychogenic or malingering if relief is obtained with the placebo or no pain relief occurs with the procaine hydrochloride. If pin sensation returns with the pain sensation, the origin is considered to be somatic, not sympathetic. If motor function and pin sensation return but the pain continues to be absent with the block, a sympathetic origin of pain is postulated.(51) Relief from pain symptoms after the block confirms the diagnosis as CRPS1, although a negative result does not rule out CRPS1.(52)

SIGNS AND SYMPTOMS

The early and late signs and symptoms of CRPS1 are noted in Tables 5 and 6. These two categories are not fixed and static. Rather, they represent a generalized, dynamic description of a typical CRPS1 experience. Each person's individual expression of CRPS1 is variable as signs and symptoms will vary in severity and frequency. In general, sympathetic dysfunction is evidenced by pain and skin, soft tissue, vascular, and bone changes.(53)

Table 5

EARLY SIGNS AND SYMPTOMS OF CHRONIC REGIONAL PAIN SYNDROME TYPE (1)

NOTE

(1.) P H Veldman et al, "Signs and symptoms of reflex sympathetic dysthropy: Prospective study of 829 patients," Lancet 342 (1993) 1012-1016; L van der Laan, R J A Goris, "Reflex Sympathetic dysthropy: An exaggerated regional inflammatory response?" Hand clinics 13 (August 1997) 375; S Sintzoff et al, "Imaging in reflex sympathetic dysthrophy," Hand Clinics 13 (August 1997) 431-442; A F Thomas, Reflex Sympathetic Dysthropy Syndrome (RSDS): Help Us Stop the Pain (Haddonfield NJ: Reflex Sympathetic Dystrophy Syndrome Association) 1-16; H Gellman, D Nichols, "Reflex sympathetic dystrophy in the upper extremity," Journal of the American Academy of Orthopedic Surgeons 5 (November/December 1997) 313-332; J Arlet, B Mazieres, "Medical treatment of reflex sympathetic dystrophy," Hand Clinics 13 (August 1997) 447-483.

Table 6

LATE SIGNS AND SYMPTOMS OF CHRONIC REGIONAL PAIN SYNDROME TYPE 1(1)

NOTE

(1.) H Gellman, D Nichols, "Reflex sympathetic dystrophy in the upper extremity," Journal of the American Academy of Orthopedic Surgeons 5 (November/December 1997) 313-322; R M Davis, A F Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain (Haddonfield NJ: Reflex Sympathetic Dystrophy Syndrome Association) 1-16; M M Kiroglu et al, "Reflex sympathetic dystrophy following neck dissections," American Journal of Otolaryngology 18 (March-April 1997) 104; R L Arden et al, "Reflex sympathetic dystrophy of the face: Current treatment recommendations," Laryngoscope 108 (March 1998) 437-442; M A Hardy, S G P Hardy, "Reflex sympathetic dystrophy: The clinician's perspective," Journal of Hand Therapy 10 April-June 1997) 137-150; P C C Doury "Algodystrophy: A spectrum of disease, historical perspective, criteria of diagnosis, and principles of treatment," Hand Clinics 13 (August 1997) 327-337.

Early signs and symptoms. Early diagnosis is important for the most favorable outcome for patients. Signs and symptoms of CRPS1 are classified as early or late.

Pain. Pain is described as diffuse, severe, and constant with a burning, throbbing, or aching quality. It usually is the first and primary complaint. The pain may be spontaneous or it can be provoked by movement or touch. In general, the severity of the pain is disproportionate in duration, severity, and distribution to that expected for the usual clinical course of the reported injury. When pain should lessen, it remains severe or may even worsen.

Soft tissue. Early dystrophic changes occur in the affected region. The skin and muscle tissues slowly atrophy. Skin becomes dry, scaly, and undergoes pigmentary changes. The skin is cool to the touch, skin temperature differences between the affected and unaffected areas can be as much as 10o F (-12.22 [degrees] C) cooler. Hair growth or hair loss occur along with finger nail changes. Along with these soft tissue changes, there also will be pitting or nonpitting edema. Muscle spasms also will be common in conjunction with moderate to severe muscle weakness, tremor, and/or dystonia.

Vasomotor instability. There are major disturbances in the local and regional vasomotor reflex of the microcirculation in the affected region. Vasodilation along with the slowing of the circulation result in increased capillary permeability and diffuse edema with alternating rubor and pallor, blotching, and blanching of the skin. The end result of this vasomotor instability is compression of the capillaries and the nociceptive and pain-transmitting nerve endings. At the onset, the skin is warm, hyperemic, and dry. It then changes to cool, pallid, mottled or cyanotic, with or without hyperhydrosis. Raynaud's phenomenon is common.

Bone and joint changes. Early signs of patchy osteoporosis are apparent with progressive bone mineral loss. The bones show increased vascularity, porosity, and osteoclastic activity, resulting in the thinning of cortical bone and loss of intramedullary trabecular bone. Joints become tender and stiff, and there is limited mobility related to articular and periarticular fibrosis. Limited range of motion occurs with joint dystrophy. Diminished motor function becomes a positive feedback cycle and worsens with time as the person guards the affected region. Guarding usually is a normal response to protect an injured body region from movement and external stimuli during healing. With CRPS1, however, guarding is exaggerated, persists after the injury has healed, and is a pathologic phenomenon.

Late signs and symptoms. As the duration of the CRPS1 progresses, signs and symptoms increase in severity.

Pain. The pain experienced is more severe than early on and is exacerbated with sensory input, pressure (ie, weight bearing), or muscular activity. There may be hyperesthesia, hyperpathia, and elevated thresholds to touch. Paradoxically, in the final stages, the pain may actually decrease or disappear in the late atrophic stage.

Soft tissue. Soft tissue dystrophy continues, and the skin is cool, ischemic, dry, thin, and shiny. Trophic signs prevail at this point. Hair becomes scant and nails become brittle, cracked, and heavily grooved. Edema spreads and changes from soft to a brawny (ie, swollen and hard) type and then resolves or becomes indurate. The muscles continue to waste with increasing atrophy. Range of motion is limited further and contractures eventually result with prolonged immobility.

Bone and joint changes. Osteoporosis is severe and diffuse. The joints' surfaces continue to become thick and fibrotic, limiting range of motion even further.

Resolution. Eventually the involved regions may return to normal hemodynamics, but permanent, irreversible tissue damage has occurred in the bone, joint capsules, subdermal fat, nails, and hair.

CLINICAL STAGES

There are three clinical progressive stages of CRPS1: acute inflammatory, dystrophy, and atrophy.(54) They are of variable length and do not occur in a fixed order.

Acute inflammatory onset with denervation and sympathetic hypoactivity. The first stage begins immediately after the injury or up to 10 days after the injury and lasts three to six months. It is defined by severe, diffuse, intense, deep, persistent, burning pain that is localized or regional, often spreading from its original site. The pain begins spontaneously and becomes continuous and more severe. The pain worsens with movement, emotional disturbance, and visual or auditory stimuli. Allodynia, hyperpathia, dysesthesia or paresthesia, and temporal summation are present. Edema, initially soft and localized, spreads, and the skin is noted to be hyperemic, hot, and dry. Tremor, muscle weakness, and muscle cramping are common, and range of motion is decreased. Guarding of the area for protection begins, and all of these symptoms are out of proportion to the initial trauma.

Dystrophy with paradoxic sympathetic hyperactivity. The second stage occurs three to six months after the onset of pain, and lasts approximately six months. The pain worsens and is more diffuse with proximal progression. Tissue edema changes from soft to hard with progressive joint stiffness. Thin, ridged, or cracked nails and thin, glossy, cool, and sweaty skin with atrophic changes and hair loss is profound. Vasoconstriction results in decreased skin temperature. There are marked changes in the joints and muscle function along with flexion deformity.

Atrophy or stiffness. The third and final phase begins six to 12 months after the initial insult and may last for years. Pain either plateaus, becomes intractable, or, paradoxically, may spontaneously improve while spreading to wider areas. The skin becomes smooth, glossy, and cyanotic and then becomes atrophic. Subcutaneous tissue atrophies and disappears, while the edema continues to harden. The extremity has a cool, pale, and dry appearance. Severe osteopenia, contracted and thickened fibrotic joint tissues and muscle atrophy are common. These final changes are irreversible with concomitant irreversible loss of function. Atrophy is usually refractory to therapy.

TREATMENT

For patients with CRPS1, treatment is aimed at addressing symptoms as they occur because the underlying pathology is unknown. Characteristically, patients initially seek treatment because their pain has been unresponsive to the usual doses of analgesics.(55)

Aggressive treatment is mandated in the early stages of the disease. There is consensus that the earlier treatment is instituted, the greater the likelihood that symptom progression will halt. Those patients presenting with moderate pain at the initial visit to the physician are more likely to have pain improvement or resolution than those presenting with severe pain at the initial visit.(56) A delay in treatment prolongs the rehabilitation period and allows the pain and physical alterations to become refractory to treatment. If the treatment is delayed and pain has persisted for more than one year, the hope of pain resolution diminishes rapidly.(57) Once in the third stage, the overall response rate to treatment is poor, with more than 50% of patients having significant pain and/or disability years later.(58) Without treatment, the result is permanent tissue damage, chronic pain, and impairment.(59)

The treatment intervention goal is to break the vicious cycle noted in patients with CRPS1. The treatment aims at symptomatic relief that permits other therapeutic measures to be instituted, such as physical therapy.(60) The treatment modality chosen depends on an individual patient's clinical presentation. There are four essential principles regarding treatment:

* early intervention (ie, within six weeks of onset);

* avoidance and elimination of pain;

* active mobilization, as long as it does not provoke or increase pain; and

* psychological support.(61)

The usual treatment method applied for pain relief and symptom resolution is the sympathetic nerve block, which includes intravenous regional block (IVRB) (ie, Bier block), brachial plexus, stellate ganglion (ie, cervical), and lumbar blocks. Some authors advocate using permanent sympathectomy when the sympathetic nerve blocks no longer prove effective.

SYMPATHETIC NERVE BLOCKS

Numerous studies in animals and humans have suggested that the interruption of sympathetic innervation may benefit patients with CRPS1.(62) Sympathetic blocks, the mainstay for CRPS1 treatment, do not block motor activity. The patient can still activate his or her own motor systems and, therefore, take advantage of this window of opportunity to perform range of motion exercises.(63) The rationale for sympathetic nerve blocks is to confine and concentrate the medication into a region directly at the sympathetic nerve endings to produce sympathetic denervation (ie, a sympathetic nerve block).(64) An anesthesiologist usually is the physician performing the sympathetic nerve block and managing the patient's pain.(65) The following focuses on sympathetic blocks including IVRB, stellate, and lumbar blocks.

At Wayne General Hospital (WGH), Wayne, NJ, patients receive IVRB, stellate, and lumbar blocks in the OR because they simultaneously require general anesthesia intervention. Perioperative nursing personnel measure and record the patient's preoperative vital signs, obtain informed consent, place a completed history and physical on the chart, and begin an IV.(66) The nurse then verifies the patient's allergy status, medical and surgical history, medications taken daily, and abnormal test results. At this time, the nurse reinforces intraoperative and postoperative teaching with the patient and family members. During the procedure, vital signs will be monitored and documented along with all other pertinent data (eg, positioning and padding, tourniquet pressures and times when applicable, personnel in attendance).

The patient must be monitored with blood pressure cuff and pulse oximetry, and electrocardiogram (ECG) leads must be applied to the patient during all sympathetic nerve block procedures. Monitoring must be continued in the postanesthesia care unit (PACU).(67) Blocks should not be performed without an IV line to allow for immediate venous access in the event of an emergency. The patient also should remain under medical surveillance when the tourniquet is removed to monitor for the generalized effects of the anesthetic agent used in the block (eg, dizziness, dry mouth, nausea, excessive orthostatic hypotension).(68) At any point during or after the procedure, the patient may respond with severe hypotension, malignant hyperthermia (when general anesthesia is administered), or an adverse systemic reaction to the medications used. Resuscitation medications and equipment need to be available for immediate use.(69) Patients receiving anesthesia should be monitored for untoward events for 45 minutes to one hour in the PACU.

Criteria for selecting blocks. The type of block administered is dictated by what the patient can tolerate and how early the disease has been diagnosed. For early stages of CRPS1, cervical or stellate (upper limbs, head or neck), thoracic (chest and viscera), coeliac plexis (gastrointestinal tract and abdominal viscera), hypogastric plexus (pelvic organs), lumbar (lower limbs and distal colon), or regional (eg, Bier block) sympathetic chain blocks with local anesthetic agents are successful for pain relief and are the treatment of choice. Stellate, lumbar, and Bier blocks are most commonly used. The more chronic the illness, the more often nerve blocks are necessary.

The primary reason for the effectiveness of neural blockade is the interruption of nociceptive input at its source. Blockade also interrupts the afferent limb of abnormal reflex mechanisms that may contribute to the pathogenesis of chronic pain syndrome, and it may be used to eliminate sympathetic hyperactivity that often contributes to the pathophysiology.(70) Sympathetic blocks grant a temporary reprieve from pain thereby maintaining the patient's motion and flexibility and decreasing edema while simultaneously optimizing both the comfort and function of the affected region.(71) The blocks can be administered either singularly in a series (eg, over a period of weeks) or continuously with an indwelling catheter. It rarely is expected that the patient will require only one block, as blocks have a 25% to 41% pain relapse rate.(72) The frequency of blocks usually is contingent on the patient's response to the block (ie, the duration of relief). Blocks, in general, should provide relief for several days beyond the time of the block itself and, in some cases, even longer. Scheduling a block without also scheduling immediate physical therapy is a lost opportunity. It is very important to reintroduce pain-free motion during this post-block period. Normal stimuli must predominate and be maintained as the effects of the block diminish.(73)

Success of sympathetic blocks during and after the procedure can be monitored using the quantitative sweat test, laser Doppler flowmetry combined with infrared thermography, continuous skin temperature recordings, thermographic studies, and quantitative sensory and pain responses.(74) In addition, postoperatively the patient's motor function is monitored to be sure no inadvertent somatic involvement occurred with the block.(75)

The benefits of sympathetic blocks range from short- to long-term pain relief depending on the severity of the injury, the length of time between injury onset and treatment, the patient's personality type, and the physician's technique. Pain relief also can be partial or complete. In general, pain relief tends to be complete, but temporary. For some patients, however, no benefit has been noted. The side effects and complications that may occur with sympathetic nerve blocks are noted in Table 7.

Table 7

SYMPATHETIC NERVE BLOCK SIDE EFFECTS AND COMPLICATIONS(1)

NOTE

(1.) F A Papay et al, "Complex regional pain syndrome of the breast in a patient after breast reduction," Annals of Plastic Surgery 39 (October 1997) 347-352; F F Bonica, S H Butler, "Local anaesthesia and regional blocks," in Textbook of Pain, third ed, P D Wall, R Melzack, J Bonica, eds (New York: Churchill Livingstone, 1994) 997-1006; F G Harrington-Kiff, "Sympathetic nerve blocks in painful limb disorders," in Textbook of Pain, third ed, P D Wall, R Melzack, J Bonica, eds (New York: Churchill Livingstone, 1994) 1035-1051.

Some researchers contend that sympathetic nerve blocks are not the panacea they are made out to be. They feel that sympathetic blocks are not more effective in alleviating the pain than administering a placebo. The small population of patients who actually do benefit from blocks, in these researchers' opinions, may be a subgroup of patients with specific clinical features (in particular allodynia, where pain is more likely to respond to blocks). Pain relief, however, invariably remains unpredictable and of uncertain duration. The optimal number and frequency of anesthetic or chemical blocks is unknown. One patient may receive 12 sympathetic blocks and another may require 40 for pain relief.(76) These researchers find that response to blocks is refractory, absent, or, at best, only lasts as long as the duration of the local anesthetic block.

MEDICATIONS USED WITH NERVE BLOCKS

Intravenous regional nerve blocks (IVRB), stellate ganglion (cervical) sympathetic blocks, and lumbar sympathetic nerve blocks all are used to relieve the pain of CRPS1, and various medications are used to accomplish the block and relieve pain.

Guanethidine monosulfate. Guanethidine monosulfate (ie, Esimil), is a postadrenergic blocking agent.(77) Guanethidine is an established method of procuring efferent peripheral sympathetic block in the limbs. It is the most commonly used medication noted in the literature, although it is not marketed in the United States in IV form. This medication currently is under investigation by the US Food and Drug Association. The drug depletes norepinephrine stores from adrenergic endings and prevents the release of norepinephrine from adrenergic nerve endings in response to sympathetic nerve stimulation.(78) It also has a local anesthetic effect.

The side effects for guanethidine include bunting sensations during injection if no local anesthetic is used, stinging sensations under the pneumatic cuff, hypertension, nausea, vomiting, dizziness, diarrhea, weakness, pruritus, urticaria, tinnitus, chest pain, vertigo, syncope, and marked orthostatic hypotension. Complications include deep phlebitis in the lower limbs, vasculitis, and ventricular ectopic beats during the procedure. In sufficient quantities, it can cause permanent damage to the cells' noradrenaline reuptake pump. Chronic administration of guanethidine can lead to a hypersensitization to catecholamines. The effects of the medication can be inhibited by tricyclic antidepressants and digitalis. Concomitant administration of monamine oxidase (MAO) inhibitors and vasopressors are contraindicated.(79)

The benefits of guanethidine are noted by improved pain relief and grip strength and decreased finger stiffness and swelling.(80) The duration of improvement after the regional block with guanethidine has been reported to be up to several months.(81) Blocks often are repeated within a three- to five-day time frame, and the block usually lasts from two to five days.(82) If no improvement occurs after the second block, the treatment should be discontinued.(83)

In addition to guanethidine, some authors also recommend adding phentolamine mesylate (ie, Regitine) to the regime to allow for earlier vasodilation than guanethidine provides alone. Other authors recommend adding a local anesthetic, such as lidocaine hydrochloride 0.5% (ie, Xylocaine) to the solution because the initial release of noradrenaline, caused by the guanethidine injection, causes a considerable exacerbation of pain.(84)

Peripheral sympathetic blockade with regional IV guanethidine infusion has been used for 25 years in Europe. Though some research claims the efficacy of guanethidine, there are opposing studies questioning its use in the management of CRPS1. Some studies were unable to find a significant difference between guanethidine and a placebo.(85) These authors feel that, at the present time, the evidence seems insufficient to support the use of peripheral sympatholytic procedures in the routine management of pain.

Bretylium tosylate. Bretylium tosylate (ie, Bretylol) is an IVRB adrenergic blocking agent that also is used as an antiarrhythmic.(86) This medication has a mode of action similar to guanethidine, but the effects are shorter duration and less profound.(87) Initially, bretylium releases norepinephrine from sympathetic ganglia and terminal endings of postganglionic adrenergic neurons. The medication then blocks the release of norepinephrine in response to sympathetic nerve stimulation by depressing adrenergic nerve terminal excitability.(88)

Bretylium has been found to prolong the duration of pain relief when combined with lidocaine in an IVRB.(89) It is a quarternary compound that does not cross the blood-brain barrier. The treatment, therefore, will not lead to depression and excessive sedation.(90)

The side effects of bretylium include increased blood pressure and heart rate, orthostatic hypotension, and increased sensitivity to catecholamines. In addition, vertigo, lightheadedness, faintness, syncope, bradycardia, precipitation of angina, nausea, and vomiting can occur. This medication is contraindicated in patients taking cardiac glycosides and should be used cautiously with patients taking antiarrhythmic medications.(91)

Reserpine. This medication is an IVRB rauwolfia alkaloid, adrenergic blocking agent.(92) Reserpine has a similar, although less profound, action to guanethidine.(93) It acts to deplete catecholamine and serotonin stores and reduce the uptake of catecholamines.(94) Unfortunately, with repeated treatments of reserpine, the patient could experience depression and excessive sedation because reserpine is a tertiary amine capable of crossing the blood-brain barrier.(95) In addition, convulsions, extrapyramidal reactions, and respiratory depression occur with large doses. Patients receiving MAO inhibitors should not be given reserpine, and patients taking hypotensive agents, beta adrenergic blockers, cardiac glycosides, and sympathomimetic amines should be monitored for adverse effects. Side effects include hypotension, bradycardia, nasal congestion, drowsiness, fatigue, lethargy, and mental depression.(96)

Phentolamine mesylate. Phentolamine mesylate (ie, Regitine) is an IVRB, alpha adrenergic receptor antagonist/imidazoline blocking agent.(97) Phentolamine inhibits responses to adrenergic stimuli by competitively blocking alpha adrenergic receptors.(98) The relief from phentolamine lasts several hours. Tachycardia, prolonged hypotension, cardiac arrhythmias, weakness, dizziness, flushing, orthostatic hypotension, nausea, vomiting, and diarrhea are potential side effects of IV phentolamine. The disadvantage is its short duration.(99)

Local anesthetics. Local anesthetics block the generation and conduction of all nerve impulses--sensory, motor, and autonomic--depending on the site of injection. The result is a temporary loss of feeling or sensation in a limited body area. Parenteral local anesthetics are used for infiltration and nerve block anesthesia. Adverse effects result from high plasma concentrations of the drug caused by excessive dosage, excessive rate of injection, or slow metabolic degradation of the medication. Adverse effects initially include anxiety, apprehension, disorientation, confusion, dizziness, tremors, shivering, and seizures. These central nervous system stimulatory effects then are followed by drowsiness, unconsciousness, and respiratory arrest. Other adverse effects include nausea, vomiting, tinnitus, myocardial depression, bradycardia, cardiac arrhythmias, hypotension, and cardiac arrest.(100)

Lidocaine hydrochloride. Lidocaine hydrochloride (ie, Xylocaine) is an IVRB amide local anesthetic. Short-term analgesia has been noted with intravenous lidocaine, either 0.5% or 1%.(101) Lidocaine is sometimes used along with other injectable medications as the diluent solution to provide local anesthesia.(102) The onset of anesthesia with lidocaine is more rapid and the duration of action is longer than with procaine hydrochloride.

Bupivacaine hydrochloride. Bupivacaine hydrochloride (ie, Sensorcaine) is a stellate and paravertebral lumbar block amide local anesthetic. Bupivacaine depresses adrenergic transmission. Its duration is three to four hours, and it is not recommended for IVRB because high plasma concentrations of the drug may occur following the tourniquet release, resulting in cardiac arrest and death.(103)

COMMON SYMPATHETIC NERVE BLOCKS USED WITH CRPS1

Several types of nerve blocks (ie, IVRB, stellate ganglion [cervical] sympathetic blocks, lumbar sympathetic blocks) are used to treat CRPS1.

Intravenous regional sympathetic blocks. Anesthesia personnel achieve an IVRB by first introducing a 20-g angiocatheter into a vein on the affected limb as distal as possible to facilitate the injection of a sedative and to allow for the injection of the blocking agent. Placement of the venous catheter may be difficult in a hyperesthetic and edematous limb. The nurse applies all routine monitoring devices (ie, blood pressure cuff, ECG leads, pulse oximetry) to the patient in a manner that will not interfere with administration of the IVRB and assists anesthesia personnel in monitoring the patient throughout the procedure and in the PACU.

No prepping or draping is done for this procedure as all medications enter through an IV line or heparin lock. The nurse applies padding and the correct size pneumatic cuff proximally to the injection site to provide arterial occlusion. He or she sets the cuff pressure at least 50 mmHg above the patient's systolic blood pressure when the block site is in the arm and 100 mmHg above systolic pressure if the block is in the leg. In sedated patients, higher tourniquet pressures can be set. The upper arm usually is used as the tourniquet cuff site, although the forearm is an alternative. In the lower limb, the cuff is applied to the upper thigh. The cuff should not be applied to the calf because of the risk of deep vein thrombosis with the potential for pulmonary embolus.(104) The nurse assists anesthesia personnel in raising the limb well above heart level for about two minutes to drain venous blood or in wrapping an elastic compressive bandage tightly around the limb to exsanguinate it. After the cuff is inflated, the arm is returned to a horizontal position, the elastic wrap is removed, and anesthesia personnel inject the blocking solution.

The injection is administered during 90 seconds so that the injection pressure is never greater than the cuff pressure. The cuff is left in place for a minimum of six minutes if a nonsympathoplegic substance is used, 10 minutes if a local anesthetic agent is not used, or 15 to 20 minutes when sympathoplegic substances are used or if a local anesthetic has been added to the formula.(105) Premature release or accidental failure of the pneumatic cuff poses the greatest unforeseen hazard to the patient. Systemic effects should be minimal if the tourniquet is kept inflated for at least 20 minutes to allow fixation of the injected drug to the tissues.(106)

The treated limb will show patchy areas of pallor caused by arteriolar constriction. This probably is the result of the noradrenaline released by guanethidine, and it is at this time that burning pain may occur in the conscious patient. At WGH, the anesthesiologist performs the block with the patient under general anesthesia because the patient is in pain, the tourniquet is uncomfortable, and the injection bums even when the medication is diluted. The procedure also could be performed with IV conscious sedation.

The tourniquet should not be removed after it has been released so that it can be reinflated in an emergency situation (eg, hypotension, systemic reactions). Reinflation will prevent the release of any more medication into the patient's system. The danger of hypotension after the injection has been noted in the literature, and intensive care equipment and resuscitation facilities must be readily available.(107) After the procedure, patients should be confined to bed for two hours, especially if they have had any form of sedation or general anesthesia.

Contraindications for IVRB are infection, history of phlebitis, distal nerve injury, ischemia, and arteritis. In the case of ischemia and arteritis, the physician can still perform the procedure as long as he or she gives the patient 500 IU of heparin.(108) Complications of an IVRB include transient vertigo and tinnitus, numbness, and carpopedal spasms in extremities; superficial infection; and superficial thrombophlebitis. Unwanted systemic effects are unusual if careful attention is given to the application of a pneumatic cuff. Physiotherapy should immediately follow the block. Blocks may be repeated at three- to four-day intervals for up to four blocks given per series.(109)

Stellate ganglion (cervical) sympathetic blocks. The stellate ganglion incorporates the cervicothoracic ganglia, which usually includes C7 to T1.(110) The block is performed under sterile conditions using the anterior paratracheal approach, with or without fluoroscopic guidance, at the level of the C6 vertebral body and transverse process using 5 mL to 15 mL of 1% lidocaine injected through a 22 g or 25 g needle (Figure 1). Fluoroscopic imaging with dye allows increased accuracy of medication placement. The stellate ganglia also are reached through the posterior paravertebral route in the upper thoracic region or through the subclavian.

[Figure 1 ILLUSTRATION OMITTED]

The nurse should place the patient supine for the block with his or her neck slightly extended by removing the pillow and using a small roll placed under the patient's shoulders to facilitate palpation of the C6 tubercle.(111) Another author suggests the patient should be in a sitting position from the beginning.(112) The anesthesiologist preps the area with povidone iodine and covers it with a fenestrated drape. He or she inserts the needle above the sternoclavicular joint and lateral to the midline (while the carotid artery is retracted laterally) until it contacts the transverse process of C6. He or she then withdraws the needle approximately 1 mm to 2 mm and injects 5 mL to 15 mL of local anesthetic after aspirating the syringe to ensure the needle is not in a blood vessel. It is imperative that the needle be positioned correctly so the recurrent laryngeal and phrenic nerves are not infiltrated with medication. Conscious patients should be cautioned that they may experience the sensation of a lump in their throats or a sense of dyspnea.

The nurse and anesthesia personnel continuously monitor and record the patient's blood pressure, heart rate, pulse oximetry, and surface temperature of both hands during the procedure. The presence or absence of Homer's syndrome (ie, contraction of the pupil, partial ptosis of the eyelid, enophthalmos, facial anhydrosis) is noted and recorded as well. An increase in skin surface temperature on the ipsilateral limb, visible engorgement of the veins on the back of the hand and forearm, dryness of the skin, and subjective feelings of warmth are used to determine sympathetic blockade.(113) Bupivacaine 0.25% also can be used with stellate ganglion blocks.(114)

Effective sympatholysis to the chest wall requires interruption of the preganglionic sympathetic efferents from T1 through T7. A stellate ganglion block will provide partial sympatholysis, depending on the amount of local used. One patient noted in the literature, for instance, had a modified radical mastectomy. She presented with chronic burning breast pain with cutaneous hypersensitivity to light touch and temperature changes, skin discoloration, epidermal scaling, swelling, scar formation, and stiffness of the right shoulder and upper arm. Previous oral medications such as antibiotics, anti-inflammatory agents, narcotics, calcium channel blockers, and antidepressants provided no relief. This patient received a right stellate ganglion block with bupivacaine. After the block, the right breast immediately warmed, skin became pink, and pain disappeared from the right breast and upper extremity.(115)

The stellate ganglion block should be repeated every other day until the pain is controlled, for a maximum of 12 blocks. Intermittent use of stellate ganglion block (eg, three times per week for four weeks) also is effective.(116) If there is no response after two stellate ganglion blocks, the procedure should not be administered again as the pain is not sympathetically mediated. If the patient received pain relief after the 12-block series but the pain recurs after a short period of time, surgical sympathectomy (as discussed later) is indicated.(117)

Complications of stellate sympathetic blocks can be very serious and may be life threatening. They include malaise, loss of consciousness, Horner's syndrome (temporary), pneumothorax, bradycardia and dysrhythmia with right stellate block, vertebral artery injection (which leads to seizure and death), inadvertent brachial plexus block, inability to cough, hoarse voice, epidural or subdural injection, and migraines.(118)

Lumbar sympathetic blocks. The lumbar sympathetic plexus is continuous with the thoracic sympathetic chain above and the pelvic chain below. It runs along the medial border of the psoas muscle, entering the abdomen from behind the medial arcuate ligament. The right sympathetic trunk lies behind the lateral border of the inferior vena cava and the left sympathetic trunk lies close the lateral border of the aorta.(119) The lumbar sympathetic nervous system forms the major efferent component of the peripheral nervous system, and it regulates the function of innervated tissues and organs. These functions include regulation of blood flow, digestion, reproduction, thermal regulation, and evacuation of body waste.

Three main types of lumbar sympathetic nerve blockades for pain include the paravertebral approach and spinal and epidural injections of local anesthetics. These are performed with single-shot injections or with indwelling lumbar catheters with continuous or intermittent bolus dosing.(120) The paravertebral blockade is the best method for spinal blockade for SMP.(121) With this method, a local anesthetic is delivered to the sympathetic chain in the paravertebral area. The advantage is that long-lasting anesthetic agents can be delivered outside of the spinal column to the sympathetic ganglia, thereby avoiding any blockade of sensory or motor nerves. A skilled anesthesiologist is required to administer the anesthetic effectively.

There are two thoughts on patient positioning for lumbar blocks: patients can be either prone or lateral lying in a fetal position. In the first case, the nurse places the patient prone with a pad under the abdomen to flatten the normal lumbar lordosis. In the lateral position, the nurse places the patient on his or her lateral side with the affected side down, knees flexed into the chest, and head tucked into the chest. In either scenario, the nurse pads all prominences and assists anesthesia personnel in maintaining the airway. He or she preps and drapes the patient in a sterile fashion. Blood pressure, heart rate, oxygen saturation, ECG, and skin temperatures of the affected extremities are continuously monitored and recorded during the procedure.

Anesthesia personnel place a 19 g needle or epidural catheter apparatus 5 cm to 7 cm lateral to the midline of the third lumbar vertebral body based on mapping determined by computed tomography (CT) scan or with fluoroscopy during the procedure. The objective is to place the needle or catheter anterior to the psoas muscle and posterolateral to the inferior vena cava or aorta. Computed tomography or fluoroscopy with contrast media confirms the needle-tip position along with negative aspiration of the needle for blood return. The advantage of CT over fluoroscopic techniques is that the CT scan shows the exact position of the catheter, where the anesthetic material is distributed, and major surrounding anatomic structures so that inadvertent puncture of the kidney, lung, or vessels can be avoided.

The complications of fluoroscopic procedures include puncture of the renal pelvis or ureter, epidural injection, disk perforation, L1 nerve damage, and lymphocele formation.(122) If fluoroscopy is used, the image should be in real time to ensure that the material is not being injected into a blood vessel or ureter.(123)

A paravertebral block of the T2 and T3 sympathetic ganglia will relieve pain in the upper limbs without involving roots of the brachial plexus. Similarly, blockade of the lumbar sympathetic chain relieves SMP in the foot or leg without involving the roots of somatic nerves.(124) In the case of lower extremity CRPS1, lumbar sympathetic neural blockade should be performed on the ipsilateral extremity on a daily or every-other-day basis. Bilateral sides can be performed at the same time sequentially or the procedure can be ipsilateral. Blocks may be given as frequently as every other day for two weeks to achieve a long-lasting effect.(125) Continuous infusion occurs during a one- to eight-day period and bolus injections are provided once per day during a three- to four-day period.(126) Continuous and repetitive lumbar sympathetic blocks have the potential to break the vicious cycle of chronic excitation of nerve fibers that in turn leads to distorted information processing in the spinal cord.(127)

When diagnosed early, repeated long-lasting paravertebral blocks can be an effective form of treatment. These blocks may provide pain relief for much longer than the expected duration of the pharmacologic effect of the anesthetic agent. The more complete and long lasting the pain relief from a lumbar sympathetic block, the better the prognosis for recovery.(128) These blocks, when successful, result in arterial vasodilation; erythema; increased temperature of 35.6 [degrees] F (2 [degrees] C) to 37.4 [degrees] F (3 [degrees] C) to the extremity; and decreased pain, sweating, and sympathetic hyperactivity.(129)

Complications of lumbar sympathetic block include perforation of the disc, somatic nerve damage (eg, genitourinary nerve damage or sciatic damage), vertebral structural damage, vena cava or aortic perforation, kidney damage, and orthostatic hypotension with bilateral blocks. In addition, with spinal injection, the patient may receive very high or total spinal anesthesia, resulting in respiratory paralysis and hypotension. This is due to accidental subarachnoid injection with concomitant rapid development of bilateral analgesia. The anesthetic agent ascends rapidly to involve the cervical and cranial nerves, especially when the injection is in the upper thoracic and cervical region. The patient will become restless, drowsy, dyspneic, unable to speak, and may lose consciousness. This can be prevented by needle aspiration before injection to observe for passive return of cerebrospinal fluid.(130)

CONCLUSION

Studies on CRPS1 have yielded conflicting results. For every study showing the benefits of sympathetic nerve blocks, there is another displaying the opposite conclusion. The literature shows the reported positive response rate for sympathetic blocks in CRPS1 patients varies from 0% to 95%.(131) Most studies on CRPS1 are flawed because there have been errors in study design (eg, poor controls, missing randomized double-blind protocols); small sample sizes; different block techniques that make comparison difficult; short clinical trials without long-term outcome variables; an inability to develop cause-effect relationships between treatment and outcomes (ie, patient may feel better because symptoms resolved naturally rather than related to the block); high subject drop out rates, which compromise randomness; inability to replicate results; questionable reliability of outcome measures (eg, quantitative versus qualitative); anecdotal evidence with no statistical analysis; inadequate dosages of medication; development of drug tolerance; or early termination of the treatment.(132)

In spite of their drawbacks, the major points that are gleaned from these studies are that

* a better understanding of the pathophysiology of CRPS1 is mandatory to develop improved treatment plans;

* treatment must be instituted early on (ie, within 3 months of diagnosis) before the disease progresses for positive outcomes;

* sympathetic blocks provide temporary pain relief for a majority of CRPS1 patients and should be instituted in tandem with physical therapy; and

* controlled, well-designed, long-range studies are needed to better evaluate different treatments.

These important points can help professionals caring for patients with chronic pain keep abreast of current research and determine the best treatment for these patients.

NOTES

(1.) S Sintzoff et al, "Imaging in reflex sympathetic dystrophy," Hand Clinics 13 (August 1997) 431-442; G M Ribbers et al, "Axillary brachial plexus blockade for the reflex sympathetic dystrophy syndrome," International Journal of Rehabilitation Research 20 (December 1997) 371-380.

(2.) Sintzoff et al, "Imaging in reflex sympathetic dystrophy," 431-442; P R Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms," Hand Clinics 13 (August 1997) 367-372; H Breivik, "Chronic pain and the sympathetic nervous system," Acta Anaesthesiologica Scandinavica, suppl 110 (1997) 131-134; D W Dobritt, P Gutowski, "Successful treatment of recurrent reflex sympathetic dystrophy with bilateral lumbar sympathectomies," Journal of the American Osteopathic Association 97 (September 1997) 533-535; B V MacFarlane et al, "Chronic neuropathic pain and its control by drugs." Pharmacology and Therapeutics 75 (1997) 1-19.

(3.) J Engstrom, J B Martin, "Disorders of the autonomic nervous system," in Harrison's Principles of Internal Medicine, 14th ed, Fauci et al, eds (New York: McGraw-Hill Health Professions Division, 1998) 2372-2377.

(4.) R A Boas, "Sympathetic nerve blocks: In search of a role," Regional Anesthesia and Pain Medicine 23 (May-June, 1998) 292-305.

(5.) Sintzoff et al, "Imaging in reflex sympathetic dystrophy," 431-442; Breivik, "Chronic pain and the sympathetic nervous system," 131-134; R M Davis, A F Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain (Haddonfield, NJ: Reflex Sympathetic Dystrophy Association of America) 1-16; M M Kiroglu et al, "Reflex sympathetic dystrophy following neck dissections," American Journal of Otolaryngology 18 (March/April 1997) 103-106.

(6.) N Gordon, "Review article: Reflex sympathetic dystrophy," Brain and Development 18 (July/August 1996) 257-262.

(7.) F A Papay et al, "Complex regional pain syndrome of the breast in a patient after breast reduction," Annals of Plastic Surgery 39 (October 1997) 347-352.

(8.) S M Walker, M J Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" Anaesthesia and Intensive Care 25 (April 1997) 113-125.

(9.) Facts and Fiction about Reflex Sympathetic Dystrophy Syndrome, (Haddonfield, NJ: RSD Syndrome Association); K Kumar, R K Nath, C Toth, "Spinal cord stimulation is effective in the management of reflex sympathetic dystrophy," Neurosurgery 40 (March 1997) 503-509.

(10.) J Arlet, B Mazieres, "Medical treatment of reflex sympathetic dystrophy," Hand Clinics 13 (August 1997) 477-483.

(11.) Engstrom, Martin, "Disorders of the autonomic nervous system," 2372-2377; Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531; J Whitlow, "RSD Remains Puzzling Source of Chronic Pain," The Star-Ledger, 12 Sept 1993.

(12.) Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531; Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125; Davis, Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain, 1-16.

(13.) Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531.

(14.) Boas, "Sympathetic nerve blocks: In search of a role," 292-305.

(15.) T Keller, L Goldstein, T Chappell, "`Gamekeeper's thumb' variant, complicated by reflex sympathetic dystrophy," The Journal of Trauma 40 (April 1996) 660-662.

(16.) W P Cooney, "Somatic versus sympathetic mediated chronic limb pain: Experience and treatment options," Hand Clinics 13 (August 1997) 355-361.

(17.) Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms," 367-372; Breivik, "Chronic pain and the sympathetic nervous system," 131-134.

(18.) Kumar, Nath, Toth, "Spinal cord stimulation is effective in the management of reflex sympathetic dystrophy," 503-509.

(19.) Boas, "Sympathetic nerve blocks: In search of a role," 292-305; Breivik, "Chronic pain and the sympathetic nervous system," 131-134; D Z Levine, "Burning pain in an extremity: Breaking the destructive cycle of reflex sympathetic dystrophy," Postgraduate Medicine 90 (August 1991) 175-185; D L Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" Hand Clinics 13 (August 1997) 485-497; R K Nath, S E Mackinnon, E Stelnicki, "Reflex sympathetic dystrophy: The controversy continues," Clinics in Plastic Surgery 23 (July 1996) 435-446.

(20.) Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms," 367-372.

(21.) Ibid; Breivik, "Chronic pain and the sympathetic nervous system," 131-134.

(22.) K Honjyo et al, "An 11-year-old girl with reflex sympathetic dystrophy successfully treated by thoracoscopic sympathectomy," Acta Paediatrica 86 (August 1997) 903-905.

(23.) Levine, "Burning pain in an extremity: Breaking the destructive cycle of reflex sympathetic dystrophy," 175-185.

(24.) Ribbers et al, "Axillary brachial plexus blockade for the reflex sympathetic dystrophy syndrome." 371-380; Engstrom, Martin, "Disorders of the autonomic nervous system," 2372-2377; J P Prager, M Csete, "An unusual cause of pain after nevus excision: Complex regional pain syndrome," Journal of the American Academy of Dermatology 37 (October 1997) 652-653.

(25.) Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531.

(26.) R L Arden et al, "Reflex sympathetic dystrophy of the face: Current treatment recommendations," Laryngoscope 108 (March 1998) 437-442.

(27.) T N Lindenfeld, B R Bach, E M Wojtys, "Reflex sympathetic dystrophy and pain dysfunction in the lower extremity," Instructional Course Lectures 46 (1997) 261-268.

(28.) Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms," 367-372; H Gellman, D Nichols, "Reflex sympathetic dystrophy in the upper extremity," Journal of the American Academy of Orthopaedic Surgeons 5 (November 1997) 313-322.

(29.) Breivik, "Chronic pain and the sympathetic nervous system," 131-134; Dobritt, Gutowski, "Successful treatment of recurrent reflex sympathetic dystrophy with bilateral lumbar sympathectomies," 533-535; Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531.

(30.) Ribbers et al, "Axillary brachial plexus blockade for the reflex sympathetic dystrophy syndrome," 371-380.

(31.) Sintzoff et al, "Imaging in reflex sympathetic dystrophy," 431-442.

(32.) Ibid; Davis, Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain, 1-16; Keller, Goldstein, Chappell, "`Gamekeeper's thumb' variant, complicated by reflex sympathetic dystrophy," 660-662.

(33.) Boas, "Sympathetic nerve blocks: In search of a role," 292-305.

(34.) Gellman, Nichols, "Reflex sympathetic dystrophy in the upper extremity," 313-322.

(35.) Levine, "Burning pain in an extremity: Breaking the destructive cycle of reflex sympathetic dystrophy," 175-185.

(36.) Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms," 367-372; Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125; Nath, Mackinnon, Stelnicki, "Reflex sympathetic dystrophy: The controversy continues," 435-446.

(37.) Davis, Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain, 1-16.

(38.) Gordon, "Review article: Reflex sympathetic dystrophy," 257-262; Papay et al, "Complex regional pain syndrome of the breast in a patient after breast reduction," 347-352; Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125; Lindenfeld, Bach, Wojtys, "Reflex sympathetic dystrophy and pain dysfunction in the lower extremity," 261-268; L van der Laan, R J A Goris, "Reflex sympathetic dystrophy: An exaggerated regional inflammatory response?" Hand Clinics 13 (August 1997) 373-385.

(39.) Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125.; Lindenfeld, Bach, Wojtys, "Reflex sympathetic dystrophy and pain dysfunction in the lower extremity," 261-268; van der Laan, Goris, "Reflex sympathetic dystrophy: An exaggerated regional inflammatory response?" 373-385; M A Hardy, S G P Hardy, "Reflex sympathetic dystrophy: The clinician's perspective," Journal of Hand Therapy 10 (April-June 1997) 137-150.

(40.) MacFarlane et al, "Chronic neuropathic pain and its control by drugs," 1-19; Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and causalgia,'" 113-125; Kumar, Nath, Toth, "Spinal cord stimulation is effective in the management of reflex sympathetic dystrophy," 503-509; Keller, Goldstein, Chappell, "`Gamekeeper's thumb' variant, complicated by reflex sympathetic dystrophy," 660-662; Gellman, Nichols, "Reflex sympathetic dystrophy in the upper extremity," 313-322.

(41.) Papay et al, "Complex regional pain syndrome of the breast in a patient after breast reduction," 347-352.

(42.) Gordon "Review article: Reflex sympathetic dystrophy," 257-262.

(43.) Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531.

(44.) Gordon, "Review article: Reflex sympathetic dystrophy," 257-262; Papay et al, "Complex regional pain syndrome of the breast in a patient after breast reduction," 347-352; Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia," 113-125; van der Laan, Goris, "Reflex sympathetic dystrophy: An exaggerated regional inflammatory response?" 373-385; R F Lopez, "Reflex sympathetic dystrophy: Timely diagnosis and treatment can prevent severe contractures," Postgraduate Medicine 101 (April 1997) 185-190.

(45.) Lopez, "Reflex sympathetic dystrophy: Timely diagnosis and treatment can prevent severe contractures," 185-190.

(46.) Sintzoff et al, "Imaging in reflex sympathetic dystrophy," 431-442; Davis, Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain, 1-16.

(47.) Engstrom, Martin, "Disorders of the autonomic nervous system," 2372-2377; Kumar, Nath, Toth, "Spinal cord stimulation is effective in the management of reflex sympathetic dystrophy," 503-509; R J Schwartzman et al, "Long-term outcome following sympathectomy for complex regional pain syndrome type 1 (RSD)," Journal of the Neurological Sciences 150 (1997) 149-152.

(48.) Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms," 367-372; Schwartzman et al, "Long-term outcome following sympathectomy for complex regional pain syndrome type 1 (RSD)," 149-152.

(49.) MacFarlane et al, "Chronic neuropathic pain and its control by drugs," 1-19.

(50.) Lopez, "Reflex sympathetic dystrophy: Timely diagnosis and treatment can prevent severe contractures," 185-190; Schwartzman et al, "Long-term outcome following sympathectomy for complex regional pain syndrome type 1 (RSD)," 149-152.

(51.) Lopez, "Reflex sympathetic dystrophy: Timely diagnosis and treatment can prevent severe contractures," 85-190.

(52.) Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531.

(53.) Sintzoff et al, "Imaging in reflex sympathetic dystrophy," 431-442; Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531; Davis, Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain, 1-16; Kiroglu et al, "Reflex sympathetic dystrophy following neck dissections," 103-106; Arlet, Mazieres, "Medical treatment of reflex sympathetic dystrophy," 477-483; Arden et al, "Reflex sympathetic dystrophy of the face: Current treatment recommendations," 437-442; Gellman, Nichols, "Reflex sympathetic dystrophy in the upper extremity," 313-322; van der Laan, Goris, "Reflex sympathetic dystrophy: An exaggerated regional inflammatory response?" 373-385; Hardy, Hardy, "Reflex sympathetic dystrophy: The clinician's perspective," 137-150; P C C Doury, "Algodystrophy: A spectrum of disease, historical perspectives, criteria of diagnosis, and principles of treatment," Hand Clinics 13 (August 1997) 327-337.

(54.) Sintzoff et al, "Imaging in reflex sympathetic dystrophy," 431-442; Engstrom, Martin, "Disorders of the autonomic nervous system," 2372-2377; Walker, Cousins, "Complex regional pain syndromes: Including reflex sympathetic dystrophy' and `causalgia,'" 113-125; Davis, Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain, 1-16; Kumar, Nath, Toth, "Spinal cord stimulation is effective in the management of reflex sympathetic dystrophy," 503-509; Cooney, "Somatic versus sympathetic mediated chronic limb pain," 355-361; Levine, "Burning pain in an extremity: Breaking the destructive cycle of reflex sympathetic dystrophy," 175-185; Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497; Nath, Mackinnon, Stelnicki, "Reflex sympathetic dystrophy: The controversy continues," 435-446; Gellman, Nichols, "Reflex sympathetic dystrophy in the upper extremity," 313-322; W S Kingery, "A critical review of controlled clinical trials for peripheral neuropathic pain and complex regional pain syndromes," Pain 73 (November 1997) 123-139.

(55.) Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531; Prager, Csete, "An unusual cause of pain after nevus excision: Complex regional pain syndrome," 652-653.

(56.) R Kaplan et al, "Intravenous guanethidine in patients with reflex sympathetic dystrophy," Acta Anaesthesiologica Scandinavica 40 (1996) 1216-1222.

(57.) Breivik, "Chronic pain and the sympathetic nervous system," 131-134; Dobritt, Gutowski, "Successful treatment of recurrent reflex sympathetic dystrophy with bilateral lumbar sympathectomies," 533-535.

(58.) Davis, Thomas, Reflex Sympathetic Dystrophy Syndrome (RSDS): Help Us Stop the Pain, 1-16.

(59.) Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms," 367-372.

(60.) F F Bonica, S H Butler, "Local anaesthesia and regional blocks" in Textbook of Pain, third ed, P D Wall, R Melzack, J R Bonica, eds (Edinburgh, New York: Churchill Livingstone, 1994) 997-1006.

(61.) Doury, "Algodystrophy: A spectrum of disease, historical perspectives, criteria of diagnosis, and principles of treatment," 327-337.

(62.) Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497.

(63.) Ibid.

(64.) F G Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders" in Textbook of Pain, third ed, P D Wall, R Melzack, eds (Edinburgh, New York: Churchill Livingstone, 1994) 1035-1051.

(65.) Boas, "Sympathetic nerve blocks: In search of a role," 292-305.

(66.) Bonica, Butler, "Local anaesthesia and regional blocks," 997-1006.

(67.) Kaplan et al, "Intravenous guanethidine in patients with reflex sympathetic dystrophy," 1216-1222; Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(68.) Arlet, Mazieres, "Medical treatment of reflex sympathetic dystrophy," 477-483.

(69.) Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497.

(70.) Bonica, Butler, "Local anaesthesia and regional blocks," 997-1006.

(71.) Levine, "Burning pain in an extremity: Breaking the destructive cycle of reflex sympathetic dystrophy," 175-185.

(72.) Boas, "Sympathetic nerve blocks: In search of a role," 292-305.

(73.) Hardy, Hardy, "Reflex sympathetic dystrophy: The clinician's perspective," 137-150.

(74.) Boas, "Sympathetic nerve blocks: In search of a role," 292-305.

(75.) Levine, "Burning pain in an extremity: Breaking the destructive cycle of reflex sympathetic dystrophy," 175-185.

(76.) G D Schott, "Interrupting the sympathetic outflow in causalgia and reflex sympathetic dystrophy," British Medical Journal 316 (March 14, 1998) 792-793.

(77.) MacFarlane et al, "Chronic neuropathic pain and its control by drugs," 1-19; Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497; Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(78.) Gordon "Review article: Reflex sympathetic dystrophy," 257-262; Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic: dystrophy' and `causalgia,'" 113-125; Arlet, Mazieres, "Medical treatment of reflex sympathetic dystrophy," 477-483; G K McEvoy ed, AHFS Drug Information 1999, (Bethesda, Md: American Society of Health System Pharmacists, 1999) 1167-1170, 1393-1396, 1593-1595, 1627-1630, 2804-2807, 2811-2813.

(79.) Boas, "Sympathetic nerve blocks: In search of a role," 292-305; Kaplan, et al, "Intravenous guanethidine in patients with reflex sympathetic dystrophy," 1216-1222; Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051; McEvoy, AHFS Drug Information 1999, 1593-1595.

(80.) Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125.

(81.) Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497.

(82.) J M Farcot, M Gautherie, G Foucher, "Regional intravenous sympathetic nerve blocks," Hand Clinics 13 (August 1997) 499-517.

(83.) Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125; Farcot, Gautherie, Foucher, "Regional intravenous sympathetic nerve blocks," 499-517.

(84.) Kaplan et al, "Intravenous guanethidine in patients with reflex sympathetic dystrophy," 1216-1222; Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(85.) Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125; Kingery, "A critical review of controlled clinical trials for peripheral neuropathic pain and complex regional pain syndromes," 123-139; Schott, "Interrupting the sympathetic outflow in causalgia and reflex sympathetic dystrophy," 792-793.

(86.) Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497.

(87.) Ibid; Farcot, Gautherie, Foucher, "Regional intravenous sympathetic nerve blocks," 499-517.

(88.) Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125; Kingery, "A critical review of controlled clinical trials for peripheral neuropathic pain and complex regional pain syndromes," 123-139.

(89.) Gellman, Nichols, "Reflex sympathetic dystrophy in the upper extremity," 313-322.

(90.) Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(91.) McEvoy, AHFS Drug Information 1999, 1393-1396.

(92.) Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(93.) Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497; Farcot, Gautherie, Foucher, "Regional intravenous sympathetic nerve blocks," 499-517.

(94.) McEvoy, AHFS Drug Information 1999, 1627-1630.

(95.) Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(96.) McEvoy, AHFS Drug Information 1999, 1627-1630.

(97.) Nath, Mackinnon, Stelnicki, "Reflex sympathetic dystrophy: The controversy continues," 435-446.

(98.) McEvoy, AHFS Drug Information 1999, 1167-1170.

(99.) Lindenfeld, Bach, Wojtys, "Reflex sympathetic dystrophy and pain dysfunction in the lower extremity," 261-268.

(100.) McEvoy, AHFS Drug Information 1999, 2804-2807.

(101.) Kingery, "A critical review of controlled clinical trials for peripheral neuropathic pain and complex regional pain syndromes," 123-139; McEvoy, AHFS Drug Information 1999, 2811-2813.

(102.) Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497.

(103.) D D Price et al, "Analysis of peak magnitude and duration of analgesia produced by anesthetics injected into sympathetic ganglia of complex regional pain syndrome patients," The Clinical Journal of Pain 14 (September 1998) 216-226.

(104.) Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(105.) Farcot, Gautherie, Foucher, "Regional intravenous sympathetic nerve blocks," 499-517.

(106.) Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(107.) Gordon "Review article: Reflex sympathetic dystrophy," 257-262.

(108.) Farcot, Gautherie, Foucher, "Regional intravenous sympathetic nerve blocks," 499-517.

(109.) Kasdan, Johnson, "Reflex sympathetic dystrophy," 521-531; Gordon "Review article: Reflex sympathetic dystrophy," 257-262; Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125; Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497; Kaplan et al, "Intravenous guanethidine in patients with reflex sympathetic dystrophy," 1216-1222; Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(110.) Gellman, Nichols, "Reflex sympathetic dystrophy in the upper extremity," 313-322.

(111.) Price et al, "Analysis of peak magnitude and duration of analgesia produced by anesthetics injected into sympathetic ganglia of complex regional pain syndrome patients," 216-226.

(112.) Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(113.) MacFarlane et al, "Chronic neuropathic pain and its control by drags," 1-19; Brown, "Somatic or sympathetic block for reflex sympathetic dystrophy: Which is indicated?" 485-497.

(114.) Price et al, "Analysis of peak magnitude and duration of analgesia produced by anesthetics injected into sympathetic ganglia of complex regional pain syndrome patients," 216-226.

(115.) Papay et al, "Complex regional pain syndrome of the breast in a patient after breast reduction," 347-352.

(116.) Gellman, Nichols, "Reflex sympathetic dystrophy in the upper extremity," 313-322.

(117.) Ibid.

(118.) Arlet, Mazieres, "Medical treatment of reflex sympathetic dystrophy," 477-483; Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051; G Lamacraft et al, "Interrupting the sympathetic outflow in causalgia and reflex sympathetic dystrophy: Intravenous regional guanethidine blockade is a safe and effective treatment," British Medical Journal 317 (Sept 12, 1998) 752-753; L J Lehmann, C A Warfield, Z H Bajwa, "Migraine headache following stellate ganglion block for reflex sympathetic dystrophy," Headache 36 (May 1996) 335-337.

(119.) R J Wechsler et al, "Percutaneous lumbar sympathetic plexus catheter placement for short- and long-term pain relief: CT technique and results," Journal of Computer Assisted Tomography 22 (July/August 1998) 518-523.

(120.) Papay et al, "Complex regional pain syndrome of the breast in a patient after breast reduction," 347-352; Wechsler et al, "Percutaneous lumbar sympathetic plexus catheter placement for short- and long-term pain relief: CT technique and results," 518-523.

(121.) Lindenfeld, Bach, Wojtys, "Reflex sympathetic dystrophy and pain dysfunction in the lower extremity," 261-268.

(122.) Boas, "Sympathetic nerve blocks: In search of a role," 292-305; Wechsler et al, "Percutaneous lumbar sympathetic plexus catheter placement for short- and long-term pain relief: CT technique and results," 518-523.

(123.) Hannington-Kiff, "Sympathetic nerve blocks in painful limb disorders," 1035-1051.

(124.) Bonica, Butler, "Local anaesthesia and regional blocks," 997-1006.

(125.) Lindenfeld, Bach, Wojtys, "Reflex sympathetic dystrophy and pain dysfunction in the lower extremity," 261-268.

(126.) Wechsler et al, "Percutaneous lumbar sympathetic plexus catheter placement for short- and long-term pain relief: CT technique and results," 518-523.

(127.) Ibid.

(128.) Lindenfeld, Bach, Wojtys, "Reflex sympathetic dystrophy and pain dysfunction in the lower extremity," 261-268.

(129.) Dobritt, Gutowski, "Successful treatment of recurrent reflex sympathetic dystrophy with bilateral lumbar sympathectomies," 533-535; Gordon "Review article: Reflex sympathetic dystrophy," 257-262.

(130.) Kingery, "A critical review of controlled clinical trials for peripheral neuropathic pain and complex regional pain syndromes," 123-139.

(131.) Wilson, "Post-traumatic upper extremity reflex sympathetic dystrophy: Clinical course, staging, and classification of clinical forms." 367-372; Wechsler et al, "Percutaneous lumbar sympathetic plexus catheter placement for short-and long-term pain relief: CT technique and results," 518-523.

(132.) Walker, Cousins, "Complex regional pain syndromes: Including `reflex sympathetic dystrophy' and `causalgia,'" 113-125; Kingery, "A critical review of controlled clinical trials for peripheral neuropathic pain and complex regional pain syndromes," 123-139; Schott, "Interrupting the sympathetic outflow in causalgia and reflex sympathetic dystrophy," 792-793.

Examination

CHRONIC REGIONAL PAIN SYNDROME, TYPE 1: PART I

AORN, Association of periOperative Registered Nurses, is accredited as a provider of continuing education in nursing by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. AORN recognizes this activity as continuing education for registered nurses. This recognition does not imply that AORN or the ANCC's Commission on Accreditation approves or endorses any product included in the activity. AORN maintains the following state board of nursing provider numbers: Alabama ABNP0075, California CEP 13019, Florida FBN 2296, and Kansas LTO114-0316. Check with your state board of nursing for acceptability of education activity for relicensure.

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Answer Sheet

CHRONIC REGIONAL PAIN SYNDROME, TYPE 1: PART I

Please fill out the application and answer form on this page and the evaluation form on the back of this page. Tear the page out of the Journal or make photocopies and mail to:

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A score of 70% correct is required for credit.

Event #01024

Session #6130

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[ILLUSTRATION OMITTED]

Learner Evaluation

CHRONIC REGIONAL PAIN SYNDROME, TYPE 1: PART I

The following evaluation is used to determine the extent to which this Home Study Program met your learning needs. Rate the following items on a scale of 1 to 5.

OBJECTIVES

To what extent were the following objectives of this Home Study Program achieved?

(1) Discuss chronic regional pain syndrome type 1 (CRPS 1).

(2) Describe the way in which CRPS1 is diagnosed.

(3) Discuss the treatment of patients with CRPS1.

PURPOSE/GOAL

To educate nurses about the care of patients with CRPS1.

CONTENT

(4) Did this article increase your knowledge of the subject matter?

(5) Was the content clear and organized?

(6) Did this article facilitate learning?

(7) Were your individual objectives met?

(8) How well did the objectives relate to the overall purpose/goal?

TEST QUESTIONS/ANSWERS

(9) Were they reflective of the content?

(10) Were they easy to understand?

(11) Did they address important points?

What other topics would you like to see addressed in a future Home Study Program? Would you be interested or do you know someone who would be interested in writing an article on this topic?

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[ILLUSTRATION OMITTED]

Debra G. Dunn, RN, MBA, CNOR, is a perioperative educator and project coordinator in the OR at Wayne General Hospital, Wayne, NJ.

COPYRIGHT 2000 Association of Operating Room Nurses, Inc.
COPYRIGHT 2001 Gale Group