eMedicine Specialties > Rheumatology > Soft Tissue and Regional Rheumatic Disease

Reflex Sympathetic Dystrophy

Author: Don R Revis Jr, MD, Consulting Staff, Department of Surgery, Division of Plastic and Reconstructive Surgery, University of Florida College of Medicine
Coauthor(s): Elliot Goldberg, MD, Dean of the Western Pennsylvania Clinical Campus, Professor, Department of Medicine, Temple University School of Medicine
Contributor Information and Disclosures

Updated: Aug 5, 2009

Introduction

Background

Reflex sympathetic dystrophy (RSD) is a clinical syndrome of variable course and unknown cause characterized by pain, swelling, and vasomotor dysfunction of an extremity. This condition is often the result of trauma or surgery. In 1864, Mitchell referred to this malady as causalgia, a Greek word meaning burning pain. Newer taxonomy refers to RSD as a type of complex regional pain syndrome (CRPS), which may develop after an initiating event such as trauma or surgery or may occur spontaneously.¹ Under this classification, causalgia is a type of CRPS that develops after nerve injury. In patients with either of these conditions, sympathetic mediation of the pain (ie, improvement with sympathetic blockade) may or may not be evident.

Pathophysiology

The pathogenesis of RSD is unknown. Three conditions are deemed important in the development of RSD, including a persistent painful lesion, a predisposition or susceptibility to developing RSD, and an abnormal sympathetic reflex. Susceptibility factors are unknown and may include genetic predisposition (HLA typing)² and, in some patients, a tendency toward increased sympathetic activity. This includes cold hands, hyperhidrosis, or a history of fainting.

Healthy individuals undergo a sympathetic response to injury, with vasoconstriction designed to prevent blood loss and swelling. This initial response soon subsides and gives way to vasodilatation and increased capillary permeability, allowing tissue repair.

In patients with RSD, this sympathetic response continues unabated. The reasons for the perpetuation of the response are unknown but may be related to central dysregulation of nociceptive impulses. This dysregulation may be mediated by wide dynamic range neurons in the spinal cord. Prolonged ischemia caused by the vasoconstriction produces more pain, establishing a reflex arc that promotes further sympathetic discharge and vasospasm. This is compounded by the local response to trauma, with liberation of substantial amounts of proinflammatory mediators, such as histamine, serotonin, and bradykinin. The result is a swollen, painful, stiff, nonfunctioning extremity. At least partial sympathetic mediation of this phenomenon is likely because of the ability of sympathetic nerve blockade to relieve pain and other features of RSD in some patients.

Frequency

United States

An estimated 5% of patients who experience trauma to the upper extremity develop RSD, although this figure is not known with certainty because of confusion over the diagnosis. Extremity immobilization can trigger RSD. Without prophylactic measures (active physical therapy), RSD can develop in 12-20% of people who experience a hemiplegic stroke.

Mortality/Morbidity

RSD causes essentially no mortality.

Race

No racial predilection exists.

Sex

Sexual distribution is equal.

Age

• The age of onset in most patients with RSD is 30-60 years, and the mean age is 49 years.
• RSD affects children and carries a much better prognosis than in adults.³

Clinical

History

The 3 clinical stages of reflex sympathetic dystrophy (RSD) are acute, subacute, and chronic. The acute form lasts approximately 3 months. Pain, often burning in nature, is one of the first symptoms that initially limits function. Swelling, redness with vasomotor instability that worsens with dependency, hyperhidrosis, and coolness to the touch are common physical findings. Demineralization of the underlying bony skeleton begins because of disuse.

If the process is not arrested or reversed in the acute phase, the condition may progress to the subacute stage, which can last for up to 9 months. The patient develops persistent severe pain in the extremity and fixed edema that would have been reversible with elevation during the acute phase. The redness of the acute stage gives way to cyanosis or pallor and hyperhidrosis to dry skin. Loss of function progresses, both because of increased pain and fibrosis of the joints caused by chronic inflammation. In the hand, this leads to flexion deformity of the fingers. The skin and subcutaneous tissues begin to atrophy. Demineralization of the underlying bony skeleton becomes pronounced.

If the process continues, the chronic phase may develop approximately 1 year after disease onset. This stage may last for many years or can be permanent. Pain is more variable during this period. It may continue undiminished or abate. Edema tends to subside over time, leaving fibrosis around the involved joints. The skin is dry, pale, cool, and shiny. Flexion and extension creases are absent. Loss of function and stiffness are marked, and osteoporosis is extreme. In the upper extremity, this can manifest as a frozen shoulder and claw hand.

A thorough general history is strongly suggested. Maintaining a high index of suspicion is important because proper treatment requires rapid diagnosis and prompt therapy.

• RSD commonly involves only one extremity. It is bilateral in approximately 25% of cases but is usually more prominent on one side.
• Pain
  • Usually constant and disproportionate to the precipitant injury
  • May be exacerbated by ambient factors such as loud noises and emotional factors (eg, stress, light touch, active motion, passive motion)
  • May be described as burning, cutting, searing, pressure, or tearing
  • Usually begins locally but may progress to involve the entire extremity
• Possible evidence of prior increased sympathetic activity
  • Hyperhidrosis
  • Cold hands
  • Fainting
• Prior trauma, which may be trivial or significant (eg, Colles fracture), with or without diagnosable nerve injury
• Prior surgery
• Recent limb immobilization due to hemiplegic stroke, myocardial infarction
• Systemic disease such as diabetes

Physical

Perform a thorough physical examination followed by a focused examination of the involved extremity. Patients with RSD may present with suggestive physical findings that point to a presumptive diagnosis.

• Edema
  • Edema is the most consistent physical finding and is always disproportionate to the severity of the precipitant injury or event.
  • Pain, swelling, and color change may be more prominent with dependency in the early stages.
  • Edema worsens rather than improves and extends beyond the region of initial concern.
  • It evolves into a brawny, nonpitting edema that may progress to an intense fibrosis in all the joints of the extremity.
• Stiffness is more severe than expected and may be very distressing to the patient.
• Discoloration
  • Varies depending on the stage of disease
  • May be dusky, cyanotic, pale, or red and may eventually lead to skin hypopigmentation
  • Begins as redness over the metacarpophalangeal (MCP) or proximal interphalangeal (PIP) joint flexion creases early in the disease and progresses as a streak across the palm
• Abnormal skin moisture
  • Hyperhidrosis (early)
  • Dry skin (late)
• Tenderness is initially localized but may progress to generalized tenderness. Exquisite tenderness, both periarticular and interarticular, is often present. Patients may exhibit allodynia (ie, pain with nonnoxious stimuli) and hyperpathia (ie, persistent pain after light pressure).
• Atrophy of the skin and subcutaneous fat pads
• Fibrosis of the palmar fascia
• Absence of extensor and flexor creases over joints
• Frozen shoulder, flexion deformities of the fingers, claw hand

Causes

RSD is usually posttraumatic or postsurgical; however, it can occur in a previously healthy extremity with no known trigger.

• Trauma
  • Penetrating wounds
    • Lacerations
    • Abrasions
    • Venipuncture
    • Intramuscular injection of medication or illicit drugs
    • Gunshot wounds
  • Crush injuries and blunt trauma
  • Neck or shoulder injuries
  • Acute traumatic carpal tunnel syndrome
  • Chest trauma
  • Sprain, fracture, or dislocation
• Postsurgery
  • Carpal tunnel release
  • Dental extractions
  • Cervical rib resection
  • Fracture repair (Colles fracture)
  • Postarthroscopy
• Local disease
  • Nerve compression syndromes
  • Arthritis
  • Tissue ischemia
  • Stenosing tenosynovitis
• Systemic disease
  • Myocardial infarction
  • Stroke
  • Pancoast tumor
  • Pancreatic cancer
  • Herpes zoster

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