Complex regional pain syndrome (CRPS)

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Complex regional pain syndrome (CRPS)

• Syed M. Nasir, M.D.
• Assistant Professor
• The University of Texas Medical School at Houston
• Department of Anesthesiology

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What is Reflex Sympathetic Dystrophy (RSD)?

• Reflex sympathetic dystrophy (RSD), or complex
  regional pain syndrome-CRPS I, applies to a
  variety of seemingly unrelated disorders having
  similar clinical features and manifesting the
  same fundamental disturbed physiology. The term
  reflex indicates a response to a primary exciting
  stimulus that is traumatic, medical, infectious,
  or vascular the term sympathetic indicates the

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What is Reflex Sympathetic Dystrophy (RSD)?
(cont.)

• neurologic pathway subserving the development and
  maintenance of these syndromes and the term
  dystrophy indicates that, if untreated, these
  syndromes uniformly result in trophic changes as
  a result of the persistent sympathetic
  stimulation.

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What is Causalgia?

• Causalgia, which means burning pain, is a
  historical term describing a reflex sympathetic
  dystrophy that follows partial or, rarely,
  complete injury to a peripheral nerve trunk.1 It
  is also called complex regional pain
  syndrome-CRPS II. It is characterized by
  constant, spontaneous, severe, burning pain and
  is usually associated with hypoesthesia (decrease
  sense of touch or sensation or partial loss of
  sensitivity to sensory

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What is Causalgia? (cont.)

• stimuli) and hyperesthesia (abnormal increase in
  sensitivity to stimuli of senses), hyperpanthia
  (exaggerated pain sensation to nociceptive
  stimuli), and allodynia, along with vasomotor and
  sudomotor (sweat glands) disturbances that, if
  persistent, result in trophic changes
  (interruption of nerve supply). RSD need not be
  initiated by damage to a major peripheral nerve
  trunk.

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Mechanism
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Causes of RSD

• I. Trauma
• Accident injury
• Sprain, dislocations, fracture (usually of the
  hands, feet, or wrists)
• Minor cuts or pricks, lacerations, contusions
• Crush injury of fingers, hands, or wrists
  traumatic amputation of fingers
• Burns

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Causes of RSD (cont.)

• Surgical
• Procedures on the extremities
• Excision of small tumors, ganglia wrist
• Forceful manipulation, tight casts
• Surgical scars
• Damage to small peripheral nerves with a needle
  (e.g., during its insertion for infusion,
  transfusion, injection therapy, or analgesic
  block)
• Injections or irritants

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Causes of RSD (cont.)

• II. Diseases
• Visceral diseases (e.g., myocardial infarction)
• Neurologic diseases
• Cerebral vascular accidents (posthemiplegic
  dystrophy), tumors, syringomyelia, and others
• Spinal cord poliomyelitis, combined
  degeneration, tumors, syringomyelia, and others

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Causes of RSD (cont.)

• Spinal nerves or their roots herpes zoster,
  radiculitis
• Brachial plexus
• Infiltrating carcinoma from the breast, apex of
  the lung (upper extremity), or pelvis (lower
  extremity)
• Glomus tumor (benign tumor that differentiates to
  become modified smooth muscle cells called glomus
  cell)

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Causes of RSD (cont.)

• Infections
• Extremity skin and other soft tissues
• Periarticular
• Vascular
• Generalized periarthritis nodosa, diffuse
  arteritis, arteriosclerosis
• Peripheral thrombophlebitis, tissues

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Causes of RSD (cont.)

• Musculoskeletal disorders
• Postural defects
• Myofascial syndromes
• III. Idiopathic

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Sympathetically Maintained Pain
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Mechanism of Generation of RSD

• REFLEX SYMPATHETIC DYSTROPHY
• (ALGODYSTROPHY)
• Trauma with
• Nerve lesion
• Abnormal state of
• afferent neurones
• Distorted information
• Processing in spinal cord
• Dysregulation of
• sympathetic activity
• (vasomotor, sudomotor)

Pain
Trophic changes
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Clinical Presentation

• Trauma secondary to accidental injury is probably
  the most common cause. Peculiar to sympathetic
  dystrophy is the lack of correlation among
  severity of injury, incidence, and subsequent
  severity of the resultant syndrome.
• In the majority of cases, the precipitating
  injury may be so minor and to the patient so
  insignificant that he or she may forget the
  incident questioned by the physician.

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Signs and Symptoms

• RSD is manifested by pain, hyperesthesia,
  vasomotor and sudomotor disturbances, and
  increased muscular tone, followed by weakness,
  atrophy, and trophic changes involving the skin,
  and its appendages, muscles, bones, and joints.
• However, common to all cases of sympathetic
  dystrophy is the fact that the pain and physical
  signs do not conform to known patterns of nerve

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Signs and Symptoms (cont.)

• distribution, either segmental (dermatomes,
  myotomes, and sclerotomes) or peripheral.
  Moreover, they have a tendency to spread
  proximally to involve the contralateral and
  ipsilateral extremity. Once RSD has become
  established, the entire syndrome will continue
  even after the causal mechanism has healed or
  disappeared. An important characteristic common
  to all of the sympathetic dystrophies is the fact
  that the symptoms

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Signs and Symptoms (cont.)

• can be abolished by sympathetic block at an
  appropriate level if carried out before the
  point at which the syndrome becomes irreversible,
  repetitive interruption of the involved
  sympathetic pathways can result in resolution of
  the entire syndrome.

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Course

• Sympathetic dystrophy has three phases, and the
  presenting signs and symptoms will vary somewhat
  depending on the stage at the time the patient is
  first seen.
• Acute (hyperemic) stage
• During this stage, the syndrome can be
  completely reversed by sympathetic blockade.

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Course (cont.)

• Dystrophic (ischemic) stage
• If the acute stage is untreated, it can be
  expected to progress to the second, or
  dystrophic, stage. During this stage,
  sympathetic blocks may still be effective in
  reversing the process, although the response to
  blockade may be short-lived and less pronounced.
  A larger series of blocks or prolonged
  sympathetic blockade may be necessary to afford
  permanent relief.

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Course (cont.)

• Atrophic stage
• The third stage is characterized by marked
  trophic changes that eventually became
  irreversible. At this point many of the trophic
  changes produced by the syndrome become
  irreversible, and although interruption of
  sympathetic pathways by blocks may still provide
  temporary relief, repetitive sympathetic blocks
  alone are no longer effective in terminating the
  process permanently. An

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Course (cont.)

• aggressive approach including physical therapy,
• psychologic counseling, and sympathetic and
  somatic nerve blockade is needed to reverse the
  process as much as possible.

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Stages and Characteristics of RSD
Stage Stage Stage
Characteristic I Acute II Dystrophic III Atrophic
Pain Burning/neuralgia Burning/throbbing Burning/throbbing
Dysthesia
Function Minimal impairment Restricted Severely restricted
Autonomic dysfunction Increased blood flow NI or decreased flow Decreased blood flow
Temperature Increased Decreased Decreased
Discoloration Erythematous Mottled/dusky Cyanotic
Sudomotor dysfunction Minimal
Edema
Trophic changes 0
3-phase bone scan Increased activity, all images Normal uptake, all phases except increased static phase Decreased activity, all phases except NI static
Osteoporosis _
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Diagnosis

• A diagnosis of RSD may be obvious if
• there is a history of recent or remote trauma,
  infection, or disease
• there is persistent, spontaneous pain that is
  burning, aching, or throbbing in character
• there are vasomotor or sudomotor disturbances
  and
• there are obvious trophic changes

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Diagnosis (cont.)
PUTATIVE DIAGNOSTIC CRITERIA FOR RSD
Clinical symptoms and signs Burning pain Hyperpathia/allodynia Temperature/color changes Edema Hair/nail growth changes
Laboratory results Thermography/thermometry Bone x-ray Quantitative sweat test Response to sympathetic blockage
Interpretation based on number of criteria present gt6, probable RSD 3-5, possible RSD lt3, unlikely RSD
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Diagnosis (cont.)

• A score of 0 is assigned if the criteria is
  absent, ½ if it is equivocal, and 1 if it is
  present. These scores are tabulated, and the
  following categories are arbitrarily determined

Interpretation based on these Criteria Interpretation based on these Criteria
0 to 2 ½ RSD absent
3 to 4 ½ Possible RSD
5 to 9 Probable RSD
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Current Treatment

• Because the pathophysiology of RSD is
  predominantly a hyperactivity of the regional
  sympathetic nervous system, pain management in
  such patients should focus on interrupting the
  activity of the sympathetic nervous system. This
  interruption can be produced by different
  modalities classified as pharmacologic, nerve
  blocks, surgical or chemical sympathectomy,
  physical therapy, and psychology.

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Treatment of RSD
Treatment of RSD Treatment of RSD
Antidepressants Bier block
Sedative-hypnotics Sympathetic blocking agents
Anxiolytics Vasodilators
Anticonvulsants Neurolytics
Muscle relaxants Nerve block
Narcotic analgesics Surgical sympathectomy
Nonnarcotic analgesics Chemical sympathectomy
Nonsteroidal antiinflammatory agents Physical therapy
Corticosteroids Transcutaneous electrical nerve stimulation (TENS)
Local anesthetics Psychology
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Reflex Sympathetic DystrophyReview Questions

• Questions from P. Prithvi Raj, M.D., Pain
  Management A Comprehensive Review

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1. In reflex sympathetic dystrophy there is

• A. Correlation between pain and known
  dermatomal distribution
• B. Abnormality in EMG studies
• C. Abnormality in peripheral angiograms
• D. Abnormality in triple-phase bone scan

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1. In reflex sympathetic dystrophy there is

• D. Abnormality in triple-phase bone scan

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2. When considering psychotherapy for
longstanding reflex sympathetic dystrophy
patients, one should not plan for

• A. Management of depression
• B. Psychologic factors that affect compliance
  with treatment
• C. Teaching of effective coping strategies
• D. Learning new skills at work

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2. When considering psychotherapy for
longstanding reflex sympathetic dystrophy
patients, one should not plan for

• D. Learning new skills at work

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3. One of the reasons for failure of surgical
sympathectomy has been

1. Reinnervation from contralateral sympathetic
   chain
2. Permanent destruction of the cut sympathetic
   chain
3. Inability of myelinated A fibers to take over the
   function of sympathetic fibers
4. Increased vascularity of the region effected by
   sympathectomy

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3. One of the reasons for failure of surgical
sympathectomy has been

• A. Reinnervation from contralateral sympathetic
  chain

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4. Appropriate medications for chronic reflex
sympathetic dystrophy are all of the following
EXCEPT

1. Tricyclic antidepressants
2. Anticonvulsants
3. Narcotics
4. Calcium channel blockers

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4. Appropriate medications for chronic reflex
sympathetic dystrophy are all of the following
EXCEPT

• C. Narcotics

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5. Several clinical measurements and
investigations are available for the diagnosis of
reflex sympathetic dystrophy. These tests
include the following EXCEPT

1. Temperature measurements
2. Triple-phase bone scan
3. Q-START test
4. MRI

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5. Several clinical measurements and
investigations are available for the diagnosis of
reflex sympathetic dystrophy. These tests
include the following EXCEPT

• D. MRI
• This presentation material was referenced from
  (1) P. Prithvi Raj, M.D., Pain Management A
  Comprehensive Review and (2) Gerald M. Aronoff,
  M.D., Evaluation and Treatment of Chronic Pain,
  Third Edition