Archives of Physical Medicine and Rehabilitation
Volume 89, Issue 3, Supplement 1 , Pages S38-S40, March 2008

Interventions in Chronic Pain Management. 1. Update on Important Definitions in Pain Management

  • Michele Y. Holding, MD

      Affiliations

    • The Back Pain Center PC, Phoenixville, PA
    • Corresponding Author InformationCorrespondence to Michele Y. Holding, MD, The Back Pain Center PC, 100 First Ave, Phoenixville, PA 19460
    • ,
  • Michael F. Saulino, MD

      Affiliations

    • Moss Rehabilitation, Elkins Park, PA
    • ,
  • E. Anthony Overton, DO

      Affiliations

    • Rothman Institute, Philadelphia, PA
    • ,
  • Ira D. Kornbluth, MD

      Affiliations

    • Spine Medicine and Rehabilitation Therapies, Westminster, MD.
    • ,
  • Mitchell K. Freedman, DO

      Affiliations

    • Rothman Institute, Philadelphia, PA

Article Outline

Abstract 

Holding MY, Saulino MF, Overton EA, Kornbluth ID, Freedman MK. Interventions in chronic pain management. 1. Update on important definitions in pain management.

This self-directed learning module highlights definitions used in pain management. It is part of the chapter on chronic pain management in the Self-Directed Physiatric Education Program for practitioners in physical medicine and rehabilitation. Terms that describe pain and narcotic use that are frequently used and misused are reviewed. Complex regional pain syndrome criteria are presented. Mechanisms, criteria, and potential problems for practitioners to become certified in various areas of pain management are discussed.

Overall Article Objective

To define common terminology used in pain management, complex regional pain syndrome, and the criteria for pain management certification.

Key Words: Analgesics, opioid, Complex regional pain syndromes, Pain, Rehabilitation

 

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1.1 Clinical Activity: A clinician is considering treatment with long-term opiates for a patient with chronic knee pain and a failed joint replacement. The patient is concerned that she will become addicted. Discuss the basic terminology of pain 

THE INTERNATIONAL ASSOCIATION for the Study of Pain (IASP) defines pain as: “An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.” Acute pain is postevent pain that completely resolves in 3 months; subacute pain completely resolves within 6 months after the precipitating event. Chronic pain persists for 6 months or more. Suffering describes the physical sensation of pain in combination with the negative psychologic impact of pain on an individual’s quality of life.1

Tolerance is a physiologic state resulting from the regular use of a drug, in which an increased dosage is needed to produce the same effect. A reduced effect may occur with a constant dose, provided that all other factors are constant. Pseudotolerance, the patient’s perception that the drug has lost its effectiveness, is a concept that is increasingly recognized in clinical practice. It may occur when the medication dose is escalating because of factors such as increased physical activity, disease progression, the presence of a new disease, changes in other medications, or drug interactions.2

Physical dependence is a physiologic state of neuroadaptation that is characterized by the emergence of a withdrawal syndrome if the drug is stopped or decreased abruptly or if an antagonist is administered.2

Addiction is a primary neurobiologic disease that is influenced by genetic, psychosocial, and environmental factors. It is a psychologic and behavioral disorder that has nothing to do with physical dependence. Addiction is characterized by chronicity, loss of control, compulsive use of a drug despite adverse consequences, continued use of the drug, and cravings. The majority of patients on opiates do not become addicted.2

Pseudoaddiction occurs when a patient is not receiving an adequate dose of medication. The patient may embellish his/her symptoms in an attempt to obtain enough medication to provide pain relief. Medication may be hoarded for times of severe pain. It may be diagnosed retrospectively after the patient’s inappropriate behavior normalizes with adequate dosing of the medication.2

Opioid withdrawal typically begins 6 to 12 hours after the discontinuation of short-acting opiates. Symptoms peak at 48 to 72 hours and are not observable 7 to 14 days later. Withdrawal after the cessation of longer-acting agents such as methadone occurs in 36 to 48 hours. Symptoms include eye watering, runny nose, yawning, sweating, restlessness, piloerection, tremors, irritability, anorexia, bone and joint pain, and stomach cramps. At the peak of withdrawal, there is insomnia, loss of appetite, severe yawning and sneezing, eye watering, nasal discharge and inflammation of the nasal mucous membranes, anxiety and irritability, chills, nausea, diarrhea, and generalized weakness. Withdrawal from opiates is rarely life threatening. It varies with the type and dose of opioid taken, duration of use, general physical health, fears of withdrawal, psychologic profile of the individual, and reasons behind withdrawal. The acute phase may be followed by a protracted withdrawal phase that may last for 6 months. Symptoms include a lack of feeling well, malaise, fatigue, poor tolerance of stress, and cravings.3, 4

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1.2 Clinical Activity: A patient who has been diagnosed with complex regional pain syndrome (CRPS) does not understand her diagnosis. Discuss the clinical features of CRPS 

IASP convened in 1993 to define and establish diagnostic criteria for reflex sympathetic dystrophy (RSD). The result was a revised taxonomic system for this disorder and a new term, complex regional pain syndrome (CRPS), types 1 and 2.5 CRPS type 1 describes what was originally described as RSD. The diagnostic criteria for CRPS 1 include the following: (1) the presence of an initiating noxious event or a cause of immobilization (5% to 10% of patients will not have this inciting event); (2) continuing pain, allodynia, or hyperalgesia in which the pain is disproportionate to any known inciting event; (3) evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of pain (this factor can be a sign or a symptom); or (4) the diagnosis is excluded by the existence of other conditions that would otherwise account for the degree of pain and dysfunction.6

CRPS type 2 is the new terminology for what was initially described as causalgia. The criteria are similar to the criteria for CRPS type 1 except that type 2 occurs after a nerve injury and is not necessarily limited to the territory of the injured nerve.7 CRPS 1 versus 2 is descriptive, but the diagnostic and prognostic utility of this differentiation remains to be proven.8

More recent studies on the validation of IASP criteria have suggested that the diagnosis of CRPS patients should be revised in an attempt to improve specificity. There should be continuing pain disproportionate to any inciting event. There should be at least 1 symptom reported in each of the 4 following categories: (1) sensory (hyperesthesia), (2) vasomotor (temperature asymmetry, skin color changes, or asymmetry), (3) sudomotor and edema (edema, sweating changes, or asymmetry), and (4) motor and trophic (decreased range of motion and/or motor dysfunction, weakness, tremor, dystonia, and/or trophic changes in the hair, nail, and skin). The patient should also have 1 sign within 2 or more of the preceding categories.8, 9

To improve the sensitivity of the criteria, a 2004 workshop in Budapest proposed that the diagnostic criteria require that 3 of the 4 symptom categories and 2 of the 4 signs be positive. This change increases sensitivity to .75, whereas specificity is .69. At this time, the official IASP criteria are unchanged.10

Patients with CRPS type 1 have 3 different patterns of pain spread: (1) contiguous spread is characterized by the gradual progression from distal to more proximal regions of the limb, (2) independent spread occurs when CRPS arises in sites distant and noncontiguous from the initial site (70% of patients), and (3) mirror image spread develops in the opposite limb in a region similar to the site of the initial presentation (15% of cases).11 The classic staging (stages 1–3) of what was once known as RSD has been questioned, and research is ongoing to clarify the validity of staging this syndrome now known as CRPS type 1.

Physical and neurologic examinations will help with differential diagnosis, including neuropathies, thoracic outlet syndrome, diskogenic disease, deep vein thrombosis, cellulitis, vascular insufficiency, lymphedema, and erythromelalgia.

Although the value of tests have not been substantiated by outcomes research, increased periarticular uptake in delayed bone scintigraphy and demineralization on fine-detail radiography have been used to reinforce the diagnosis in the subacute (<1y) and chronic stages. Electrodiagnostic tests of the sensory system (quantitative sensory tests to examine small fiber function), motor findings (electromyography and nerve conduction studies), autonomic dysfunction (quantitative sudomotor axon reflex test, thermography), and radiographs have been used to reinforce the diagnosis. Selective and specific local anesthetic sympathetic blocks may help to determine the involvement of the sympathetic nervous system. However, these procedures are performed for therapeutic not diagnostic purposes. The terms sympathetically mediated pain and sympathetic independent pain are no longer used to describe subtypes of CRPS.6, 10

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1.3 Educational Activity: To discuss with your medical practice business administrator the rationale for getting credentialed as a pain management specialist 

The ubiquitous nature of pain compels almost all medical specialties to have a basic knowledge of pain assessment and management skills. More challenging clinical problems can benefit from referral to physicians with specific expertise in the care of the pain patient. Historically, anesthesiology has been considered the primary medical specialty for pain management12; more modern approaches have expanded the designation of pain specialist to several specialties, including physiatry. This extension of expertise is shown by a number of professional groups. The major professional societies that focus on the study of pain do not restrict their membership exclusively to anesthesiology.13, 14, 15 Recently approved requirements by the Accreditation Council for Graduate Medical Education (ACGME) for a pain medicine fellowship mandate the multidisciplinary nature of the subspecialty with the inclusion of at least 2 of the following specialties: anesthesiology, neurology, physical medicine and rehabilitation, and psychiatry.16

The designation “pain specialist” can create a great deal of confusion to both the lay public and referring physicians. Several organizations provide a specialty certification in pain management. A better designation is board certified in pain management, which implies recognition by the American Board of Medical Specialties (ABMS). Currently, the only mechanism by which a physician can achieve board certification in pain medicine is to meet the following 4 criteria: (1) be a current diplomate in good standing of a member board of ABMS; (2) possess a current, valid and unrestricted license to practice medicine in the United States, Puerto Rico, or Canada; (3) successfully complete 1 postresidency year in an ACGME-accredited fellowship; and (4) pass an examination developed and administered by the American Board of Anesthesiology.17, 18 As of June 2007, there were 103 ACGME-accredited fellowships in pain medicine, of which 11 were led by physiatry.16 Between 1995 and 2004, ABMS issued 3421 subspecialty certificates in pain medicine, of which 875 (26%) were issued to physiatrists.19

One component of pain management that elicits considerable discussion is the credentialing required to prove that a given practitioner has attained the necessary expertise to perform interventional techniques. With the ever-increasing involvement of multiple specialties performing invasive procedures, the debate over credentialing is likely to accelerate. Some procedural volume guidelines have been put forth by a number of professional groups including ACGME (in their pain fellowship program requirements),16 the American Society of Interventional Pain Physicians, and the Physiatric Association of Spine, Sports and Occupational Rehabilitation.20 A multidisciplinary approach to pain management should encourage collegiality not competition. As with all aspects of medicine, practitioners should complete both didactic and technical training as a demonstration of clinical competency in pain procedures.

A potential area of collateral interest for the pain management specialist is the field of addiction medicine. Professional groups that focus on this topic include an ABMS-recognized psychiatry subspecialty, the American Board of Psychiatry and Neurology,21 and a group not recognized by ABMS, the American Society of Addiction Medicine.22 Certain administrative concerns surround agents used to treat addictions. Specifically, there are regulatory issues regarding the use of buprenorphine for opioid addiction. This agent, a partial opioid agonist, has a pharmacologic ceiling effect. In contrast to full opioid agonists such as morphine or heroin, buprenorphine can reduce opioid-related cravings and withdrawal symptoms. Buprenorphine is available as a solo agent or as a combination agent with naloxone (an opioid antagonist). The use of the combination product limits the possibility of diversion or misuse.3 The use of this agent for opioid dependence is allowable outside of methadone clinics by appropriately qualified physicians. Qualification requirements are described by the Drug Addiction Treatment Act (2000).23 Currently, qualified physicians are limited to treating 30 patients with buprenorphine. Pending federal legislation will raise the treatment limit to 100 patients.23

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References 

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 No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated.

 Reprints are not available from the author.

PII: S0003-9993(07)01859-X

doi:10.1016/j.apmr.2007.12.011

Archives of Physical Medicine and Rehabilitation
Volume 89, Issue 3, Supplement 1 , Pages S38-S40, March 2008

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