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19 Articles in Volume 20, Issue #4
20/20 with Dr. Nathaniel Katz: Pain Research and Future Therapeutics
A 20-Year Timeline: Pain Therapeutics and Regulations
A Comparison of the Alpha-2-Adrenergic Receptor Agonists for Managing Opioid Withdrawal
A Pain Assessment Primer
After the Task Force: A Conversation with Vanila A. Singh, MD
Ask the PharmD: Can opioids and benzodiazepines ever be used together?
Cognitive Strategies and Mindful Awareness for Integrative Pain Care
COVID: Clinical Considerations for Acute and Post-Infection Symptoms
Editorial: Fudin and Gudin Tackle Pain Care History – Asking, Have We Done a 180?
From Hands-On to Home-Based Care: Physical Therapy Undergoes a Paradigm Shift Due to Pandemic
MS-Related Pain and Spasticity: Are Cannabinoids an Option?
New Biological Agents for Psoriatic Arthritis: A Monoclonal Antibody Primer
Pandemic Presents Unexpected Opportunity to Embrace Multimodal Analgesia and the Integrative Care Team
Provider Perspective on Knee OA: Injections and RFA Options
Redefining the “Pain Specialist” of Today
Resident’s Corner: Climbing the Learning Curve in Pain Management
The Evolution of Pain Management: Experts Weigh In
Tips from the Field: How to Enhance Practice Efficiency
Tumor Necrosis Factor (TNF) Inhibitors: A Clinical Primer

A Pain Assessment Primer

Chronic pain assessment and treatment decision-making must address new categories of chronic pain and incorporate patient self-report measures of mental health, daily function, and quality of life. A clinician’s updated guide.

The Scope of Pain

Measurement is an integral part of any clinical evaluation. To measure pain effectively, we need to understand the scope of chronic pain – its etiology and its underlying pathophysiological mechanisms. Described as a complex combination of neurobiological, psychosocial (mood, expectations, beliefs, fear of pain, social context, culture) and behavioral factors (dynamics of the environments and response of others to pain), the chronic pain experience is unique to each person.1,2

The World Health Organization has updated its classification of pain in the pending 11th edition of the International Classification of Diseases and Related Health Problems (ICD-11). Scheduled to go into effect in the year 2022, the update lists chronic pain diagnoses systematically, recognizing that pain can be either the sole complaint or a leading complaint and that either one requires special treatment and care.

The new ICD-11 chronic pain categories are:

1.     Chronic primary pain (pain is the leading complaint, eg,  fibromyalgia, nonspecific low back pain)

2.     Chronic cancer-related pain

3.     Chronic neuropathic pain

4.     Chronic secondary visceral pain

5.     Chronic posttraumatic and postsurgical pain

6.     Chronic secondary headache and orofacial pain

7.     Chronic secondary musculoskeletal pain.

In Categories 2 through 7, pain is considered secondary to an underlying disease.3

The goal of the ICD-11 is to create a classification system that is applicable in primary care and in specialized pain management settings. Future pain scales and assessment measures will invariably have to consider this approach.

Editor’s Note: This primer provides an update to the authors’ prior work on pain assessment and monitoring tools (Part 1 and Part 2).

 

Pain cannot be categorized into a purely pathophysiological model, especially when comparing the personal chronic pain experience to acute pain nociception. (Image: iStock: tolgart)

Expanding Definitions Require Evolving Assessments

Chronic pain assessment is pertinent to accurately classifying a patient’s chronic pain, as described by the ICD-11, and to facilitating a clinician’s treatment decisions. When done well, an assessment can provide information that guides patient-specific treatment planning between the chronic pain sufferer and their specialists.4

When conducting a full assessment, the authors propose the following considerations.

1. Chronic Pain Is Not Equivalent to “Acute Pain Plus Time”

The temporal classification of pain based purely on the length of the pain experience (ie, 3 months or more for chronic pain) should not be a determining factor for possible underlying mechanisms of pain. For many years, chronic pain assessment has been guided by acute pain guidelines; we now know that this approach is deficient and can be neglectful.

Pain cannot be categorized into a purely pathophysiological model, especially when comparing the personal chronic pain experience to acute pain nociception. Tissue damage alone does not account for the large majority of individuals reporting chronic pain to their physicians.5 Neurophysiological and psychological change from nociception to protracted and chronic pain goes through a process of algopathy, evolving from mostly nociceptive body defense to a neuropsychiatric disorder of chronic pain.6

2. Mental Health and Daily Function as Pain Factors

Pain mediators must be accessed in those presenting with chronic pain. Depression and anxiety ­– two comorbid psychiatric conditions – commonly occur alongside chronic pain due to the bidirectional relationship.7,8 Several studies have concluded that pain intensity is often reduced indirectly when other factors are treated and reduced, including depression and anxiety.9

It is therefore imperative to identify and accurately assess not only pain intensity but also the multidimensional factors associated with chronic pain. In addition to mental health, factors such as functional abilities, pain perception, life satisfaction, and emotions must be a part of an appropriate pain assessment.1,2

To date, there are limited ways to objectively measure the subjective experience of chronic pain. Part of the problem is that pain is complex, with many aspects to measure, including:

  • duration (acute, chronic)
  • intensity (mild, severe)
  • location (head, leg)
  • internal organs (liver, lungs)
  • suspected underlying mechanism (peripheral neuropathic, central neuropathic)
  • causation (traumatic, ischemic), and more.

Thus, constructing scales and questionnaires that adequately measure all aspects, unfortunately, do not exist.7

 

Current Tools for Assessing Chronic Pain

A typical pain assessment usually begins with a thorough history (eg, patient/proxy reports and medical records review) and physical examination, often followed byh laboratory tests and diagnostic imaging to understand the pathophysiology of the pain generator.1,4

Understanding pain intensity, location, duration, sensory qualities (word descriptors), cognitive features (perceived impact on activities of daily life), and affective factors (pain unpleasantness), as well as contextual and situational characteristics, gives the practitioner a deeper understanding of the origin and/or type of chronic pain that the individual is experiencing.4,6,10

Assessing all of these constructs within a time-limited appointment, however, can be a daunting task. Several standardized tools are available to help clinicians measure chronic pain factors, including self-report scales and observational measures, as well as emerging test approaches – each briefly described below.2

Self-Report Scales

The use of self-report scales has become the gold standard in the assessment of patients in a chronic pain population.4,11-14 Information obtained through self-report measures can be used to corroborate data gathered through interview, medical records, physical exam, and diagnostic tests. Self-report results help guide treatment decisions, improve communication between the patient and provider, and track the progression of a condition over time.

Self-reporting is not always reliable, however, and should not be taken at face value but rather should be viewed as just one component of the overall assessment used to support findings.

There are various categories of self-report measures, the two most common being:

  • unidimensional–measure one underlying dimension or construct. Examples include: Numerical Rating Scales (NRS), Verbal Rating scales (VRS), Visual Analog Scales (VAS), Facial Pain scales, and the Pain Thermometer.15
  • multidimensional– assess the level of disability/physical functioning, quality of life, emotional functioning (anxiety and depression), psychosocial aspects (support, culture), attitudes/beliefs, coping, and change,6,11 as well as other important constructs that may have a reciprocal relationship with chronic pain, including fatigue, sleep, addiction, and trauma. Examples include the: Patient-Reported Outcomes Measurement Information System (PROMIS).

Unidimensional self-report measures are the most widely used because they are simple to administer, valid, reliable, and easily understood by diverse populations, including children, adolescents, older adults, and those with communication deficits.1,2,15,16 Unidimensional scales are typically used to assess pain intensity, pain affect (unpleasantness), and perceptual qualities of chronic pain.4 Other types of self-report pain measures assess duration, location, onset, and course of chronic pain. These may or may not be devised using a unidimensional scale.

The PROMIS multidimensional scale has become widely used as a comprehensive, standardized, reliable, and valid measure of many of the multidimensional constructs of chronic pain presented above. However, this tool is long and complicated, and not usually feasible in a clinical setting.11,12

Behavioral Observation and Proxy Reports

Another subset of chronic pain assessment tools employs standardized, objective behavioral observation methods to assess controllable and uncontrollable pain behaviors in the chronic pain patient. These types of tools are typically used in research but have been useful in clinical work to help quantify chronic pain and to gain further understanding of the potential pain reinforcers that exist in the environment.1

Behavioral observation methods are generally effective with non-communicative, illiterate, or cognitively impaired patients, where direct observation provides the most objective approach to assessing pain behavior. Direct observation can consist of a standardized task or occur in a natural setting.13

Proxy or surrogate reports from family members and caregivers can provide a wealth of information about chronic pain that is experienced by the individual sufferer who is unable to communicate through self-report.2 When appropriate, self-report measures may be compared to proxy reports to gain additional information that will help to generate a discussion between the patient and practitioner.

Genetic Testing, Imaging

Lastly, there are emerging assessment techniques such as genetic testing and brain neuroimaging that can help to provide a full picture of what the patient is experiencing.4 Pharmacogenomic testing, for example, may shed light on neurotransmitter synthesis and degradation and receptor formation, aiding in the understanding of pain threshold and emotional patterns as well as possible response/nonresponse to various medications. Functional brain studies may allow clinicians to judge brain activity in association with the patient’s pain experience.

A comprehensive list currently available pain evaluation scales may be found in Fillingim, et al;4 Turk, et al,5and Arbuck, et al.9

 

Deficiencies of Current Pain Testing

In addition to the technical challenges of pain assessment, there is an ethical challenge: the assumption is that the chronic pain sufferer or their proxy is capable of reliably and objectively communicating about their pain. Since chronic pain has been deemed a subjective, personal, and private experience, there may be difficulties in objectively measuring it with self-report or observational tools alone.17 Patients with communication difficulties, depression, anxiety, and/or somatization may have difficulty accurately assessing their pain experience as these factors may skew the way the pain is expressed and eventually measured. (Editor’s Note: Studies have shown that up to one-third of chronic pain patients enrolled in a pain trial cannot report their pain accurately – more on this in our Side Chat with Dr. Nathanial Katz

Additionally, there are some cases where patients may have be drug-seeking, facing addiction, or suffering from malingering, which raises concern for the clinician. Many of the self-report tools are face-valid, resulting in an easier ability to falsify reports.

Other factors affecting self- and proxy-based reports have to do with how the patient or caregiver conceptualizes pain and the questions they ask. Responses may be influenced by pain severity, circumstance (eg, movement, inertia), or medication need at the time of answering a questionnaire.1,18,19 Asking the right questions – and then interpreting the responses for the individual patient – may seem difficult with so many factors to consider.

One study concluded that fewer than half of the practitioners from a sample of primary care clinicians working with chronic pain patients were apt to use chronic pain assessments to help guide treatment decisions. Reasons for this consisted of a lack of knowledge of effective measures, lack of time, and preference to just talk to their patients.20

Other standardized tools may seem too exhausting and time-consuming to use, such as the PROMIS tool as noted, which was developed for research purposes.

 

Future Pain Assessment: Moving Toward Optimal Measures and Testing


Recent research suggests that the ideal assessment and treatment of chronic pain conditions comes from an interdisciplinary approach incorporating simultaneous assessment and treatment of a chronic pain patient by multiple specialists.21 While this may be the best practice, it is likely not the most feasible as a large percentage of patients frequent their primary care physician for assessment and treatment of pain.

Pain is one of the top reasons for patients to see a physician in the office. Four out of the 10 most frequent complaints in physicians’ offices include: arthritis, abdominal problems, headache, and back pain.22

In a pediatric primary care setting, Grout and colleagues found that pain was reported by the patient or caregiver in 14.9% of visits.23

In the primary care setting, a more practical approach, in the authors’ view, may include supplementing a regular chronic pain assessment (eg, clinical interview, records review, physical exam, and diagnostic tests) with various self-report measures and referring out to specialists (eg, physiatrists, anesthesiologists, psychiatrists, neurologists, and orthopedists). This may be especially useful when certain underlying biomedical and psychosocial constructs present challenges beyond the practitioner’s expertise.24 If the patient is already seeing a specialist, coordination between offices becomes especially important. The same condition should not be treated in disconnect, it being pneumonia, heart disease, or pain.

Clark and Galati suggested that practitioners become comfortable with a few valid and reliable measurements relevant to their patient population.15 Practitioners could then create a short battery of adjunctive tools to help account for the multitude of factors that affect pain. For instance, a minimum requirement for chronic pain assessment in back pain patients in one study included assessment in pain intensity, pain duration, affect, and pain disability.18

Predetermined scales used in clinical practice should be easy to understand, time-efficient, flexible for a patient or a caregiver to learn quickly and intuitively, as wide in scope as possible, inexpensive, and based on principles already familiar to the patients.

The assessments can be used throughout the course of treatment to help assess the effectiveness of treatment, changes in pain, and account for other psychosocial factors that may influence chronic pain, which could flag those patients who may require further evaluation by specialists.

Case Example

This paper’s authors practice in an interdisciplinary chronic pain setting and use a battery of assessment measures to guide diagnosis and treatment planning. Specifically, we use the Indiana Polyclinic Combined Pain Scale (IPCPS) developed by IPC clinical staff and refined over the past 20 years on the basis of clinical experience and practicality. The IPCPS has the ability to quickly assess pain intensity over time and captures how pain interferes with function and the relationship between pain, depression, and anxiety.9

Some of the measures are administered at each appointment, even if a patient comes daily or weekly, allowing frequent assessment of pain intensity, location, temporal changes, and psychosocial factors that ultimately create a dialogue between patient and clinician and identify effective treatment planning that is patient specific.

At initial contact with a patient presenting with chronic pain, we conduct VAS, NRS, Pain Diagram, and Opiate Risk intake questionnaires. Patients are then seen by a behavioral health clinician who further assesses psychosocial factors using a biopsychosocial interview as well as a core battery of self-assessment measures including but not limited to the Pain Catastrophizing Scale (PCS), Pain Self-Efficacy Scale (PSEQ), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-15 (PHQ-15), Adverse Childhood Events (ACE), and the Duke Social Support Index.1,25-28

This type of extensive evaluation likely cannot be achieved without the involvement of a behavioral health professional; however, identifying a local behavioral health professional for further consultation is workable for smaller clinics or for those who need to refer out. This battery typically takes individuals with an 8th grade reading level approximately 10 to 15 minutes to complete.

When creating the IPCPS, the developers took into account a hectic, fast-paced clinical practice and a diverse patient population. They took the basics of a VAS and combined it with both numerical and verbal descriptors to create a unique rating system. The IPCPS utilizes the familiar 11-point scale with 0 “no pain, depression, or anxiety” and 10 “the worst imaginable pain, depression, and anxiety.”

The IPCPS modified the Functional Independence Measure and likened it to the same familiar 11-point VAS scale with 0 “no disability or disruptions in functioning” and 10 “complete disability and disruption in functioning.”9,29 More than one site of pain may be reported (eg, back pain is 5 out 10 while a headache is 2 out of 10).

One unique feature of the IPCPS scale is that it allows patients to report two values of pain at the same time:

  • more objective pain rating based on verbal descriptors
  • a more subjective personal experience rating

The latter is similar to a weather report when the temperature is officially “30° F” but due to wind chill (or humidity) mayfeel like “16° F” (eg, a patient may report pain as 5/10 but it feels like 8/10). Allowing a patient the ability to use these scales flexibly generates practical conversations between practitioner and patient. Hearing that a patient’s pain rating is a 4/10 but feels like an 8/10 may generate questions by the practitioner to help understand what psychosocial factors may be influencing the pain experience.          

Additionally, the reported pain intensity rating can be compared to behavioral observation of the patient’s pain behaviors that may lead to uncomfortable yet important conversations (eg, a patient may report pain at 9/10; however, the clinician notes that they are smiling and ambulating without discomfort).

Practical scales like the IPCPS allow a clinician to have a better understanding of the scope of the chronic pain affecting a patient, and ultimately those factors amplifying the pain experience and possible disability. With this fuller assessment, treatment decisions may be made with more confidence.

 

Clinical Takeaways: How to Move Pain Assessment Forward

As stated, neglecting the psychosocial and behavioral aspects of chronic pain could lead to inaccurate diagnosis and ineffective treatment as chronic pain cannot be determined solely by a biomedical assessment. Such a rigid approach could maintain the suffering reported by chronic pain patients, increase healthcare utilization, and contribute to rising healthcare costs. Further, bare-bones assessment strategies may increase the risk of leaning toward the use of treating pain intensity by opioid-based therapies alone without adjunctive treatments.

As the scientific understanding of pain evolves, additional evaluation tools are destined to be created. Attempting to assess every chronic pain mediator may seem excessive, so clinicians − whether in primary or specialty care − are encouraged instead to develop a brief battery using valid and reliable self-report measures that complement their current assessment process and enhance the understanding of their patient population. While scans, sophisticated labs, and biomedical tests will continue to advance, self-report scales used to assess the multifaceted nature of chronic pain will not disappear.

The best chronic pain assessments, therefore, must be clinically useful and not simply research responsive. Such tools need to be practical in the hands of both general clinicians as well as specialists, user friendly, and convenient to use both digitally and on paper. Assessments must address a multitude of factors including the patient’s function and mental health. Ideally, they will help to distinguish between acute and chronic pain and guide effective treatment to improve the life of the pain sufferer. While this achievement is still ahead of us but, with a biopsychosocial approach, we will be moving in the right direction.

 

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Last updated on: August 3, 2020
Continue Reading:
New ICD-11 Codes Set to Improve Pain Care in the Primary Setting
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