Pain, as every textbook will report, is a warning system designed to protect our bodies from injury. To do this well, we must be able to determine the site of pain, its intensity, its meaning, and how much it should bother us.

All pain has four dimensions:

When we ask people to rate their pain, most patients will understand this as a rating for the first dimension alone. This is of course what most clinicians are after and document. But, how can patients separate these dimensions to rate only one part?

The role of a pain assessment is to sort out the different contributors to each dimension and their relative importance in affecting the functional impact of pain in each individual. This assessment should then direct treatment recommendations for each individual.

Consider this scenario. On a particularly bad Friday, a physician discovers that he has been suspended from practice following a college review. (He does not recall this review but opened the letter late on Friday, too late to call the college for details!) Distracted while driving home, he is involved in an accident and discovers his car insurance has lapsed. Distraught, he arrives home, in a taxi, and hears a family argument in the kitchen. Walking up the steps, he stubs his toe, and it bleeds. At that moment, his partner opens the door, notices the hopping behavior and the blood and asks, “Where would you rate your pain between 0 and 10?” The clinician, still hopping, shouts, “15 out of 10!!!!”

Later, in a calmer environment, he finds out his partner had renewed his auto insurance but had left the papers at home. On Monday, he finds out the college letter was meant to go another provider of the same name, and on Tuesday, he wins the local lottery, more than enough to retire on. That Friday, while walking up the steps of the theater to pick up the ceremonial lottery check, he again stubs his toe and it bleeds. His partner notices this and again asks, “Where would you rate your pain between 0 and 10?” The clinician, beaming, strides unbroken murmurs, “What pain?” and proceeds to center stage.

In both of these scenarios, the injury is both acute and identical, but the pain ratings are not. What then is the clinician rating?

He is rating primarily how much the pain bothered him, not what it meant or the stimulus intensity.

In a different scenario, a young women with a history of a slow growing tumor waits in the reception area for the results of her magnetic resonance imaging (MRI) to find out if her recent back pain is due to tumor recurrence. When completing the assessment forms that morning, she rated her back pain, then present for a month, at 8/10. One hour later, at the end of a consult which showed no recurrence of her tumor, she now rates her back pain at 4/10.

What was she rating? The sensory experience? Or perhaps the rating and the reduction more accurately reflected the cognitive component of the pain, what it meant to her.

Identifying each of these dimensions and the role they play in any individual’s total pain forms the basic “layers” of an initial chronic pain assessment. Each layer will have important contributors, and this chapter attempts to provide an outline to assist the clinician or team perform an accurate and detailed assessment.

In addition to identifying each dimension of the pain experience, the clinician is expected to also identify the layers of each dimension. For example, with regard to the pain stimulus, research suggests that it is important not just to make a diagnosis but to identify individual pain mechanisms.

As a result of the location of the pain and the mechanisms involved, what does the patient report and what can we find on examination? Provoked or unprovoked pain? Muscle spasm, weakness, tremors, or reduced range of motion? Sensory changes of small fibers (changes to thermal stimuli or pinprick) or changes of central pain processing (widespread pain, light touch allodynia, cold hyperalgesia, or pressure allodynia.)?

Assessing for layers of the affective component of the pain means asking about adverse childhood events and current stressors and screening for anxiety, depression, posttraumatic stress disorder (PTSD), addiction, and others. Are patients having problems with motivation, insomnia, difficulties with memory, and focus?

Assessing for layers of the cognitive component means looking for pain beliefs. The two commonest beliefs to be assessed are the tendency to catastrophize and to experience fear of movement. Perceived injustice is another construct that seeks to look at the effect on an individual when he or she experiences chronic pain as a result of, or the perception of, another’s error or negligence. If these “cognitive distortions” are present, how have they affected the patient? Do they have limited coping skills, deconditioning, or other problems?

Creating an individual “layer cake” for each patient fosters a very different approach that removes the focus from the pain and provides an image of potential treatment opportunities (Figs. 17.1 and 17.2).

In a traditional biologic model of pain, the pain is proportional to the tissue injury. In persistent pain, this linear relationship is often lost, and the patient may be labeled with pain out of proportion to physical findings. Under certain circumstances, this may be associated with malingering (a legal not a medical diagnosis) or secondary gain, but for most patients, this simply represents a clinician’s inability to identify all of the layers contributing to the total pain.

The overall effect of persistent pain is a result of a complex interplay between the pain itself, other comorbidities, physical, psychiatric, and psychological as well as psychosocial factors such as support from significant others, financial factors, and job stability. Failure to identify and address these factors may lead to mutual frustration between the patient and the health care provider and poor therapeutic results.

For example, patients with kinesophobia fears moving because they believe the pain with movement is causing additional tissue damage. This leads to progressive physical deactivation and pain exacerbation with further loss of function. This can lead to feelings of unworthiness and poor self-esteem.¹ If this affects their ability to work and leads to financial stress, this can exacerbate anxiety and depression. Compounding these issues, the medications themselves may be a cause of fatigue and debility.

In today’s health care environment, time to evaluate complex pain patients is limited. Where appropriate, this chapter suggests time-saving, self-assessment, nonproprietary questionnaires that can help a clinician to know where to perform a more detailed evaluation now or later.

Response to therapy should be gauged more by functional improvement than by a decrease in the pain score. The patient’s trust in the health care provider is important. Patients should feel that they have been listened to, their fears have been acknowledged, and the provider is “there for them.” People will forget what you said and forget what you did but never forget how you make them feel. This latter statement does not imply the practitioner has to feel the suffering of the patient. The practitioner should remain empathetic and compassionate to the patient’s issues while trying to remain emotionally resilient.

The examination of the patient presenting with the various specific persistent pain syndromes is not addressed in this chapter. These are described in the chapters allotted to those problems. This chapter addresses some of the practical problems of assessing the patient with persistent pain so that treatment can be individualized. Some tools are provided that may assist the clinician and are included as appendices.

The appendices include the following:

It is important to assess the following:

Questionnaires used should ideally be

Davidson et al.² suggested that seven factors accounted for 59% of the total variance in outcomes of pain treatment. These were pain and disability, pain description, affective distress, support, positive coping strategies, negative coping strategies, and activity. A pain assessment should try to capture most of these factors.

Different practices will require different levels of questionnaire. Solo practitioners may differ in their need to validate their role in a health care organization. Other considerations are whether the questionnaire is proprietary, meaning its use for research in large organizations or in digital format on the web will need to be licensed. In the examples discussed in this chapter, most questionnaires are nonproprietary or available to be used freely. Most questionnaires may be used for individual practices and in paper format without licensing, as long as they are not going to be used in publications.

The Patient-Reported Outcomes Measurement Information System (PROMIS) initiative was a National Institutes of Health (NIH)-funded program to develop new ways to measure patient-reported outcomes (PROs), such as pain, fatigue, physical functioning, emotional distress, and social role participation. PROMIS has also created a psychometrically robust computer adaptive testing (CAT) system based on item response theory (IRT) to administer these items. Whether administered through the CAT system, or by paper version short forms, PROMIS questionnaires have been validated and have shown equal or even improved in efficiency and sensitivity in comparison with existing PROs (https://commonfund.nih.gov/promis/index).

The history of each pain condition provides important clues to the underlying etiology and the chronicity of each condition. It is important to document the etiologies of all the patient’s pain diagnoses. The mechanism, if known, date of onset, overall severity, and factors that worsen or improve pain should be noted. It can be formally done during an interview by having a patient-completed history form. For children, or patients with cognitive impairment, a caregiver should be present to provide additional information.

A pain diagram can often provide a “quick look” picture and, when colored ones are used, can help to determine potential areas of neuropathic pain (see Appendix 17.4 or Fig. 17.3 as examples).

Past medical conditions should be noted that could be an important cause of current or potential pain conditions (multiple sclerosis, prior cancer diagnoses, diabetes). The past surgical history should be obtained when relevant. Visceral dysfunctions such as renal or hepatic compromise or short gut syndrome that could affect absorption or metabolic function have an important role when considering pharmacologic treatments.

Dementia, depending on the severity, may affect how the pain is assessed and is discussed in a different chapter.

Opioid dependence exists as a spectrum disorder and can complicate the management of a patient with persistent pain. It is important to screen for opioid misuse and abuse and to reevaluate for all of these problems in each follow-up visit for patients who take these and other controlled substances.

There are several questionnaires that can screen for the risk of aberrant behaviors that may occur with opioid use or assess the risk of addiction to alcohol or other substances or behaviors.²⁰

Summary with potential questionnaires

Urine toxicology testing can be done as a point-of-care test with the results available in as early as 5 minutes. This allows a discussion about potential aberrant results, either positive or negative, to be held at the time of the appointment. If no obvious explanation is forthcoming, without any accusation, the urine should be sent for more sensitive and specific laboratory confirmation. There are many medications that may give false positives on a clinic test, so laboratory confirmation and, if necessary, discussion with a forensic pathologist are important before potentially accusing the patient of aberrant behavior.

If available, a review of the local prescription monitoring program or pharmacy printout, to assess previous prescriptions of scheduled medications such as opioids and benzodiazepines, is important.

The prescription drug monitoring programs (PDMPs) are electronic databases run by all individual states in the United States except Missouri. They collect data entered by pharmacists on dispensed controlled medications. The data is housed by a specified statewide regulatory, administrative, or law enforcement agency.

The benefit is that they allow health care providers see patients’ prescribing histories which may influence their prescribing decisions. Unfortunately, as yet, there is no conformity among states on the time to enter data after the prescription has been filled. This ranges from monthly to daily or even in “real time”; that is, under 5 minutes. Timely data should maximize the utility of the prescription history data, with significant implications for patient safety and public health.

Partly because of poor utilization, some states have implemented polices that require providers to check a state PDMP prior to prescribing certain controlled substances. PDMPs can also be used to send “proactive” reports to authorized users to protect patients at the highest risk and identify inappropriate prescribing trends. One study reported on sending prescribers unsolicited reports about individuals on opioids who fulfil certain criteria such as multiple prescribers. Compared to a comparison group whose prescribers were not sent a report, the interventional group had significant decreases in number and dosage of opioids prescribed, number of pharmacies used, and number of prescribers visited.²¹

States have taken a number of steps to make PDMPs easier to use and access. These include integrating PDMPs into electronic health record (EHR) systems, permitting physicians to delegate PDMP access to other allied health professionals in their office (e.g., physician assistants and nurse practitioners), and streamlining the process for providers to register with the PDMP. PDMPs are also used by state health departments to inform and evaluate interventions of perceived overprescribing of controlled substances. A 2017 study²¹ reported that states with a strong PDMP program, calculated using legal data compiled by the Prescription Drug Abuse Policy System (PDAPS), together with other covariates such as laws that regulate pain clinics, access to naloxone, use of emergency services (Good Samaritan laws), and medical marijuana, had a significantly lower opioid overdose rate than states with a less robust program.²²

PDMPs are playing an important role in evaluating the prescribing of controlled substances both for the prescriber and the regulatory authorities. Given the other general recommendations for careful charting of function and mood, opioid agreements, and random urine toxicology screens, PDMPs give the health care provider another objective way of assessing patients. The concern about opioid knowledge and too much regulation was addressed in a study by Hwang et al.²² in 2016. Their conclusion was that “although physicians are unaware of some facets of prescription opioid-related morbidity, most support a variety of clinical and regulatory interventions to improve the risk-benefit balance of these therapies.” Only a third of physicians contacted believed that interventions to reduce prescription opioid abuse would have a moderate or large effect on preventing patients’ clinically appropriate access to pain treatment.²³

Assessment and treatment of addiction is covered in a separate chapter.

It is important to assess the functional impact of persistent pain by trying to quantify an individual’s ability to engage in a number of different activity domains. Function is one domain measured in quality-of-life assessments, so most questionnaires have overlapping questions that measure some aspects of both.

Three kinds of self-assessment questionnaires have been developed: general questionnaires applicable to all kinds of pain like the EuroQol, which is short, six questions but has complex scoring and weighting, or the four-, six-, or eight-item PROMIS Measures of Physical Function; disease-specific ones like the Fibromyalgia Impact Questionnaire; and regional ones, for example, the Oswestry Disability Index for back pain.

The questions should cover all of the relevant areas and usually include the impact of pain on domains such as employment, social, recreational, family, or home responsibilities. It should assess self-care and ideally evaluate the overall quality of life.

Summary of potential questionnaires

It is not uncommon in clinical practice to see a patient in follow-up who declares the pain to be much better, yet a review of the functionality questionnaire indicates a higher score than the previous visit.

For instance, on the Brief Pain Inventory, patients may rate their leg pain at 8/10 and the pain interference for walking at 6/10 one week and a month later rate their leg pain less at 5/10 yet rate their pain interference for walking at 9/10.

This may be because they are walking less due to depression, are not paying attention to the weighing scale, or have forgotten how bad their pain used to be (recall bias).

But pain interference scales also suffer from something called response drift, which involves reprioritization, recalibration, and reconceptualization.

A patient can reprioritize his or her disabilities depending on the current circumstances. The main problem may have been headaches, and if the patient substantially improves, now the leg pain becomes the biggest issue and so not walking seems more impairing.

They may recalibrate it. In this case, a 5/10 one day is different than a 5/10 the next day. In the last month, the patient may have had a fracture dislocation of his left elbow and has now decided, that what he thought was 8/10 leg pain, he would now rate at 5/10.

When a patient reconceptualizes his or her disability, he or she has changed the internal concept of what disability due to leg function is. So, in this case, before, the patient felt disabled if he could not get to the bathroom, and now, he feels disabled if he can not get to the store.²⁴