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11 Articles in Volume 17, Issue #4
Algopathy—Acknowledging the Pathological Process of Pain Chronification
Are Abuse-Deterrent Opioid Products A Double-Edged Sword?
CMS Tackles Opioid Prescribing
How do you handle end-of-life care in a patient who does not know they are dying?
Letters to the Editor: Functional Medicine, Naloxone, Hormone Testing, CRPS
Look at the Patient’s Life Story, Then Implement a Management Plan
Myofascial Pain: Overview of Treatment Options
Pain in Parkinson’s Disease: A Spotlight on Women
Parkinson's Initiative—Women and PD Talk
Patient in Pain? When to Refer for Physical Therapy
Somatic Symptom Disorder: DSM-5's Removal of Mind-Body Separation

Algopathy—Acknowledging the Pathological Process of Pain Chronification

A case must be made that the best way forward in pain management requires a concept that presents a clear distinction between and an accounting of the chronicity, central sensitization, plasticity, and wind-up of pain.

Despite its ubiquity, sustained, long-term pain still defies definition. The traditional medical/scientific approach to pain has relied on a rigid dichotomy between mind and body, resulting in pain that is considered either physical (eg, related to tissue injury) or psychological (eg, pain with no obvious physical causation).1 This duality in pain, however, was challenged in the 1970s and 1980s by a move to recognize a mind-body connection and a more holistic approach to patient care.2

Defining pain requires acknowledgement of the chronicity, central sensitization, plasticity, and wind-up of pain

Pain may arise from damage to non-neural tissue (nociceptive pain), the bones and muscles (somatic pain), the internal organs (visceral pain), or nerve damage or aberrant neural processing (neuropathic pain), and may be associated with inflammation, which in turn causes pain.3 In effect, many patients present with multiple mechanisms of pain that also contribute to their perceived pain.

The basis for our modern understanding of pain is that it is a complex biopsychosocial phenomenon that can vary widely among individuals.4 Many interlinking factors contribute to the inherent subjectivity of pain: age, gender, genetic factors, demographics, ethnicity, culture, familial beliefs, and past experiences. Other factors, such as stress and catastrophizing, play a role in pain perception.4 Pain, therefore, is both a physical symptom and an emotional response to that symptom.

This growing appreciation for the complexity of pain has implications in defining pain, including how clinicians and their patients talk about pain. Pain is essentially an experience;5 by helping patients articulate their specific experience, clinicians may to better respond to and manage that pain.

Taxonomies of Pain

Scientific taxonomies of pain may help shape our clinical thinking but are not always intuitively grasped by patients. Nevertheless, pain taxonomies are useful in that even with imperfect definitions of various pain types, they have allowed practitioners to classify different pain experiences in ways that help in the diagnosis and treatment of them. The International Association for the Study of Pain has published a lexicon of pain terminology and taxonomy to aid in and formalize the communication of the pain experience.6

To reinforce the complexity of pain terminology, consideration of the differences in nociceptive versus neuropathic pain pathways is a good exercise.

Nociceptive pain, for instance, refers to the pain that results from a noxious stimulus at the periphery, which is then transmitted via the neural network to the spinal cord and from there upward to the brain for interpretation and response. The brain then processes this signal and may take action in an adaptive mechanism aimed at preventing further injury to the body. A good example of this might be burning one’s hands on a hot pot—the nociceptive signal results in both pain perception and the quick withdrawal from the hot surface. Nociceptive pain may be further subdivided into somatic pain (nociceptive pain that occurs in somatic tissue, or muscles and bones) and visceral pain (nociceptive pain in internal organs). Nociceptive pain is perceived via sensory receptors in the peripheral somatosensory nervous system.6

Neuropathic pain, on the other hand, is caused by a lesion, disease, or damage to the somatosensory nervous system, although a precise definition eludes taxonomists. Neuropathic pain is regarded as pain that results from aberrant neural processing, not from a noxious stimulus. Neuropathic pain can be peripheral, such as peripheral diabetic neuropathy, or centralized (eg, fibromyalgia, phantom limb pain). Neuropathic pain typically presents without structural damage or injury to the body and can be difficult to diagnose.

A simplistic yet helpful way to think of nociceptive versus neuropathic pain is that nociceptive pain primarily relates to what could be called “hardware,” while neuropathic pain often (but not always) relates to the “software” of the body. Neuropathic pain may originate from a “hardware” problem (eg, causalgia, multiple sclerosis, Parkinson’s disease) or as a “software” problem, arising from conditions such as depression, anxiety, or post-traumatic stress disorder. Examples of these various pain types appear in Table 1.

It is important for clinicians to distinguish between nociceptive and neuropathic pain sensations, as these types of pain respond to different treatments, in order to manage the intensity of the pain.

Temporal Aspects of Pain

Pain is routinely described as acute, subacute, or chronic. While it is typical and easy to differentiate these categories by the length of time that the pain persists, acute pain is fundamentally different from chronic pain in more ways than just the duration of the experience.

While there is no consensus on the length of time pain needs to be present to be defined as acute, common definitions exist for different conditions. For example, low back pain lasting less than 4 weeks in duration is acute, whereas subacute low back pain persists for 4 to 12 weeks, and chronic low back pain after 12 weeks. Other definitions for acute pain range from 72 hours to 1 or 2 weeks and so on.7-11

The term “persistent pain” is sometimes used clinically and appears in the literature, although it is not always clear if and how it differs from the older and more established “chronic pain. “Acute pain is typically nociceptive pain that follows a trajectory of decreasing pain intensity as tissue heals. It is thought that acute pain is adaptive, such that it encourages the individual to rest, withdraw, and protect the injury.

In contrast, chronic pain is often maladaptive, as it persists long after the tissue has healed. Chronic pain involves centralization or a migration from the peripheral to central nervous systems (central sensitization). Acute pain may transition into chronic (centralized) pain in a process known as chronification or wind-up,12,13 although the exact mechanisms behind this, and why it occurs in some patients but not in others, remain unclear.

In keeping with this model for defining pain, subacute would represent the transitional state from acute to chronic pain. During this stage, the emotional component of the pain experience increases even as the physical component decreases. In fact, it may be helpful to think of acute pain as perception colored by emotions, while chronic pain is emotion colored by perception.

Chronic pain is problematic for patients to talk about, difficult for clinicians to assess, and challenging to treat. Chronic pain is often diffuse or migratory and may be intermittent, all qualities that make it easy for the patient to doubt the validity of the clinical symptoms. Chronic pain may also be characterized by unpredictable flares.14

The Emotional Component of Pain

Little has been done to scientifically quantify or describe the emotional component of pain, other than to offer a general recognition that there is an emotional aspect to pain. When acute pain occurs and follows the healthy trajectory of resolving over the course of days or weeks as the injury heals, the patient is primarily concerned about the physical sensations of pain even as there may be an emotional component. If the acute pain does not decrease in intensity as anticipated but rather lingers and possibly changes in character and nature, the emotional aspect of this pain will likely deepen and even eclipse the physical sensation.

For reasons that remain unclear to the medical community, acute pain sometimes transitions to centralized or chronic pain. Chronic (centralized) pain is maladaptive and may be considered a disease unto itself. The transition from acute to chronic pain involves aberrations in neural processing that typically have a neuropathic component.

Far less well studied is the emotional impact of centralized pain, which may coincide with neural changes in the way pain signals are processed and interpreted.

Proposing the Use of Algopathy to Reflect the Continuum of Pain

The term “algopathy” is presented to describe a continuum from an acute, adaptive, expected pain to a chronic, maladaptive, centralized pain, as well as the multitude of changes: in the neural-system perception of pain, changes in pain processing by the brain, and changes in the way patients perceive pain in an emotional context. Thus, this new term, algopathy, is not limited to the well-elucidated mechanisms of how a noxious stimulus can result in the perception of pain, but rather reflects a complex interplay of physical, neurological, psychological, and emotional factors that encompass patients’ experiences of pain.

In defining the patients’ pain experience, the impact of catastrophizing on painful symptoms is another factor that has long been recognized.15 Depression, stress, and a pervasive sense of helplessness all have been associated with chronic pain.16 Phenotype, including familial function, likewise appears to play a role in the overall pain experience.17 For instance, modeling of parents’ pain behavior may increase expression of pain in children. In similar fashion, interventions aimed at empowering patients, such as recognizing their resilience, have improved the function of patients facing chronic pain.18,19 Thus, offering the term algopathy helps to place an emphasis on the profound emotional transitions that parallel the shift from acute to chronic (centralized) pain. Just as a pain condition evolves from an acute to a chronic state, there are emotional changes as the patient experiences and must come to terms with unabating, painful conditions that defy physical explanation.

The practicality of adopting this new term (although not included in coding or billing) is proposed as a necessary means to address the processing of pain management that has been sufficiently incorporated into a patient’s experience. It honors, at least to some degree, patients’ attempts to communicate the full experience of their pain (Table 2).

An Algopathic Continuum of Pain

The authors propose the adoption of algopathy to elevate pain chronification to allow for a clinical perceptiveness in pain management. The algopathic continuum involves a transition both from acute to chronic pain and from nociceptive to neuropathic (or peripheral to centralized) pain.

Clinicians may observe that as patients advance along the pain continuum, their therapeutic needs change. The emotional context of their pain will gradually increase until it eclipses much of the physical aspect of the initial pain. This evolving experience makes chronic pain more challenging to treat, particularly as patients may be unaware of the extent to which pain may be interfering with their emotional lives and impacting their psychological well-being.

Treating patients with fibromyalgia (FM) offers an excellent example of applying algopathy to the process of pain management, since a characteristic symptom is pain with functional abnormalities occurring concurrently. In addition, patients with FM frequently present with endocrine imbalances, metabolic disturbances, cervical stenosis, and other physiological changes. Yet, these latter changes are rarely viewed in the context of the patient’s overall pain level.20 Algopathy would suggest that all of these changes play into the patients’ pain intensity, including their emotional response to and understanding of the painful condition coloring their pain experience. The use of algopathy may facilitate a more holistic consideration of chronic pain that encompasses the many symptoms that are typically present in chronic pain syndromes.

Using algopathy to describe the emotional ramping up of symptoms in the context of pain chronification may accelerate recognition of the acute-to-chronic pain transition, leading to more responsive and effective approaches to treatment. Adopting this terminology also may engender the application of more appropriate therapeutic interventions while more readily enabling the dismissal of treatments likely to offer little relief. At the very least, algopathy may heighten clinical awareness that chronic pain requires attention to the complex interplay of physical and psychological factors that will shape patients’ full experience of their pain.

Communicating Effectively With Patients in Pain

From the outset, pain levels should be evaluated whether the pain appears acute or chronic. Initiating a discussion with the patient even if there is resistance is essential to obtaining a full assessment. Patients may be hesitant to mention pain or other symptoms for any number of reasons, including:

  • The fear of appearing weak
  • Influenced by cultural norms
  • Concern about family expectations

The genuine discounting or denial of pain symptoms may be a hoped-for part of their situation. A number of validated pain assessment metrics are available, including visual analog pain scales, numeric scales, qualitative scales, and others. With this connection, the scale selected is less important than the consistency with which the clinical team uses the same scale.21-23 There are even pain scales for specific conditions, such as low back pain24 and dementia.25

In addition to the usual physical pain scales, patients should also be asked to complete the Adverse Childhood Experiences (ACE) questionnaire, since there is mounting evidence that ACEs predispose individuals to chronic pain conditions as adults.26

Pain assessments provide important metrics by which to deliver comprehensive pain care to patients, but chronic pain patients often experience pain in an erratic, diffuse, or vague way. Pain may be severe one day, mild on other days, or altogether gone. For that reason, clinicians should ask about the location of the pain. It is usually easier for patients to point to pain sites on a drawing of a human figure than on their own bodies. It is not uncommon for patients to experience pain at multiple locations, making it important to inquire about the possibility of more than 1 site of pain and then account for different characteristics in these pains. One by one, the clinician should assess pain intensity by location and then explore the patient’s pain experience through a series of questions (Table 3).

Since the vocabulary describing pain is limited and patients may have little experience trying to articulate how their pain feels, it would be appropriate to provide prompts to help guide the patient in describing any and all pain experiences.

Patients with a strong emotional component to their pain may benefit from psychotherapy and medications such as antidepressants, mood stabilizers, and antipsychotic drugs. It is the experience of the authors that when chronic pain transitions to the point that it has a predominant emotional component, interventional pain therapies become less effective. It may be the reason that many chronic pain patients do not respond to conventional analgesic regimens; pain syndromes may be better maintained with psychotherapeutic modalities.

Case 1: Recovery Following an Auto Accident

Two years ago, a 46-year-old divorced woman (based on a composite of patient experiences rather than an actual patient) injured her back in a vehicular accident and appeared to make good progress with rehabilitation despite experiencing fairly high levels of occasional pain. She was mildly obese (body mass index of 31) and had been diagnosed with prediabetes within the previous 6 months.

The patient was diligent about attending biweekly physical therapy sessions and had made modest lifestyle changes, including alterations to her diet and occasional neighborhood walks when the pain was mild. These efforts led to a weight loss of about 10 pounds over the course of the last 4 months.

Recently, she reported feeling depressed. Her injury had resulted in lost time and wages from her job, creating unanticipated debt. She admitted to the nurse that things went “out of control” following the accident. Although family and friends had been very supportive of her immediately following the accident, she was unable to participate in some family activities such as swimming or boating as a result of the injury and related back pain, making her feel worse about herself.

As her physical condition deteriorated, she lost interest in physical therapy and walking, which led to weight regain and social isolation. The more she withdrew from friends and family, the greater her pain levels rose, as did her demand for increased dosages in her pain medications.

In an interview with the nurse, she voiced concern about the possibility of losing her job and not being able to find a new one. She was referred to a psychiatrist to address the torrent of post-accident emotions and worries as well as to address the growing anger at the circumstances (divorce, medical diagnoses, back pain from the auto accident) that had significantly changed her life.

Through regular therapy sessions, she was given tools to help regain some personal control, such as encouragement to return to physical therapy, and to follow the modified diet and exercise plan as she began to address the emotional barriers. As her equilibrium was restored, she took a more active role in family activities and events. Her pain levels decreased as she experienced functional improvements in her physical health, but also because she had an outlet to discuss the painful events that followed the auto accident.

Case 2: Bypass Surgery

A 65-year-old (fictitious) man underwent open-heart surgery for a coronary artery bypass graft. The surgery was successful, but the pain was reported at 8/10 on a visual analog scale that extended from weeks to months. The patient, a business executive, complained about his ongoing discomfort to his cardiologist, who prescribed pain medication. The pain complaints seemed to worsen without a change in the patient’s pain level, which remained at an 8/10.

Despite having no history of prior substance abuse, the patient began to exhibit drug-seeking behaviors, which included frequent late-hour calls to the office, approaching several physicians for pain medication prescriptions, insistence on ever higher doses of medications, and anger when concern was expressed about the possibility that he might be developing a problem with his opioid use.

He was referred to a pain specialist who was able to help manage his pain more satisfactorily by adding gabapentin and administering an intercostal nerve block. It was concluded that the patient’s seeming drug-seeking efforts stemmed from a valid attempt to better manage his pain rather than overt abuse.

Despite medical advice, the patient resisted attending rehabilitation therapy, but he did agree to meet with a psychiatrist. The patient told the therapist that he was highly distressed about having heart problems, yet he had hidden these feelings from his wife, colleagues at work, clients, and his children, out of a desire to appear strong. Although he was a well-educated and articulate sales professional, he was catastrophizing that his life was about to end. His receptiveness to intensive counseling provided a way for him to come to terms with the pain and provided a much-needed outlet to explore these irrational thoughts.

During this time, the patient continued to experience chronic pain at the level of 5/10 but was able to refocus away from chemical coping to a more holistic approach to managing his pain. The pain-management specialist continued to work with the patient, steadily decreasing his pain medications.

Through counseling, he was helped to recognize the value of attending cardiac rehabilitation. As rehabilitation progressed, the patient stopped using opioids, his pain was downgraded to 2/10, and he was referred to his primary care provider for maintenance on gabapentin.

Conclusion

Despite our growing understanding of pain mechanisms, a gap remains in our approach to chronic pain management. The best way forward in managing chronic pain is to recognize the emotional component, which progressively increases as the pain becomes more centralized and intractable.

The algopathic continuum attempts to define this acute-to-chronic transition in terms of a ratio of physical and emotional symptoms of pain. By recognizing and addressing the emotional components of the pain, clinicians may be more successful in helping patients manage the pain and achieve a better quality of life.

Last updated on: June 13, 2017
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