La. Admin. Code tit. 40, § I-2105 - Introduction to Chronic Pain

A. The International Association for the Study of Pain (IASP) defines pain as "an unpleasant sensory and emotional experience with actual or potential tissue damage." Pain is a complex experience embracing physical, mental, social, and behavioral processes that often compromises the quality of life of many individuals. Pain is an unpleasant subjective perception usually in the context of tissue damage.

B. Pain is subjective and cannot be measured or indicated objectively. Pain evokes negative emotional reactions such as fear, anxiety, anger, and depression. People usually regard pain as an indicator of physical harm, despite the fact that pain can exist without tissue damage and tissue damage can exist without pain. Many people report pain in the absence of tissue damage or any likely pathophysiologic cause. There is no way to distinguish their experience from that due to actual tissue damage. If they regard their experience as pain and they report it the same way as pain caused by tissue damage, it should be accepted as pain.

C. Pain can generally be classified as:

1. Nociceptive which includes pain from visceral origins or damage to other tissues. Myofascial pain is a nociceptive type of pain characterized by myofascial trigger points limited to a specific muscle or muscles.

2. neuropathic including pain originating from brain, peripheral nerves or both; and

3. psychogenic which originates in mood, characterological, social, or psychophysiological processes.

D. Recent advances in the neurosciences reveal additional mechanisms involved in chronic pain. In the past, pain was seen as a sensation arising from the stimulation of pain receptors by damaged tissue, initiating a sequence of nerve signals ending in the brain and there recognized as pain. A consequence of this model was that ongoing pain following resolution of tissue damage was seen as less physiological and more psychological than acute pain with identifiable tissue injury. Current research indicates that chronic pain involves additional mechanisms that cause: neural remodeling at the level of the spinal cord and higher levels of the central nervous system; changes in membrane responsiveness and connectivity leading to activation of larger pain pathways; and recruitment of distinct neurotransmitters.

E. Changes in gene function and expression may occur, with lasting functional consequences. These physiologic functional changes cause chronic pain to be experienced in body regions beyond the original injury and to be exacerbated by little or no stimulation. The chronic pain experience clearly represents both psychologic and complex physiologic mechanisms, many of which are just beginning to be understood.

F. Chronic pain is defined as "pain that persists for at least 30 days beyond the usual course of an acute disease or a reasonable time for an injury to heal or that is associated with a chronic pathological process that causes continuous pain (e.g., Complex Regional Pain Syndrome)." The very definition of chronic pain describes a delay or outright failure to relieve pain associated with some specific illness or accident. Delayed recovery should prompt a clinical review of the case and a psychological evaluation by the health care provider. Referral to a specialist with experience in pain management is recommended.

G. The term "chronic pain syndrome" has been incorrectly used and defined in a variety of ways that generally indicate a belief on the part of the health care provider that the patient's pain is inappropriate or out of proportion to existing problems or illness. Use of the term "chronic pain syndrome" should be discontinued because the term ceases to have meaning due to the many different physical and psychosocial issues associated with it. The IASP offers taxonomy of pain, which underscores the wide variety of pathological conditions associated with chronic pain. This classification system may not address the psychological and psychosocial issues that occur in the perception of pain, suffering, and disability and may require referral to psychiatric or psychological clinicians. Practitioners should use the nationally accepted terminology indicated in the most current ICD system. Chronic pain can be diagnosed as F45.42 "Pain disorder with related psychological factors" when the associated body part code is also provided. Alternately, chronic pain can also be diagnosed as F54 "Psychological factors affecting physical conditions," and this code should also be accompanied by the associated body part. G89.4 "chronic pain associated with significant psychosocial dysfunction" may also be utilized.

H. Injured patients generally initiate treatment with complaints of pain, which is generally attributable to a specific injurious event, but occasionally to an ostensible injury. Thus, the physician should not automatically assume that complaints of acute pain are directly attributable to pathophysiology at the tissue level. Pain is known to be associated with sensory, affective, cognitive, social, and other processes. The pain sensory system itself is organized into two parts, often called first and second pain. A-Delta nerve fibers conduct first pain via the neospinalthalamic tract to the somatosensory cortex and provide information about pain location and quality. In contrast, unmyelinated C fibers conduct second pain via the paleospinalthalamic tract and provide information about pain intensity. Second pain is more closely associated with emotion and memory neural systems than it is with sensory systems.

I. As a patients condition transitions through the acute, subacute, and chronic phases, the central nervous system (CNS) is reorganized. The temporal summation of second pain produces a sensitization or "windup" of the spinal cord, and the connections between the brain regions involved in pain perception, emotion, arousal, and judgment are changed by persistent pain. These changes cause the CNSs "pain neuromatrix" to become sensitized to pain. This CNS reorganization is also associated with changes in the volume of brain areas, decreased grey matter in the prefrontal cortex, and the brain appearing to age more rapidly. As pain continues over time, the CNS remodels itself so that pain becomes less closely associated with sensation, and more closely associated with arousal, emotion, memory, and beliefs. Because of these CNS processes, all clinicians should be aware that as the patient enters the subacute phase, it becomes increasingly important to consider the psychosocial context of the disorder being treated, including the patients social circumstances, arousal level, emotional state, and beliefs about the disorder. However, behavioral complications and physiological changes associated with chronicity and central sensitization may also be present in the acute phase, and within hours of the initial injury. It is the intent of many of the treatments in this guideline to assist in remodeling these CNS changes.

J. Chronic pain is a phenomenon not specifically relegated to anatomical or physiologic parameters. The prevailing biomedical model (which focuses on identified disease pathology as the sole cause of pain) cannot capture all of the important variables in pain behavior. While diagnostic labels may pinpoint contributory physical and/or psychological factors and lead to specific treatment interventions that are helpful, a large number of patients defy precise taxonomic classification. Furthermore, such diagnostic labeling often overlooks important social contributions to the chronic pain experience. Failure to address these operational parameters of the chronic pain experience may lead to incomplete or faulty treatment plans. The concept of a "pain disorder" is perhaps the most useful term, in that it captures the multi-factorial nature of the chronic pain experience.

K. It is recognized that some health care practitioners, by virtue of their experience, additional training, and/or accreditation by pain specialty organizations, have much greater expertise in the area of chronic pain evaluation and treatment than others. Referrals for the treatment of chronic pain should be to such recognized specialists. Chronic pain treatment plans should be monitored and coordinated by physicians with expertise in pain management including specialty training, and/or certification.

L. Most acute and some chronic pain problems are adequately addressed in other OWCA medical treatment guidelines, and are generally not within the scope of this guideline. However, because chronic pain is more often than not multi-factorial, involving more than one pathophysiologic or mental disorder, some overlap with other guidelines is inevitable. This guideline is meant to apply to any patient who fits the operational definition of chronic pain discussed at the beginning of this Section.

Notes

La. Admin. Code tit. 40, § I-2105

Promulgated by the Louisiana Workforce Commission, Office of Workers Compensation Administration, LR 37:1683 (June 2011), Amended LR 46197 (2/1/2020).

AUTHORITY NOTE: Promulgated in accordance with R.S. 23:1203.1.