Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Pain, Chronic


Related Terms

  • Chronic Pain Syndrome
  • Fibromyalgia
  • Unresolved Pain

Differential Diagnosis

Specialists

  • Anesthesiologist
  • Clinical Psychologist
  • Dentist
  • Neurologist
  • Pain Medicine Physician/Pain Specialist
  • Physiatrist (Physical Medicine and Rehabilitation Specialist)
  • Psychiatrist

Comorbid Conditions

Factors Influencing Duration

Although individuals with CPS may have no objective medical impairment, their self-perception of incapacity depends on many variables, including character traits, personality, ethnic and cultural background, the presence of support systems, motivation and prior job satisfaction.

Medical Codes

ICD-9-CM:
338.21 - Chronic Pain Due to Trauma
338.22 - Chronic Post-thoracotomy Pain
338.28 - Chronic Postoperative Pain, Other
338.29 - Chronic Pain, Other
338.3 - Neoplasm Related Pain (Acute) (Chronic)
338.4 - Chronic Pain Syndrome; Chronic Pain Associated with Significant Psychosocial Dysfunction

Overview

Chronic pain generally refers to persistent, non-acute, sometimes disabling pain in the extremities or other areas of the body. The pain can be associated with a known cause such as a major or minor injury, or it can be a symptom of a painful chronic condition such as fibromyalgia. It can just as often be of unknown origin. Considerable controversy continues to surround the cause (etiology), definition, diagnosis, and treatment of chronic pain.

The term "chronic pain" is not used consistently. The term can refer to pain that has been present for an arbitrarily defined period, for example, longer than 6 months. Chronic pain is not the same as acute pain or recurrent acute pain. Acute pain is due to actual or developing tissue damage. Its duration is short and its psychosocial consequences are minimal. A person's perception of acute pain, and behavior following the onset of acute pain, are commensurate with the inciting event. Acute pain resolves as healing occurs. Acute pain is common, occurring for example with fractured bones, skin lacerations, sprains, and other similar events. Recurrent, acute pain refers to episodic pain associated with chronic conditions such as trigeminal neuralgia or cluster migraine headaches.

Although chronic pain differs from acute pain, the current understanding of neurophysiologic mechanisms involved in the development and persistence of pain recognizes that transmission of pain (nociceptive signals) from peripheral sites results in changes at all levels of the central nervous system (CNS) (Henry). Genetic and environmental factors along with increases in innate (endogenous) CNS excitatory controls and decreases in inhibitory controls are also believed to contribute to the evolution of chronic pain (Marchand). Evidence-based research suggests that when acute pain does not resolve within a few months, continued activation of nerves that transmit pain (nociceptors) may result in changes in the spinal cord and brain (CNS changes) that can eventually lead to the development of chronic pain (Apkarian; Bushnell). This knowledge of CNS changes due to prolonged pain may help to explain the disproportionate and non-dermatomal presentation of chronic pain and may help in the diagnosis and treatment of the individual.

Alternatively, the term "chronic pain" is often used as a synonym for "chronic pain syndrome (CPS)," a term used to describe physical and psychological changes due to chronic pain that include complaints of constant pain, subjective symptoms in excess of objective findings, associated dysfunctional pain behaviors, and self-limitation in activities of daily living. CPS refers to persistent pain that usually has no identifiable source and is associated with abnormal illness behaviors, including expressions of pain (e.g., moaning, groaning, gasping, grimacing) that are grossly disproportional to any underlying cause; substance abuse involving prescription drugs, non-prescription drugs, and alcohol; self-imposed prolonged excessive disuse; self-limitation of social and recreational activities; and a self-perception of total occupational disability. CPS is complex and involves multiple factors, but should be considered if an individual does not respond to appropriate medical care within a reasonable time frame, or if the individual's pain behavior greatly exceeds the usual response to a specific disorder. However, explaining all current and future conditions of an individual by only one diagnosis of CPS may be misleading and dangerous.

CPS is not to be confused with "complex regional pain syndrome" (CRPS), also called reflex sympathy dystrophy (RSD), which also involves chronic pain but is defined and diagnosed using an established set of clinical criteria.

For more information refer to "Disease and Injury Causation," pages 221–236.

Incidence and Prevalence: Prevalence estimates indicate that about 31% of the American population has chronic pain lasting 6 months or more, and about 17% of those are partially or totally disabled (Johannes). Pain is the most frequent complaint leading individuals to seek medical care.

Source: Medical Disability Advisor



Causation and Known Risk Factors

Chronic pain is reported more frequently in women than men. Prevalence of pain increases with increasing age until about age 65 when it levels off. Other risk factors include marital status of divorced or separated, lower socioeconomic status, higher body mass index, and poor self-assessed health. Whites are more likely to report chronic pain than other racial/ethnic groups (Johannes).

Source: Medical Disability Advisor



Diagnosis

History: A thorough history will include assessment of major organ systems, including musculoskeletal, reproductive, gastrointestinal, and urologic systems. The use of standardized questionnaires can be very helpful in gathering information about the location, quality, and severity of pain, as well as its effects on sleep and on the individual’s level of function. Risk assessment questionnaires are used as a part of history to verify the psychological and dependency risks in the pain management setting.

Individuals with CPS describe persistent pain with subjective symptoms disproportionate to their objective findings, and often have a history of prescription or non-prescription drug abuse, alcohol abuse, treatment by multiple medical professionals, extensive diagnostic testing and treatment, psychological disorders, and self-limitations in personal and occupational activities of daily living. Physicians may assess the individual for Sternbach’s 6 D’s of CPS (dramatization of complaints, drug misuse, dysfunction, dependency, depression, and disability) to establish the diagnosis.

Physical exam: Individuals with CPS can have normal physical examinations with no evidence of neurologic, musculoskeletal, or other impairment. Individuals with CPS usually exhibit expressions of pain, such as moaning, groaning, gasping, or grimacing that are inconsistent with the absence of medical impairment. Individuals with this syndrome often exhibit so-called nonorganic findings, such as little or no active range of motion but normal passive range of motion.

Tests: An individual with chronic pain should be thoroughly and periodically investigated as should any other individual with pain. Individuals with CPS may have no abnormalities identified on diagnostic testing. However, routine blood tests and neurologic evaluation may be ordered to investigate possible underlying conditions. Psychological testing may be done, particularly if organic diseases have been excluded.

Source: Medical Disability Advisor



Treatment

Therapeutic measures for chronic pain can include physical therapy, occupational therapy, recreational therapy, interventional treatments (such as nerve blocks, nerve ablations, spinal surgeries and stimulation, and intrathecal morphine pumps), psychological therapy, biofeedback, cognitive behavioral therapies, and medications including nonsteroidal anti-inflammatory drugs, antidepressants, and anticonvulsants.

In persons with CPS, the focus of treatment should be on management rather than cure. The goals should be clearly defined and articulated. Goals include an increase in functional capacity and a decrease in dependencies on medication and medical providers. Abnormal illness behavior usually can be diminished. Return to the work force is highly desirable but depends on many variables, including character traits, personality, ethnic and cultural background, the presence of support systems, motivation, and prior job satisfaction. Effective management is based upon rehabilitation, behavior modification, and therapy.

Source: Medical Disability Advisor



ACOEM

ACOEM's Practice Guidelines, the gold standard in effective medical treatment of occupational injuries and illnesses, are provided in this section to complement the disability duration guidelines.*
 
Chronic Pain
 
* The relationship between the MDGuidelines (MDA) content and ACOEM's guidelines is approximate and does not always link identical diagnoses. The user should consult the diagnostic codes in both guidelines, as well as the clinical descriptions, before assuming an equivalence.

Source: ACOEM Practice Guidelines



Prognosis

The prognosis for individuals with CPS has not been adequately defined in scientifically valid outcome studies. However, individuals fitting the criteria for CPS are likely to have a poor prognosis.

Source: Medical Disability Advisor



Complications

Complications may be related to the secondary gain factors that reinforce CPS, including a life structured around disability, treatment by multiple medical professionals, extensive diagnostic testing and treatment, treatment with prescription narcotic medication and other addictive drugs, relief from occupational activities, attention and support of spouse and family, and financial compensation. Comorbidity with other conditions like sleep disorders or depression can increase the chance of complications.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Although individuals with CPS self-limit their occupational activities, there may be no objective medical basis for work restrictions or accommodations. Furthermore, prescribed work restrictions or accommodations can reinforce the individual's self-perception of incapacity, thereby prolonging the duration of this syndrome.

For more information refer to "Work Ability and Return to Work," pages 427–432.

Risk: Risk is not an issue for working despite CPS. The Americans with Disabilities Act test of significant risk of substantial harm that is imminent is not applicable. While symptoms of pain and fatigue may increase with activity, this pain does not constitute "substantial harm." There are no published medical reports of individuals being harmed by activity.

Some medications used in CPS treatment are sedating, and some safety sensitive jobs may exclude those taking sedating medications on the basis of risk by either government regulation (such as pilots and commercial drivers) or employer policy.

Capacity: Capacity is hard to measure in CPS. Individuals self-limit activity due to symptoms, which may fluctuate over time, with the result that self-limitations of activity also fluctuate. Thus a prior assessment of capacity may underestimate the performance an individual is willing to demonstrate today, just as it may overestimate the performance next week. When tested on a cardiopulmonary treadmill or a bicycle, individuals typically self-terminate the test due to pain or fatigue prior to reaching the anaerobic threshold, showing that it is tolerance and not capacity creating limitations.

Individuals with CPS are frequently deconditioned as the result of a sedentary lifestyle, but their level of conditioning can improve with activity, or it can further decrease with activity restriction.

Tolerance: Tolerance for symptoms such as pain and fatigue is typically the issue in CPS. The individual can choose to work or participate in an activity despite symptoms, or the individual can choose not to participate because of symptoms. These variations are not something that physicians or medical testing can evaluate or substantiate.

Accommodations: Individuals with CPS have multiple differing symptoms, and an activity that increases symptoms for one individual may not affect another. Thus, if employers wish to accommodate individuals with CPS, they may discuss with the employee the specific activities that increase symptoms beyond the individual’s tolerance, and what accommodations help minimize those activities.

Source: Medical Disability Advisor



Maximum Medical Improvement

180 to 270 days. More than most conditions, MMI does not mean stop treating.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • How was the diagnosis of CPS established?
  • Does individual fit the diagnostic criteria of Sternbach's 6 D’s?
  • Have alternative explanations for the individual's symptoms been investigated?
  • Has an underlying major organ system disease been identified?
  • Has psychological testing been done?
  • Has substance abuse (or the risk of it) been confirmed?
  • Is this a somatoform disorder?
  • Is this a factitious disorder?
  • Is individual malingering?

Regarding treatment:

  • Have physical therapy, occupational therapy, or recreational therapy been employed?
  • Has mobilization, stretching, and strengthening been employed?
  • Has behavioral modification, including operant conditioning and relaxation therapy, been employed?
  • Has cognitive therapy been employed?
  • Have nerve blocks, spinal surgeries and stimulation, or intrathecal morphine pumps been employed?
  • Has treatment reinforced the presence of CPS (treatment by multiple medical professionals, extensive diagnostic testing and treatment, treatment with narcotic medication and other addictive drugs)?

Regarding prognosis:

  • Have psychosocial factors, such as family and workplace dynamics, been considered?
  • Has individual responded favorably to use of nerve blocks, spinal surgeries and stimulation or intrathecal morphine pumps?

Source: Medical Disability Advisor



References

Cited

Apkarian, Vania A., et al. "Chronic Back Pain is Associated with Decreased Prefrontal and Thalamic Gray Matter Density." Journal of Neuroscience 24 6 (2004): 10410-10415. The Journal of Neuroscience. Society for Neuroscience. 29 Oct. 2014 <http://www.jneurosci.org/cgi/content/abstract/24/46/10410>.

Bushnell, M. C., M. Ceko, and L. A. Low. "Cognitive and Emotional Control of Pain and Its Disruption in Chronic Pain." Nature Reviews. Neuroscience 14 (2013): 502-511.

Henry, D. E. , A. E. Chiodo, and W. Yang. "Central Nervous System Reorganization in a Variety of Chronic Pain States: A Review." P M & R: The Journal of Injury, Function, and Rehabilitation 3 (2011): 1116-1125.

Johannes, C. B., et al. "The Prevalence of Chronic Pain in United States Adults: Results of an Internet-Based Survey." Journal of Pain 11 (2010): 1230-1239.

Marchand, Serge. "The Physiology of Pain Mechanisms: From the Periphery to the Brain." Rheumatic Disease Clinics of North America 24 2 (2008): 285-309.

Melhorn, J. Mark, and William Ackerman, eds. Disease and Injury Causation, Guides to the Evaluation of. AMA Press, 2008.

Singh, Manish K. "Chronic Pain Syndrome." eMedicine. 20 Mar. 2014. Medscape. 29 Oct. 2014 <http://emedicine.medscape.com/article/310834-overview>.

Talmage, J. B. , J. M. Melhorn, and M. H. Hyman, eds. Work Ability and Return to Work, AMA Guides to the Evaluation of. Second ed. Chicago: AMA Press, 2011.

Source: Medical Disability Advisor






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