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.

Complex Regional Pain Syndrome


Related Terms

  • Algodystrophy
  • Causalgia
  • CRPS
  • CRPS I
  • CRPS II
  • Neurodystrophy
  • Reflex Sympathetic Dystrophy Syndrome
  • RSD
  • RSDS
  • Shoulder-hand Syndrome
  • Sudeck's Atrophy
  • Sympathalgia

Specialists

  • Anesthesiologist
  • Clinical Psychologist
  • Ergonomist
  • Hand Surgeon
  • Neurologist
  • Occupational Therapist
  • Physiatrist (Physical Medicine and Rehabilitation Specialist)
  • Physical Therapist
  • Psychiatrist
  • Psychologist

Comorbid Conditions

Factors Influencing Duration

The factors influencing duration of disability in CRPS have not been precisely determined. Remission is common for periods (weeks, months, years); however, the duration of disability is influenced by the severity of the condition, the individual's response to treatment, and the development of complications or the presence of a comorbid condition.

Medical Codes

ICD-9-CM:
355.9 - Causalgia; Mononeuritis, Unspecified Site; Complex regional pain syndrome NOS

Overview

The following discussion on the CRPS condition is highly controversial. Attempts are currently underway by some specialty societies to explore the entire diagnosis and treatment of this condition. The vast majority of the literature that has been relied upon for diagnosis and treatment is, at best, limited and not reproducible. The discussion herein should be viewed as a possible suggestion but not to a level of any substantial medical certainty

Complex regional pain syndrome (CRPS) is a complicated chronic neurological condition characterized by severe burning pain, skin and bone pathological changes, excessive sweating, tissue swelling, and extreme sensitivity to touch. The syndrome produces significant disability and dysfunction. CRPS is often divided into two types. CRPS I, formerly known as reflex sympathetic dystrophy syndrome (RSD), generally follows an illness or injury that has not directly affected the nerves in the painful extremity. CRPS II, formerly known as causalgia, presents the same symptoms but occurs after specific nerve injury. Symptoms of both types of CRPS usually develop within one month after the inciting event and often first appear near the area of injury. CRPS is not a psychological syndrome. Nevertheless, psychological problems may arise if complaints of pain are dismissed by physicians, family, friends, and co-workers.

Diagnostic criteria for CRPS were adopted by the International Association for the Study of Pain (IASP) in 1994 and reviewed by investigators. These criteria are as follows: The presence of an inciting noxious event (such as a crush or soft tissue injury, or immobilization, such as a tight cast or frozen shoulder, for type I, or a nerve injury for type II). Continuing pain that is disproportionate to any known inciting event. Presence of at least 1 symptom in at least 3 of the following categories: sensory (hyperesthesia or allodynia [pain evoked buy a stimulus that does not normally evoke pain]), vasomotor (temperature asymmetry, skin color changes or asymmetry), sudomotor/edema (edema, sweating changes or asymmetry), and motor/trophic (decreased range of motion, motor dysfunction [weakness, tremor, dystonia], or trophic changes [hair, nail, skin]). In addition, at least 1 sign must be present at the time of evaluation in at least two of the following categories: sensory (hyperalgesia to pinprick; allodynia to light touch, temperature sensation, deep somatic pressure, or joint movement), vasomotor (temperature asymmetry [>1°C], skin color changes or asymmetry), sudomotor/edema (edema, sweating changes or asymmetry), and motor/trophic (decreased range of motion, motor dysfunction [weakness, tremor, dystonia], or trophic changes [hair, nail, skin]); the signs and symptoms are not better explained by other diagnosis (Wheeler).

The syndrome can be described as having three general stages although these may not apply to the disease pattern or clinical course of all individuals. Stage I (acute) usually lasts from 1 to 3 months. It is characterized by intense, burning pain accompanied by muscle spasm, joint stiffness, rapid hair growth, and alterations in the blood vessels that cause the skin to redden and become warm. Stage II (dystrophic) is subacute, lasting from 3 to 12 months. It is characterized by increasing pain, stiff joints, swelling, cracked, brittle or pitted nails, decreased hair growth, and weak muscle tone. Stage III (atrophic) is chronic, starting typically after 12 months and resulting in irreversible damage to the skin and bones. Pain intensifies and can be continuous, involving the entire limb or affected area of the body. In some individuals, pain may decrease. Muscle atrophy may occur along with contraction of joints, resulting in contortion of the affected limb, severely limited range of motion, inability to initiate movement, and involuntary contractions of the muscles or tremors. Some affected individuals do not progress beyond stage I, and only a relatively small number of individuals progress to stage III.

Early diagnosis of CRPS is considered essential for effective management of the syndrome before the development of any permanent disability. Because symptoms may vary dramatically among individuals, and also vary from day to day within the same individual, the combination of the individual's medical record, self-reported symptoms, clinical observation, and supportive testing and diagnostic imaging will be needed to confirm a diagnosis of CRPS. Positive findings may support a diagnosis of CRPS but the absence of positive findings (e.g., negative results of x-ray, bone scan, or sympathetic nerve block) does not necessarily rule out the condition.

Incidence and Prevalence: Incidence of CRPS type I is about 5.5 per 100,000 person-years at risk, and prevalence is about 21 per 100,000. Incidence of CRPS type II is 0.8 per 100,000, and prevalence is about 4 per 100,000. The incidence of CRPS type I after fractures is 1% to 2%; the incidence of CRPS type II after peripheral nerve injury is about 1% to -5%. The incidence of CRPS is 12% after a brain injury, and 5% after a heart attack (myocardial infarction) (Wheeler). CRPS occurs in about 1% to15% of all cases of peripheral nerve injury in conjunction with various fractures, sprains, and soft tissue injury; incidence ranges from 10% to 30% after fractures and contusions. About 90% of individuals with CRPS have type I. Upper extremities are affected more than lower. About 50% of individuals with CRPS type I report it is associated with a work-related injury (Wheeler).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Complex regional pain syndrome occurs in both sexes and all ages but is reported to be more common in women (ratio: 2:1 to 4:1) (Wheeler). It occurs most often among young to middle-aged adults, although is also reported to develop in children and senior adults. Risk may be somewhat greater for individuals with an existing neurological impairment such as carpal tunnel syndrome or for immobilized or chronically ill individuals.

In a majority of cases, CRPS follows acute trauma or major injury to an arm or leg (e.g., gunshot wound or fracture). Surgery, such as carpal tunnel decompression, can also trigger CRPS. It may also be triggered by a minor injury, such as a strain, sprain, or laceration, just as it may be triggered by a clinical condition, such as stroke, myocardial infarction, burns, cancer, arthritis, polymyalgia, spinal cord injury, or infection. Finally, it can develop in the absence of a remembered inciting event or illness.

The cause of CRPS is not entirely understood, although in some cases is thought to stem from dysfunction of the sympathetic nervous system that controls blood flow and sweat gland activity. While it is normal for the sympathetic nervous system to respond to injury, the response normally quiets down as healing occurs. In individuals with CRPS, it can remain active despite a lack of ongoing trauma.

Source: Medical Disability Advisor



Diagnosis

History: The approach to diagnosing CRPS begins with a detailed medical history, with an emphasis on any recent injury, as well as prior illnesses and injuries. CRPS usually affects the upper or lower extremities, although it can affect other areas of the body as well. The main symptom is intense, constant, burning pain that occurs without stimulation or movement. The pain is beyond the territory of a single peripheral nerve, often with spreading of pain away from the original site (distally) or next to it (proximally). The pain is often disproportionate to the severity of the initial inciting event.

Symptoms and physical signs may be described by the individual as coming and going. A limb may be normal temperature one moment and cold the next, making the patient's self-reported history an important diagnostic tool.

Physical exam: Signs may include dramatic changes in the color and temperature of the skin over the affected limb or body part, skin sensitivity and tenderness to touch (allodynia), sweating, changes in skin texture (from dry and scaly to thin and shiny), changes in hair and nail growth, swelling and stiffness in joints, and decreased motor ability, especially in the affected body part. Tremor and muscle spasm may develop, and edema of the affected limb can be marked. Muscle atrophy and joint tightening (contracture) may occur, and bones of the limb can become osteoporotic.

Other signs include characteristic hand or arm positioning, signs of carpal tunnel syndrome, dystrophic skin changes, and muscle weakness suggestive of a neurologic cause. Psychological or emotional factors may also be observed. To aid in diagnosis, a stimulus test (with touch, pinprick, heat, or cold) may be employed to gauge the pain level at the affected site.

Tests: No single test is available to confirm CRPS, and specific test results may vary widely from individual to individual. A triple-phase bone scan may be used to reveal osteoporosis or increased circulation to the joints in the affected areas, providing radiographic evidence of CRPS and ruling out other conditions. An x-ray may demonstrate a loss of bone minerals, which can occur in progressive CRPS. Positive tests or scans can be definitive for CRPS, but negative tests or scans do not necessarily rule out CRPS.

Source: Medical Disability Advisor



Treatment

Treatment is complex and multi-disciplinary, and often fails, especially if it is delayed. Treatment for CRPS includes use of medications such as oral corticosteroids, calcium-regulating drugs (e.g., calcitonin, clodronate, or alendronate), non-steroidal anti-inflammatory drugs (NSAIDs), anticonvulsants, antispasmodics, antidepressants (tricyclic antidepressants or selective serotonin reuptake inhibitors [SSRIs]), calcium channel blockers, and vasodilators, among others. Opioid analgesics may be prescribed for pain, but their long-term efficacy has not been established. In selected cases, implantation of an intrathecal opioid pump may be considered after more conservative therapies have failed. Topical medications may also be employed to relieve pain in the affected limb or area.

Invasive procedures used to treat CRPS include regional sympathetic blocks. Surgical sympathectomy is a very controversial technique that only should be used as a last resort for individuals whose pain is dramatically (but temporarily) relieved by selective sympathetic nerve blocks. Neuromodulation includes implanted spinal cord stimulators, transcutaneous electrical nerve stimulation (TENS), and brisk rubbing of the involved part (counterirritation), as well as acupuncture.

Rehabilitation and functional restoration approaches include physical therapy and psychological services such as psychotherapy, as well as pain control measures that may include biofeedback, stress reduction, meditation, relaxation training, and hypnosis.

While medications can be helpful, there is no single proven treatment for CRPS. The most important intervention appears to be appropriate, aggressive, active and passive physical therapy with cognitive behavioral therapy as part of the treatment plan. Other modalities may be used, but a coordinated functional restoration approach is critical.

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 persons with CRPS varies. Remission from symptoms occurs in certain individuals; others have unyielding pain and irreversible damage in spite of treatment. About 30% of individuals will have spreading of symptoms to other extremities and ongoing musculoskeletal discomfort due to changes that occur with dysfunction of one limb. Research suggests that prognosis improves with early treatment.

Source: Medical Disability Advisor



Rehabilitation

The focus of rehabilitation in individuals with CRPS is to decrease symptoms and to promote function. Treatment depends on the location, the severity, and the stage of the syndrome. Although individuals may benefit from a multidisciplinary rehabilitation program, to date no evidence exists to substantiate this. Based on common clinical practice, numerous treatment options may be explored.

The duration and intensity of rehabilitation varies among individuals. CRPS may take up to 1 to 2 years to resolve, and it is not uncommon for residual deficits to persist.

The first goal of rehabilitation during the inflammatory stage is to decrease pain and swelling of the affected body part. In combination with pharmacological management, thermal modalities can be used to relieve symptoms. During this stage, some common findings associated with CRPS may include local discoloration, sweating, and changes in hair distribution.

Once pain and swelling have decreased, the second goal is to prevent any loss of functional ability and possibly to improve function. Rehabilitation should include gentle range of motion and strengthening exercises, progressed according to the individual's tolerance. Efforts should be made to promote full range of motion and prevent contractures. In addition to supervised rehabilitation, individuals should be instructed in an independent home exercise program to be performed daily.

If a functional deficit is evident, the individual may be evaluated for assistive devices. A home assessment may be beneficial to determine the need for modifications. An ergonomic evaluation may help to maintain the individual's employment status.

FREQUENCY OF REHABILITATION VISITS
Nonsurgical
SpecialistComplex Regional Pain Syndrome
Occupational / Hand / Physical TherapistUp to 52 visits within 26 weeks
The table above represents a range of the usual acceptable number of visits for uncomplicated cases. It provides a framework based on the duration of tissue healing time and standard clinical practice.

Source: Medical Disability Advisor



Complications

Movement limitation of an extremity due to pain or stiffness may result in tissue wasting (atrophy) and muscle contracture. Other possible complications are osteoporosis and nodular fasciitis of the palmar or plantar skin. Complications are often related to the inciting event (i.e., fracture, infection, crush injury), and to the person's psychosocial behavior (i.e., self-limitation of activities of daily living). The treatment itself as it pertains to medications and invasive interventions may potentially result in complications.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Categorical statements regarding work restrictions and accommodations are not possible due to the wide range of clinical presentations in individuals with CRPS. Work restrictions and accommodations are based upon the interaction between a person's medical impairment (if any) and the job requirements.

Risk: There are no known risk factors for the development of CRPS or risk to the individual for performing work activities when the condition is present.

Capacity: There is no objective measure for capacity in this condition.

Tolerance: Tolerance and symptom intensity varies between individuals, but the hyperesthesia and intense burning pain associated with severe CRPS can be extreme in some cases. Progressive work activity and performance of tasks that involve weight bearing through the affected extremity may be therapeutic.

Accommodations: The need for accommodations may be assessed on a case-by-case basis.

Source: Medical Disability Advisor



Maximum Medical Improvement

120 days.

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:

  • Were alternative diagnoses investigated?
  • Were concurrent or comorbid diagnoses investigated?
  • Was diagnosis based solely on the individual's self-report?
  • Was diagnosis based on objective diagnostic criteria identified during a standard examination and by standard clinical and radiologic techniques?

Regarding treatment:

  • Was appropriate, aggressive, active, and passive physical therapy performed?
  • Have unproven treatments resulted in unwanted side effects?
  • Have treatment methods reinforced counterproductive behaviors?

Regarding prognosis:

  • Were psychosocial factors such as family and workplace dynamics considered?
  • Were mental and behavioral disorders (depression, somatoform disorders, factitious disorders) considered?
  • Were inappropriate illness behaviors (symptom exaggeration, malingering) considered?

Source: Medical Disability Advisor



References

Cited

Wheeler, Anthony H., et al. "Complex Regional Pain Syndromes." eMedicine. 8 Sep. 2014. Medscape. 22 Apr. 2015 <http://emedicine.medscape.com/article/1145318-overview>.

Source: Medical Disability Advisor






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