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What Is Chronic Pain?

March 10, 2016  |  Posted by: Sam Menteith

By Dr Mary Obele, Occupational Physician

What is Chronic Pain?

Pain is defined by the International Association for the Study of Pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.” Pain is a subjective experience that cannot be objectively measured; it depends on what the patient self-reports. There is wide variability in how people experience and report pain.

Acute Pain:

  • Cause Usually known
  • Duration Short
  • Treatment Treat the injury or disease

Chronic Pain:

  • Cause Often known
  • Duration Persists after healing; or more than 3 months
  • Treatment Treat the underlying disease and pain disorder

Most people have tried self-management before seeing a medical professional. When assessing pain, doctors take a detailed history and do a clinical examination.
The history usually includes:

  • Characteristics of the pain: position, description, intensity, onset, timing, duration, aggravating and relieving factors.
  • Associated symptoms: weakness, unusual sensations.
  • Systemic symptoms: weight loss, fevers, bowel and bladder problems.
  • Behavioural, psychological and psychosocial factors.

The physical examination usually includes:

  • A musculoskeletal examination: range of motion, straight leg raise, other tests.
  • A neurological examination: tone, power, reflexes, sensation, gait.
  • Other relevant signs.

Investigations may be ordered, such as X-rays, ultrasound scans, CT and MRI scans and nerve conduction studies. Successful management of acute pain can prevent chronic pain developing. The aims are:

  • Reduce pain.
  • Return to activity and work as soon as possible.
  • If there is slow progress or no improvement by two weeks, then check for factors that may be delaying recovery.

Chronic Pain

Chronic pain is one of today’s most demanding and challenging health care issues. The treatment costs are similar to treating cancer and diabetes. Almost one in five Australians report chronic pain at some time in their lives. Up to two-thirds of General Practitioner visits involve chronic pain. It is difficult to accurately diagnose chronic pain. There are currently no accurate or reliable methods for determining the accuracy of self-reported pain complaints.

Chronic Pain Warning Signs

After two weeks, warning signs may include:

  • Slow recovery; the patient’s function does not improve.
  • Symptoms and pain are out of proportion to the degree of trauma.
  • Worsening symptoms.

At this stage, doctors will take a further history, repeat the physical examination and consider altering the management.
Many patients get transient features of complex regional pain syndrome, for example, transient skin mottling and swelling, during their recovery. Some patients develop other diagnoses, such as blood clots (DVT) or infection, which are medically treated.

Complex regional pain syndrome (CRPS) describes painful conditions with continuing regional pain seems to be out of proportion to the usual course of pain after trauma.
There is no relationship between the severity of trauma and development of CRPS.

The European incidence rate of CRPS is 26 per 100,000 person years. It is 3 to 4 times more common in females than males, and the peak incidence is at 50 – 70 years. It can spread to the other limb in 7% of cases.

CRPS may be associated with disability, dysfunction, distress and disturbance of body image. The subtypes are:

  • CRPS Type 1 (previously called reflex sympathetic dystrophy) can develop after any type of trauma. This is the most common type.
  • CRPS Type 2 (previously called causalgia) occurs after nerve damage.
  • CRPS-NOS (Not Otherwise Specified) Pain Syndrome.

CRPS is medically diagnosed using the clinical “Budapest criteria”:

  1. Continuing pain, which is disproportionate to any inciting event.
  2. Must report at least one symptom in three of the four following categories:
    A. Sensory: hyperalgesia, allodynia.
    B. Vasomotor: temperature or skin colour changes.
    C. Sudomotor/edema: swelling, sweating.
    D. Motor/trophic: decreased range of motion, motor dysfunction (weakness, tremor), trophic changes (hair, nails, skin).
  3. Must display at least one sign at time of evaluation in two or more of the above listed categories (2.A – D)
  4. There is no other diagnosis that better explains the signs and symptoms.

Approximately 15% of people with CRPS have pain and physical impairment for more than two years. Most patients have less pain intensity and dysfunction over time.

Assessment of CRPS

The diagnosis of CRPS is difficult, especially in the early stages. There is no known diagnostic laboratory or imaging test.
A bio-psycho-social pain assessment addresses the patient’s individual neurobiological, psychological, cognitive, social, environmental and other factors that are contributing to their perception and presentation of chronic pain.

Biological (What is happening to the person’s body?):

This involves understanding the history of the pain, a physical examination, ruling out any red flags (such as cancer) and assessing other medical conditions that may be contributing to chronic pain and its management.

Psychological (What is happening in the person’s life?) :

This identifies psychological contributors such as fear, worry, anxiety, depression; the pain’s impact on daily activities and sleep; and unhelpful behaviours, thoughts and beliefs (yellow flags).

Social (What is happening in the person’s world?):

This considers the patient’s work, health literacy, and socioeconomic situation including impact on their relationships with family and friends, work and leisure (blue and black flags). For example, it is useful to know how the patient perceives their work:

  • Do they think their work is satisfying?
  • Is work sufficiently challenging without being overwhelming?
  • Are there long hours, shift work, physically difficult or harmful tasks?
  • Do they feel they have a degree of control over their work tasks?
  • Are they able to self-pace? How easy is it to take a small break?
  • Do they get on well with their boss and co-workers?

All of these factors, and more, can influence everyday function and return to work in the face of chronic pain. Assessing each of these three domains via a comprehensive evaluation can be critical to make the right treatment decisions which can optimise outcomes. Conducting this type of comprehensive pain assessment can take time, and may need more than one appointment with a number of medical providers.

Management of CRPS

Although there is no known medical cure, multidisciplinary pain management and functional restoration can provide significant benefits. This can include:

  • Education and support for patients and their families.
  • Self-management with relaxation, pacing, goal-setting and incrementally increasing activities over time.
  • Effective pain medication and procedures that allow the affected limb to be mobilized.
  • Physical therapy. When a person becomes over-reliant on rest and inactivity, with or without medications, they can experience a decrease in muscle mass (atrophy), skeletal density and connective tissue strength. These can result in anatomical and physiological (structural and functional) weaknesses that make it harder for the body to adequately recover and respond to treatments. The longer a person is inactive, the longer it takes to restore them functionally. Physical treatments can include desensitation, active and passive mobilisation, edema control, and activity programs These aim to return the limb to normal function as soon as possible.
  • Psychological help, such as cognitive behavioural therapy and mood management.
  • Vocational assistance and work rehabilitation.
  • Drug and alcohol treatment.
  • Regular follow-up and care.

Conclusions

Pain complaints can be complex, and sometimes do not respond to a simple prescription alone.
Best medical practice in chronic pain management involves a comprehensive biopsychosocial approach, where a number of aspects of the patient’s presentation are managed simultaneously for a better outcome.