Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.

• Chronic pain can be described as ongoing or recurrent pain, lasting beyond the usual course of acute illness or injury or more than 3 to 6 months, and which adversely affects the individual’s well-being.
• Chronic or persistent pain is pain that continues when it should not.

Acute pain:

• nociceptive pain that follows a trajectory of decreasing pain intensity as tissue heals.
• Adaptive - encourages the individual to rest, withdraw, and protect the injury.

Chronic pain:

• persists long after the tissue has healed.
• Maladaptive, causes patient to develop kinesiophobia.

The pathophysiology of pain follows a 1-2-3 sequence:

1. Nociceptors sit on peripheral nerves, the peripheral nerves carry the message up to the spinal cord
2. At the level of the spinal cord; the peripheral nerves synapse with spinal nerves in the dorsal horn. The message crosses over and travels up the spinal cord
3. The spinal nerves synapse in the thalamus message is sent to various areas of the brain including the somatosensory cortex and the Limbic system.

1. Pain stimulates nociceptors
2. Stimulus is transferred via primary sensory neuron to the spinal cord (second order neuron).
3. Message ascends the spinal cord, gets processed in the thalamus (third order neuron) and finally reaches the cerebral cortex where the final perception occurs.

Non-physical factors such as social, emotional and spiritual aspects that together with the physical factors comprise the concept of “Total Pain”.

• Systemic diseases:
  • Rheumatoid/Osteoarthritis
  • Lupus
  • Sickle cell disease
  • Inflammatory bowel disease
  • Endometriosis
  • Rheumatoid arthritis
  • Osteoarthritis
  • Lupus
  • Sickle cell disease
  • Inflammatory bowel disease
• Cancer: itself and treatment
• Trauma

Yellow flags are psychosocial factors shown to be indicative of long term chronicity and disability:.

They include:

• Negative attitude that back pain is harmful or potentially severely disabling
• Fear avoidance behaviour and reduced activity levels
• An expectation that passive, rather than active, treatment will be beneficial
• A tendency to depression, low morale, and social withdrawal
• Social or financial problems

Pain catastrophizing is when patient's ruminate, magnify and feel helpless about their chronic pain. The pain catastrophizing scale is a 13 item questionnaire  that assesses the patients rumination, magnification and helplessness about their chronic pain.

Interdisciplinary approach:

• Participation in an interdisciplinary pain program (education, physiotherapy, exercise and psychological interventions) lead to a 40% reduction in scores on the pain catastrophizing scale.

For example:

• The Nova Scotia Workers Compensation Board used the pain catastrophizing scale on a sample of injured workers who had initiated a time loss claim with the Nova Scotia Workers Compensation Board
• For patients who scored higher than 30
  • 70% remained unemployed one year post injury
  • 70% described themselves as totally disabled
• Catastrophic thinking might be a risk factor for chronicity.
• The literature on pain catastrophizing recommends that if the patient scores higher than 30 (considered clinically relevant level of catastrophizing) on the pain catastrophizing questionnaire that they would benefit from a pain self management group or a CBT group for chronic pain. Research shows that cognitive interventions for these patients can reduce their catastrophizing and help them with more realistic thinking.

• PTSD symptoms are characterized by 3 major symptom clusters including
  • re-experiencing symptoms (e.g., thought intrusion, nightmares)
  • avoidance symptoms (e.g., avoidance of stimuli associated with the traumatic situation, social withdrawal)
  • arousal symptoms (e.g., hypervigilance, heightened startle reactions)
• PTSD symptoms are prevalent in whiplash injuries following MVA (25%).
• PTSD symptoms add to the burden of disability following whiplash injury and might contribute to the heightened risk of chronicity