Chronic pain is different than acute pain because the physical manifestations are not always apparent; chronic pain is not just "longer lasting acute pain." Changes include:
Nervous system changes
Peripheral level: upregulation of adrenergic and some peptide receptors
Dorsal horn level:
Ý in the size and dendritic tree of neurons
Spinal cord and brainstem: wind-up phenomenon, change of cutaneous representations
Changes in the transmitter populations
Loss of autonomic changes associated with acute pain (nausea, pupillary dilatation, sweating, etc..)
Behavioral changes
Personality change – always irritable and moody, can result in family problems and shifting of family dynamics (such as going from a 2 income family to a 1 income family)
Reduced performance leading to loss of job productivity
Depression and anxiety disorders common
Typical chronic pain syndromes
Low back pain syndromes (30% of all primary care physician visits)
Cervical pain syndromes
Headache syndromes, chronic daily headache, severe, chronic migraine and tension headache (40% of PCP visits)
Limb pain syndromes, including reflex sympathetic dystrophy, and pain/dysfunction syndromes.
Other special pain syn: cancer-related, chronic facial pain, recurrent abdominal pain, pelvic pain. (10% PCP visits)
Maintenance of Pain Cycle
Once a chronic pain syndrome is established, maintenance of pain cycle is usually multifactorial; these factors include physical, neurologic, and psychologic components
Goal of management:
It is crucial that a specific goal be set, and that this not be pain relief. Goals are generally functional, such as return to a specific job or activity.
Physical Therapy/Occupational Therapy:
General goals include increasing endurance, mobility and functional capacity. Specific goals include loading and unloading the involved body part, desensitization, and improving tolerances.
Psychology
: General goals include improving coping mechanisms and reducing pain behavior.
Identifying complicating factors such as depression, anxiety, stress syndromes, etc., and rendering non-pharmacologic treatment
Especially for headache and fibromyalgia syndromes, extensive use of relaxation and biofeedback.
Anesthesiology
provides different types of nerve/sympathetic blocks, which provide a window of pain relief, during which OT/PT goals can be reached, and long-term functional improvement can ensue.
Alternative methods
, including self-hypnosis and acupuncture can be quite helpful. Note that acupuncture is reversed by naloxone (opiod antagonist).
Neurology proves the mainstay of drug treatment
. Treatment includes: (a) starting appropriate medications which are generally selected based on the specific quality of pain as shown in the table, as well as on anticipated beneficial side effects such as sleep-induction etc., (b) stopping pain-cycle enhancing medications, especially benzodiazepines, and opiates. This sometimes needs to be done in an inpatient detoxification setting.
Drug Choices for Various Conditions
:
Deep Aching (musculoskeletal) – Non-steroidal agent
Deep Burning (nerve problem) – Tricyclic Antidepressants
Surface Burning – Capsaicin Ointment
Spasms (convulsions) – Clonazepam, Baclofen
Shooting Pain (nerve problem) – Carbamazepine
Paresthesiae – Mexylitene
Sympathetic Pain – Phenoxybenzamine
Early RSD, Acute LBP Exacerbation, Chronic Cluster Headache – Steroids
Stable Patient – Short Course Opiate
Use of opioids – should be used for a limited time (6-18 weeks) to achieve a specific goal. Function is the fundamental issue; if function is not increasing, they should not be used. Patients have actually seen a decrease in pain level when withdrawn from long-term opiates and narcotics