Chronic Pain: Fundamental concepts and clinical syndromes

Difference acute vs. chronic pain
Guy Hans
Multidisciplinary Pain Center
Antwerp University Hospital
Chronic Pain:
Fundamental concepts
and clinical syndromes
• Acute Pain
• Short duration
• Preventive function
• Protecting the body
against lesioning
• Presence of lesion
• Wound
• Burn injury
• Fracture
• ...
• Chronic Pain
• Long duration
• > 6 months
• No preventive function
• No protection against
lesioning
• Often no anatomical lesion
to be identified
• Temporary dysfunction?
The Process of Pain: From Acute
to Chronic Low Back Pain
From Chronic Pain to Chronic
Pain Syndrome
20%
Chronic
3-4
months
3-4
Months
1
month
20%
10%
Chronic
2
weeks
2
weeks
50%
• Fortunately, most individuals
recover from episodes of acute
LBP (Deyo, 1983).
• 50% in 2 weeks, 70% by 1
month, 90% by 3-4 months.
(Mayer & Gatchel, 1988).
• Unfortunately, beyond 3-4
months (now meeting the
Chronic definition), full recovery
is unlikely for the remaining
10%.
Chronic
Pain Syndrome
Chronic Pain
• 75% of the 10% (or more) of
individuals who develop chronic
pain lead relatively normal lives,
although they may not return to
full-time employment.
• About 25% of those with chronic
pain develop Chronic Pain
Syndromes (Klapow et al.,
1993).
Comparison of Chronic Pain and
Chronic Pain Syndromes
Pain Components CP CPS
Nerve involvement strong varies
Pain varies varies
Suffering varies intense
Pain Behavior limited strong
____________________________________________
CP=Chronic Pain CPS= Chronic Pain Syndrome
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CHRONIC PAIN SYNDROME
SYMPTOMS
How Chronic Pain Syndromes
Develop: The Chronic Pain Cycle
• Reduced activity
• Impaired sleep
• Depression
• Suicidal ideation
• Social withdrawal
• Irritability and Fatigue
• Strong somatic focus
• Memory and cognitive
impairment
• Misbehavior by children in the
home
• Less interest in sex
• Relationship problems
• Pain behaviors
• Helplessness
• Hopelessness
• Alcohol abuse
• Medication abuse
• Guilt
• Anxiety
• Poor self-esteem
• Loss of employment
• Kinesiophobia
• This is the typical cycle that
individuals with chronic pain
syndromes experience. Efforts to
minimize pain by reducing
activity work only for the short
term. Over time, the lowered
activity results in reductions in
muscle strength, general
deconditioning, and
INCREASED pain.
Chronic Pain Syndromes:
Typical Treatment Progression
Identify presence of a chronic noncancer pain problem
Specialty Medical Interventions (i.e., surgery, blocks, meds)
IMPROVED
Return to Primary Care
Ambulatory Care Clinic
UNIMPROVED
Refer to Multidisciplinary
Pain Clinic or Program
• Typically, patients with
persistent chronic pain are
referred to specialists for
treatment.
• Some (those with chronic
pain syndromes included) do
not improve, and eventually
may be referred to
multidisciplinary clinics or
programs where they are
more likely to benefit.
• Unfortunately, this results in
delayed access, increased
costs, and patient frustration.
Chronic Pain Syndromes:
Alternative Treatment Strategy
Identify presence of a chronic noncancer pain problem
Identify presence or absence of a chronic pain syndrome
Syndrome Present
Refer to Multidisciplinary Pain Clinic
or Program for Evaluation
Ambulatory Care Clinic
Specialty Medical Evaluations and
Treatments (i.e., surgery, blocks, meds)
UNIMPROVED
Refer to Multidisciplinary
Pain Clinic or Program
Syndrome absent
IMPROVED
Return to Primary Care
• In this alternative model,
identification of a chronic pain
syndrome occurs much earlier
in the process.
• Early identification would lead to
more timely multi-disciplinary
intervention, improved patient
satisfaction, medical cost
savings, and, for some,
improved outcomes.
ALGORITHM FOR CHRONIC PAIN
Core questions !
Negative Neurological
Deficits
Conservative Treatment
(bedrest, NSAIDS, traction, etc.)
Not better
ANESTHESIOLGY
(Nerve blocks for RSD, neuropathic pain,
trigger points, neuromas, radiculopathy,
complex acute pain problems, etc.)
NOTES:
*Send to Neurology if headache or TMJ. Send
to Neurology or Oncology if cancer pain.
CHRONIC PAIN PATIENTS
(persistent pain > 6 months)
PM&RS
(Physical modalities)
PSYCHOLOGY
(evaluation, coping skills training,
biofeedback, relaxation, etc.)
Conservative Treatment
(rest, NSAIDS, traction, etc.)
Positive Neurological
Deficits
•Motor weakness
•Objective sensory (dermatomal)
•Bowel/Bladder dysfunction
•Must be new pain if + for
previous surgery
MRI and NEUROLOGY *
Not better
NEUROSURGERY
Consult to CHRONIC PAIN CLINICS
• What is the type or category of pain?
• Is there a primary cause of pain?
• What additional factors are contributing to the pain?
• Are treatments available for the primary cause of the
pain?
• Are treatments available for additional factors which
contribute to the pain?
• Are there other medical or psychosocial conditions
that should influence the choice of treatment?
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Pain evaluation
Types of Pain
Neuropathic
Pain
•Peripheral
•Central
•Dysesthesia
•Paresthesia
•Allodynia
•Hyperalgesia
•Hyperpathia
•Wind-up
Pain Characteristics
Spontaneous
Pain
Evoked
Pain
Sensory
Disturbances
Patient Characteristics
Nociceptive
Pain
•Somatic Pain
•Muscle
•Bone
•Visceral Pain
•Superficial
•Deep
• Visceral pain
• Internal organs
• Somatic pain
• Superficial
• Deep
• Neuropathic pain
• Central
• Peripheral
• Mixed pain
• (psychogenic pain)
Lower Back Pain
• $20B annually in direct health care costs 1
Some Common Pain Conditions
• 5 th most common reason for MD visit 1
1 Rives & Douglass, J Am Board Fam Pract 2004;17:S23–31.
Complex Regional Pain Syndrome
CRPS - Continued
• Approximately 10% of patients referred to pain clinics have CRPS
• Includes reflex sympathetic dystrophy (CRPS 1) and causalgia
(CRPS 2)
• includes burning pain, hypersensitivity, allodynia, edema, and,
sometimes, muscle spasms and dystonias
• Sympathetically maintained pain - The pain is accompanied
by signs of autonomic dysfunction, and sympathetic blockade
generally relieves pain.
• Sympathetically independent pain - the pain state that occurs
most often in treatment-resistant cases of CRPS, in which
sympathetic blockade or sympathectomy yields no clinical
reduction in pain.
• CRPS 1
• An initiating noxious event, however trivial,
• Ongoing pain, allodynia, or hyperalgesia that is not limited to the
distribution of a single peripheral nerve and is disproportionate to the
inciting event, and
• Evidence of edema, blood-flow abnormalities (such as mottled skin), or
abnormal sudomotor activity in the region of pain (such as sweaty
skin).
• CRPS 2
• Development after a nerve injury,
• Ongoing pain, allodynia, or hyperalgesia that usually exceed the
distribution of the injured nerve, and
• Evidence of edema (figure 1), skin blood-flow abnormalities, or
abnormal sudomotor activity in the region of pain (as in CRPS 1).
Hayek & Mekhail, The Physician and Sports Medicine:
VOL 32 - NO. 5 - MAY 2004
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Neuropathic Pain
• 4M People in the US/year suffer from Neuropathic pain (NP),
caused by a primary lesion or dysfunction in the nervous
system 1
• Associated with diabetic peripheral neuropathy, postherpetic
neuralgia, human immunodeficiency
virus-related disorders, and chronic radiculopathy.
• Treatment often fails because 2 :
• inadequate diagnosis and a lack of appreciation of the
mechanisms involved
• insufficient management of comorbid conditions
• incorrect understanding or selection of treatment options
• the use of inappropriate outcomes measures
Thank you !
1 Mayo Clin Proc. 2004 Dec;79(12):1533-45.
2 J Pain Symptom Manage. 2003 May;25(5 Suppl):S12-7
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