Transcript Chronic pain - Calgary Emergency Medicine

ED Pain Management
(and the Drug-seeking Patient)
Grant Innes, MD
Pain hurts!
Objectives
Acute pain vs. chronic pain
Chronic pain vs. addiction
Impact of pain biology on patient
behaviour and response to therapy
Basic concepts in pain Rx for ED
patients who may be opioid dependent
Pain management may be the most
important thing we do, but . . .
It is a secondary consideration for
most physicians,
We under-treat pain.
We underutilize potent analgesics
Trust me! I’m a doctor.
Medical school time devoted to
rare metabolic disorders . . .
400 hours
Time devoted to studying pain and
pain management . . .
1 hour
Textbook of Surgical Analgesia
Chapter 1. Parenteral analgesia
Demerol 50-75 mg IM q4h prn
Chapter 2. Oral Analgesia
Tylenol #3, I-II tabs po q4h prn
Case 1
An unkempt 32 year-old man presents with
a severe toothache. His chart shows he was
seen 2 days earlier and given a Rx for 20
Tylenol #3 tabs, which he says were
ineffective. Your next step is:
A. Call security
B. Suggest OTC Tylenol, then call security
C. Prescribe an unusual NSAID (“Idarac”)
D. Give him 4 “T3” to go
E. None of the above
***
Treatment – Case 1
Infra-orbital nerve block
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Marcaine
Xylocaine with epi
Ibuprofen to start before the pain recurrs
Tylenol to start when the pain recurrs
Oxycodone
Treating Acute Pain:
The Modified WHO Pain Ladder
Step 1: Acetaminophen
Step 2: NSAID (ibuprofen)
Step 3: Syndrome-specific agent
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“muscle relaxant” for back pain
Dopamine antagonist for migraine
Step 4: Opioid
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Pretend opioid (codeine)
Real opioid (morphine, hydronorphone)
Acute Pain Physiology
(in 2 slides)
Mechanical, thermal or chemical stimuli (with
tissue injury) lead to local inflammatory
mediator release
Pain impulses transmitted to spinal cord
At DRG: neuropeptides mediate sensitization
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pain threshold decreases, and
central response to pain increases
Antidromic conduction/recruitment
To DRG
Neurogenic inflammation
Antidromic conduction and inflammatory
mediator release
Secondary hyperalgesia; recruitment
Pain is a vicious cycle. Preempt it
Acute pain: More biochemical than neural
Migraine: An Inflammatory Syndrome
Noxious triggers activate trigeminal
nociceptors
Trigeminal brainstem sensory complex
receives input from 7,9,10,12
Antidromic trigeminal activation leads to
release of vasoactive neuropeptides!
Opioids
Codeine (Tylenol #3):
- Moderately effective
- GI upset (low abuse potential)
Meperidine:
- Poorly absorbed. Shorter acting. AEs.
Potent oral opioids:
- Less GI upset
- Effective but more euphoria/CNS effects
- Potential for abuse
Multimodal Analgesia
Acetaminophen
NSAIDs or COX-2
Opioids
“Muscle relaxants”
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Cyclobenzeprine
Methocarbamol
Antidepressants
Sedative-hypnotics
Regional blocks
Anticonvulsants
Dopamine antagonists
Antimigraine drugs
Heat and Ultrasound
Massage
Acupuncture
Alternative remedies
Case 2: A young female, disabled by chronic leg pain
(compartment syndrome), presents with a painful arm.
When you pass by the bed, she moans and clutches her
arm. She is on methadone for chronic pain and has told
the nurse she will need 250 mg of Demerol because she
has a “high pain threshold”. She is febrile and has a
markedly swollen arm with multiple recent needle
tracks. When you touch the skin lightly, she screams
and pulls her arm away
Q. The best treatment is:
IV antibiotics + acetaminophen and ibuprofen
Antibiotics + additional methadone
Antibiotics + high-dose titrated IV morphine
Antibiotics + 4 “Tylenol #3 to go”
Vancouver, BC - 1.2 million people
Canada’s richest
postal code
Canada’s poorest
postal code
St. Paul’s
Hospital
HIGH Prevalence of Opioid
Addiction and Dependency
Features of the Case
She moans and clutches her arm—as you pass
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Drug-seeking behavior: She is communicating with you
She is febrile with a +++ swollen arm.
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This is an acute exacerbation—not her steady state
She says she needs 250 mg of Demerol
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Tolerance
When you touch the skin lightly, she screams
and pulls her arm away
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Allodynia
Q. The best treatment is:
IV antibiotics + acetaminophen + ibuprofen
Antibiotics + additional methadone
Antibiotics + high-dose titrated IV morphine
Antibiotics + 4 “Tylenol #3 to go”
A. For opioid dependent patients with
unequivocal and uncontrolled pain,
treat the pain aggressively
Substance abuse disorder (Addiction)
A complex neurochemical disorder that:
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causes behaviour patterns that are
misunderstood and aggravating to ED staff
makes it difficult for addicts to make
constructive and rational decisions
Substance abuse disorder
Cognitive, behavioural and physiological symptoms
Substance use despite significant related problems.
At least three of the following:
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Tolerance;
Withdrawal;
Larger amounts and longer time periods than intended;
Persistent desire or unsuccessful attempts to control use;
Disproportionate time and effort to obtain the substance;
Impact on social, occupational, or recreational activities
Continued use despite health, social or economic problems
Case 3: A middle-age woman presents with chronic upper back
pain that is worse since a recent fall. Her oxycodone is not
working and she hasn’t slept for 3 days. She feels she cannot
manage at home and may need hospitalization.
PMH: depression and fibromyalgia.
Meds: Diclofenac (50 mg tid) and oxycodone (80 mg/day).
Exam: She lies motionless in bed with her eyes closed. She is in
no evident pain and appears depressed. She winces in pain
when her skin is touched over the upper back, but there are no
objective findings.
Your treatment options might include:
A. NSAIDs
B. IV opioids
D. Antidepressants
C. Oral hydromorphone
E. Other
Features of the case
She lies motionless in bed with her eyes closed.
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A complex neurochemical disorder causing behaviour
patterns that are misunderstood and aggravating to ED staff
She is in no evident pain
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Chronic pain does not look like acute pain
She appears depressed.
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Depression travels with chronic pain
She winces in pain when her skin is touched lightly
over the upper back
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Allodynia
Chronic pain
Definition: Lasts longer than expected
Ongoing pain increases the expression of CNS pain
receptors that influence pain experience
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Allodynia and hyperalgesia
• A chronic disease with exacerbations + remissions
At steady state with their analgesics, unless change
in disease status: may need dose increase w flareup
Inflammation is a minor concern in chronic pain
and an insignificant concern in neuropathic pain
Chronic Pain doesn’t “look like” acute pain
Acute pain:
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protective activation of the ANS
Pallor, anxiety, tachy, diaphoresis, restless
Chronic pain:
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Not inflammatory
Minimal ANS activation
Depression
Directed combination therapy for chronic pain
Simple analgesics
NSAID if an acute component or chronic
inflammatory state—not in neuropathic pain.
Opioids often necessary but rarely sufficient as a
single agent
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Consider opioid rotation (different opioid receptor
subtypes respond to different drugs)
For rapid analgesia, titrate short-acting agents
If addictive tendency, consider longer acting or SR
agents, with less euphoric effects and less intense W/D
Treat related symptoms (e.g. anxiety, insomnia,
depression) with specific agents
Other “Analgesic” Options
Dopamine antagonists and antimigraine drugs for HA
“Muscle relaxants” (e.g. cyclobenzeprine, methocarbamol)
Antidepressants (e.g. Amitryptiline, Trazodone)
Anticonvulsants for neuropathic pain
Sedative-hypnotics for anxiety
Regional blocks
Physical modalities (heat, US, massage, acupuncture)
Alternative remedies
Definitions
Tolerance: Adaptation with diminished drug efficacy.
Physical dependency: cessation causes withdrawal sx
Addiction: maladaptive behavior including: loss of
control, compulsive substance use, preoccupation with
using a substance despite negative consequences.
Pseudoaddiction: a behavioral response to inadequate
pain control (perceived as drug seeking). Aberrant
behavior ceases with appropriate pain management*.
Note: Tolerance and dependency do not indicate addiction
Differential Diagnosis:
Chronic pain vs. addiction
Overlap between chronic pain and addiction.
Some chronic pain patients are addicted.
No objective test to differentiate
Non-addicts often display drug seeking behavior
Hi likelihood of diagnostic error
Important Findings—or not??
Dress and grooming?
Appearance and vital signs?
A lost prescription; out of meds;
Asks for drugs and doses by name
A tale of woe: many causes of pain
Different opioids - different doctors
Stable employment, family, and function
Noncompliant with Rx plan
Is it real, or . . .
Using my best judgment, how patients with real pain
will I refuse to treat? (assuming 80% sensitivity, 80%
specificity and 5% prevalence of drug-seekers).
Truth Addict
Judgment
Addict
40
Pain
190
230
PPV=17.4%
Pain
10
760
770
NPV=98.5%
50
950
1000
Pts with pain of uncertain validity
When in doubt . . . Treat the pain!
Pain is what the patient says it is -- usually
Old records and Pharmanet
Frequent flyer (DMP) program:
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DMP committee develops an ED care protocol defining a
consistent approach to subsequent ED visits.
Plan is consistent with the pt’s overall care plan, and is
printed automatically at triage each time the pt comes to ED.
Pts with no primary care provider are referred to one
Pts likely to benefit from other expertise (e.g. psychiatry,
chronic pain service) are referred during their next ED visit
Summary
Acute pain concepts:
Neurogenic inflammation
Multimodal analgesia
Chronic pain concepts
Cognitive/behavioural changes. Depression
Loss of autonomic activation.
Hyperalgesia and allodynia
Directed combination therapy
Tolerance and dependency = addiction
Pain is (usually) what the patient says it is
Speaker
Pain Management
and theEvaluations
Drug-Seeking Patient (Innes)
How would you rate this presentation?
A. Excellent!! This was the finest educational experience I’ve
ever had—by far!
B. Superb! The speaker was incredible. This information will
change my practice dramatically for the better.
C. Outstanding! It scares me how I was practicing medicine
before I saw this presentation
D. Fair. Please report me to the FBI for fraudulent billing
practices
Opioid Equianalgesic Data
Opioid
Parenteral (mg) Oral (mg)
Morphine
10
30*
Hydromorphone
1.5
7.5
Oxycodone
---
20
Codeine
130
200
Fentanyl
0.1^
---
Methadone
---
3-5
The Causes of Drug-Seeking
Commerce: To acquire drugs to sell
Misuse: Using drugs for euphoric effect
Inadequately treated acute pain
Inadequately treated chronic pain