19 sept dolor (pp tshare)

Dolor: Definición

Prevalencia Dolor Neuropático.

Dolor Crónico: Prevalencia

Dolor y Sexo.

Dolor y Edad.

Dolor e Intensidad.

Dolor y Vida Diaria.

Dolor Crónico

Dolorímetro.

Dolor. Discriminación y Cuantificación

Dolor. Escalas de Evaluación.

Mixed Type

Nociceptive vs Neuropathic Pain

NociceptivePain

Neuropathic Pain

Postoperativepain

Mechanicallow back pain

Arthritis

Sports/exerciseinjuries

Postherpeticneuralgia

Neuropathic low back pain

Trigeminalneuralgia

Polyneuropathy (diabetic, HIV)

Mixed TypeCaused by a

combination of both primary injury and secondary effects

Nociceptive vs Neuropathic LBP

NociceptivePain

Caused by activity in neural pathways in

response to potentially tissue-damaging stimuli

Neuropathic Pain

Initiated or caused by primary lesion or dysfunction in the nervous system

Postoperativepain

HNP* withoutnerve root

compression

Facet jointarthropathy

Sciatica

Sports/exerciseinjuries

*Herniated nucleus pulposus.

Medial branchneuropathyHNP* with

nerve rootcompression

Internal discdisruption

Degenerative

disc disease

Dolor Neuropático.

Generador de Dolor.

Percepción de Dolor.Fisiología.

Patología

Mecanismos PeriféricosHiperexitabilidad.

Nervo Nervorum

Dolor NeuropáticoMecanismos.

Control de Dolor Neuropático.Objetivos.

Where Can We Intervene?

Topical Agents Act Locally

• Aspirin Preparations– eg, aspirin in chloroform or ethyl ether

• Capsaicin– extracted from chili peppers

• EMLA (eutectic mixture of local anesthetics)

• Lidocaine patch 5%

Agentes Tópicos.

Tratamiento Tópico

Dolor Neuropático Tratamiento Tópico.

Tratamiento Neuropático

Dolor Neuropático.Tratamiento Farmacológico.

Polineuropatía Diabética y Neuralgia Postherpética.

Polineuropatía Diabética.Tratamiento.

Neuralgia Postherpética.Tratamiento.

Opioides

Antidepresivos.

Dolor e Inhibidores de Recaptura de Serotonina.

Antidepresivos Tricíclicos.

Efectos Adversos.Antidepresivos.

Dolor Neuropático. Anticonvulsivos.

Tratamiento de Dolor con Anticonvulsivos.

Dolor y Corticoesteroides.

Resumen de Tratamiento Dolor Neuropático

Dolor.Guias de Tratamiento OMS

Dolor Neuropático que no emplear.

Dolor Crónico.Patologías Asociadas.

Dolor Neuropático .Patologías Asociadas.

Dolor Crónico.Enfermedades Psiquiatricas.

Dolor y Ansiedad.

Dolor y Depresión

Dolor y Sueño.

Dolor y Adicciones.

Evolución Disturbios Asociados.

Dolor y Patologías Asociadas.

Dolor y Educación.

Dolor y Comorbilidad Tratamiento.

Dolor y Biofeedback

Dolor: Importancia.

Dolor Persistente.

Dolor :Tratamiento Oportuno.

Dolor: Transmisión Neural.

Anatomía del Dolor.

Dolor y sus Vías

Dolor. Sinapsis.

Dolor Neuropático Tratamiento Intervencionista.

Bloqueo Nervioso.

• Diagnóstico

• Terapéutico.

• Pronóstico.

Estimulación Corteza Cerebral.

• La estimulación de la corteza cerebral motora alivia dolor neuropático.

• Dolor central secundario a Stroke.

• Neurálgia Trigeminal atípica.

• Craniotomía y electrodo epidural/corteza motora

• Neuronavegación, RM funcional, Potenciales evocados.

Estimulación Cerebral Profunda.

• Talámica.

• Sustancia Gris Periacueductal.

• Implantes x Estereotaxia y Generador Permanente.

• Principalmente en Dolor Nociceptivo. (ej.

• Failed Back Sx.

Estimulación de Médula Espinal.

Estimulación Eléctrica.

• Bloquea vías dolorosas.

• Electrodos en espacio epidural percutáneos o por laminectomía.

• Paciente despierto durante implante.

• Útil en zonas con parestesias.

• Transitorio o Definitivo.

• Programable el voltaje, la frecuencia y amplitud del pulso.

Dolor y Estimulación Eléctrica.

Estimulación Eléctrica.Indicaciones.

• Failed Back Sindrome.• Dolor isquémico.• Dolor Vascular. (ej Raynaud)• Neuralgia postherpética.• Dolor Regional Complejo.• Lesión Médula espinal.• Lesión nerviosa.• Neuropatía periférica.

Medicamentos Intraespinales.

• Permite mayor concentración del mismo en el neuroeje.

• Evita aumento de dosis sistémicas.

• Indicado en cáncer.

• Cateter percutáneo subdural.

• Reservorio externo/interno.

• Recarga percutánea.

Medicamentos Intraespinales.

• Morfina.

• Morfina + Bupivacaina.

• Morfina + Lidocaina.

• Morfina + Clonidina. (dolor Neuropático.)

• Complicaciónes: Depresión Respiratoria, Supresión de eje hipotálamo/hipofisario.

Cingulotomía.

• Sufrimiento intolerable asociado a dolor por cáncer..

• No se modula dolor sino el impacto emocional.

• Alivio en 50% de los casos.

• Útil bilateral.

• Estereotaxia y Radiofrecuencia.

Mesencefalotomía.

• Proximidad de Tracto espinotálmico, sustancia gris periacueductal y tracto trigémino-talámico.

• Útil en dolor de cabeza y cuello.

Mielotomía.Lesión Columnas Dorsales.

• Indicaciónes: Dolor Visceral.

• Espasticidad Dolorosa.

• Lesión Medular.

• Éxito en 60-70%.

Mielotomía Cervical Percutánea

Cordotomía.Sección T. Espino-Talámico.

• Indicación: Dolor Nociceptivo y Neuropático.

• Bilateral : Dolor Abdominal, Pélvico o ambas extremidades inferiores.

• Laminectomía o Percutánea.

• Restringido a dolor por Cancer.

• Efecto por 2 años.

• No útil en Cervical.

Simpatectomía.Ablación de Cadena Simpática.

• Indicaciones:

• Sx de Dolor Regional Complejo.

• Toracotomía.

• Toracoscopía Endoscópica.

• Bloqueo de prueba.

• 30% Recidiva a 5 años

• Hiperhidrosis compensatoria.

Lesión Médula Espinal.

• Tratamiento Difícil.

• Mielotomía: en Espasticidad Dolorosa.

• DREZ: en Dolor intermitente.

• Estimulación Medular: en lesión incompleta.

DREZ (Dorsal Root Entry Zone)

• Indicaciones :Avulsión Cervical / Lumbar.

• Lesión Medular Espinal con dolor restringido al nivel de la lesión.

• Requiere Laminectomía amplia.

• Requiere apoyo Neurofisiológico.

Problemas Específicos.Cáncer:

• Bomba Infusión.

• Cordotomía.Dolor Extremidades.

• Mielotomía: Dolor Visceral.

• Mesencefalotomía: Dolor cabeza y cuello.

• Cingulotomía

• Estimulación médula espinal.

Neurálgia Trigeminal:1

• Craniectomía: Descompresión Microvascular.

• Percutánea: 1) Lesión con glicerol, Alcohol absoluto.

• 2) Termocoagulación por radiofrecuencia.

• 3) Compresión con balón.

Neurálgia Trigeminal : 2

• Radiocirugía (gama knife) 8000 Rads 80Gy.

• Repetible.

• Alivio diferido. 2-6/12.

• 70% alivio completo al año.

• 56% alivio a los 5 años.

• Anestesia dolorosa.

Neuralgia Trigeminal Tratamiento:

• Compresión por Balón.

Failed Back Síndrome.

• Dolor Neuropático y Nociceptivo.

• Estimulación.

• Estimulación Cerebral Profunda.

• Bomba de Infusión

Chronic Pain Affects All Aspects of Patient’s Life

Social Consequences• Marital/family

relations• Intimacy/sexual activity• Social isolation

Socioeconomic

Consequences

• Healthcare costs

• Disability

• Lost workdays

Quality of Life• Physical functioning• Ability to perform

activities of daily living• Work• Recreation

Psychological Morbidity• Depression• Anxiety, anger• Sleep disturbances• Loss of self-esteem

Opioides.

Dolor y Comorbilidad.

Problem Solving in Persistent Pain Syndromes:

a case-based approach

Pain, Neural Excitation (“Wind-up”), and the HPA Axis

• Neuropathic pain induces changes in peripheral and central nervous system

• In the dorsal horn this results in dramatic increase in firing of neurons– from 1 every 3 seconds – to up to 30/second

• In the brain, hypothalamic activation by increased nociceptive input causes activation of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in discharge of peripheral cortisol and activation of vasoactive immune system compounds

Blackburn-Munro G, et al. J Neuroendocrinology. 2001;13:1009-1023.17

Wind-up Pain: Mood Effects

• Activation of serotonergic and noradrenergic centers in brain stem

• Stimulation and dysfunction of limbic system, prefrontal cortex, hypothalamus, dorsal horn of spinal cord

• Depression, anxiety, panic, vegetative signs of depression, suicidal thoughts, and chronic pain

Blackburn-Munro G, et al. J Neuroendocrinology. 2001;13:1009-1023.

Stahl SM. J Clin Psychiatry. 2002;63:382-383.18

DorsalHorn

Pharmacologic Agents Affect Pain Differently

Descending Modulation

PeripheralSensitization

Central Sensitization

Local Anesthetics

Topical Analgesics

Anticonvulsants

Tricyclic Antidepressants

Opioids

Anticonvulsants

Opioids

NMDA-Receptor Antagonists

Tricyclic/SNRI Antidepressants

Anticonvulsants

Opioids

Tricyclic/SNRI Antidepressants

SPINALCORDCNS

Mechanisms of Action: Analgesic Agents

• Anticonvulsants– sodium-channel blockade (oxcarbazepine)– calcium-channel blockade (gabapentin)

• Antidepressants– inhibit reuptake of norepinephrine and serotonin into

presynaptic neurons (duloxetine)• Opioids

– block neurotransmitter-release by nociceptive fibers, thus decreasing transmission of pain-producing signals (oxycodone)

• Topical Analgesics– sodium-channel blockade (lidocaine patch 5%)– vanilloid receptor (capsaicin)

FDA-Approved Treatments for Neuropathic Pain

• Carbamazepine– trigeminal neuralgia

• Duloxetine– peripheral diabetic neuropathy

• Gabapentin– postherpetic neuralgia

• Lidocaine Patch 5%– postherpetic neuralgia

• Pregabalin– peripheral diabetic neuropathy– postherpetic neuralgia

Antidepressants in Neuropathic Pain Disorders*

• Multiple proposed sites and mechanisms of action – central and peripheral nervous system– anticholinergic, serotonergic, noradrenergic

• RCTs show benefit (especially amitriptyline, nortriptyline, desipramine)

• Improvements in insomnia, anxiety, depression

*Not approved by FDA for this use.

Amitryptyline – Sites of Action

Amitriptyline(anticholinergic,

Inhibits 5-HT and NE

reuptake)

Tricyclic antidepressants are thought to affect pain transmission primarily in the CNS by inhibiting the reuptake of norepinephrine and serotonin, both of which influence descending pain pathways.

Maizels M, McCarberg B. Am Fam Phys. 2005;71:483-490.

Na channel

blocker

DorsalHorn

SPINALCORD

Tricyclic Antidepressants: Adverse Effects

• Commonly reported AEs (generally anticholinergic):– blurred vision– cognitive changes– constipation– dry mouth– orthostatic hypotension– sedation– sexual dysfunction– tachycardia– urinary retention

• Desipramine

• Nortriptyline

• Imipramine

• Doxepin

• Amitriptyline

FewestAEs

Most AEsAEs = adverse effects.

Tricyclic Antidepressantsfor Neuropathic Pain Disorders*

• Consider preprescription cardiac evaluation• Intolerable side effects more frequent with amitriptyline

– not recommended in patients 601

• Use drug with fewer side effects • Can split dose to reduce side effects• Start at 10 to 25 mg at bedtime

– increase every week as tolerated to a target dose of 25 to 150 mg– expect individual variability in treatment response

• Expect partial effect– use multiple agents (other classes and mechanism)

• Not being used simultaneously to treat depression

*Not approved by FDA for this use.1. AGS Panel on Persistent Pain in Older Persons. JAGS. 2002;50:S205-S224.31

Lidocaine Patch 5% Works Locally Through Sodium Channels

DorsalHorn

SPINALCORD

CentralSensitization

Lidocaine Patch 5%

Na channel

blocker

Lidocaine Patch 5% for Diabetic Neuropathy*

Barbano RL et al. Arch Neurol. 2004;61:914-918.

BPI=Brief Pain Inventory.

*Not approved by FDA for this use.†P0.001 at Week 3 versus baseline.

BPI: Daily Pain Diary Ratings and Pain Relief Scores

0123456789

Baseline Week 3

0102030405060708090

Baseline Week 3

Gabapentin Works Centrally Through Calcium Channels

Anticonvulsants act at several sites that may be relevant to pain, but the precise mechanism of analgesic effect remains unclear. They are thought to limit neuronal excitation and enhance inhibition at various ion channels, especially the calcium channels.

Maizels M, McCarberg B. Am Fam Phys. 2005;71:483-490.40

DorsalHorn

SPINALCORD

Gabapentin

Lidocaine Patch 5% With Gabapentin

DorsalHorn

SPINALCORD

CNSDescending Modulation

Lidocaine Patch 5%

Gabapentin

Gabapentin in Neuropathic Pain Disorders*

• FDA approved for PHN

• Anticonvulsant: alpha2delta calcium channel antagonist

• Limited intestinal absorption• Usually well tolerated; serious adverse effects rare

– dizziness and sedation can occur• No significant drug interactions• Peak time: 2 to 3 h; elimination half-life: 5 to 7 h• Usual dosage range for neuropathic pain up to

3,600 mg/d (tid–qid)*

Screening 1 2 3 4 5 6 7 8

*Not approved by FDA for this use.† P<0.01. ‡ P<0.05.

Gabapentin in the Treatment of Painful Diabetic Neuropathy*

PlaceboGabapentin

Adapted from Backonja M et al. JAMA. 1998;280:1831-1836.

‡†

‡ ‡ ‡

Anticonvulsant Drugs for Neuropathic Pain Disorders

• Postherpetic neuralgia– gabapentin*– pregabalin*

• Diabetic neuropathy– carbamazepine– gabapentin– lamotrigine– phenytoin– pregabalin*

• HIV-associated neuropathy – lamotrigine

• Trigeminal neuralgia– carbamazepine*– lamotrigine– oxcarbazepine

• Central poststroke pain– lamotrigine

*Approved by FDA for this use.HIV = human immunodeficiency virus.

Serotonin and Norepinephrine Reuptake Inhibitors

Randomized clinical trials show benefit from dual

action neurotransmitter reuptake inhibitors

• Duloxetine – FDA approved for peripheral diabetic

neuropathy

• Venlafaxine

DorsalHorn

SPINALCORD

Duloxetine Works Centrally in Descending Pathways and Spinal

CordDescending Modulation

Duloxetine is a dual reuptake inhibitor that enhances the levels of the neurotransmitters serotonin and norepinephrine.

Duloxetine

NE, 5-HT

Duloxetine Is Effective for Diabetic

Neuropathic Pain

1 2 3 4 5 6 7 8 9 10 11 120

Placebo (n=108)Duloxetine 60 mg qd (n=114)Duloxetine 60 mg bid (n=112)

* * * * * * * *

** * * * * * * * * *

*P<0.001 vs placebo.

Wernicke J et al. J Pain. 2004;5(suppl 1):S48.

Duloxetine

• Approved 9-7-2004 for management of pain association with diabetic neuropathy

• Once-daily dosing available in 20, 30, and 60 mg strengths

• Contraindicated in patients with uncontrolled narrow-angle glaucoma and patients taking monoamine oxidase inhibitors (MAOIs)

• Common sides effects include nausea, diarrhea, constipation, dizziness, drowsiness, anxiety, nervousness, insomnia

Short- and Long-acting Opioids

• Morphine sulfate• Codeine• Hydrocodone • Oxycodone• Hydromorphone • Oxymorphone• Fentanyl

• Methadone • Sustained-release

morphine • Sustained-release

oxycodone• Transdermal fentanyl• Levorphanol

Short-acting Opioids Long-acting Opioids

Opioid Efficacy Studies in Neuropathic Pain

Disorders• Diabetic neuropathy

– tramadol– oxycodone

• Nonmalignant neuropathic pain disorders– IV fentanyl

• Postherpetic neuralgia– IV morphine– controlled-release oxycodone

• Phantom limb pain– oral morphine

IV = intravenous.55

Mean daily pain Steady pain Brief pain Skin pain

Placebo (benztropine 0.25 mg)

CR oxycodone (10 mg)

CR Oxycodonefor Diabetic Neuropathy*

†† †

*Not approved by FDA for this use.†P=0.0001.

Adapted from Watson CP et al. Pain. 2003;105:71-78.

Efficacy of Tramadol in Painful Polyneuropathy

Adapted from Sindrup SH et al. Pain. 1999;83:85-90.

Placebo

(0–1

Pain Paresthesia Touch-evoked pain

Tramadol

P=0.001 P=0.001

P<0.001

Summary

• Customize therapy due to variance in response, individual clinical/social circumstances, and toxicity

• Rational polypharmacy – mechanisms, drug synergy, additive effects, or complementary effects

• Consider consultation for complex cases or patients who are refractory to first- or second-line therapies

• Never lose focus on managing the whole patient

Algorithm for Opioid Treatment of Chronic Pain

Patient Selection

Initial Patient Assessment

Trial of Opioid Therapy

Alternatives

to Opioid Therapy

Patient Reassessment

Implement Exit Strategy Continue Opioid Therapy

Comprehensive Pain Management Plan

Patient Selection

• Persistent pain despite reasonable trials of non-opioid analgesics and adjuvants

• Severe pain requiring rapid relief

• Patient characteristics contraindicate use of other analgesics

Pain Assessment: Making the Diagnosis

• Defining medical diagnosis and potential primary treatments

• Pain diagnosis is not always readily defined and may change with time

• More common pain diagnoses include: back pain, fibromyalgia, neuropathic pain, cancer-related pain

• Chronic pain itself may be considered a diagnosis that merits consideration of all available treatment options

Why Assess Pain?

• Inadequate assessment a major barrier to treatment

• Appropriate decisions regarding opioid therapy require comprehensive assessment

• Comprehensive assessment required by JCAHO

• Assessment required by opioid treatment guidelines

Pain Assessment: When to Refer?

• Previous failure with opioids or other analgesics

• Significant psychosocial issues

• Conviction of a drug-related crime

• Current use of illicit drugs

• Regular contact with drug high-risk groups

• History of substance abuse

Patient Selection

Alternatives

to Opioid Therapy

Comprehensive Pain Management Plan Components

• Bio/Physical Approaches – pharmacologic and/or

nonpharmacologic therapies

– physical rehabilitation• physical/

occupational therapy• home exercise

program

• Psychological Intervention– mood disturbances– coping skills– sleep disturbance

• Social Issues– family/social

relations– work issues

Patient Selection

Alternatives

to Opioid Therapy

Alternatives to Opioid Therapy

• Alternative pain management strategies– adjuvant analgesics– nonpharmacologic modalities– complementary medicine

• Refer complex or high-risk patients for– multidisciplinary pain management

Questions to Consider Before Initiating

a Trial of Opioid Therapy• What pain syndromes are appropriate for

opioid analgesia?• What patients are appropriate candidates

for opioid analgesia?• Should opioids be the first analgesic class

prescribed?• What patients are at high risk for abuse and

diversion of opioids?

Initiating Opioid Therapy

You’ve made the decision to prescribe opioid analgesics

for your patient. Now you must:

• Consider cost, tolerability, ease of administration, compliance

• Decide whether to start a short-acting opioid analgesic or a low dose of a long-acting opioid analgesic, with or without short-acting “rescue” doses if breakthrough pain occurs

• Develop and document an Exit Strategy

Create an Exit Strategy

• Upon initiating opioid therapy, agree with patient on criteria for failure of the trial

• Common failure criteria include:– lack of significant pain reduction– lack of improvement in function– persistent side effects– persistent noncompliance

• Document method for tapering off opioids if trial is not successful

Patient Selection

Alternatives

to Opioid Therapy

Patient Reassessment ModelThe "Four A's of Pain"

Analgesia

Activities of daily living

Adverse effects

Aberrant drug-taking behaviors

Important to remember two other “A’s”

Assessment

Action (treatment plan)

Questions to Consider In Modifying a

Trial of Opioid Therapy• When should opioid dose be raised?

• When should a different opioid be tried?

• What factors guide the choice of a second opioid?

• How reliable are urine screenings?

Deciding to Convert From a Short-acting to a Long-acting

OpioidShort-acting Opioids

Long-acting Opioids

Advantages

Fast-acting; appropriate for acute pain, breakthrough pain

May be more appropriate for patients with a constant pain component; analgesic stability

Disadvantages

Need for repetitive dosing

Initial delayed onset of action

Rationale for Opioid Rotation

• Ineffectiveness of initial opioid

• Adverse effects/toxicity of initial opioid

• Inter-patient variability of response

• Incomplete cross-tolerance

Note: Conservative dose-conversion ratios are advised

Side Effects Amelioration

Management of Opioid Side Effects

Nausea and vomiting Switch opioids;anti-emetics

Sedation Lower dose (if possible); add co-analgesics; add stimulants

Constipation Treat prophylactically with stool softeners, bowel stimulants; non-pharmacological measures; switch opioids

Management of Opioid Side Effects (cont’d)

Itching Switch opioids; antihistamines

Endocrine dysfunction/ reduced libido

Endocrine monitoring; testosterone replacement; endocrine consultation

Edema and sweating Switch opioids

Dizziness Antivertiginous agents(eg, scopolamine)

Confusion Titrate dose; switch opioids

ApparentTolerance

Opioid Dose Escalation

Worsening Pain State

CellularMechanisms

PharmacologicalTolerance

Opioid-Induced Pain Sensitivity

Development of Tolerance

Patient Selection

Alternatives

to Opioid Therapy

Continue Opioid Therapy

• An option if there is – effective pain relief– improvement in ADLs and psychosocial functioning– management of side effects

• Reassessment using the "Four A's of pain" model should be ongoing to – guide optimal pain management– decide if continuation, modification, or

discontinuation is needed

Regulatory Issues

• Risk of regulatory censure low if procedures are followed and documented

• Relevant regulations include:– federal (DEA)– state policies

• Useful model guideline from Federation of State Medical Boards. Available at: www.fsmb.org

Opioid Release/Delivery Systems and Formulations in Development

• Extended-release formulations – eg, oxymorphone (FDA approved June 24, 2006 for relief

of moderate-to-severe pain) • New methods of drug delivery

– implantable device (eg, Chronogesic™ [sufentanil]) – disposable ambulatory PCA opioid device– Iontophoresis-based patch (eg, E-TRANS® fentanyl)

• Methods of controlling administration rate– new implantable pump or continuous release technology

with computer-assisted rate settings• Methods to reduce abuse liability/tampering

– addition of high-viscosity release component (eg, Remoxy™)

– new formulations (eg, inseparable matrices)

Patient Selection

Alternatives

to Opioid Therapy

Exit Strategy

• Documentation of lack of pain reduction and/or lack of functional improvement– criteria for tapering emphasized in the initial

patient agreement

• Distinguish between abandoning opioid therapy, abandoning pain management, and abandoning patient

• Taper off opioid therapy, with or without specialty assistance

Summary: Ground Rules for Prescribing

Opioid AnalgesicsREMEMBER!

• Proper patient selection is THE key

• Proper patient assessment is mandatory

• Opioid analgesics are but one component of a comprehensive treatment plan

• Prescribing opioids on a trial basis MUST be monitored

• Patient reassessment is KEY to ongoing monitoring of opioid therapy

• Any medical treatment can be continued, discontinued, or modified

Patient Selection

Alternatives

to Opioid Therapy

Patient Selection

• Persistent pain despite reasonable trials of non-opioid analgesics and adjuvants

• Severe pain requiring rapid relief

• Patient characteristics contraindicate use of other analgesics

Patient Selection

Alternatives

to Opioid Therapy

Pain Assessment: Making the Diagnosis

• Defining medical diagnosis and potential primary treatments

• Pain diagnosis is not always readily defined and may change with time

• More common pain diagnoses include: back pain, fibromyalgia, neuropathic pain, cancer-related pain

• Chronic pain itself may be considered a diagnosis that merits consideration of all available treatment options

Why Assess Pain?

• Inadequate assessment a major barrier to treatment

• Appropriate decisions regarding opioid therapy require comprehensive assessment

• Comprehensive assessment required by JCAHO

• Assessment required by opioid treatment guidelines

Pain Assessment: When to Refer?

• Previous failure with opioids or other analgesics

• Significant psychosocial issues

• Conviction of a drug-related crime

• Current use of illicit drugs

• Regular contact with drug high-risk groups

• History of substance abuse

Patient Selection

Alternatives

to Opioid Therapy

Comprehensive Pain Management Plan Components

• Bio/Physical Approaches – pharmacologic and/or

nonpharmacologic therapies

– physical rehabilitation• physical/

occupational therapy• home exercise

program

• Psychological Intervention– mood disturbances– coping skills– sleep disturbance

• Social Issues– family/social

relations– work issues

Patient Selection

Alternatives

to Opioid Therapy

Alternatives to Opioid Therapy

• Alternative pain management strategies– adjuvant analgesics– nonpharmacologic modalities– complementary medicine

• Refer complex or high-risk patients for– multidisciplinary pain management

Patient Selection

Alternatives

to Opioid Therapy

Questions to Consider Before Initiating

a Trial of Opioid Therapy

• What pain syndromes are appropriate for opioid analgesia?

• What patients are appropriate candidates for opioid analgesia?

• Should opioids be the first analgesic class prescribed?

• What patients are at high risk for abuse and diversion of opioids?

Initiating Opioid Therapy

You’ve made the decision to prescribe opioid analgesics

for your patient. Now you must:

• Consider cost, tolerability, ease of administration, compliance

• Decide whether to start a short-acting opioid analgesic or a low dose of a long-acting opioid analgesic, with or without short-acting “rescue” doses if breakthrough pain occurs

• Develop and document an Exit Strategy

Create an Exit Strategy

• Upon initiating opioid therapy, agree with patient on criteria for failure of the trial

• Common failure criteria include:– lack of significant pain reduction– lack of improvement in function– persistent side effects– persistent noncompliance

• Document method for tapering off opioids if trial is not successful

Patient Selection

Alternatives

to Opioid Therapy

Patient Reassessment Model

The "Four A's of Pain"

Analgesia

Activities of daily living

Adverse effects

Aberrant drug-taking behaviors

Important to remember two other “A’s”

Assessment

Action (treatment plan)

Questions to Consider In Modifying a Trial of Opioid Therapy

• When should opioid dose be raised?

• When should a different opioid be tried?

• What factors guide the choice of a second opioid?

• How reliable are urine screenings?

Deciding to Convert From a Short-acting to a Long-acting Opioid

Short-acting OpioidsLong-acting Opioids

Advantages

Fast-acting; appropriate for acute pain, breakthrough pain

May be more appropriate for patients with a constant pain component; analgesic stability

Disadvantages

Need for repetitive dosing

Initial delayed onset of action

Rationale for Opioid Rotation

• Ineffectiveness of initial opioid

• Adverse effects/toxicity of initial opioid

• Inter-patient variability of response

• Incomplete cross-tolerance

Note: Conservative dose-conversion ratios are advised

Management of Opioid Side Effects

Nausea and vomiting Switch opioids;anti-emetics

Sedation Lower dose (if possible); add co-analgesics; add stimulants

Constipation Treat prophylactically with stool softeners, bowel stimulants; non-pharmacological measures; switch opioids

Management of Opioid Side Effects (cont’d)

Itching Switch opioids; antihistamines

Endocrine dysfunction/ reduced libido

Endocrine monitoring; testosterone replacement; endocrine consultation

Edema and sweating Switch opioids

Dizziness Antivertiginous agents(eg, scopolamine)

Confusion Titrate dose; switch opioids

ApparentTolerance

Opioid Dose Escalation

Worsening Pain State

CellularMechanisms

PharmacologicalTolerance

Opioid-Induced Pain Sensitivity

Development of Tolerance

Patient Selection

Alternatives

to Opioid Therapy

Continue Opioid Therapy

• An option if there is – effective pain relief– improvement in ADLs and psychosocial functioning– management of side effects

• Reassessment using the "Four A's of pain" model should be ongoing to – guide optimal pain management– decide if continuation, modification, or

discontinuation is needed

Regulatory Issues

• Risk of regulatory censure low if procedures are followed and documented

• Relevant regulations include:– federal (DEA)– state policies

• Useful model guideline from Federation of State Medical Boards. Available at: www.fsmb.org

Opioid Release/Delivery Systems and Formulations in Development

• Extended-release formulations – eg, oxymorphone (FDA approved June 24, 2006 for relief

of moderate-to-severe pain) • New methods of drug delivery

– implantable device (eg, Chronogesic™ [sufentanil]) – disposable ambulatory PCA opioid device– Iontophoresis-based patch (eg, E-TRANS® fentanyl)

• Methods of controlling administration rate– new implantable pump or continuous release technology

with computer-assisted rate settings• Methods to reduce abuse liability/tampering

– addition of high-viscosity release component (eg, Remoxy™)

– new formulations (eg, inseparable matrices)27

Patient Selection

Alternatives

to Opioid Therapy

Exit Strategy

• Documentation of lack of pain reduction and/or lack of functional improvement– criteria for tapering emphasized in the initial

patient agreement

• Distinguish between abandoning opioid therapy, abandoning pain management, and abandoning patient

• Taper off opioid therapy, with or without specialty assistance

Summary: Ground Rules for Prescribing

Opioid AnalgesicsREMEMBER!• Proper patient selection is THE key

• Proper patient assessment is mandatory

• Opioid analgesics are but one component of a comprehensive treatment plan

• Prescribing opioids on a trial basis MUST be monitored

• Patient reassessment is KEY to ongoing monitoring of opioid therapy

• Any medical treatment can be continued, discontinued, or modified

Key Learning Points From: Clinically Managing Chronic

Low Back Pain

Natural History of LBP• Acute LBP

– inflammatory or neuropathic injury

– resolves spontaneously with minimal treatment

• Intermittent, relapsing LBP – more challenging diagnostic and treatment dilemma

– precipitates symptomatic care and more aggressive interventions aimed at specific underlying pathology

• Unremitting, recurring chronic LBP– structural, neurophysiological, and biopsychosocial

pathology

– requires management at all these levels

– major public health problem

Referred LBP Is Remote From Source of Pain

• LBP may radiate into – groin – buttocks– upper thigh

areas that share an interconnecting nerve supply• Source of somatic referred pain is a skeletal or myofascial

structure of the lumbar spine• Source of visceral referred pain is within a body organ

– ovarian cysts may refer pain to low back– cancer of head of pancreas can present as low back

pain becoming excruciating at night

Radicular LBP Results From Irritation of Spinal Nerve or Its

Roots• Damage to specific nerve root

– pain may radiate along the nerve down the lower extremity

• Lumbosacral radiculopathy often manifests as sciatica

LBP Patient Treatment Prototypes

• Chronic axial LBP– pain does not extend beyond mid-buttock– absence of radicular pain or sensory symptoms below

the knee• Chronic axial LBP with radiation

– pain with radiation beyond mid-buttock– absence of radicular pain or sensory symptoms below

the knee• Chronic axial LBP with radicular component

– radicular pain or sensory symptoms below the knee

Structure of Lumbar Spine Basic functional units of spine—motion

segments—consist of two posterior zygapophyseal (facet) joints and an intervertebral disc, forming a tri-joint complex

Zygapophyseal joint

Lumbar Structural Pathology and Degenerative Cascade

• In all individuals, there is natural, progressive degeneration of the motion segments over time

• This results in anatomic, biochemical, and clinical sequelae

• Although lumbar motion segment degeneration is not a normal process, it may not be painful

Three phases of degenerationDysfunction

Instability

Stabilization

Sources of LBP• Damage to several

structures in the low back can result in severe pain– vertebrae– thoracolumbar fascia– ligaments– joints

• specifically sacroiliac joint

– discs– muscle

Deyo RA, Weinstein JN. N Engl J Med. 2001;344:363-370.

LBP Psychological Factors• Prolonged back pain may be associated with

a psychological disturbance, manifesting as– behavioral– cognitive– affective– somatoform (psychophysiological)

• Psychological factors that may contribute to or be caused by chronic LBP include– depression– anxiety – somatization– post-traumatic stress disorder– pre-existing bipolar or other disorders

Andersson GBJ. Lancet. 1999;354:581-585.

Social Issues May Contribute to Chronic LBP

• Job dissatisfaction/loss of ability to work

• Pursuit of disability compensation

• Substance abuse

• Family dynamics

• Financial issues

• Loss of social identity or context

• Loss of ability to participate in recreational activities

Wheeler AH, Stubbart JR. Pathophysiology of chronic back pain. Available at: www.emedicine.com/neuro/topic516.htm.

Goals of Clinical Assessment

Medical History

General

Neurologic

Psychosocial

Pain Scales/Questionnaires

Factors in the Elderly

Making the Diagnosis

Physical Examination

Neurologic

Diagnostic Studies

Evaluation of the Elderly

Considerations in the Clinical Assessment and Diagnosis of

Chronic LBP

Medical History

• Symptom onset/cause of LBP

• Duration, location, and character of LBP (pain scales/questionnaires)

• Physical/functional impairment

• Factors that exacerbate or relieve LBP

• Associated features or secondary signs/symptoms

• Neurologic history

• Psychosocial history

Red Flags• Diagnostic tests indicated early on for

– current medical history: significant trauma, recent intervention, pain unrelieved or worse with lying down, pain worse at night, progressive neurological deficit

– past medical history: cancer, recent rapid weight loss, immunosuppression or systemic steroids, IV drug use, recent bacterial infection, chills or fever, first incident of back pain in older patient

• Patient offered appointment within 24 hours for– fever lasting >48 h, new below-the-knee pain or numbness, new leg

weakness, loss of bladder or bowel control (retention or incontinence), progressive neurologic deficit

• Psychosocial red flags

– suicidal ideation, social withdrawal, panic attacks, serious financial reversal, homelessness: refer for psychiatric consultation or send to psychiatric crisis center

Deyo RA, Weinstein JN. N Engl J Med. 2001;344:363-370.Institute for Clinical Systems Improvement (ICSI). Adult low back pain. Bloomington, Minn: ICS;

September 2003:63.

Neurologic History• Symptoms• Onset• Common etiologic factors

– leg pain (HNP with nerve root compression L4, L5, S1 )

– leg weakness (HNP, extrusion, fragment)– groin pain (HNP with nerve root compression L2, L3)– back pain with allodynia of skin (inflammatory

recruitment of non-nociceptors)

– non-dermatomal leg pain with weakness, mottling of skin, temperature change, asymmetric hair growth, sweating, allodynia, hyperalgesia (CRPS 1 or 2)

HNP=herniated nucleus pulposus; CRPS=complex regional pain syndrome

Musculoskeletal Examination

• Observation– pain behaviors–groaning, position changes, grimacing, etc– atrophy, swelling, asymmetry, color changes

• Palpation– palpate area of pain for temperature, spasm, and pain

provocation– point palpation for trigger points/tender points

• Range of motion– active and passive– flexion, extension, rotational, lateral bending– leg raising

Neurologic Exam Determines Presence/Absence and Level of Radiculopathy and Myelopathy

• Motor elements– muscle bulk/tone

• atrophy/flaccidity

– muscle strength– coordination– gait

• Sensory elements– sensory deficits, eg, touch,

position sense, temperature, vibration

– allodynia: light touch– hyperalgesia: single or multiple

pinpricks

• Autonomic elements– limb temperature– sweating– hair/nail growth– skin color changes

• Deep tendon reflexes

The exam should include

Medical Red Flags = Early Warning

• Cauda equina syndrome– LBP; sciatica

– saddle anesthesia

– urinary incontinence/hesitancy

– fecal incontinence

– unilateral or bilateral lower extremity motor and sensory loss

• Spinal epidural hematoma/abscess– severe pain– urinary/fecal

incontinence– focal neurologic findings

Boukobza M, et al. Neuroradiology. 1994;36:456-459.Gleave JR, Macfarlane R. Br J Neurosurg. 2002;16:325-328.

Thongtrangan I, et al. Neurosurg Focus. 2004;16(6):e6.

Surgical emergency procedures scheduled

When to Refer for Surgical Consultation

• Motor weakness of one or both legs

• New bowel and urinary incontinence

• MRI HNP compressing nerve root

• MRI of grade 3 spondylolisthesis

• MRI/CT evidence of severe spinal stenosis with correlative leg weakness and pain

• Standing flexion/extension films showing significant movement

Surgery Options• Primarily involve correction or stabilization of the underlying

pathological condition• Principal reasons are to relieve pressure and nerve irritation

caused by a prolapsed lumbar disc or to stabilize spinal structures

• Techniques include:– spinal fusion

• one or more vertebrae are fused to prevent motion– decompression

• removal of bone or disc material to prevent pinching of the nerve (neural impingement)

• Surgery may improve pain and lead to more effective nonsurgical pain interventions

Pharmacotherapy Options*

• Antidepressants

• Anticonvulsants

• Muscle relaxants

• Opioid analgesics

• Corticosteroids

• NSAIDs

• Topical analgesics

* Except for certain opioids, none of these agents are indicated for chronic LBP.

Constant burning, stabbing, or deep aching groin or leg pain

Treatment Strategies for LBP

Moskowitz MH. Curr Pain Headache Rep. 2003;7:178-187.

Clinical Presentation

Possible Cause of LBP Treatment Strategies

Intermittent unilateral leg pain, numbness, weakness radiating to foot

Intermittent nerve entrapment with nerve root inflammation

• Short-acting opioids

• NSAIDs

Permanent nerve damage

• Opioids

• Tricyclic antidepressants

• Anticonvulsants

Treatment Strategies for LBP (cont’d)

Moskowitz MH. Curr Pain Headache Rep. 2003;7:178-187.

Clinical Presentation

Possible Cause of LBP Treatment Strategies

Axial, aching, throbbing and/or stabbing LBP with trigger points radiating to buttocks and anterior thigh

Inflammation of surrounding tissue or joint, myofascial

• NSAIDs

• Opioids

Pain > expected from injury, burning, electrical, to one or both limbs, edema, mottling, nail, skin, and hair changes, temperature change, allodynia, hyperalgesia

Sympathetically maintained pain

• Opioids

• Tricyclic antidepressants

• Anticonvulsants

Interventional Treatment Options

• Neural blockade– selective nerve root blocks– facet joint blocks, medial branch blocks

• Neurolytic techniques– radiofrequency neurotomies– pulse radio frequency

• Stimulatory techniques– spinal cord stimulation– peripheral nerve stimulation

• Intrathecal medication pumps– delivery into spinal cord and brain via CSF

Physical Treatment Options• Exercise (stabilization training)• Neutral position• Soft tissue mobilization• Transcutaneous electrical nerve stimulation

(TENS)• Electrothermal therapy• Complementary measures (acupuncture;

relaxation/hypnotic/biofeedback therapy)• Spinal manipulative therapy• Multidisciplinary treatment programs (back

schools/education/counseling/pain clinic)

Summary• Chronic LBP is a disease, not a symptom

• Progress is focused on targeting treatment at the mechanisms that produce pain rather than ameliorating the symptoms

• Biopsychosocial approach is critical for the successful management of chronic LBP

• Promising treatments for chronic LBP include– new agents– new uses of agents– new combinations of agents

• Wong-Baker FACES Pain Rating Scale • No Hurt Hurts Little Bit Hurts Little More Hurts Even

More Hurts Whole Lot Hurts Worst

• Explain to the person that each face is for a person who feels happy because he has no pain (hurt) or sad because he has some or a lot of pain. Face 0 is very happy because he doesn’t hurt at all. Face 1 hurts just a little bit. Face 2 hurts a little more. Face 3 hurts even more. Face 4 hurts a whole lot. Face 5 hurts as much as you can image, although you don’t have to be crying to feel this bad. Ask the person to choose the face that best describes how he is feeling.

• Rating scale is recommended for persons age 3 years and older. • Brief word instructions: Point to each face using the words to

describe the pain intensity. Ask the child to choose face that best describes own pain and record the appropriate number.

• From Wong DL, Hockenberry-Eaton M, Wilson D, Winkelstein ML, Schwartz P: Wong’s Essentials of Pediatric Nursing, 6/e, St. Louis, 2001, P. 1301. Copyrighted by Mosby, Inc. Reprinted by permission.

Key Learning Points From:

Advances in Opioid Analgesia: Maximizing Benefit While Minimizing Risk

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