Neuropathic Pain Slides

7/24/2019 Neuropathic Pain Slides

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Key Strategies for ManagingNeuropathic Pain

Copyright © 2005 Thomson Professional Postgraduate Services®. All rights reserved.



2

IASP Definition of Pain

“Pain is an unpleasant sensory

and emotional experience

associated with actual or potential

tissue damage or described in

terms of such damage.”



3

Acute vs Chronic Pain

Characteristic Acute Pain Chronic Pain

Cause Generally no!n "ften unno!n

#uration of $ain Short%!ell&characteri'ed

Persists after healing%

≥( months

Treatment

a$$roach

)esolution of

underlying cause%usually self&limited

*nderlying cause and $ain

disorder+ outcome is often$ain control% not cure



4

Domains of Chronic Pain

Social Conseuences, -aritalfamilyrelations

, /ntimacyseual activity

, Social isolation

SocioeconomicConseuences

, 1ealthcare costs

, #isaility

, 3ost !ordays

!uality of "ife

, Physical functioning

, Aility to $erformactivities of daily living

, 4or, )ecreation

Psychological Mor#i$ity

, #e$ression

, Aniety% anger

, Slee$ disturances

, 3oss of self&esteem



%

Mi&e$ 'ypeCaused y a

comination of oth

$rimary inury and

secondary effects

Nociceptive vs Neuropathic Pain

Nociceptive

PainCaused y activity in

neural $ath!ays in

res$onse to $otentially

tissue&damaging stimuli

Neuropathic

Pain/nitiated or caused y

$rimary lesion or

dysfunction in the

nervous system

Postoperative

pain

Mechanical

lo( #ac) pain

Sic)le cell

crisis

Arthritis

Postherpetic

neuralgia

Neuropathic

lo( #ac) pain

C*PS+

Sports,e&ercise

in-uries

6Com$le regional $ain syndrome

Central post.

stro)e pain

'rigeminal

neuralgia

Distal

polyneuropathy

/eg0 $ia#etic0 1I



Possi#le Descriptions

of Neuropathic Pain

, Sensations

7 numness

7 tingling

7urning

7 $aresthetic

7 $aroysmal

7 lancinating

7 electriclie

7 ra! sin

7 shooting

7 dee$% dull% onelie ache

, Signs,Symptoms

7 allodynia8 $ain from a

stimulus that does not

normally evoe $ain, thermal

, mechanical

7 hy$eralgesia8 eaggerated

res$onse to a normally

$ainful stimulus



Physiology of Pain Perception

, Transduction, Transmission

, -odulation

, Perce$tion

, /nter$retation

, 9ehavior

In-ury

Descen$ing Path(ay

PeripheralNerve

Dorsal*oot5anglion

C.6i#er

A.#eta 6i#er

A.$elta6i#er

Ascen$ingPath(ays

Dorsal1orn

7rain

Spinal Cor$ Ada$ted !ith $ermission from 4e-# Scientific American® -edicine.

8



Pathophysiology of

Neuropathic Pain

, Chemical ecitation of nonnocice$tors

, )ecruitment of nerves outside of site of inury

, :citotoicity

, Sodium channels, :cto$ic discharge

, #eafferentation

, Central sensiti'ation

7 maintained y $eri$heral in$ut, Sym$athetic involvement

, Antidromic neurogenic inflammation


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Multiple Pathophysiologies May

7e Involve$ in Neuropathic Pain

, -ore than one mechanism of action liely involved

, ;euro$athic $ain may result from anormal $eri$heral

nerve function and neural $rocessing of im$ulses due to

anormal neuronal rece$tor and mediator activity, Comination of medications may e needed to manage

$ain8 to$icals% anticonvulsants% tricyclic antide$ressants%

serotonin&nore$ine$hrine reu$tae inhiitors% and o$ioids

, /n the future% aility to determine the relationshi$ et!eenthe $atho$hysiology and sym$tomssigns may hel$ target

thera$y


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Percentages of 1erpes =oster

Patients >ith Persistent Pain

<

;<

2<

3<

4<

%<

<

8<

9<

< ;: 2: 3: 4: %: :

8<

Age /y

; month

; year

? o

f p a t i e n

t s

Ada$ted from #e-orgas <-% =ierland )). Arch Dermatol . >?5@+@58>?(&>?.


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>hat Are the 5oals of

Clinical Assessment@

, Achieve diagnosis of $ain

, /dentify underlying causes of neuro$athy

, /dentify comorid conditions

, :valuate $sychosocial factors

, :valuate functional status Bactivity levels

, Set goals

, #evelo$ targeted treatment $lan, #etermine !hen to refer to s$ecialist or multidisci$linary

team B$ain clinic


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Assessing the Patient >ith Pain

, "nset and duration

, 3ocationdistriution

, Duality

, /ntensity, Aggravatingrelieving factors

, Associated features or secondary signssym$toms

, Associated factors

7 moodemotional distress 7 functional activities

, Treatment res$onse



Pain 'reatment Continuum

"east

invasive

Most

invasive

Psychological$hysical a$$roaches

To$ical medications

6Consider referral if $revious treatments !ere unsuccessful.

Systemic medications6/nterventional techniEues6

Continuum not relate$ to efficacy



Nonpharmacologic ptions

, 9iofeedac

, )elaation thera$y

, Physical and occu$ational thera$y, Cognitiveehavioral strategies

7 meditation+ guided imagery

, Acu$uncture

, Transcutaneous electrical nerve stimulation


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Pharmacologic 'reatment ptions

, Classes of agents !ith efficacy demonstrated

in multi$le% randomi'ed% controlled trials for

neuro$athic $ain

7 to$ical analgesics Bca$saicin% lidocaine $atch 5F

7 anticonvulsants Bgaa$entin% lamotrigine% $regaalin

7 antide$ressants Bnortri$tyline% desi$ramine

7 o$ioids Boycodone% tramadol

, Consider safety and toleraility !hen initiating

treatment


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6DA.Approve$ 'reatments for

Neuropathic Pain

, Carama'e$ine

7 trigeminal neuralgia

, #uloetine

7 $eri$heral diaetic neuro$athy

, Gaa$entin

7 $osther$etic neuralgia

, 3idocaine Patch 5F


, Pregaalin6

7 $eri$heral diaetic neuro$athy


6Availaility $ending ased u$on controlled sustance scheduling y the #:A.



7*AIN

Pharmacologic Agents

Affect Pain Differently

Descen$ing Mo$ulation

Central SensitiBationPNS

"ocal Anesthetics

'opical Analgesics

Anticonvulsants

'ricyclic Anti$epressants

pioi$s

Anticonvulsants

pioi$s

NMDA.*eceptor Antagonists

'ricyclic,SN*I Anti$epressants

Anticonvulsants

pioi$s

'ricyclic,SN*I Anti$epressants

CNS

Spinal

Cor$

Peripheral

SensitiBation

Dorsal

1orn



;9

'opical vs 'rans$ermal

Drug Delivery Systems

Systemic activity A$$lied a!ay from $ainful site

Serum levels necessarySystemic side effects

Peri$heral tissue activity A$$lied directly over $ainful site

/nsignificant serum levelsSystemic side effects unliely

'opical/li$ocaine patch %?

'rans$ermal/fentanyl patch



;:

"i$ocaine Patch %?

, 3idocaine 5F in $liale $atch

, *$ to ( $atches a$$lied once daily directly over

$ainful site

7 >2 h on% >2 h off B#A&a$$roved lael

7 recently $ulished data indicate H $atches B>I72H h safe

, :fficacy demonstrated in ( randomi'ed controlled trials on

$osther$etic neuralgia

, #rug interactions and systemic side effects unliely

7 most common side effect8 a$$lication&site sensitivity

, Clinically insignificant serum lidocaine levels

, -echanical arrier decreases allodynia



2<

Anticonvulsant Drugs for

Neuropathic Pain Disor$ers

, Posther$etic neuralgia

7 gaa$entin6

7 $regaalin 6

, #iaetic neuro$athy 7 carama'e$ine

7 $henytoin

7 gaa$entin

7 lamotrigine 7 $regaalin 6

, 1/J&associated neuro$athy

7 lamotrigine

, Trigeminal neuralgia

7 carama'e$ine6 7 lamotrigine

7 ocara'e$ine

, Central $oststroe $ain

7 lamotrigine

6A$$roved y #A for this use.1/J K human immunodeficiency virus.



2;

5a#apentin in Neuropathic

Pain Disor$ers

, #A a$$roved for $osther$etic neuralgia

, Anticonvulsant8 uncertain mechanism

, 3imited intestinal asor$tion

, *sually !ell tolerated+ serious adverse effects rare

7 di''iness and sedation can occur

, ;o significant drug interactions

, Pea time8 2 to ( h+ elimination half&life8 5 to @ h, *sual dosage range for neuro$athic $ain u$ to (%00

mgd Btid7Eid6

6;ot a$$roved y #A for this use.



22

Anti$epressants in

Neuropathic Pain Disor$ers+

, -ulti$le mechanisms of action

, )andomi'ed controlled trials and meta&analyses

demonstrate enefit of tricyclic antide$ressants

Bes$ecially amitri$tyline% nortri$tyline% desi$raminefor $osther$etic neuralgia and diaetic neuro$athy

, "nset of analgesia variale

7 analgesic effects inde$endent of antide$ressant activity

, /m$rovements in insomnia% aniety% de$ression

, #esi$ramine and nortri$tyline have fe!er adverse effects

6;ot a$$roved y #A for this use.



23

'ricyclic Anti$epressants

A$verse ffects

, Commonly re$orted A:s

Bgenerally anticholinergic8

7 lurred vision

7 cognitive changes

7 consti$ation

7 dry mouth

7 orthostatic hy$otension

7 sedation

7 seual dysfunction

7 tachycardia

7 urinary retention

, #esi$ramine

, ;ortri$tyline

, /mi$ramine

, #oe$in

, Amitri$tyline

e!est

A:s

Most

As

A:s K adverse effects.



24

Principles of pioi$ 'herapy

for Neuropathic Pain

, "$ioids should e titrated for thera$eutic efficacy

versus A:s

, ied&dose regimens generally $referred over $rn regimens

, #ocument treatment $lan and outcomes, Consider use of o$ioid !ritten care agreement

, "$ioids can e effective in neuro$athic $ain

, -ost o$ioid A:s controlled !ith a$$ro$riate s$ecific management

Beg% $ro$hylactic o!el regimen% use of stimulants

, *nderstand distinction et!een addiction% tolerance% $hysical

de$endence% and $seudoaddiction



2%

Distinguishing Depen$ence0

'olerance0 an$ A$$iction

, Physical de$endence8 !ithdra!al syndrome arises

if drug discontinued% dose sustantially reduced%

or antagonist administered

, Tolerance8 greater amount of drug needed to maintainthera$eutic effect% or loss of effect over time

, Pseudoaddiction8 ehavior suggestive of addiction+

caused y undertreatment of $ain

, Addiction B$sychological de$endence8 $sychiatricdisorder characteri'ed y continued com$ulsive use of

sustance des$ite harm



2

Interventional 'reatments

for Neuropathic Pain

, ;eural locade

7 sym$athetic locs for C)PS&/ and //

Brefle sym$athetic dystro$hy and causalgia

, ;eurolytic techniEues 7 alcohol or $henol neurolysis

7 $ulse radio freEuency

, Stimulatory techniEues

7 s$inal cord stimulation 7 $eri$heral nerve stimulation

, -edication $um$s

C)PS K com$le regional $ain syndrome.



28

Summary of A$vances in

'reatments for Neuropathic Pain+

, 9otulinum toin8 lo! ac $ain

, 3idocaine $atch 5F8 lo! ac $ain% osteoarthritis% diaetic and

1/J&related neuro$athy% !ith gaa$entin

, C) oycodone8 diaetic neuro$athy, Gaa$entin8 1/J&related neuro$athy% diaetic $eri$heral

neuro$athy% others

, 3evetiracetam8 neuro$athic $ain and migraine

, "cara'e$ine8 neuro$athic $ain+ diaetic neuro$athy, 9u$ro$ion8 neuro$athic $ain

, Transdermal fentanyl8 lo! ac $ain

6A$$lications not a$$roved y #A.



29

Summary

, Chronic neuro$athic $ain is a disease% not a sym$tom

, L)ationalM $oly$harmacy is often necessary

7 comining $eri$heral and central nervous system agents

enhances $ain relief , Treatment goals include8

7 alancing efficacy% safety% and toleraility

7 reducing aseline $ain and $ain eacerations

7 im$roving function and D"3, ;e! agents and ne! uses for eisting agents offer

additional treatment o$tions

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