dr. Ken Wirastuti, MKes, Sp.SBagian Ilmu Penyakit Saraf

Fakultas Kedokteran-Universitas Islam Sultan Agung

Classification of Neuropathic Pain Duration

– Acute neuropathic pain (< 3 months)– Chronic neuropathic pain(>3 months)

Location Peripheral neuropathic pain Central neuropathic pain Sympathetically maintained pain

Describe Non-painful stimuli are now painful Can be episodic or continuous Example: trigeminal neuralgia (light touch)

Nonsympathetically mediated pain=Peripheral Neuropathic Pain is due to damage to a peripheral nerve without autonomic change (eg, post-herpetic neuralgia, neuroma formation).

Central Neuropathic Pain arises from abnormal central nervous system (CNS) activity (eg, phantom limb pain, pain from spinal cord injuries, and post-stroke pain).

Sympathetically mediated pain from peripheral nerve lesion and associated with autonomic changes (eg, complex regional pain syndrome I and II [reflex sympathetic dystrophy and causalgia]).

What is Neuropathic Pain? Nyeri biasanya bertahan lebih lama dan merupakan proses

input sensorik yang abnormal oleh sistem saraf perifer atau Seringkali tidak diketahui penyebabnya dan respon

terhadap terapi standart buruk lebih sulit diobati Dapat berakhir indefinitely dan bahkan meningkat dari

waktu ke waktu Mengakibatkan disabilitas berat

Wall PD. Textbook of Pain. 4th ed. 1999; Dworkin RH, et al. Arch of Neuro. 2003;60:1524-1534; Belgrade MJ. Postgraduate Medicine.1999;106(6):127-140.

Neuropathic Orofacial Pain Perubahan menetap pada daerah dimana saraf

pertamakali mengalami injuri Perubahan tersebut dapat mengakibatkan nyeri yang

berlangsung terus meski telah sembuh Sistem saraf dapat mengalami perubahan baik di

perifer muapun di sentral Nyeri bisa diprovokasi oleh sentuhan ringan, panas,

dingin (Allodynia, Hyperalgesia) Nyeri paroxysmal, nyeri umum, tumpul sampai

tajam, seperti ditusuk, seperti disetrum Nyeri kronis yang berasal dari otak, saraf kranialis,

wajah dan leher. Dapat diterapi secara efektif jika diagnosa sudah

ditegakkan.

How Neuropathic Pain Happens

When nerves become damaged or injured, they stop working properly May send the wrong signal to the brain Injured nerves might tell the brain that your

foot is experiencing burning pain even when you aren’t stepping on something hot

Nerves can be injured or damaged in a number of ways, including a spinal cord injury or a medical condition such as diabetes, shingles or a stroke

Price SA. Pathophysiology: Clinical Concepts of Disease Processes. 5th ed; 1997

Pain MediatorsCell Damage

Brain

Spinal cord

Aa K+ BK

PG

Nociceptor

Peptides, eg, SUBSTANCE P

HISTAMINE

SEROTONIN

Mast Cell

PlateletAa = arachidonic acid; BK = bradykinin; PG = prostaglandin

Role of Neurotransmitters

Excitatory Glutamate, aspartate, ATP Mediate afferent synaptic transmission

Inhibitory GABA, glycine, norepinephrine, 5-HT, adenosine,

Ach Analgesia at spinal and higher levels Altered function hyperalgesia, neuropathic or

chronic pain

GABA = -aminobutyric acid; 5-HT = 5-hydroxytryptamine (serotonin); Ach = acetylcholineDougherty PM, Raja SN. In: Benzon HT, et al, eds. Essentials of Pain Medicine and Regional Anesthesia; 1999:7–9.

Role of NeuropeptidesRole of NeuropeptidesExcitatory Substance P, neurokinin A Ca2+, induce sensitization, hyperalgesia Transsynaptic transmitters

Inhibitory Somatostatin, enkephalins, endorphins,

dynorphins Modulate intracellular cAMP, K+

Act at , , opioid receptorscAMP = cyclic adenosine monophosphateDougherty PM, Raja SN. In: Benzon HT, et al, eds. Essentials of Pain Medicine and Regional Anesthesia; 1999:7–9.

(Peripheral Afferent Nerves)

Central SensitizationPeripheral

Sensitization Tissue Injury

C-fiber output Hyperalgesia (1, 2)

Allodynia Activation of NMDA

receptors

Spinal cord

Sensitization

Gottschalk A et al. Am Fam Physician. 2001;63:1979-84.

InjuryInjury

Pai

n I

nte

nsi

ty

10

8

6

4

2

0

Stimulus Intensity

NormalPain

Response

Allodynia

Hyperalgesia

Hyperalgesia—heightened sense of pain to noxious stimuli

Allodynia—pain resulting from normally painless stimuli

HyperalgesiaPrimary Sensitization of primary neurons threshold to noxious

stimuli within site of injury May include response to innocuous stimuli pain from suprathreshold stimuli Spontaneous pain

Secondary Sensitization of primary neurons in surrounding uninjured areas May involve:

– Peripheral sensitization– Central sensitization

Raja SN, et al. In: Wall PB, Melzack R, eds. Textbook of Pain. 4th ed; 1999:11–57.

Allodynia

Pain evoked by innocuous stimuli Central sensitization pain produced

by A fibers1

Possibly mediated by spinal NMDA receptors2

1. Woolf CJ. Drugs. 1994;47(suppl 5):1–9.2. Dolan S, Nolan AM. Neuroreport. 1999;10(3):449–452.

Possible Descriptions of Neuropathic Pain

Sensations numbness tingling burning paresthetic paroxysmal lancinating electriclike raw skin shooting deep, dull, bonelike ache

Signs/Symptoms allodynia: pain from a

stimulus that does not normally evoke pain

thermal mechanical

hyperalgesia: exaggerated response to a normally painful stimulus

Neuropathic Pain is Different from Muscle/skeletal Pain

Neuropathic Pain Muscle/skeletal Pain

Chronic pain (months/years) Acute pain (hours or days)

Caused by injury or disease to nerves

Caused by injury or inflammation that affects both the muscles and

joints

Mild to excruciating pain that can last indefinitely

Moderate to severe pain that disappears when the injury heals

Causes extreme sensitivity to touch –simply wearing light

clothing is painful

Causes sore, achy muscles

Sufferers can become depressed or socially withdrawn because they see no relief in sight and

may experience sleep problems

Sufferers can become anxious and distressed but optimistic

about relief from pain

Wall PD. Textbook of Pain. 4th ed; 1999; Jude EB. Clin in Pod Med and Surg.1999;16:81-97; Price SA. Pathophysiology: Clinical Concepts of Disease Processes. 5th ed; 1997: Goldman L. Cecil Textbook of Medicine. 21st ed; 2000

Emotional and Social Impact of Neuropathic PainPeople with neuropathic pain report: Difficulty sleeping A lack of energy Drowsiness Difficulty concentrating Strained relationships with family and friends An inability to work, walk, or even wear

clothes as the contact with their skin can cause an unbearable burning pain

Meyer-Rosberg K. Euro J of Pain. 2001;5:379-389; Berger A.. Pain. 2004;5(3):143-9

The most common neuropathicpain syndromes in the orofacial traumatic neuropathy; trigeminal neuroma; postherpetic neuralgia; diabetic neuropathy; cancer-related neuropathy; neuropathy induced by acquired

immunodeficiency syndrome, or AIDS;