Neuropathic Pain - Diagnosis Mechanism and Management

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Neuropathic Pain - Neuropathic Pain - Diagnosis Mechanism Diagnosis Mechanism and Managementand Management

Neuropathic Pain - Neuropathic Pain - Diagnosis Mechanism Diagnosis Mechanism and Managementand Management

Dr Amit VermaDr Amit VermaM.D, D.N.B, P.D.C.C, F.I.P.PM.D, D.N.B, P.D.C.C, F.I.P.P

CONSULTANT ANAESTHESIOLOGISTCONSULTANT ANAESTHESIOLOGISTDR BALWANT SINGH’S HOSPITALDR BALWANT SINGH’S HOSPITAL

Dr Amit VermaDr Amit VermaM.D, D.N.B, P.D.C.C, F.I.P.PM.D, D.N.B, P.D.C.C, F.I.P.P

CONSULTANT ANAESTHESIOLOGISTCONSULTANT ANAESTHESIOLOGISTDR BALWANT SINGH’S HOSPITALDR BALWANT SINGH’S HOSPITAL

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CASE 1CASE 1CASE 1CASE 1

• 55 yr. , Female

• Presented with pain in back of chest for 5 yrs

• No h/o HZ, DM, Trauma, Loss of weight

• Quality - burning

• Intensity 5 - 6 / 10

• Tried NSAIDs multiple times

• 55 yr. , Female






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CASE 2CASE 2CASE 2CASE 2• 75 yrs, Female

• Feels Depressed due to Pain in chest

• Severe lancinating pain with increased sensitivity

• H/O very painful rash in the same distribution 5 months back

• Rash subsided but pain didnt

• 75 yrs, Female


• Severe lancinating pain with increased sensitivity



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• 35 yr., female patient with severe headache.

• Diagnosed as a case of migraine

• Wincing in pain , ℅ jolts of pain while combing her hair

• On Migraine prophylaxis



• Wincing in pain , ℅ jolts of pain while combing her hair


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CASE 4CASE 4CASE 4CASE 4• 45 yr. Old Male on a hot summer day with a

wool shawl draped around his shoulder and right arm

• ℅ Pain in the right hand following closed reduction of wrist fracture

• Right arm was cold and sometimes sweaty

• Severe pain on cutting nail

• Visited three physician who referred her to a psychiatrist with the diagnosis of Conversion disorder

• 45 yr. Old Male on a hot summer day with a wool shawl draped around his shoulder and right arm





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Pain Pain Pain Pain

Poena - penalty / punishment

Start of Pain Clinics

Insight into the Etiopathogenesis

Fifth vital Sign

Poena - penalty / punishment

Start of Pain Clinics

Insight into the Etiopathogenesis

Fifth vital Sign

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Classification ( IASP)Classification ( IASP)Classification ( IASP)Classification ( IASP)

Region

System

Acute Vs Chronic

Mild / Moderate / Severe

Nociceptive / Inflammatory/ Neuropathic ( Clifford J Woolf )

Region

System

Acute Vs Chronic

Mild / Moderate / Severe

Nociceptive / Inflammatory/ Neuropathic ( Clifford J Woolf )

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DefinitionDefinitionDefinitionDefinitionIASP defines Pain as

an unpleasant sensory or emotional experience which we primarily associate with tissue damage or describe in terms of such damage , or both

Neuropathic Pain as -

Pain initiated or caused by a primary lesion or dysfunction of the peripheral or central nervous system

IASP defines Pain as

an unpleasant sensory or emotional experience which we primarily associate with tissue damage or describe in terms of such damage , or both

Neuropathic Pain as -

Pain initiated or caused by a primary lesion or dysfunction of the peripheral or central nervous system

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Neuropathic Pain - Neuropathic Pain - DifficultiesDifficulties

Neuropathic Pain - Neuropathic Pain - DifficultiesDifficulties

No Consensus on Definition

Pain Perception is subjective

Rarely One Diagnostic Test

Lack Of Specificity in Diagnosis

Signs & Symptoms Change Over Time

Patients not believed

No Consensus on Definition

Pain Perception is subjective

Rarely One Diagnostic Test

Lack Of Specificity in Diagnosis

Signs & Symptoms Change Over Time

Patients not believed

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Components of Components of Neuropathic PainNeuropathic PainComponents of Components of

Neuropathic PainNeuropathic Pain

Pain

Lancinating/burning/pricking/stabbing

No ongoing tissue damage

Delay in onset after nerve injury

Spontaneous paroxysmal electric shock sensation

Pain

Lancinating/burning/pricking/stabbing

No ongoing tissue damage

Delay in onset after nerve injury

Spontaneous paroxysmal electric shock sensation

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Abnormal SensationsAbnormal Sensations

PAIN INCREASED PAIN

Low Intensity Stimulation

Innocuous sensation

ALLODYNIA

PAINFUL STIMULUS

HYPERALGESIA

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Negative sensory signs

Pain with numbness

Presence of neurologic deficit

Negative sensory signs

Pain with numbness

Presence of neurologic deficit

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Descriptions of Neuropathic Descriptions of Neuropathic PainPain

Descriptions of Neuropathic Descriptions of Neuropathic PainPain

“I feel as though someone has pulled the skin off my left arm and is then constantly rubbing salt into the wound.”

“I feel as though my leg is on fire. My skin feels burnt, and it is as though someone is taking a claw and tearing into my skin 24 hours a day.”

“I feel as though someone has taken a hot poker knife and is jabbing it deep into my right eye. If I could pull my eye out, only to remove the sensation, I would gladly do so.”

“I feel as though someone has pulled the skin off my left arm and is then constantly rubbing salt into the wound.”

“I feel as though my leg is on fire. My skin feels burnt, and it is as though someone is taking a claw and tearing into my skin 24 hours a day.”

“I feel as though someone has taken a hot poker knife and is jabbing it deep into my right eye. If I could pull my eye out, only to remove the sensation, I would gladly do so.”

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Neuropathic Pain Syndromes

Neuropathic Pain Syndromes

1.Peripheral Nervous System ( focal and multifocal lesions )

2.Peripheral Nervous System ( Generalized polyneuropathies )

3.Central Nervous System Lesions

4.Complex Neuropathic Disorders

1.Peripheral Nervous System ( focal and multifocal lesions )

2.Peripheral Nervous System ( Generalized polyneuropathies )

3.Central Nervous System Lesions

4.Complex Neuropathic Disorders

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Peripheral Nervous System (focal and multifocal lesions)

Peripheral Nervous System (focal and multifocal lesions)

Trigeminal neuralgia

Post herpetic neuralgia

Diabetic Mono neuropathy

Entrapment Syndrome

Ischemic Neuropathy

Phantom Limb

Post Traumatic Neuralgia

Trigeminal neuralgia

Post herpetic neuralgia

Diabetic Mono neuropathy

Entrapment Syndrome

Ischemic Neuropathy

Phantom Limb

Post Traumatic Neuralgia

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Peripheral Nervous System Peripheral Nervous System Generalized Polyneuropathies Generalized Polyneuropathies

Peripheral Nervous System Peripheral Nervous System Generalized Polyneuropathies Generalized Polyneuropathies

Metabolic - DM, Amyloid

Toxic - Alcohol, taxanes

Infective - HIV

Autoimmune - GBS

Hereditary - Fabry’s Disease

Malignancy

Metabolic - DM, Amyloid

Toxic - Alcohol, taxanes

Infective - HIV

Autoimmune - GBS

Hereditary - Fabry’s Disease

Malignancy

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Central Nervous System Central Nervous System LesionsLesions

Central Nervous System Central Nervous System LesionsLesions

Spinal Cord Injury

Prolapsed Disc

Stroke

Multiple Sclerosis

Parkinson’s Disease

Surgical Lesions

Spinal Cord Injury

Prolapsed Disc

Stroke

Multiple Sclerosis

Parkinson’s Disease

Surgical Lesions

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Complex Neuropathic DisordersComplex Neuropathic DisordersComplex Neuropathic DisordersComplex Neuropathic Disorders

Complex Regional Pain Syndrome I

Complex Regional Pain Syndrome II

Complex Regional Pain Syndrome I

Complex Regional Pain Syndrome II

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MECHANISM OF MECHANISM OF NEUROPATHIC PAINNEUROPATHIC PAIN

MECHANISM OF MECHANISM OF NEUROPATHIC PAINNEUROPATHIC PAIN

1717Ascending Pain PathwayAscending Pain PathwayAscending Pain PathwayAscending Pain Pathway17

1818Descending Pain PathwayDescending Pain Pathway

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Brain

Spinal Cord

Peripheral nerve fibers

Sympathetic Fibers

Cerebral ReorganizationMolecular Changes

Spinal Cord anatomical reorganizationDorsal Horn Denervation SensitivityMolecular Changes

Ephaptic Crosstalk

•Ectopic Discharge•Collateral Sprouting

•Nociceptive sensitization

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Ectopic DischargesEctopic DischargesEctopic DischargesEctopic Discharges

• Increase in the level of spontaneous firing in the injured neurons as well as their uninjured neighbor neuron

• Result of alteration in the expression of Sodium channels

• Increase in the level of spontaneous firing in the injured neurons as well as their uninjured neighbor neuron

• Result of alteration in the expression of Sodium channels

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Ephaptic ConductionEphaptic ConductionEphaptic ConductionEphaptic Conduction

• Cross excitation among the neurons having spontaneous firing capacity leading to amplification of depolarization

• Important in association of Sympathetic system

• Cross excitation among the neurons having spontaneous firing capacity leading to amplification of depolarization

• Important in association of Sympathetic system

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Collateral SproutingCollateral SproutingCollateral SproutingCollateral Sprouting

• Primary afferent neuron injury leads to sprouting of collateral fibers from sensory axon in their attempt to regenerate

• These sprouts are sensitive to low threshold stimulus

• Primary afferent neuron injury leads to sprouting of collateral fibers from sensory axon in their attempt to regenerate

• These sprouts are sensitive to low threshold stimulus

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SNS AND PNS COUPLINGSNS AND PNS COUPLINGSNS AND PNS COUPLINGSNS AND PNS COUPLING

• DUE TO ENHANCED SENSITIVITY TO CATECHOLAMINES LEADING TO PAIN PERCEPTION

• DUE TO ENHANCED SENSITIVITY TO CATECHOLAMINES LEADING TO PAIN PERCEPTION

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Nociceptive SensitizationNociceptive SensitizationNociceptive SensitizationNociceptive Sensitization

• Increase in Bradykinin binding sites within DRG following axotomy leading hyperalgesia

• Increase in Bradykinin binding sites within DRG following axotomy leading hyperalgesia

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Central & Spinal Central & Spinal Cord Cord

Central & Spinal Central & Spinal Cord Cord

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CENTRAL MECHANIMSCENTRAL MECHANIMSCENTRAL MECHANIMSCENTRAL MECHANIMS

• Spinal Cord reorganization

• Spinal Cord hyper excitability ( central sensitization )

• Cerebral Reorganization

• Spinal Cord reorganization

• Spinal Cord hyper excitability ( central sensitization )

• Cerebral Reorganization

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DIAGNOSIS OF DIAGNOSIS OF NEUROPATHIC PAINNEUROPATHIC PAIN

DIAGNOSIS OF DIAGNOSIS OF NEUROPATHIC PAINNEUROPATHIC PAIN

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Healing begins with the History

Clinical description and history taking are the best mechanism to diagnose Neuropathic Pain

Identify

Painful symptom

Altered sensation

History

Healing begins with the History

Clinical description and history taking are the best mechanism to diagnose Neuropathic Pain

Identify

Painful symptom

Altered sensation

History

} All matching neuroanatomical or dermatomal pattern

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Leeds Assessment of Neuropathic Symptoms and Signs ( LANSS ) scale

Sens / Spec - 83 / 87 %

Pain DETECT questionnaire

Neuropathic Pain Questionaire

Neuropathic Pain Scale

Leeds Assessment of Neuropathic Symptoms and Signs ( LANSS ) scale

Sens / Spec - 83 / 87 %

Pain DETECT questionnaire

Neuropathic Pain Questionaire

Neuropathic Pain Scale

Screening MethodsScreening MethodsScreening MethodsScreening Methods

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Bedside ExaminationBedside ExaminationBedside ExaminationBedside Examination

Identify the altered sensation in painful area ( compare with non painful area )

Dysesthesia (Allodynia, Hypoalgesia, Hyperalgesia )

Inability to distinguish warm and cold objects

Identify the altered sensation in painful area ( compare with non painful area )

Dysesthesia (Allodynia, Hypoalgesia, Hyperalgesia )

Inability to distinguish warm and cold objects

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Pain & Functional Brain Pain & Functional Brain ImagingImaging( F.B.I )( F.B.I )

Pain & Functional Brain Pain & Functional Brain ImagingImaging( F.B.I )( F.B.I )

Positron Emission Tomography

Functional MRI

Both Measure energy consumption in activated brain regions

FBI has mapped the brain neuromatrix ( area of brain that processes pain response )

Positron Emission Tomography

Functional MRI

Both Measure energy consumption in activated brain regions

FBI has mapped the brain neuromatrix ( area of brain that processes pain response )

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Functional Brain ImagingFunctional Brain ImagingFunctional Brain ImagingFunctional Brain Imaging• Neuromatrix -

• 1o & 20 somatosensory cortex ( mediate sensory discriminative features of pain )

• Anterior cingulate gyrus cortex and insula ( mediate affective motivational component of pain

• Pre frontal cortex - mediate cognitive aspects of pain

• Thalamus - gateway between cortex and brainstem

• Increased regional blood flow of neuromatrix in Neuropathic Pain

• Neuromatrix -

• 1o & 20 somatosensory cortex ( mediate sensory discriminative features of pain )

• Anterior cingulate gyrus cortex and insula ( mediate affective motivational component of pain

• Pre frontal cortex - mediate cognitive aspects of pain

• Thalamus - gateway between cortex and brainstem

• Increased regional blood flow of neuromatrix in Neuropathic Pain

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Approach To TreatmentApproach To Treatment

TREAT UNDERLYING CONDITION

DIAGNOSIS

REDUCEPSYCHOLOGICAL DISTRESS

IMPROVE QUALITY OF LIFE

PREVENTION

IMPROVE PHYSICAL FUNCTION

REDUCE PAIN

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ManagementManagementManagementManagement

Mx of ectopic activity / Ephaptic Conduction

Na+ Channel Blockers -

Phenytoin

Lignocaine

Oxcarbazepine

Gabapentin

Mx of ectopic activity / Ephaptic Conduction

Na+ Channel Blockers -

Phenytoin

Lignocaine

Oxcarbazepine

Gabapentin

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Reducing Central Sensitization

NMDA receptor antagonistKetamine

Amitryptyline

Methadone

Gabapentin, Pregabalin

Reducing Central Sensitization

NMDA receptor antagonistKetamine

Amitryptyline

Methadone

Gabapentin, Pregabalin

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Improving Descending Control

Local Inhibitory controlsGABA - B agonist - Baclofen

Opioids - Oxycodone, tramadol

Descending inhibition form brain Clonidine

TCA

Improving Descending Control

Local Inhibitory controlsGABA - B agonist - Baclofen

Opioids - Oxycodone, tramadol

Descending inhibition form brain Clonidine

TCA

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Sympathetically Mediated Sympathetically Mediated PainPain

Sympathetically Mediated Sympathetically Mediated PainPain

Sympathetic Plexus Block

Stellate ganglion

Lumbar Sympathetic chain block

Central Neuraxial Block

Epidural infusions of adjuvants and local anesthetics

Intrathecal infusions - opioids / baclofen

Sympathetic Plexus Block

Stellate ganglion

Lumbar Sympathetic chain block

Central Neuraxial Block

Epidural infusions of adjuvants and local anesthetics

Intrathecal infusions - opioids / baclofen

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Somatic / Sensory Nerve Block

Brachial Plexus Block

Para - vertebral Block

Lateral Cutaneous Nerve of Thigh Block

Intercostal Nerve Block

Somatic / Sensory Nerve Block

Brachial Plexus Block

Para - vertebral Block

Lateral Cutaneous Nerve of Thigh Block

Intercostal Nerve Block

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Interventional StrategiesInterventional StrategiesInterventional StrategiesInterventional Strategies

Diagnostic

Break in cycle of Pain

Should be Imm. Followed by active physiotherapy

Epidural, Trans Foraminal , Facet Blocks

Spinal Cord Stimulation

Diagnostic

Break in cycle of Pain

Should be Imm. Followed by active physiotherapy

Epidural, Trans Foraminal , Facet Blocks

Spinal Cord Stimulation

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Complementary TherapiesComplementary TherapiesComplementary TherapiesComplementary Therapies

Acupuncture

Nutritional Counseling

Massage Therapy

Mirror Therapy

Acupuncture

Nutritional Counseling

Massage Therapy

Mirror Therapy

PharmacotherapyPharmacotherapyPharmacotherapyPharmacotherapy

• Carbamazepine

• Dose – 100 mg BD - 1000 mg / day

• S/I – Dizziness, Ataxia, N/V, S.J Syndrome, TCP

• C/I – Liver Dysfunction, B.M suppresion

• Carbamazepine

• Dose – 100 mg BD - 1000 mg / day

• S/I – Dizziness, Ataxia, N/V, S.J Syndrome, TCP

• C/I – Liver Dysfunction, B.M suppresion

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GabapentinGabapentinGabapentinGabapentin

• Multi modal action - Reduces ectopic activity, dampens central sensitization and decreases glutamate activity

• Dose – 300 – 3000 mg / day

• S/I – dizziness, sedation, weight gain

• C/I - Hypersensitivity

• Multi modal action - Reduces ectopic activity, dampens central sensitization and decreases glutamate activity

• Dose – 300 – 3000 mg / day

• S/I – dizziness, sedation, weight gain


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PregabalinPregabalinPregabalinPregabalin

• Dose – 75 – 600 mg / day in divided doses

• S/E – Dizziness, sedation, confusion, peripheral edema


• Dose – 75 – 600 mg / day in divided doses

• S/E – Dizziness, sedation, confusion, peripheral edema


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TCA - AmitriptylineTCA - AmitriptylineTCA - AmitriptylineTCA - Amitriptyline

• Dose – 10 – 75 mg / day in EDD

• S/E – anticholinergic, constipation, confusion

• C/I – narrow angle glaucoma, urinary retention, 2nd or 3rd degree heart block

• Dose – 10 – 75 mg / day in EDD

• S/E – anticholinergic, constipation, confusion

• C/I – narrow angle glaucoma, urinary retention, 2nd or 3rd degree heart block

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KetamineKetamineKetamineKetamine

• Dose – 0.25 mg / kg – 1000mg/day

• S/I - delirium, hallucinations, confusion, night mares

• C/I – hypersensitivity, psychiatiric disorders

• Dose – 0.25 mg / kg – 1000mg/day

• S/I - delirium, hallucinations, confusion, night mares

• C/I – hypersensitivity, psychiatiric disorders

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Lignocaine Lignocaine Lignocaine Lignocaine

• Dose – 5 mg/kg over 1 hour

• S/E- hypotension, Neurotoxicity, sedation

• Effective diagnostic tool to identify responsiveness to Na channel blockers

• Dose – 5 mg/kg over 1 hour

• S/E- hypotension, Neurotoxicity, sedation

• Effective diagnostic tool to identify responsiveness to Na channel blockers

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Tramadol Tramadol Tramadol Tramadol

• Dose – 50mg bd – 400 mg /day

• S/I – sedation , Nausea

• C/I- hypersensitivity, drowsy , elderly

• Dose – 50mg bd – 400 mg /day

• S/I – sedation , Nausea

• C/I- hypersensitivity, drowsy , elderly

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5959


• 55 yr. , Female






• 55 yr. , Female






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• 75 yrs, Female




• 75 yrs, Female




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• Wincing in pain , ℅ jolts of pain while talking, combing her hair




• Wincing in pain , ℅ jolts of pain while talking, combing her hair


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CASE 4CASE 4CASE 4CASE 4• 45 yr. Old Male on a hot summer day with a

wool shawl draped around his shoulder and right arm





• 45 yr. Old Male on a hot summer day with a wool shawl draped around his shoulder and right arm





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ConclusionConclusionConclusionConclusion

Neuropathic pain is a neuropsychiatric condition in which pain is initiated or caused by a primary lesion or dysfunction in the nervous system. Understanding the complexity of neuropathic pain becomes the cornerstone for appropriate diagnosis and management. Successful management depends on realistic patient-physician expectations and an individualized, multidisciplinary approach that takes advantage of the ever-evolving armamentarium of evidenced- based treatments.

Neuropathic pain is a neuropsychiatric condition in which pain is initiated or caused by a primary lesion or dysfunction in the nervous system. Understanding the complexity of neuropathic pain becomes the cornerstone for appropriate diagnosis and management. Successful management depends on realistic patient-physician expectations and an individualized, multidisciplinary approach that takes advantage of the ever-evolving armamentarium of evidenced- based treatments.

Thank YouThank YouThank YouThank You

• We must all die. But that I can save him from days of torture, that is what I feel as my great and ever new privilege. Pain is a more terrible lord of mankind than even death itself

• Albert Schweitzer

• We must all die. But that I can save him from days of torture, that is what I feel as my great and ever new privilege. Pain is a more terrible lord of mankind than even death itself

• Albert Schweitzer

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Neuropathic Pain - Diagnosis Mechanism and Management

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