Neuropathic Pain Presented At Primed 5.11.09

Neuropathic Pain

Dr. Christopher A. Jenner MB BS, FRCA

Consultant in Pain Medicine, Imperial Healthcare NHS Trust

Medical Director London Pain Consultants and Spinal Healthcare

5th November 2009VXXXX

Date of preparation October 2009

Agenda

• Definition• Neuropathic v. nociceptive • Physiology• Epidemiology• Diagnosis• Management options

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Definitions (1)

• Pain. ‘An unpleasant sensory and emotional experience which we primarily associate with tissue damage or describe in terms of tissue damage, or both.’ (IASP 2001)

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Definitions (2)

• Time-course:

• acute

• chronic

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Definitions (3)

• Type:

• nociceptive

• neuropathic

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Nociceptive Pain

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Neuropathic Pain

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Pain Physiology

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Neuropathic Pain

Aetiology of NP

I

N

V

I

T

E

D

A

M

P

C

Aetiology of NP

Infection

Neoplasia

Vascular

Iatrogenic

Trauma

Endocrine

Drugs

Autoimmune

Metabolic

Psychiatric

Congenital

Peripheral

Chemotherapy-induced neuropathyComplex regional pain syndromeHIV sensory neuropathyNeuropathy secondary to tumour infiltrationPainful diabetic neuropathyPhantom limb painPostherpetic neuralgiaPostmastectomy painTrigeminal neuralgia

Central

Central post-stroke painMultiple sclerosis painParkinson disease painSpinal cord injury pain

Dworkin R.H. A overview of Neuropathic pain: Syndromes, Symptoms, Signs and several Mechanisms

Clin J Pain (2002) 18:343-349

Neuropathic pain syndromes

Epidemiology of Neuropathic Pain

The Neuropathy Trust

Epidemiology of Neuropathic Pain

Prevalence of 2-4% in UK Over 30% neuropathy prevalence in

diabetesPredicted by 2010 ~ 1 million diabetes

sufferers with neuropathyUp to 70% neuropathy patients

experience pain

The Neuropathy Trust

Neuropathic Pain in Primary Care

Common after surgery? 1 in 6 experience post mastectomy phantom pain 1 in 7 experience post-thoracotomy neuralgia 1 in 8 experience severe post herniorraphy pain 1 in 33 experience phantom tooth pain after extraction

Macrae WA. Chronic pain after surgery BJA 87 (2001) 88-98

How Common is Neuropathic Pain in Primary Care?

Epidemiology of conditions (per 100,000 person yrs)

Post Herpetic Neuralgia = 40 ↓

Trigeminal Neuralgia = 27

Phantom Limb Pain = 1 ↓

Painful Diabetic Neuropathy = 15 ↑

Hall G. et al. Epidemiology and treatment of neuropathic pain: The UK primary care perspective.

Pain 2006; 122: 156–162

Clinical features of Neuropathic Pain

History

• Pain description- – burning/ shooting/ stabbing/ electric shock/

lancinating/ severe/ constant…..

• Local hypersensitivity- – allodynia/ hyperalgesia/ dysaesthesia

• Dysfunction

Examination

Check for: Allodynia (mechanical, thermal &

punctate)

Skin changes (autonomic activity)

Sensory disturbances Cold

Pin

Vibration

Soft touch

Diagnostic & Screening Tools

All based on use of pain descriptors and simple examination

LANSS scale Bennett, 2001 Neurop. Pain Questionnaire Krause, 2003 DN4 Bouhassira, 2005 ID Pain Portenoy, 2006 Pain Detect Freynhagen, 2006

Diagnostic & Screening Tools

LANSS Questionnaire

Items Common to all Screening Tools

Bennett et. al. Using screening tools to identify neuropathic painPain 127 (2007) 199–203

Pharmacological Treatment

• WHO analgesic ladder (abridged)

• + tramadol

• + opioids- buprenorphine TDD/ oxycontin/ fentanyl TDD

(New: sufentanyl TDD/ product X)

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Pharmacological treatment of Neuropathic Pain

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Neuropathic Pain Management

• Antidepressants – Amitryptilline

• Anticonvulsants- Gabapentin/ Pregabalin/ Carbamazepine/ Valproate

• Opioids• Local Anaesthetics/Analgesics

– Lidocaine/ EMLA

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• NMDA antagonists

• Sympatholytics

• GABA –ergics

• Capsaicinwww.londonpainconsultants.com

Future Agents for Neuropathic Pain

• Ziconotide (sea snail, conus magnus)

• P2X3- (purine) receptor antagonists (ATP) (knockout mice)

• Epibatidine (Equadorian poison dart frog)

• Morphine and ketamine

• Regular gabapentinwww.londonpainconsultants.com

Lidocaine plaster v. Pregabalin in PHNBaron et al., 2009: Study overview and design

* according to SmPC

Baron et al., (2009) CMRO. 25: 1663-1676.

NRS-3 response rate after 4 weeks, Per protocol (PP)

Baron et al., 2009: Results – PHN

Baron et al., (2009) CMRO. 25: 1663-1676.

Subject-based adverse event (AE) evaluation, Safety population

* p = 0.0020 * * p = 0.0001

Baron et al., 2009: Results – PHN

Baron et al., (2009) CMRO. 25: 1663-1676.

Physical and Alternative Treatments

Physical and Alternative Treatments

• Graded desensitisation

• Mirror box therapy

• Rehabilitation

Psychologically based therapy

Pain Management

• Psychological

CBT

Operant Conditioning

Psychoanalysis

Relaxation

Biofeedback

• Psychiatricwww.londonpainconsultants.com

Pain Management Programmes

Medication

• Goals (SMART- specific/ measured/ agreed/ realistic/ timed)

• Coping

• Contingency

• Pacing

• Education

• Pain Behaviours

• Reinforcement www.londonpainconsultants.com

Advanced Pain Management Techniques

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Nerve Stimulation

Nerve Stimulation (2)

Intrathecal Pumps

The Future?

• Demographics

• Healthcare advances

• ↑ Patient expectations and involvement

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Summary

• Incidence of NP increasing

• Nociceptive v neuropathic

• Management of NP in primary care

• When to refer

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Case reports/ Blogs/ Links/ Appointments

dr.jenner@satellitesec.co.uk

0845 045 0250

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Any Questions