Pain in the Older Patient.

Dr. Christopher A. JennerConsultant in Anaesthesia and Pain Medicine, SMH

20th June 2005

Agenda

• Definition

• Physiology

• Acute

• Chronic

• Neuropathic

• Differences

• NSAID/ COX 2 controversy

Definitions

• 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)

• Time-course: acute/ chronic

• Type: nociceptive/ neuropathic

Pain Physiology (boring)

Pain Physiology (funky)

Prevalence

• Acute pain • SMH 13,213 operations p.a. (Nov 03-04, DSU 41%)

• SMH 484 operations p.m. (Sep 04, Main, 15% PCA/ epi)

• Chronic pain

• 7-14% UK population

• ‘1 in 7’ figure

The Challenges of Acute Pain

• Primary Care

• ↑ healthcare utilisation

• Secondary Care

• ↑ length stay/ complications • 10-15% post-op chronic pain (Macrae)

The Challenges of Chronic Pain

• Bio-psycho-social model

• Individual and societal costs

• Biological- pain/ suffering/ disability

• Psychological- anxiety/ depression

• Social- work/ relationship/ family/ benefits

Acute Pain Management

• Non-pharmacological • RICE

• Pharmacological • WHO ladder (amended from cancer)

Step 1 paracetamol/ NSAID/ COX 2

Step 2 + weak opioids

Step 3 + strong opioids

Massive Financial Burden

• NHS/ DWP/ tax-payers

• Lower back pain (CSAG 1994)

• NHS £481 million

• The Exchequer £1.4 billion

Chronic Pain Management

• Non-pharmacological • Physical- heat/ cold/ TENS/ hydro/ supports/ US/ IR

• Manipulation- PxTx/ chiropracter/ osteopathy/ deep tissue massage

• Alternative- acupuncture

Headache!

5. (a) Veterinary practitioners?

Chronic Pain Management

• Nerve block techniques: epidurals

facets

tenoperiostial

ON

SSN

Occipital N

Ilioinguinal

Chronic Pain Management

• Nerve stimulation- spinal cord stimulation

peripheral nerve stimulation

• Pumps-

Intrathecal pump delivery systems

Chronic Pain Management

• Pharmacological

• WHO analgesic ladder (abridged)

• + tramadol • + opioids- buprenorphine TDD/ oxycontin/ fentanyl TDD

• (New: sufentanyl TDD/ product X)

Neuropathic Pain Management

• Non-pharmacological •Nerve blockade- lumbar sympathectomy/ stellate/

guanethidine

Neuropathic Pain Management

• Antidepressants- Amitryptilline

• Anticonvulsants- Gabapentin/ Pregabalin/ Carbamazepine/ Valproate

• Opiods• Local Anaesthetics- Lignocaine/ EMLA

• NMDA antagonists• Sympatholytics• GABA ergics• Capsaicin

Future Agents in Neuropathic Pain

• Ziconotide (sea snail, conus magnus)

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

• Epibatidine (Equadorian poison dart frog)

• Morphine and ketamine

• Regular gabapentin

• Dexmetomidine

Differences

• ‘Intense pain which interferes with functioning is not a normal part of ageing and should never be accepted as such.’ Textbook of Pain. Melzack and Wall 1984

Physiological Differences

• ↑ pain threshold/ tolerance

• ↓ discrim. to suprathreshold noxious• CVS- ↑ ihd/ ↓ compliance/ ↓ CO/ ↓ bf organs/ HT/ DVT

• RS- ↑ close capacity/ ↓ response hypercapnia/ hypoxia/ ↑ atelectasis/ ↑ chest infections

Physiological Differences

• Metabolic- ↓ BMR/ ↓ renal function/ ↓ rbf/ dehydration/ heat loss

• CNS- cerebrovascular disease/ confusion (hypoxia/ drugs/ hospital/ illness)/ ↓ hearing n memory

• ↑ systemic disease

• Biological age versus Chronological age

Pharmacological Differences

• ↓ TBW so ↑ proportion body wt. fat

• ↑ sensitivity many drugs esp. CNS depressants

• ↓ plasma proteins- binding/ ↑ free unbound

• ↑ t ½ many drugs

• ↑ multiple drug treatments (Bdz n LBP patient)

• Start low, go slow!

Psychological Differences

• Stoical

• Afraid of diagnosis

• Take me home/ kept in

• Not seen as capable

• Adverse effects• Concern over drugs- newspaper cuttings

Clinical Differences

• Less reporting

• ↓ post-op

• undertreated

• MDT

• non-pharmacological

• Pain- the 5th vital sign!

Clinical Differences

• Beware- no complaints/ pain on movement or resisting movement/ lying quietly/ ask, don’t assume/ pain scores/ friends and relatives/ prejudices

The NSAID/ COX 2 controversy

The NSAID/ COX 2 controversy

• COX 1/ 2/ 3

• Asthma/ GI/ renal/ platelets/ bone healing

The NSAID/ COX 2 controversy

• VIGOR (Vioxx- Rofecoxib)- ↑ CVS/ change labelling

• APPROVE (Vioxx)- Colonic polyps/ 18/12 ↑ CVS ↑ stroke

• 23/12/04 FDA warning- celecoxib/ valdecoxib/ naproxen

• 7/4/04 FDA Pfizer Valdecoxib withdrawal/ celecoxib box warning

The NSAID/ COX 2 controversy

• 4/05 FDA

‘ Long-term controlled clinical trials have not been conducted on most NSAIDs. However, available data suggests that use of COX 2 may increase cardiovascular risk. Difficult to draw conclusions about relative cardiovascular risk of COX 2 and NSAIDs with the data available.’

The NSAID/ COX 2 controversy

• FDA- no rank for valdecoxib/ rofecoxib/ celecoxib

• BMJ 2005; 330; 1366 ↑ MI

NNH

ibuprofen 1005

rofecoxib 695

diclofenac 521

The NSAID/ COX 2 controversy

• S/T L/T- risk- benefit

The Future?

The Future?

• Demographics

• Healthcare advances

• ↑ Patient expectations and involvement

Summary

• Very common

• Time course- acute n chronic

• Nociceptive and neuropathic

• Differences

• Start low, go slow!

• NSAID/ COX2 controversy

Any Questions