Chronic Pain SAQ's

8/3/2019 Chronic Pain SAQ's

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Chronic Pain SAQ¶sChronic Pain SAQ¶s

-- Final FRCAFinal FRCA

Dr. Richard Walker Dr. Richard Walker FRCA, Dip MS Med, MLCOM, FFPMRCAFRCA, Dip MS Med, MLCOM, FFPMRCA

Consultant inConsultant in Pain MedicinePain Medicine




A 60 year old man is referred to you with Reflex A 60 year old man is referred to you with Reflex

Sympathetic Dystrophy following an injury at theSympathetic Dystrophy following an injury at the

elbow 6 months earlier.elbow 6 months earlier.

Outline the treatment.Outline the treatment.




CRPS I = RSD, CRPS II = Causalgia

Symptoms ± Neuropathic pain ± vibrational + thermal allodynia

± Sympathetic over activity

± Secondary muscle wasting, joint contractures, osteopaenia /osteoporosis

Signs ± Allodynia, cold, sweaty peripheral limb

± ? Signs of peripheral nerve injury

Ix ± Thermograms, EMG, triple phase bone scan, ? MRI c/spine

r/o disc, ? MRI scan elbow

Overview




Reduce the pain, rehabilitate the arm, rehabilitate the

brain ± multi-disciplinary team work

Oral Dugs

± Gabapentin / pregabalin titration + TCA (amitriptyline)

± Multi-modal analgesics (paracetamol + NSAID + opioid)

± ? Nifedipine for peripheral vasoconstriction

± ? Ketamine 30 ± 80 mg per day (NMDA blocker)

Treatment OptionsTreatment Options




Treatment OptionsTreatment Options

Occupational Therapy ++

Psychological Assessment / Support

Nerve Blockade ± Guanethidine Biers Block x 3

± Diagnostic Stellate Thoracoscopicsympathectomy

± ? IV lignocaine infusion

Treatment Specific for peripheral nerve injury

Spinal Cord Stimulation ± Trial Implantation




List with examples the causes of neurogenic pain.List with examples the causes of neurogenic pain.

What symptoms are produced ?What symptoms are produced ?

What treatments are available ?What treatments are available ?




Causes of neurogenic painCauses of neurogenic pain

Ischaemic - Central post stroke pain, PVD

Compression - Peripheral / Spinal nerve entrapment

Degenerative - Multiple Sclerosis

Inflammatory ± Sciatica with disc annular tear Infective ± Post Herpetic Neuralgia, Guillain Barre

Post Traumatic ± Surgery + other trauma ± iliohypogstricneuralgia post hernia

Toxic ± alcoholic peripheral neuropathy, heavy metals

Metabolic ± Diabetic Peripheral Neuropathy, vitamin deficiency Autoimmune ± RA / SLE / PAN

Hereditary ± Charcot Marie Tooth (Myelin)




SymptomsSymptoms

Pain

± Spontaneous ± burning, shooting, electrical, formication

± Evoked

Hyper(hypo)aesthesia, Hyper(hypo)algesia

Allodynia ± thermal and vibrational

Nerve irritation signs on stretching

± Referred ± spinal root / plexus / peripheral nerve

Signs of Nerve Dysfunction

± Tingling, numbness, weakness, wasting, fasciculations

± Sympathetic over activity




Treatment (1)Treatment (1) Oral Medications

± Anti-depressants ± TCA¶s ± amitriptyline

± Anti-convulsants ± pregabalin / gabapentin (calcium

channel), carbamazepine (sodium channel)

± Anti-arrhythmics ± IV lignocaine, oral mexiletine,

flecainaide, tocainide (sodium channel)

± Simple analgesics (paracetamol + NSAID + opioid) -

weak activity

± Ketamine orally 30 ± 80 mg / day (NMDA)




Treatment (2)Treatment (2) Topical

± Lignocaine patch (5%)

± Capsaicin 0.025%, 0.075% (substance P depletion c fibres)

± Barrier methods (cling film)

Injections ± IV lignocaine infusion

± Somatic / spinal nerve block,

± Epidural steroids (inflammatory sciatica)

± IVRA (guanethidine) ± Continuous epidural / nerve block techniques

Stimulation ± Spinal cord stimulation




What methods are available for

therapeutic nerve blockade ?

Explain the mechanism of action of

each method.




Mechanical (rubbing) ± A beta stimulation ± dorsal horn gate theory ± reversible

nerve blockade

Ischaemia (tourniquets)

± Intraneuronal hypoxia ± reversible loss of nerve function Acupuncture / Dry Needling ± A delta stimulation - dorsal horn gate theory ± reversible

nerve blockade

Electrical Stimulation

± TENS ± A-beta stimulation ± dorsal horn gate theory ±reversible nerve blockade

± Spinal cord stimulation ± ? Dorsal horn ± mechanismuncertain

Local anaesthetic ± Reversible conduction block ± sodium channel

Methods (1)Methods (1)




Methods (2)Methods (2)

Radiofrequency ± High frequency heats needle tip to 80 deg C ± permanent

nerve disruption

± Pulsed RF heats to 42 deg C ± reversible loss of nerve

function Alcohol / Phenol

± Coagulation of vasa nervorum ± permanent nerve disruptionsecondary to hypoxia

Cryotherapy ± Rapid cooling of neurons ± intraneuronal ice formation ±

permanent nerve disruption




Draw a labelled diagram of the anatomicalDraw a labelled diagram of the anatomical

relations of the stellate ganglion.relations of the stellate ganglion.

How is it blocked and what are the possibleHow is it blocked and what are the possible

complications ?complications ?




Anatomy Anatomy




Anatomical Relations Anatomical Relations

Sympathetic outflow to head and neck = T1 ± T4-6

Stellate = fused 1st thoracic and inferior cervical

ganglion

Posteriorly - neck of the first rib, C7 transverse process

Anteriorly

± Lower part - dome of the diaphragm

± Upper part ± vertebral artery

Medially ± longus colli muscle

Laterally ± anterior / medius scalene muscles




TechniqueTechnique Stand on the side to be blocked

2 operators / full precautions / monitoring / IV access

Anterior para-tracheal approach / semi-reclining

C6 level = middle cervical ganglion ± not stellate

Chassaignac¶s Tubercle = C6 transverse process =level with cricoid cartilage

Pull carotid gently towards you / hit bone and pull back2 mm

1´ blue needle / connecting tubing / 10 ml syringe

De-aerate the system ± bubbles + vertebral artery

10 ml x 50 / 50 2% lignocaine / 0.5% bupivacaine

0.5 ml increments ± aspirate for blood and CSF




Technique




SuccessfulSuccessful

BlockBlock




ComplicationsComplications Common

± Hoarseness / lump in the throat (recurrent laryngeal)

± Horners

± Haematoma

± T1 neuralgia ± inner arm / chest wall Uncommon ± Brachial plexus block

± Phrenic Nerve Block (bilateral injections inadvisable)

± Pneumothorax

± Infective osteitis (transverse process ± sterility!!) Life threatening ± Vertebral artery injection ± immediate CNS effects

± Intra-dural injection ± total spinal




Describe the anatomy of the coeliac plexusDescribe the anatomy of the coeliac plexus

What are the indications for it¶s therapeuticWhat are the indications for it¶s therapeutic

blockade.blockade.




Anatomy Anatomy




Anatomy Anatomy

Largest of the sympathetic plexuses(parasympathetic fibres pass straight throughwithout synapsing)

Supplies stomach liver, biliary tract, pancreas,spleen, kidneys, adrenal, omentum, small andlarge bowel

Greater Splanchnic Nerve ± T5-6 to T9-10

Lesser Splanchnic Nerve ± T10-11

Least Splanchnic Nerve ± T11-12




IndicationsIndications

Diagnostic

± To assess whether pain has visceral origin or not

when the cause of the pain is uncertain

Therapeutic

± Acute pain relief during surgery

± Chronic pancreatitis management (LA only)

± Upper GI cancer pain management (Neurolytic)




TechniqueTechnique




Describe the features and managementDescribe the features and management

of phantom limb pain.of phantom limb pain.




Pain ClassificationPain Classification Phantom Pain

± Neuropathic pain in the amputated limb

± Burning, stabbing, shooting, cramping, clawed digits

Stump Pain ± Pressure sensitive pain around the stump

Tissue ischaemia / infection

Major nerve trunk neuroma formation

Interferes with wearing a prosthesis

Phantom Experiences

± Sensory experiences in the amputated limb




CausesCauses

Poor surgical technique ± nerve trunk too close to stump

Poor peri-operative pain management ± ? Improved by multi-modal analgesia ± we see them too late

± ? epidurals infusions

± ? Intravenous Ketamine Protracted time course - incidence in traumatic amputation

± Dorsal Horn Sensitisation

± NMDA receptors

± Silent Channels ± sodium channel blockers

± Cortical Remapping - Homunculus

Co-existing history of sciatica in the same leg ± Lumbar MRI to check for disc lesion




ManagementManagement Exclude treatable causes - Sciatica, stump neuroma

Psychological support

Oral medication ± TCA + gabapentin / pregabalin, ? Oral Ketamine

Injections

± LA Sympathetic Blocks (not phenol) ± Stump neuroma desensitisation

± Caudal epidural steroid for sciatica

± Intravenous lignocaine infusion

Mirror Box Therapy (Ramachandran) ± for clawed toes

Surgical Stump Refashioning ± prosthetic comfort

Implantation ± Spinal Cord Stimulation

± Deep brain stimulation




What aims and strategies are emphasized in aWhat aims and strategies are emphasized in a

Pain Management ProgramPain Management Program




Aims Aims

At least ± 50% less pain

± 50% reduction in analgesic consumption

± 50% improvement in physical functioning

Reduce frequent GP / hospital attendances

Increase education about the pain managementtechniques

Teach coping strategies / self management

Reduce behavioural problems like fear avoidance,catastrophising etc

Work integration, work hardening etc




StrategiesStrategies

Pain camps ± outpatient vs. inpatient

Cognitive behavioural therapy

± Behaviour is dependant upon your belief system

± Remodel beliefs Rehabilitation with physio / occupational therapy

Medical input to help treatable conditions

Social - Family + work involvement

± reduce secondary gain / abnormal reinforcements

± Improve job satisfaction




List the indications and contraList the indications and contra--indications for indications for

TENS ?TENS ?

What does the patient need to know whenWhat does the patient need to know when

using a TENS machine ?using a TENS machine ?




IndicationsIndications

Pain management

± Acute vs. chronic

± Mainly musculoskeletal ± Help reduce analgesic consumption

Not much evidence it helps at all




ContraContra--indicationsindications Physical

± Frail elderly, rheumatoid fingers, can¶t reach

Mental ± Low IQ, dementia / confusion

Communication

± Lack of interpreter

Anatomical ± Not over the heart or carotid arteries

± Painful area difficult to adhere to withpads

Neuropathic pain area ± too sensitive

Numb skin ± prevents large A fibre input

Allergy to self adhesive pads




What does the patient need to know ?What does the patient need to know ? Where to put / not to put the pads

± Dermatomes

± 2 pads versus 4 pads

How to look after the self-adhesive pads

Where to buy more pads How to connect the leads

How to switch it on / change the battery

How long to keep it on for ± not overnight and not whilst driving

Initial settings ± for amplitude / frequency / pulse width ± see next slide

Telephone number of who to contact for advice / repair




TENS SettingsTENS SettingsParameter Traditional (Hi-TENS) Acupuncture (Lo-TENS)

Use General Pain Relief Muscle Pain

Frequency Range 90 ± 130 Hz 2 ± 5 Hz

Pulse Width Start at 100 us 200 ± 250 us

Sensory Nerves

Stimulated

A beta A delta

Mechanism of Action Gate Theory Endorphin Release

Stimulation Intensity Present but not

uncomfortable

Strong Sensation

Reversed By Naloxone No Yes

Duration of analgesia Short Long




Describe 2 assessment tools for the measurement of Describe 2 assessment tools for the measurement of acute pain in adultsacute pain in adults

Describe the McGill pain questionnaire used to assessDescribe the McGill pain questionnaire used to assess

chronic painchronic pain

Include the strengths and weakness of each aboveInclude the strengths and weakness of each above

Why do assessment tools used in acute and chronicWhy do assessment tools used in acute and chronic

pain differ pain differ




Acute pain assessment tools Acute pain assessment tools

Visual Analogue Score

± 0 ± 100 mm

Verbal Rating Score ± None / Mild Moderate / Severe

Numeric Rating Sore

± 0 ± 10




McGill Pain QuestionnaireMcGill Pain Questionnaire

Sensory, Affective, Evaluative, Miscellaneous

Pain Patterns

Present pain intensity ± None, Mild, Discomforting, Distressing, Horrible,

Excruciating

Pain Diagram

http://www.painclinic.org/articles/CoventryPainCl

inicQuestionnaire.doc




Strengths and WeaknessesStrengths and Weaknesses

VAS ± Strengths

Simple bedside tool, continuous scale

± Weaknesses

Comprehension, confusional states Good at looking at pain changes in an individual not across a range of

individuals

VRS ± Strengths

Simple bedside tool ± Weaknesses

discontinuous, limited by choice of words




Strengths and WeaknessesStrengths and Weaknesses

MPQ

± Strengths

Validated for pain research

Useful for cancer pain

± Weaknesses

More complex to administer

Requires greater comprehension




Difference between acute / chronic painDifference between acute / chronic pain

Acute pain

± short lived

± acute physiological derangements ± expect to recover

Chronic pain

± Long term pain > 3 -6 months

± Associated psychological / socioeconomic changes




A patient presents to the pain clinic with low back A patient presents to the pain clinic with low back

pain.pain.

List the indications (³red flags´) that would alert you toList the indications (³red flags´) that would alert you to

the possibility of serious pathology.the possibility of serious pathology.

In their absence what is the early management of In their absence what is the early management of

simple mechanical low back pain ?simple mechanical low back pain ?




Back Pain Red FlagsBack Pain Red Flags Spinal Nerve Root Compromise

± Limb numbness, weakness, saddle sensation, incontinence /anal tone

± Progressive neurological deficit involving more than onespinal nerve root

Spinal Abscess / TB ± PUO, progressive paralysis, upper motor neurone signs

Spinal Tumour ± Constant and progressive night pain, +ve spring test, weight

loss, known primary, limb neurology changes Consider retroperitoneal, renal, gynae tumours, AAA




Acute LBP Management Acute LBP Management

Biopsychosocial assessment for risk factors ± Bio = Diagnostic triage for red flags

± Psycho = beliefs, pain avoidance

± Social = secondary gain, job satisfaction

Analgesia ± Paracetamol + codeine + nsaid

± Diazepam (1week), Morphine (1 week)

Reassurance (90% better in 2 weeks without treatment)

Stay active within the limits of the pain

Limit bed rest to less than 3 days Evidence for exercises and manipulation




Chronic LBP Risk FactorsChronic LBP Risk Factors Previous history of LBP

Total absence from work over the last 12 months

Radiating leg pain (sciatica)

Reduced straight leg raising (positive sciatic nerve irritation test)

Signs of nerve root involvement

Reduced trunk strength and endurance

Poor physical fitness

Poor self-rated health

Heavy smoking

Psychological distress and depressive symptoms

Disproportionate illness behaviour

Low job satisfaction

Personal problems (alcohol, marital, financial)

Adversarial medico-legal proceedings



What safety features should be incorporated into

a patient controlled analgesia (PCA) system and

what is the purpose of each? What instructionswould you give to the nursing staff, having set

up the PCA?




PCA Safety FeaturesPCA Safety Features Nursing familiarity / training / PCA guidelines

Quality control ± drugs and sterility

Tamper proof lock box / non-return filling ports

Lockout time = 5 ± 6 min ± negative feedback loop 4 hour limit (electronic devices only)

Bolus / background dose settings

± Programming errors ± electronic vs. mechanical

Separate IV line or non return valve Air in line / over pressure alarm




Nursing Instructions Patient Observations

± Hourly P / BP / RR / SpO2 for 24 hours

Device Observations

± Hourly volume infused / remaining / pump settings PCA not NCA or RCA (except paediatrics)

Supplemental O2 x 24 hours

No other opioids ± except

± IV rescue bolus by anaesthetist / pain nurse

± Chronic pain / addicts allowed background opioids




How would you provide optimal pain relief for a 60

year old man undergoing shoulder replacement?




Acute Pain Options Acute Pain Options Multimodal oral / parenteral analgesics

± Paracetamol / NSAID¶s / Opioids

IV PCA

LA wound infusion system Single shot suprascapular nerve block

Single shot interscalene brachial plexus block

Brachial plexus infusion


Chronic Pain SAQ's

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