Pain Flashcards
(90 cards)
1
Q
Give the classes of drugs used to treat post-amputation pain syndrome
A
- Triyclic antidepressants e.g. amtitriptyline
- Gabapentinoids e.g. gabapentin, pregabalin
- Selective serotonin reuptake inhibitors e.g. duloxetine
- TRPV1 receptor antagonists e.g. capsaicin cream
- Opioids e.g. tramadol for acute control whilst awaiting specialist input
- NMDA antagonists e.g. ketamine for acute control
2
Q
Define neuropathic pain
A
Unpleasant sensation which arises as a consquence of lesion or disease affecting somatosensory system
3
Q
Give characteristic features of neuropathic pain
A
- Associated paraesthesia
- Spontaneous episodes of pain
- Allodynia
- Shooting/electric shock/burning character
- Hyperalgesia or hypoalgesia
4
Q
Apart from diabetes, list possible causes for neuropathic pain in the feet
A
- B12 deficiency
- Alcohol excess
- Spinal stenosis
- HIV
- Hypothyroidism
BASHHD (D for diabetes)
5
Q
Give risk factors for development of peripheral neuropathy in patients affected by diabetes
A
- Hyperlipidaemia
- High BMI
- Smoking
- Hypertension
- Poor glycaemic control
- Longer duration of diabetes
6
Q
Give the main mechanisms that result in peripheral nerve damage in diabetes
A
- Hyperglycaemia damages microvascular supply to cause nervous tissue damage
- Hyperglycaemia generates inflammatory mediators to cause nervous tissue damage
7
Q
What is first line treatment for diabetic peripheral neuropathic pain
A
- Amitriptyline, duloxetine, gabapentin or pregabalin
8
Q
When would capsaicin be indicated in management of neuropathic pain
A
If pain is localised and
+ oral medication is not tolerated/patient refusal to take oral medication
9
Q
What is the mechanism of action of capsaicin in the management of neuropathic pain
A
- Stimulates TRPV1 receptors (type of calcium ion channel) in C-fibres
- Causes initial release and then depletion of substance P
- Reduces pain sensation transmission
10
Q
List the diagnostic/clinical features of trigeminal neuralgia
A
- Unilateral facial pain across distribution of trigeminal nerve or its divisions
- Electric shock-like/shooting/stabbing character
- Recurrent attacks of pain
- Pain lasts from less than a second to two minutes each time
- Precipitated by innocuous stimulation within distributon of trigeminal nerve
- Severe intensity
11
Q
Give differential diagnosis of trigeminal neuralgia
A
- Cluster headache
- Sinusitis
- Post-herpetic neuralgia
- Dental pain
- TMJ disorder
- Salivary gland stones
Ordered by location
12
Q
What causes classical trigeminal neuralgia and how is it diagnosed
A
- Compression of nerve root by local vascular structure causing morphological change
- Clinical characteristics and MRI demonstrating compression of the nerve
13
Q
Give four red flags that may suggest a serious underlying cause of trigeminal neuralgia
A
- Optic neuritis
- Opthalmic division pain only
- Deafness
- Skin or oral lesions
- Sensory changes
- Bilateral pain
- Family hx MS
- < 40 yrs at onset
Eyes and ears and mouth and MS
14
Q
Give the management options for trigeminal neuralgia
A
- First line: carbamazepine (anticonvulsant, inactivates voltage gated sodium channels)
- Second line: gabapentinoid (inactivated voltage gated calcium channels), amitriptyline (TCA, multiple effects to inhibit reuptake of serotonin and noradrenaline - including on VG K, Na, Ca, alpha adrenergic receptors, dopamine receptors), phenytoin
- Non pharmacological: microvascular decompression of trigeminal nerve root in posterior fossa, stereotactic radiosurgery, ablation of Gasserian ganglion
15
Q
What pain control issues might chronic buprenorphine use cause perioperatively
A
- Buprenorphine is a partial agonist at MOP
- It is an agonist at KOP and DOP with high affinity and so prolonged duration of action
- Continued buprenorphine may reduce maximal effect of other opioids administered perioperatively, causing analgesic failure
16
Q
List six causes of pain in a patient with advanced cancer
A
- Local mass effect
- Treatment associated including acute and chronic post-surgical pain
- Chemical release by tumour (e.g. prostaglandins) that sensitise nerve endings to painful stimuli
- Paraneoplastic phenomena causing neuropathy e.g. anti-Hu
- Associated conditions e.g. immunosuppression induced herptic reactivation, pathological fractures
- Chronic pain development consequent to primary causes
- Psychological state of patient exacerbating experience of pain
17
Q
Give three approaches to minimise side effects from opioid medications in patients with advanced cancer
A
- Minimise overal opioid dose by using WHO analgesia ladder and adjuvant therapies
- Target management of specific side effects e.g. laxatives, antiemetics
- Co-administration of antagonist e.g. naloxone
- Rotation of opioid type
- Expereinced clinician magaing prescription to maintain lowest possible dose
18
Q
Give five pharmacological approaches to managing advanced cancer pain apart from opioid medications
A
- WHO analgesic ladder: regular paracetamol, NSAIDs
- Neuropathic pain medications e.g. gabapentinoids
- Other adjuvant pain-relief e.g. ketamine
- Treat underlying cause e.g. ansitspasmodics for colic pain
- Manage associated depression or anxiety e.g. SSRO
19
Q
Give four non pharmacological approaches to managing advanced cancer pain
A
- Surgery e.g. treat pathological fractures
- Radiotherapy
- Physiotherapy e.g. graded exercise therapy
- Psychological therapy e.g. CBT
- Complementary therapy e.g. acupuncture
20
Q
Give the diagnostic features of chronic post-surgical pain
A
- Pain localised to surgical area or corresponding innervation
- Pain that develops or increases after surgical procedure
- Pain persists beyond healing process (more than or equal to 3 months)
- Other causes of pain are excluded
Site, timing, character
21
Q
List five surgical procedures commonly associated with chronic post-surgical pain
A
Top 3:
* Thoracotomy
* Mastectomy
* Amputation
By location:
* Craniotomy
* Thoracotomy
* Sternotomy
* Mastectomy
* Inguinal repair
* Cholecystectomy
* C-section
* Vasectomy
* Amputation
* Knee arthoplasty
22
Q
Give four patient related risk factors for the development of chronic post-surgical pain
A
- Younger age
- Female
- Higher BMI
- Poor social support
- Lower educational level
- Psychological factors e.g. fear of surgery
- Genetic susceptibility
23
Q
Apart from the risk attributed to specific procedures or patient factors, list four risk factors for the development of chronic post-surgical pain
A
Surgical:
* Procedures that involve significant nerve/tissue damage
* Longer duration of surgery
* Surgical complications
* Repeated surgery
Anaesthetic:
* Poor post-operative pain control
Medical:
* Adjuvant radiotherapy/neurotoxic chemotherapy
24
Q
List two anaesthetic interventions that may be employed to minise the risk of chronic postsurgical pain
A
- Regional anaesthesia
- Multimodal analgesia
25
State the peripheral and central nervous system changes that occur in the development of chronic post-surgical pain
Peripheral:
* Repeated nerve damage causes inflammation, activation of lymphocytes and release of inflammatory mediators
* Leads to increased sodium and calcium channel expression which reduces threshold for firing of peripheral nerves
* Neural sprouting at neurone terminals gives larger receptive field
Central:
* Increased glutamate release from first-order neurones at dorsal horn increases NMDA receptor density at postsynaptic membranes, increasing transmission
* There may be reduction in descending inhibitory pathway activity
* Microglia activated by nerve damage release substances that further sensitise neurones
* Increased activity in brain centres associated with perception of pain e.g. thalamus
26
Give three risk factors for the development of complex regional pain syndrome
* Female
* Prolonged immobility
* Trauma
27
Give eight features you might find on clinical examination for CRPS
* Sensory: hyperalgesia, allodynia
* Vasomotor: temperature asymmetry, skin colour changes
* Sudomotor: oedema, sweating changes
* Trophic: decreased range of motion, motor dysfunction, trophic changes
28
Give other criteria apart from symptoms and signs that are required for the diagnosis of CRPS
* Continuing pain disproportionate to inciting event
* No diagnosis that can better explain clinical picture
29
Give four conservative treatment options in CRPS
* Patient education
* Physical therapies e.g. desensitisation
* Oedema control strategies e.g. positioning
* Occupational therapy e.g. pacing
* Pyschological interventions e.g. CBT
30
Give five pharmacological options for the management of symptoms of CRPS
* Corticosteroids e.g. prednisolone
* TRPV1 receptor agonists e.g. capsaicin cream
* Gabapentinoids e.g. gabapentin
* Bisphosphonate e.g. alendronic acid
* IV ketamine
* Vasodilators e.g. CCB
31
Give three interventional techniques that may be considered in the management of CRPS
* Spinal cord stimulation
* TENS
* Sympathetic nerve block
32
Give two preventative measures that may protect against the development of CRPS
* Vitamin C 500mg OD for 50 days after wrist fracture
* Early rehabilitation with viligance for abnormal pain response
33
State the mechanism of action of intrathecal opioids in the spinal cord
* Intrathecal opiates stimulate opiate receptors in Rexed's laminae, presynaptic to C and A-delta fibres, resulting in hyperpolarisation of the cell membrane and reduced release of excitatory neurotransmitters glutamate and substance P
* Opioid receptors post-synaptically can also be activated which causes indirect activation of descending inhibitory pathways
34
State the mechanism of action of intrathecal opioids in the brain
* Opioids spread cephalad and stimulate receptors in nucleus raphe magnus and periaqueductal grey, reducing GABAergic tone on descending inhibitory pathways, so they exert an antinociceptic effect at the spinal level
35
List six major side effects of intrathecal opioids
* Nausea and vomiting
* Respiratory depression
* Pruiritus
* Sedation
* Delayed gastric emptying
* Urinary retention
36
List five factors that may increase risk of post-operative respiratory depression following administration of intrathecal opioids
* Use of hydrophilic opioids e.g. morphine
* Concomittant use of long acting sedatives
* Positive pressure ventilation
* Increasing age
* Co-existing respiratory disease
* OSA
* Obesity
37
List four regional anaesthesia techniques that may be used to support the post-operative pain management of a patient undergoing an elective laparotomy for resection of colonic tumour
* Spinal
* Rectus sheath block
* Transversus abdominis plane block
* Quadratus lumborum block
38
Give two intravenous options that may reduce opioid requirements post-laparotomy, apart from paracetamol and NSAIDs
* IV magnesium
* IV ketamine
39
Give two issues with buprenorphine transdermal patches
* Unreliable absorption intraoperatively e.g. subject to temperature changes
* Partial agonist at MOP receptors so may reduce effectiveness of other prescribed opiates
40
Give four opioid sparing techniques that can be considered as part of post-operative management for a patient taking regular opioids
* Regular patacetamol and NSAIDs
* Regional analgesia
* Neuraxial analgesia
* Ketamine infusion
* Use of gabapentinoids
* IV magnesium
41
List three clinical features of opioid withdrawal
* Adrenergic hyperactivity e.g. tachycardia, sweating, piloerection
* Abdominal cramps, diarrhoea
* Lacrimation, rhinorrhoea
* Yawning
* Generalised malaise
42
List three clinical features of opioid overdose
* Respiratory depression
* Sedation
* Pin-point pupils
43
Give the equivalent doses of the following to 10mg oral morphine:
Tramadol
Codeine
Oxycodone
* Tramadol 100mg
* Codeine 100mg
* Oxycodone 6.6.mg
| IV morphine would be 3.3mg
44
List four perioperative implications of an existing spinal cord stimulator
* Turn off SCS during surgery to avoid reprogramming or activation from electromagnetic interference
* Care with positioning to avoid pressure damage and lead migration
* Avoid neuraxial techniques which risk lead damage and infection
* Use bipolar diathermy where possible
45
List three perioperative considerations for a patient who has an intrathecal drug delivery system
* Should only be accessed by clinicians with experience in use
* Significant risk of infection, avoid spinal anaesthesia
* Opioid dosing as for opioid-naive patient
* No diathermy within 30cm of pump or catheter
46
Preoperative management of a patient for elective surgery on regular opiates
* Medication history including route, dose and frequency
* Understand indication for opiate
* Involve chronic pain team if complex pain
* Formulate plan for post-operative pain relief including opiate conversions
* Patient education about chronic versus acute pain management, advise to take regular analgesia on morning of surgery
* Aim to reduce opiate requirements with multimodal analgesia if possible
47
Intraoperative management of a patient for elective surgery on regular opiates
* Use of pain modulating medications e.g. ketamine, magnesium, clonidine
* May require higher doses of intraoperative opiates
* Decision re patches
48
Postoperative management of a patient for elective surgery on regular opiates
* Acute pain team review
* Higher boluses of opiate in PCA, consider mixed PCA with ketamine
* Use pain scores
* Be aware of signs of withdrawal or overdose
* Aim to convert IV opiates to oral dosing as soon as is feasible
* Make plan for de-escalation of opiates and include this in discharge paperwork
49
You are called to see a 25-year-old man who suffered a traumatic below knee amputation 24 hours ago. He is using a morphine patient-controlled analgesia (PCA) and was comfortable until two hours ago, when he started to experience severe pain.
Give four reasons why his pain control may be inadequate
* Failed delivery of PCA
* New surgical complication e.g. wound dehiscence/infection
* Neuropathic pain e.g. development of phantom limb pain
* Regional/neuraxial block has worn off
50
You are called to see a 25-year-old man who suffered a traumatic below knee amputation 24 hours ago. He is using a morphine patient-controlled analgesia (PCA) and was comfortable until two hours ago, when he started to experience severe pain.
Give four measures to re-establish pain control
* Intravenous morphine titrated to effect, guided by anaesthetist with RR, BP, HR, O2 monitoring
* Increase PCA bolus or background if considered safe (may require HDU)
* Ensure regular paracetamol and NSAIDs
* Initiate antineuropathic agent e.g. gabapentin
* Ketamine infusion
* Sciatic nerve catheter (femoral if above knee)
* Epidural
51
Give three features of post-amputation pain syndrome
* Character of pain: shooting, burning, cramping
* Location of pain is distal to stump
* Disproportion between pain experienced and stimulus applied
52
Give first line oral pharmacological options for long term management of post-amputation syndrome
* Amytriptyline
* Duloxetine
* Gabapentin
53
Give non-oral pharmacological options for long term management of post-amputation pain syndrome if first line treatment fails
* Capsaicin 8% patches
* Lidocaine 5% patches
54
Give four risk factors for the development of post-amputation pain syndrome
* Severe preoperative pain
* Bilateral amputation
* Repeated limb surgeries
* Increasing age
55
Give respiratory ploblems which could result from inadequate pain relief from rib fractures
* Atelectasis
* Pneumonia
* Respiratory failure due to inadequate ventilation
* Failed secretion clearance
56
State two ways effectiveness of pain relief can be assessed
* Pain scores e.g. visual analogue scores
* Frequency of use of breakthrough pain medication
57
List four factors which predict increased risk of mortality after rib fractures
* Increasing age
* Increasing number of rib fractures
* Chronic lung condition
* Lower oxygen saturations
* Use of anticoagulants prior to injury
58
State two pharmacological approaches to management of patient's pain other than paracetamol and codeine
* Consider NSAIDs
* Oral morphine immediate release solution
* Opioid PCA
59
Give four regional analgesia options which may be considered for management of rib fracture pain
* Thoracic epidural (bilateral fractures)
* Paravertebral block (unilateral fractures)
* Serratus anterior (anteriolateral fractures)
* Errector spinae block (posterior fractures)
60
Which ribs are most likely to be fractured as a consequence of trauma
Ribs 4-10
61
State five complications that should be rapidly recognisable by healthcare professionals caring for patients having continuous epidural analgesia
* Hypotension
* Total spinal
* Epidural haematoma or abscess
* Local anaesthetic toxicity
* Post-dural puncture headache
* Nerve damage
62
Give four organisational factors that are necessary to ensure safe management of continuous epidural analgesia in the ward setting
* Adequate staff training
* Inpatient pain service
* Protocols for all aspects of CEA management
* 24 hr anaesthetic service to manage any issues with CEA
* Handover of CEAs for daily review
* Resuscitation equipment, intralipid and naloxone readily available
63
State two aspects of equipment monitoring that must be undertaken regularly throughout duration of continuous epidural analgesia
* Patent venous access
* Pump infusion rate, name and concentration of drug used
64
State four aspects of patient monitoring that must be undertaken regularly throughout duration of continuous epidural analgesia
* Heart rate
* Blood pressure
* Respiratory rate
* Temperature
* Pain score
* Motor and sensory block
* Sedation score
* Visual inspection of epidural insertion site
65
Give three safety features of the pump used for CEA
* Preset limits for maximum infusion rate and bolus
* Locked box containing drug
* Code required for programming
66
Give two safety features of the epidural infusion system used for continuous epidural analgesia
* Closed system, no injection ports
* Antibacterial filter
* NRFit connections
67
Give the names of the three nerves that contribute to the coeliac plexus
* Greater splanchnic T5-10
* Lesser splanchnic T10-11
* Least splanchnic T11-12
68
Give four anatomical relations of the coeliac plexus
* Anterolateral to body of L1
* Anterior to aorta and crura of diaphragm
* Either side of the origin of the coeliac artery
* Medial to IVC
69
Give three indications for coeliac plexus block
* Pancreatic cancer pain
* Stomach cancer pain
* Chronic pancreatitis pain
70
Give two anatomical approaches used for coeliac plexus block
* Posterior
* Anterior
71
Give specific complications associated with coeliac plexus block
* Retroperitoneal bleeding (injury of aorta or IVC)
* Intravascular injection into great vessels
* Paraplegia if phenol injected into arterial supply
* Intrathecal/epidural injection
* Pneumothorax
* Chlyothorax
* Thrombosis
* Sexual dysfunction if phenol spreads to sympathetic chain
72
List eight factors in presentation of back pain that require referral or further investigation
Cancer:
* Age> 50 years
* Focal spinal tenderness
* Constitutional symptoms of weight loss and pyrexia
Fracture:
* Severe central spinal pain relieved on lying down
* History of major trauma
* Structural deformity of spine
Infection:
* Immunocompromise/HIV
* Recent infection
* Diabetes
* IVDU
Cauda equina:
* Perianal loss of sensation
* Loss of anal tone
* Urinary retention/incontinence
* Faecal incontinence
* Progression from unilateral to bilateral sciatic pain
## Footnote
Exam specific: pyrexia, focal tenderness, structural deformity of spine, perianal anaesthesia, loss of anal tone, motor weakness at legs or hips
73
List four conservative options for the management of low back pain
* Self management
* Exercise
* Manual therapy
* Psychological therapy
* Pain management programme
74
Give three pharmacological options for the management of back pain
* Paracetamol
* NSAIDs
* Short course weak opioid
75
When is radiofrequency denervation considered for back pain
* Pharmacological options not effective
* Main source of pain identified from structures supplied by medial branch nerve
* Moderate to severe localised back pain
76
State the indication for considering caudal epidural for low back pain
Severe sciatic pain
77
State a surgical option that may be considered when radiological findings are consistent with sciatic symptoms and non-surgical management has failed
Spinal decompression
78
Define chronic back pain
Pain between the costal margins and gluteal folds, which persists beyond 3 months
79
Risk factors for acute back pain to become chronic
Bio:
* Nerve root involvement
* Poor physical fitness
* Heavy smoking
Psycho:
* High levels of psychological distress
* Tendency towards depression
Social:
* Long time off work
* Ongoing compensation claim
80
Signs of nerve root irritation in back pain
Straight leg raise, femoral stretch test
81
Indications for spinal cord stimulation
* Failed back surgery
* CRP Type 1
* Chronic leg ischaemia
* Chronic angina refractory to treatment
82
Complications from spinal cord stimulator implantation
* Infection
* CSF leak
* Symptomatic haematoma
* Lead migration
83
Neuropathic features of chronic pain
* Dyaesthesia: unpleasant touch or tingling sensation
* Allodynia: pain to non-painful stimuli
* Hyperalgesia: increased pain response to nociceptive stimuli
84
Risk factors for trigeminal neuralgia
* MS
* Age
* Previous stroke
* Hypertension
* Trauma
* Trigeminal nerve root tumours
85
Which base of skull structures do the branches of trigeminal nerve pass through?
V1: superior orbital fissure
V2: foramen rotundum
V3: foramen ovale
86
List three cortical areas involved in processing nociceptive signals
* Prefrontal cortex
* Periaqueductal grey
* Reticular formation
87
Give symptoms and signs of sciatic back pain
* Unilateral pain that radiates down side of hip to below knee, with leg pain more bothersome than back pain
* Positive straight leg raise test
* Dermatomal numbness/paraesthesia (lower leg except medial side) or motor weakness (thigh extension, knee flexion)
88
Common sites for shingles (VZV)
Opthalmic division trigeminal nerve
Thoracic dermatomes
89
Risk factors for post-herpetic neuralgia
Female
>60yrs
Pain before rash
Severe pain
Severe rash
Pyrexia
90
Clinical features of post-herpetic neuralgia
* Throbbing or stabbing pain across single dermatome (> 3 months duration)
* May have allodynia and find it uncomfortable to wear clothes over area
* May have autonomic features such as skin changes, temperature changes, sweating
* May have sensory loss e.g. to heat
* Systemic features including weight loss
* Psychological features e.g. chronic fatigue and depression
* Social features including depression
