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Pain Medicine - Coggle Diagram

- - - - Empty syringe
      - Pump failure
      - Cannula issues
      - Pt issue with pump use
    - - Infection
      - Wound dishiscense
      - Bleeding/Haematoma
- - - - Reduced firing threshold or spont firing
        
        Increased glutamate release from 1st order neurones
        
        Increased glutamate R density on 2nd order neurones
        
        Transmission occurs in prev inactive neurones and those that don't normally transmit pain
  - - - Surgical approach (nerve & tissue damage)
      - Complications (infection/bruising)
    - - Radio/chemotherapy
      - Psychological
      - Uncontrolled post op pain
    - - Hx of chronic pain or neuroexcitatory condition (Raynauds, IBS, migraine)
      - Catastrophisation, anxiety
      - Repeat surgery
      - Pain >1 month @ surgical site
      - ?Female, poor social support
  - - - Ketamine/magnesium/gabapentinoids/clonidine
- - - - Inhibit ascending transmission
      - Augment descending inhibition
      - Reduce nociceptive input
    - - Ibuprofen 400mg = 2.5
      - Combined =1.5
      - PCM 1g = 3.6
    - - NMDA antagonists (ketamine)
      - NSAIDs
      - TRPV1 agonists (capsaicin cream)
      - Opioids
      - Membrane stabalisers (Gabapentinoids)
      - Cannabinoids (nabilone)
      - Reuptake inhibitors (TCAs - amitriptyline, SNRIs - duloxetine)
      - LA
      - Steroids
  - - - Heat energy is produced transversely along needle (needle aligned perpendicular to nerve)
      - Causes a thermal lesion in nerve
    - - Short bursts of RF
      - Do not produce thermal lesions
      - Temp limited to 42 degrees
- - - - Symptoms
        
        Hyperaesethsia
        
        Allodynia
      - Signs
        
        Hyperalgesia (pin prick)
        
        Allodynia (light touch or deep pressure)
    - - Symptoms
        
        Temp asymmetry
        
        Skin colour changes (asymmetry)
      - Signs
        
        As above
    - - Symptoms
        
        Oedema
        
        Asymmetrical sweating changes
      - Signs
        
        As above
    - - Symptoms
        
        Reduced RoM
        
        Motor dysfunction (weakness/tremor)
        
        Trophic changes (hair/nails/skin)
      - Signs
        
        As above
  - - - 4 criteria for diagnosis
        
        First two:
        
        1 Sx in at least 3/4 catagories
        
        1 sign in 3/4 catagories
        
        Continuing pain disproportionate to inciting event
        
        No other diagnosis to explain Sx
  - - - Patient info and education
        
        About CRPS and how it is managed
      - Physical and vocational rehab
        
        PT, desensitising, fine motor exercises, TENS
        
        Oedema control
        
        OT support
        
        MDT pain management
      - Pain control
        
        Amitryptiline -> Duloxetine -> Gabapentin -> Pregabalin
        
        Rescue Tramadol
        
        Capsaicin cream for local neuropathic pain
        
        Bisphosphonates (pamidronate 60mg) to help maintain bone function
        
        SCS if pain > 6months
      - Psychological
        
        CBT
        
        Treat other psych issues
  - - - Follows tissue injury (normally limb trauma)
    - - Follows known major peripheral nerve injury
- - - - Descending pathways alter this system to control response
      - More pain releases more glutamate but additional substance P & neurokinin via larger Ca2+ influx into 1st order endplate
        
        Leads to opening of NMDA Rs (prepolarisation required to remove Mg2+ that sits in R)
        
        Ca2+ enters 2nd order neurones - activates nitric oxide and prostaglandins (upregulate glutamate release) and effects genetics to upregulate Rs -> overall upregulation and reduced firing threshold
      - Leads to central sensitisation -> hyperalgesia and allodynia
      - Main excitatory NT is glutamate - cause Na+ channel open and depolarisation in 2nd order neurones
  - - - Posterior insula/mid-parietal operculum/mid-cingulate cortex
      - Initial response - locates where pain is
    - - Mid/anterior insula/anterior cingulated cortex/pre-frontal cortex/peri-aqueductal gray/rostoventromedial medulla/reticular formation
      - Fine distinction and variation of pain experience
- - - - Unilateral
        
        TGN, glossopharyngeal neuralgia, episoic migraine
      - Bilateral
        
        Tension headache, medication headache
    - - Unilateral
        
        Post herpetic neuralgia, post traumatic TGN, referred pain, post stroke, giant cell arteritis, chronic migraine, cancer pain
      - Bilateral
        
        TM disorders, persistant orofacial pain, burning mouth syndrome
  - - - 20-40 y/o, depression, back pain, fibromyalgia, headaches
  - - - 'Typical' neuropathic pain
      - Mx as per neuropathic pain
    - - Rare chronic condition
      - Burning of tongue and oral mucosa without dental or medical cause
      - Secondary causes - oral candida, mucosal lesions, autoimmune, drugs
    - - Sudden and unilateral breif stabbing pain in 1 or more trigem branch
      - Rarely Sx of other pathology (MS)
      - Carbemazepine or oxcarbazepine
      - Surgical intervention if pharm fails - microvasc decompression (access via pit fossa - big op!)
    - - Sx of trigeminal neuralgia but in CN IX distribution (deep ear/back of tongue/tonsils/neck)
      - Mx as with TGN
- - - - Paracetamol (not alone)
      - NSAIDS
        
        Assess risk vs benefit
        
        Consider gastric protection
        
        Low dose for shortest time
      - Weak opioid
        
        Only for acute period
      - Amitriptyline/Duloxetine/Gabapentin
        
        If neuropathic component
    - - Self management, reassurance, exercise
      - Exercise inc NHS classes
      - Manual therapy
      - Psych
        
        CBT
      - Pain management programme
        
        provide overall package of care
      - Interventional
        
        Epidurals
        
        Joint injections
      - Spinal cord stimulatiors for radicular pain
      - Surgical
        
        Laminectomy for spinal stenosis etc
  - - - Features
        
        Dull, mechanical ache
        
        Referred to legs but not below the knee
        
        Age 20-55
    - - Features
        
        Localised, sharp electric pain
        
        Radiates below the knee
        
        Worse with cough/straining
        
        Neuro - motor/sens/reflex abnormalities
- - - - Pruritis
      - Resp depression/arrest
    - - High block
        
        CVS/Resp arrest
      - Hypotension
      - Urinary retention
      - Motor block
      - Pressure sores
      - LA toxicity
    - - Unexpected migration and high block
      - PDPH/subdural haematoma
      - Superficial infection
      - Epidural haematoma/abscess
      - Meningitis
      - SC ischaemia
      - Nerve injury
        
        Paraplegia
    - - Drug errors
      - Inadequate analgesia
  - - - Nurses
      - Acute pain team
      - Anaesthetic
        
        Ongoing duty of care while in situ
    - - Staffed
      - Protocol
      - HR/BP/RR/sedation score/Temp/Pain score/motor&sens block
      - Venous access
      - Epidural site review
      - Pump documentation
  - - - Configured in ml
      - Labelled
      - Preset max inf rate and bolus volumes
      - Lock out times
      - Alarms
      - Locked box and coded protected
    - - Closed without injection ports
      - Antibacterial & glass filter
      - Yellow label
      - Anti-siphon valve
    - - NR fit
      - Low resistance syringe
      - Secure fastening connectors
      - Standardised catheter with length markings
- - - - Upregulation of voltage gated Na channels
        
        Spontaneous firing of damaged peripheral nerve or in DRG
    - - Ab fibres from laminae III and IV sprout in I and II due to absence of C fibre inputs
        
        Touch and pressure start to be interpreted as pain
      - Sympathetic nerves sprout into DRG which stimulates pain pathways
    - - Over amplification of pain experience
  - - - Paracetamol
      - NSAIDs
      - Morphine PCA
    - - Amitryptiline 1st
      - Duloxetine/Gabapentin/Pregabaln
      - Capsaicin cream
      - Tramadol rescue
    - - Sciatic or femoral nerve blockade
  - - - Burning
      - Shooting
      - Cramping
    - - Distal to stump
- - - - Opiates
      - LAs
      - Clonidine
      - Baclofen
    - - Percutaneous reservoir filling
  - - - Intrathecal bolus can be given via device if at suitable level
  - - - Migration/laceration/occlusion/disconnection
    - - Failure of power source or pump
    - - Failure of programmable pumps
    - - Refil schedule mistakes, miscalculations, programming errors
    - - Baclofen - ascending hypotonia, hypotension, hypothermia, vomiting, resp depression, seizures, drop in GCS
      - Opioids
      - Clonidine - HTN, confusion, drop in GCS, sweating, resp depression
      - Mx
        
        Supportive, consider LP and CSF aspiration (30ml) + saline re-injection
        
        Naloxone IV
        
        Restart pump within 48h to avoid damage
    - - Baclofen
        
        Exacerbation of spasticity, fever, sweating, pruritis
      - Opioid
      - Mx
        
        Supportive
        
        IV supplementation
    - - Normally minor but major will give Sx of withdrawal of Rx +/- spinal headache and CSF accumulation in body
      - Mx
        
        Surgical restoration
        
        1 or more blood patches
    - - Rare
      - Can cause SC compression or radicular pain (thoracolumbarl)
      - Mx
        
        Move catheter level +/- surgery
    - - Due to focal arachnoiditis + fibroconnective adhesions -> accumulation of medication and high concs -> further arachinoiditis
      - Mx
        
        Replace catheter
        
        Surgical adhesiolysis or balloon fenestration
- - - - Laminae I and II
        
        Presynaptically on C and A-d fibres (and some postsynaptically)
    - - Voltage sensitive Ca2+ channels to open (KOP)
        
        Hyperpolarisation of cell memebrane
        
        Reduced release of excitatory NTs (glutamate and substance P)
      - K+ channels to open (MOP & DOP)
    - - K+ channel opening
        
        Direct activation of descending inhibitory neurones
    - - Stimulation of Rs in nucleus raphe magnus & periaqueductal grey (PAG)
        
        Reduced GABAergic tone in descending pathways
        
        Antinocioceptive effect at spinal level
- - - - Paracetamol + codeine
      - Consider NSAIDs
      - Stronger opioid?
    - - PCA (morphine or fentanyl)
    - - LA patches
    - - Thoracic epidural
        
        ?Hypotensive effect
        
        ?Ward appropriate
      - Paravertebral block or catheter
        
        Avoids hypotension
      - Erector spinae plane block or catheter
      - Intercostal block or catheter
        
        Requires numerous injections
    - - Fixation
- - - - Neuropathic pain
      - CRPS
      - Ischaemic pain due to angina or PVD
    - - Pulse generator can then be placed into a subcut pocket (abdo or gluteal) and line tunnelled subcut to it
  - - - Contact team who manage patient for device check
    - - Bipolar diathermy
        
        Reduces risk of electrical passage through SCS
      - Neuroaxial block contraindicated
        
        If essential d/w pain team and do under flouroscopic or US guidance to avoid device
- - - - Phenol (denser than CSF so affected side down)
      - Alcohol (less dense so bad side up)
- - - - Trauma (external & internal ie childbirth), disc disease, hypermobilitiy, infection, neoplasm
    - - Pain over coccyx, worse on prolonged sitting & improved by standing or sitting on one side
      - Pain on rectal examination
    - - XR (dynamic are mosre useful (sitting & standing)) allows measurement if coccygeal angle
      - MRI with Tc-99 allows visualisation of inflammation
    - - Conservative
      - Non surgical
        
        NSAIDs, stool softerners, doghnut cushions, PT, steroid & LA injections, RF ablation, psych
      - Surgical
        
        Pts with coccyx instability or other Mx has failed
        
        Resection of mobile part of coccyx
        
        Risk of rectal injury, incontinence and wound infection
  - - - Intraarticular degeneration
        
        Arthritis, infection, malignancy
      - Extraarticular
        
        Fractures, ligament injuries
    - - Chronic lower back pain with Hx of injury/lack of recovery
      - Lateral buttock pain
    - - Conservative
      - Non surgical
        
        Injections of LA/steroids
        
        RF ablation
      - Surgical
        
        Fixation/fusion of SIJ
- - - - Ganglia either side of L1
        
        Aorta is posterior
        
        Pancreas & stomach anterior
        
        IVC lateral
        
        Either side of origin of coeliac artery
      - Main junction for autonomic nerves for upper abdominal organs
        
        Liver, gallbladder, spleen, stomach, pancreas, kidneys, small bowel & 2/3rd large bowel)
      - Retroperitoneal
    - - Acute pain (post operative)
      - Chronic pain (anything causing upper abdo pain ie chronic pancreatitis)
      - Cancer pain (upper abdo ie pancreatic Ca)
    - - Bleeding/infection risk
      - Pain not transmitted via autonomic nerves
      - Dangerous due to AAA
    - - Approach
        
        Posterior (commonest)
        
        Anterior
        
        Paramedian
        
        Transdiscal
      - Xray screening
    - - Retroperitoneal bleeding due to aorta or IVC injury
      - Intravascular injection into great vessels
      - Paraplegia
        
        Phenol into arterial SC supply
      - SC or nerve root damage
      - Retro crural phenol spread
        
        spinal nerve root damage
      - Visceral puncture or damage
      - Intrathecal or epidural spread
      - Pneumothorax/chylothorax
      - Thrombosis
      - Hypotension (dilatation of upper abdominal vessels)
- - - - Switch to Strong opioid