FRCA Notes

Guillain-Barré Syndrome

This topic was a CRQ in 2022 (66% pass rate), with marks lost particularly on specific intra-operative measures in a patient with GBS.

Resources

  • Guillain–Barré syndrome is a collection of diseases characterised by acute, progressive, demyelinating, immune-mediated polyneuropathy
  • Annual incidence 1-3/100,000 in the Western world
  • It has a bimodal age distribution and a slight male preponderance

  • It can be classified according to the clinical picture it provides:
    • Acute inflammatory demyelinating polyradiculopathy (AIDP)
    • Acute motor axonal neuropathy (AMAN)
    • Acute motor-sensory axonal neuropathy (AMSAN)
    • Miller-Fisher syndrome
    • Bickerstaff's brainstem encephalitis
  • Typically follows a viral or bacterial illness within the preceding 4 weeks
  • Common organisms include:
    • Upper respiratory infection
      • Epstein-Barr virus
      • Cytomegalovirus
      • Mycoplasma pneumoniae
        •
    • Covid-19

    • Gastroenteritis due to Campylobacter jejuni
      • Campylobacter GBS is associated with axonal degeneration and a more severe, debilitating form of GBS

  • May be triggered by other events e.g.:
    • Vaccines
    • Post-surgery
    • HIV
    • Other disease states e.g. lymphoma, SLE, post-organ transplant, sarcoidosis

  • Auto-antibody production leads to a cascade of myelin destruction ± axonal damage
  • These are anti-ganglioside antibodies, namely:
    • Anti-GM1 (IgG); Guillain-Barré
    • Anti-GQ1b (IgG); Miller-Fisher variant

  • Changes affect the nodes of Ranvier, and typically include:
    • Wallerian degeneration
    • Peri-axonal macrophages
    • Minimal lymphocytic response

Neurological

  • There is acute inflammatory demyelination, leading to progressive, areflexic, ascending, weakness in more than one limb (i.e. the diagnostic features)
  • Supportive features include:
    • Symmetrical weakness
    • Cranial nerve involvement leading to facial and bulbar weakness
    • Autonomic dysfunction
    • Sensory symptoms
    • Respiratory muscle weakness
  • Ophthalmoplegia may be present

  • Sensory symptoms including neuropathic pain, tends to be milder

  • Autonomic dysfunction
    • Under or over activity of both the sympathetic and parasympathetic systems
    • Can lead to arrhythmias, wide fluctuations in blood pressure and pulse, urinary retention, ileus and excessive sweating
    • Of particular importance at induction of anaesthesia

  • Miller-Fisher syndrome
    • A variant with the classic triad of ataxia, areflexia and ophthalmoplegia
    • There is also ptosis, facial nerve palsy, bulbar palsy and limb weakness

Respiratory

  • Ascending weakness can involved respiratory musculature, causing respiratory failure

  • Signs suggesting the need for intubation such as tachypnoea, hypoxia and hypercapnoea can occur late
  • Normal saturations may be falsely reassuring and should not be used as the sole indicator for more advanced respiratory support

  • Instead, monitoring with serial VC measurements should be undertaken
    • Once VC <20ml/kg, should prompt management in a higher care area
    • Once VC <15ml/kg and bulbar symptoms are present, should consider need for invasive respiratory support

Bloods

  • FBC
  • U&E; SIADH can occur
  • LFTs
  • Clotting studies; need to exclude coagulopathy prior to plasmapheresis
  • CRP

  • Cultures; blood and stool

  • For responsible micro-organism
    • Viral panel
    • Antibodies to EBV, CMV, HSV, HIV, Campylobacter and Mycoplasma
    • Anti-GM1 and -GQ1b autoantibodies

Simple investigations

  • ECG; autonomic dysfunction may cause ST-segment, T-wave and QTc interval changes
  • CXR; exclude pneumonia as driving cause

Neuro-imaging

  • CT head
  • Gadolinium-enhanced MRI spinal cord
  • Electrophysiological studies, which can aid diagnosis of GBS subtype and provide prognostic benefits

CSF analysis

  • CSF protein levels >4g/L is supportive but non-diagnostic
  • Typically <10 mononuclear cells/mm2
  • Pleiocytosis (raised CSF leukocytes) in GBS associated with HIV

Supportive care

  • MDT approach including physiotherapy and occupational therapy
  • Counselling and management of depression
  • Nutritional support, especially if bulbar symptoms preclude the enteral route i.e. NG feeding
  • VTE prophylaxis as high-risk

  • Analgesia
    • Typically in the form of a gabapentinoid or amitriptyline
    • Avoid if concerns re: respiratory depression

  • Autonomic dysfunction will need to be managed depending on symptoms, but includes:
    • Bradycardia: anticholinergics, pacing if severe
    • Tachycardia: β-blockers
    • Hypertension: β-blockers
    • Hypotension: vasopressors

Ventilatory support

  • Serial VC measurements should be undertaken
    • Once VC <20ml/kg, should prompt management in a higher care area
    • Once VC <15ml/kg and bulbar symptoms are present, should consider need for invasive respiratory support
  • 25% will require invasive ventilation
  • Increased likelihood of requiring I&V if:
    • Bulbar involvement
    • Bilateral facial weakness
    • Dysautonomia
    • Rapid disease progressio
Indications for invasive ventilatory support
VC <15 - 20ml/kg (or <1.5L or ↓30% from baseline)
Maximum inspiratory pressure <30cmH2O
Maximum expiratory pressure <40cmH2O
Hypercapnic respiratory failure on ABG
Significant autonomic lability
Bulbar involvement

Specific therapies

  • Intravenous immunoglobulin (IVIg)
    • Easier to administer than Pl/Ex
    • More readily available
    • Not necessarily cheaper than Pl/Ex
    • E.g. 5 days of 0.4mg/kg
    • Side-effects:

      • Constitutional CNS Significant
      Nausea Headache Erythroderma
      Fever Encephalopathy Hypercoagulable state
      Malaise Meningism Renal tubular necrosis
      Raised liver enzymes Anaphylaxis

  • Plasma exchange
    • E.g. five exchanges of 250ml plasma for 4.5% HAS

  • NB steroids not indicated

  • 10% will suffer long-term neurological sequelae
  • Up to 10% will die from complications

Poor prognostic indicators

  • Campylobacter infection
  • Advanced age
  • Need for invasive ventilation
  • Anti-GM1 antibodies
  • CSF features
    • Neurone specific enolase 50 - 100mg/ml
    • S-100 proteins present

  • Neurophysiological features
    • Absent CMAPs
    • Unexcitable nerves
    • Upper limb paralysis

Perioperative considerations in the patient with Guillain-Barré syndrome


Monitoring

  • AAGBI
  • Invasive monitoring as patients may have profound autonomic instability
    • Even physical stimulation e.g. suctioning airway can precipitate dysrhythmia and cardiac arrest

Induction

  • Patients with bulbar symptoms and/or muscle weakness are at increased risk of aspiration, so an RSI technique should be used
  • Depolarising NMBA (suxamethonium) should not be used
    • Even following a long period after recovering from the neurological deficit, the risk of hyperkalaemic cardiac arrest with depolarizing NMBA may persist
  • There may be increased sensitivity to non-depolarizing NMBA and these should be avoided where possible
    • If used, give small doses titrated to ToF monitoring and fully reverse with sugammadex at the end

Analgesia

  • Epidural anaesthesia may be useful to avoid postoperative opioid use in those with respiratory compromise
  • In any case, a multi-modal, opioid-sparing approach should be used

Other care

  • Ensure VTE prophylaxis as at high risk