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Guillain–Barré Syndrome

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Overview

Guillain-Barré Syndrome (GBS) is an acute inflammatory demyelinating polyneuropathy resulting in an acute and classically ascending progressive neuropathy characterised by weakness, paraesthesia, and hyporeflexia.

It is often triggered by an infection, usually Campylobacter jejuni, and emerges 1-3 weeks after. GBS is considered to be a form of molecular mimicry i.e. the antigens on the pathogens and body cells are similar and mistakenly attacked.

Epidemiology

  • Incidence is higher in men
  • Peak ages are 15-35 years and 50-75 years

Risk Factors

  • Preceding viral/bacterial infection – classically Campylobacter jejuni
    • Infections are typically gastrointestinal/respiratory
  • Malignancies e.g. Hodgkin’s lymphoma
  • Pregnancy – incidence decreases during pregnancy but increases after

Presentation

Patients classically have progressive symmetrical muscle weakness starting in the distal lower extremities and ascending. Symptoms usually emerge 1-3 weeks after an acute infective illness. Features are:

  • Back or leg pain – most patients experience this in early stages
  • Weakness
  • Sensory dysfunction – paraesthesia – tends to be mild and despite paraesthesia, sensory loss is not typical.
    • If a deficit in a specific dermatome or sensory level is found, this is unlikely to be due to GBS and instead, pathology of the spinal cord itself
  • Neuropathic pain – usually in the legs or back
  • Reflexes – reduced/absent
  • Respiratory muscle weakness
  • Autonomic involvement:
  • Cranial nerve involvement:
  • Diplopia
  • Facial nerve palsy
  • Oropharyngeal weakness

A variation of GBS is Miller-Fisher syndrome (MFS), which has a classic triad of:

  • Ataxia
  • Areflexia
  • Ophthalmoplegia

Differential Diagnoses

Myasthenia gravis (MG)

  • Early features are extraocular muscle involvement (diplopia), oropharyngeal weakness and limb weakness
  • Fatigability and weakness are worse with movement and towards the end of the day
  • Reflexes are not affected

Lambert-Eaton myasthenic syndrome (LEMS)

  • Proximal limb weakness with diminished reflexes that both improve with exercise
  • In MG weakness is worse with exercise, and reflexes are normal
  • There may be an associated small cell lung cancer in the majority of patients
  • Antibodies against voltage-gated calcium channels are present in most patients

Investigations

  • Nerve conduction studies:
    • Decreased motor nerve conduction due to demyelination
  • Lumbar puncture:
    • Classically CSF protein is significantly elevated with normal/slightly high white cells – this is known as albuminocytological dissociation

Management

  • 1st-line: IV immunoglobulin (IV IG) or plasma exchange

Patient Advice

  • Patients should be safety-netted on seeking help if any new or worsening symptoms arise e.g. weakness, numbness, paraesthesia, dysphagia, dyspnoea, bladder/bowel dysfunction
  • Patients should be educated on the long-term effects of GBS

Complications

  • Fatigue
  • Persisting paralysis
  • Respiratory failure
  • Psychological problems – depression/anxiety
  • Autonomic dysfunction – bladder incontinence/ileus

Prognosis

  • The outcome is generally excellent, but 1/5 of patients have persisting neurological deficits
  • Factors associated with a worse prognosis are:
    • Rapid progression of symptoms
    • Increased age
    • Prolonged ventilation

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