GBS is an acute immune-mediated polyradiculoneuropathy usually triggered by a recent infection. It causes progressive, symmetrical limb weakness, classically starting in the legs and ascending, with areflexia and risk of respiratory or autonomic involvement.
💡 It is the most common cause of acute flaccid paralysis in the UK.
Post-infectious autoimmune attack on peripheral nerves
Targets myelin (demyelinating form) or axons (axonal forms)
Leads to conduction block, weakness, and possible respiratory compromise
🚨 Severe inflammation may cause rapid progression to respiratory failure or sudden cardiac instability.
Recent Campylobacter jejuni gastroenteritis (most common)
Viral infections: CMV, EBV, HIV, influenza, COVID-19, Zika
Rarely after vaccination or surgery
More common in young adults and older age groups
Symmetrical weakness, starting distally and ascending
Areflexia (loss of tendon reflexes)
Paraesthesia or mild sensory symptoms
Facial weakness (often bilateral)
Back or limb pain
Autonomic dysfunction: fluctuating BP, arrhythmias, urinary retention
Respiratory involvement: reduced vital capacity, dyspnoea
🚨 Progression peaks within 4 weeks — close monitoring is essential.
Cauda equina (asymmetrical, saddle anaesthesia)
Transverse myelitis (UMN signs, sensory level)
Myasthenia gravis (fluctuating weakness, reflexes preserved)
Botulism (descending paralysis, pupillary involvement)
CSF: raised protein with normal WCC (albuminocytologic dissociation)
Nerve conduction studies: evidence of demyelination or axonal loss
Bedside: regular vital capacity checks, ECG and BP monitoring
Blood tests/serology: may support cause but not diagnostic
💡 Early nerve studies may be normal — repeat if suspicion remains high.
Supportive care: airway and breathing monitoring, cardiac monitoring, VTE prophylaxis, nutrition and physio
Specific therapy: IV immunoglobulin (IVIG) or plasma exchange are effective if started within 2 weeks
ICU referral: if respiratory or autonomic compromise develops
🚨 Up to a third of patients require mechanical ventilation — early escalation is life-saving.
Respiratory failure
Autonomic instability (arrhythmias, BP swings)
Pressure sores, DVT
Long-term disability or fatigue
Most patients recover fully within 6–12 months
Severe cases may leave residual weakness
Mortality around 5%, usually due to respiratory or autonomic complications
