Guillain-Barré syndrome

Definition/diagnostic criteria: Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy, often precipitated by an infection. Characterised by rapid onset of muscle weakness and loss of reflexes, it is considered an autoimmune disorder affecting the peripheral nervous system. Diagnostic criteria include progressive weakness in both arms and legs, and areflexia (absence of reflexes), with progression typically ceasing by four weeks.

Epidemiology: GBS affects all ages, with incidence peaking in older adults and slightly more common in males. The incidence rate in the UK is approximately 1.2–2.3 per 100,000 annually. Most cases are sporadic, though there’s a noted association with preceding infections, notably Campylobacter jejuni, and, less commonly, with influenza-like illnesses.

Diagnosis
Clinical features: Onset is typically acute, with progressive, symmetrical limb weakness and areflexia. The weakness may start in the legs, ascending to the arms and face. Sensory symptoms, autonomic dysfunction, and pain can occur. Respiratory muscle involvement may necessitate ventilatory support.

Investigations Diagnosis is primarily clinical but supported by:

  • Electrophysiological studies: Demonstrate features of demyelination or axonal degeneration.
  • CSF analysis: Reveals raised protein with normal white cell count after one week of illness onset.
  • MRI of the spine: May show nerve root enhancement in some cases.
  • Additional tests to consider include nerve conduction studies and electromyography to differentiate from other causes of acute weakness.

Treatment Immediate hospitalisation is essential. Treatment involves supportive care, including monitoring of respiratory function and autonomic instability. Specific treatments include:

  • Intravenous immunoglobulin (IVIg) or plasma exchange as first-line treatments, shown to hasten recovery. The choice between them is based on availability, patient preference and contraindications.
  • Pain management, physiotherapy and treatment of complications like deep vein thrombosis are crucial supportive measures.
  • Corticosteroids are not recommended for treating GBS.

Prognosis: Most patients reach the nadir of weakness within two weeks of onset. Recovery can be slow, taking weeks to years. About 60–80% of adults will be able to walk independently six months after diagnosis. Long-term outcomes are generally good, but approximately 20% of adults have residual weakness after one year. Mortality is 3–7%, usually due to complications such as respiratory failure or autonomic dysfunction.

References

  • BMJ Best Practice. Guillain-Barré syndrome. 2022.
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