Makindo Medical Notes

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Guillain-Barre Syndrome: Respiratory function should be monitored in all patients, as respiratory failure can occur without initial symptoms of dyspnoea. About 20% of patients with GBS develop respiratory failure and require mechanical ventilation. The bedside measure of respiratory muscle function is Forced Vital Capacity (FVC); a value <1.5 L suggests ITU admission. According to a Cochrane review, IVIG administered within 2 weeks of onset is as effective as plasma exchange and more likely to be completed.

Initial Management of GBS

About

• GBS is characterized by an acute onset of ascending weakness with areflexia.
• Although rare, GBS is potentially life-threatening, especially with respiratory failure.
• Early diagnosis and management are critical
• Also known as Acute Inflammatory Demyelinating Polyneuropathy (AIDP).

Aetiology

• Autoimmune mechanism: auto-reactive T-cells may target self-antigens.
• Possible infectious triggers include Campylobacter jejuni, CMV, HIV, HEV, EBV, Mycoplasma, Zika virus, and Lyme disease.
• Pathology includes multifocal demyelination and elevated CSF protein (often normal in early stages).

Different Forms of GBS

• AIDP (90%): Acute inflammatory demyelinating polyradiculoneuropathy, associated with various antibodies.
• AMAN (5%): Acute motor (± sensory) axonal neuropathy, often linked to Anti-GD1a antibodies (associated with Campylobacter infection).
• Miller-Fisher Syndrome (5%): Ophthalmoplegia, ataxia, and areflexia, typically anti-GQ1b positive with a good prognosis.
• AMSAN (1%): Acute motor sensory neuropathy.

Clinical Features

• Acute, progressive ascending sensorimotor neuropathy.
• Weakness typically starts in the legs and progresses to the trunk, arms, and head over hours to days, peaking within 14 days.
• Common features include:
  • Bilateral leg and arm weakness.
  • Dysautonomia: BP or heart rate instability, pupillary dysfunction.
  • Respiratory muscle weakness, with potential need for ventilatory support.
  • Back pain, which may be muscular, radicular, or neuropathic.
  • Distal sensory loss, areflexia (loss of tendon reflexes), and cranial nerve involvement.
  • Autonomic dysfunction: hypertension, arrhythmias.
  • Papilloedema due to high CSF protein.

Investigations

• Blood Tests: FBC, U&E, porphyrins.
• ECG: Monitor for arrhythmias (tachycardia, bradycardia).
• CSF Analysis: Raised protein (1-3 g) without increased WCC, normal glucose. Early protein levels may be normal.
• Nerve Conduction Studies: Proximal demyelination, slowed conduction, focal block, absent F waves. AMAN may show axonal degeneration.
• Antibody Testing: Rarely useful, except for prognostic markers like anti-GD1a.

Differential Diagnosis

• Acute spinal cord disease with flaccid weakness.
• Acute intermittent porphyria, Myasthenia gravis, Botulism.
• Tick paralysis, Diphtheria, Poliomyelitis.

Indications for ITU and/or Intubation

• Signs of respiratory distress or FVC <15–20 mL/kg or <1 L.
• Impaired maximal inspiratory/expiratory pressures.
• Severe swallowing dysfunction, diminished cough reflex, or hypoxia.
• Severe autonomic instability or abnormal ABG/pulse oximetry.

Management

• General Management:
  • ABC. Admit to HDU if respiratory concerns are present.
  • Monitor FVC, ECG, and BP regularly; watch for dysrhythmia.
  • Consider IVIG (0.4 g/kg/day for 5 days) within 2 weeks of onset. Screen for IgA deficiency to avoid allergic reactions.
  • Plasma exchange (PLEX) within 4 weeks if IVIG contraindicated (IgA deficiency, renal failure).
  • Avoid steroids, as they are ineffective in GBS.
• VTE Prophylaxis: Use Heparin/LMWH or IPC stockings due to high risk of thromboembolism.
• Rehabilitation:
  • Physiotherapy, occupational therapy, and speech therapy (for bulbar weakness).
  • Nutrition: NG tube or PEG if prolonged swallowing difficulties.
  • Neuropathic pain management: consider carbamazepine, gabapentin; avoid amitriptyline due to arrhythmia risk.

Outcome

• Most patients show maximum improvement within the first year; recovery may continue for over 5 years.
• 85% of patients have good recovery, though some may have lasting disability.
• Worse prognosis if onset is rapid, patient is older, or has preceding diarrhoeal illness or muscle wasting.

Complications

• Bulbar palsy: risk of choking, dietary deficiency.
• Autonomic instability: potential for cardiac arrhythmias.
• Immobility: risk of pressure ulcers, infections, contractures, and hyponatraemia.

References

• Diagnosis and management of Guillain Barre syndrome in ten steps