Guillain-Barre syndrome

Background

1. acute idiopathic inflammatory demyelinating polyneuropathy characterized by progressive muscle weakness and areflexia usually associated with sponatneous remission
2. Post-infectious autoimmune destruction of peripheral nerves
   1. may be associated with hx of antecedent respiratory tract or GI infection (camphylobacter)
3. Characterized by:
   1. Ascending paralysis; symmetric in legs. rapid onset.
   2. Autonomic dysfunction: 50%
   3. arrhythmias, brady/tachy, hypotension, sweating, urinary retention, respiratory failure
   4. symptoms progress and peak ~2-4 weeks after onset, plateau for 2-4 weeks then remit from weeks to months
4. Intubation in 25% of pts.
5. 90% full recovery in months with 5% Mortality
6. Forms:
   1. Acute Inflammatory Demyelinating Polyneuropathy (AIDP)
      1. demyelination is immunologically mediated
   2. Acute Motor Axonal Neuropathy (AMAN)
      1. pure motor form
      2. seasonal incidence, associated with Camphylobacter infection
      3. pts with this form tend to require ventilatory assistance
   3. Acute Motor Sensory Axonal Neuropathy (AMSAN)
      1. motor and sensory symptoms
      2. Miller-Fisher (4%) variant is descending: ophthalmoplegia, ataxia, mainly affects CN's

Diagnosis

Physical Exam:

1. symmetric weakness with diminished/absent reflexes
2. minimal loss of sensation
3. signs of autonomic dysfunction: dysarrythmias, orthostatic hypotension, transient/persistent hypertension, paralytic ileus, bladder dysfunction, abnormal sweating

Work-up

1. nerve conduction study: slowed nerve conduction velocities, partial motor conduction block, abnormal temporal dispersion, prolonged distal latencies
2. LP: normal pressure, few cells (mononuclear), elevated protein (>50mg/dL)

Treatment

1. Admit to neuro / ICU
2. Intubation (if indicated)
   1. 20/30/40 rule: patient with vital capacity <20mL/kg, max inspiratory pressure <30 cmH20, or max expiratory <40 cm H20 will generally progress to require mechanical ventilation
3. Supportive care, ABC's, close monitoring
4. Steroids iv (no proven benefit)
5. plasmaphoresis vs IVIG
6. DVT Prophylaxis (subQ heparin and SCDs)