Neuromuscular and Neuroinfectious Disease in the ICU
Neuromuscular emergencies
Recognize the "can't breathe" neuromuscular disorders: Guillain-Barré syndrome (GBS), myasthenia gravis (MG) crisis, and critical illness weakness. In GBS, monitor vital capacity and negative inspiratory force - respiratory failure can be precipitous; autonomic instability is common. In MG crisis, distinguish from cholinergic crisis and treat with plasma exchange or IVIG while avoiding contraindicated medications.
Neuroinfections
Bacterial meningitis is a medical emergency: blood cultures then immediate empiric antibiotics (with dexamethasone before or with the first dose when pneumococcal disease is suspected), and don't delay for LP if there is risk of herniation. Recognize HSV encephalitis (temporal lobe involvement) and start acyclovir empirically. Understand CSF profiles (bacterial vs viral vs fungal) and the traps of partially treated meningitis.
Traps
- Delaying antibiotics for imaging or LP in suspected bacterial meningitis.
- Missing respiratory failure in GBS because oxygen saturation is preserved until late.
- Confusing MG crisis with GBS; both cause weakness but differ in reflexes and autonomic features.
Rule of thumb
In suspected bacterial meningitis: cultures → antibiotics → (dexamethasone) → LP when safe; never delay antimicrobials.
Worked example
A patient with ascending weakness, areflexia, and vital capacity falling from 40 to 25 mL/kg: impending respiratory failure in GBS - prepare for intubation and consider IVIG or plasma exchange.