14.3 Neuromuscular Disorders, Space-Occupying Lesions, and ICP Management
Key Takeaways
- Myasthenic crisis is fatigable weakness from too little acetylcholine effect; cholinergic crisis is SLUDGE plus weakness from too much acetylcholinesterase inhibitor.
- Guillain-Barré is ascending and autonomic; intubate for a falling forced vital capacity or a worsening negative inspiratory force before you enter the cabin.
- Botulism is descending, often with pupils and a gastrointestinal prodrome; the destination gives antitoxin.
- Tumors, abscesses, hemorrhage, and hydrocephalus are space-occupying lesions that herniate along the same Cushing and pupil pathway as trauma.
- Intracranial-pressure care is head-of-bed, midline head, non-circumferential tube tape, treat fever pain and seizure, osmotherapy, and an external ventricular drain that is leveled—not drained to cabin air.
Weakness that is about to stop the diaphragm and a mass that is about to stop the brainstem are the same Domain 4.A problem. The August 2026 Board of Certification for Emergency Nursing (BCEN) Certified Flight Registered Nurse (CFRN) outline clusters neuromuscular disorders, space-occupying lesions (SOL), and intracranial pressure (ICP) management here. Chapter 11.2 owns traumatic drain technique. This section owns medical titration and the ICP flight bundle. The 2026 outline added ICP management under medical neurology—treat it as real work, not a footnote.
Neuromuscular failure: intubate before the cabin
Myasthenic crisis versus cholinergic crisis
Myasthenia gravis is antibody attack on the acetylcholine receptor: fatigable weakness, ptosis, diplopia, a weak voice, and a cough that fades through the day. Myasthenic crisis is that disease plus respiratory failure, often after infection, missed pyridostigmine, surgery, or a steroid pulse. Secretions are not drowning them, and the pupils are usually normal.
Cholinergic crisis is too much acetylcholinesterase inhibitor. Think SLUDGE—salivation, lacrimation, urination, diarrhea, gastrointestinal cramping, emesis—plus miosis, bradycardia, and weakness. Airway first, then stop the extra pyridostigmine and treat secretions with atropine per protocol. Do not give more inhibitor to a wet, miotic, bradycardic patient. Avoid magnesium, aminoglycosides, and fluoroquinolones in myasthenia.
Guillain-Barré and botulism
Guillain-Barré syndrome (GBS) is usually post-infectious, ascending, areflexic paralysis with a clear sensorium. Autonomic instability is the silent killer: wild swings in heart rate and blood pressure that do not mean you should chase every number with a new drip. The airway decision is mechanical, not cosmetic. A common bedside rule is the 20/30/40 cluster: forced vital capacity (FVC) under about 20 mL/kg, negative inspiratory force (NIF) worse than about −30 cm H2O (a NIF of −20 is weaker than −40), or maximal expiratory pressure under about 40 cm H2O—bedside teaching, not a BCEN statute. If mechanics are falling or the patient cannot lift the head, intubate on the ramp. Recumbency and Dalton's law will not restore a dying vital capacity at altitude.
Botulism is descending, symmetric, often with poorly reactive pupils and a gastrointestinal prodrome, without fever or sensory loss. The destination gives antitoxin. Do not wait for laboratory confirmation in the aircraft.
| Disease | Pattern | Airway trigger | Destination hint |
|---|---|---|---|
| Myasthenic crisis | Fatigable, ocular and bulbar, dry-ish | Weak cough, falling saturations, inability to lift the head | ICU for intravenous immunoglobulin (IVIG) or plasma exchange |
| Cholinergic crisis | SLUDGE, miosis, bradycardia | Secretions plus weakness | Stop the inhibitor; atropine; monitored bed |
| GBS | Ascending, areflexia, autonomic swings | FVC/NIF/20-30-40 or a falling neck | ICU; do not enter the cabin near failure |
| Botulism | Descending, pupils, gastrointestinal prodrome | Progressive bulbar failure | Antitoxin-capable center |
Space-occupying lesions and the same herniation pathway
A space-occupying lesion is anything that steals room in a rigid skull: tumor, abscess, intracerebral hemorrhage (ICH), and hydrocephalus (including a blocked shunt). Morning headache, vomiting, a new focal deficit, fever with a shunt, or a known tumor plus a declining exam is SOL until the scanner says otherwise.
Herniation physiology does not care whether the mass is a glioblastoma or an epidural. Uncal herniation gives an ipsilateral blown pupil and contralateral weakness. Cushing triad—hypertension, bradycardia, irregular respirations—is late. Treat the herniating SOL like herniating trauma: oxygenate, restore mean arterial pressure (MAP) if they are shocked, raise the head, give protocol osmotherapy, and fly to neurosurgery.
ICP management: a 2026 medical-neurology bundle
Ordered targets, then a cabin bundle
ICP care in flight is a bundle you can actually perform. Follow program and neurosurgery orders for numeric targets. Classic Brain Trauma Foundation (BTF)–style teaching treats ICP above about 22 mm Hg and aims cerebral perfusion pressure (CPP) near 60–70 mm Hg. CPP is MAP minus ICP. Those numbers are order-driven, not a reason to invent a drip the receiving neurosurgeon did not want.
- Position: Head of bed (HOB) about 30 degrees if shock and the aircraft allow. Keep the head midline so one jugular is not kinked.
- Venous drainage: Tape the endotracheal tube (ETT) so the ties are not a circumferential noose around the neck.
- Demand: Treat fever, pain, and seizure. A convulsion or shivering after aggressive cooling is an ICP crisis.
- Osmotherapy: Hypertonic saline (HTS) or mannitol per protocol. Mannitol can drop blood pressure in a dry patient; HTS supports volume.
- Carbon dioxide and oxygen: Target end-tidal carbon dioxide (ETCO2) 35–40 mm Hg. Hypoxia and hypercarbia at altitude both raise ICP—Dalton drops inspired oxygen, and a hypoventilating patient retains carbon dioxide. Raise fraction of inspired oxygen (FiO2) or lower the cabin. Do not prophylactically hyperventilate a tumor patient who is not herniating.
An external ventricular drain (EVD) for hydrocephalus or postoperative tumor care has two flight-specific failures. Level the transducer to the foramen of Monro—tragus or external auditory meatus—whenever you are using the number. Do not drain the EVD to cabin air. An open stopcock to the aisle is an infection source and an unmeasured siphon when vibration or a downhill load changes burette height. Clamp only if a written protocol or neurosurgery order says to clamp for loading; then reopen, re-level, and write down color and output. Do not flush in the aircraft. Known pneumocephalus can expand under Boyle's law on climb.
- Intubate GBS and failing myasthenia on the ground; do not stack pyridostigmine onto cholinergic SLUDGE.
- Run the ICP bundle: HOB, midline, non-circumferential tape, treat fever pain and seizure, osmotherapy, ETCO2 35–40, no hypoxia or hypercarbia.
- Level the EVD; never drain it to air; clamp only for a protocol load.
A Guillain-Barré patient has a forced vital capacity of 18 mL/kg and a negative inspiratory force of −18 cm H2O. The aircraft is an unpressurized rotor-wing. What is the correct airway plan?
A myasthenia patient is weak, drooling, miotic, and bradycardic after extra pyridostigmine doses. Which interpretation is correct?
You are loading a tumor patient with an external ventricular drain and a tight circumferential endotracheal-tube tape. Which ICP package is correct?