What is a myasthenic crisis?

A myasthenic crisis occurs when the muscles that control breathing weaken to the point that ventilation is inadequate, creating a medical emergency and requiring a respirator for assisted ventilation. In individuals whose respiratory muscles are weak, crises-which generally call for immediate medical attention-may be triggered by infection, fever, or an adverse reaction to medication.

Pre-hospital care-points to note;

  • May be mistaken for a stroke because of the muscle weakness
  • Patient may be conscious and with a rapid, weak respiratory rate
  • Patient may not be able to talk due to weakness/paralysis of the bulbar muscles responsible for speech and swallowing
  • Do not lay flat as patient cannot control oral secretions
  • Suction must be available and used often
  • Be prepared for airway support as respiratory arrest due to muscle weakness is very rapid
  • Gain IV access
  • Keep patient calm
  • Most of not all myasthenic people have some form of medi-alert watch/bracelet
  • Pre-alert A&E with myasthenic crisis/severe respiratory distress
  • Remember that in myasthenic crisis the patient could be thought to be drunk but without the smell of alcohol

Most people with myasthenia have very good control of their condition and when supported live fairly comfortable lives with a normal life expectancy.

The Ambulance Service is only likely to come across a myasthenic patient when in crisis and our work is to maintain and protect the airway in the pre-hospital setting.

The patient is likely to spend several days in intensive care on a ventilator whilst waiting for medication to begin restoring muscle control.

Martin Faircloth SRP 
Clinical Team Leader 
SWAST