Nursing care
Myasthenia Gravis nursing care: what to assess and what to do first
Written and reviewed by Dana Whitfield, RN, MSN · 4 min read · Updated September 2026
Short answer
Myasthenia gravis nursing care centres on a pattern unique to the disease: muscle weakness that worsens with activity and improves with rest. This is the opposite of a cholinergic crisis from the same anticholinesterase medication used to treat it, and distinguishing the two is the priority nursing judgement in this condition.
The pathophysiology in one pass
Myasthenia gravis is an autoimmune disease in which antibodies attack acetylcholine receptors at the neuromuscular junction, reducing the number of receptors available to receive the signal to contract. Each successive muscle contraction has fewer working receptors to draw on, so strength fades progressively with repeated use.
This is why the hallmark pattern is weakness that worsens with activity and improves with rest, most noticeable late in the day or after sustained effort. The thymus gland is implicated in many cases, and thymectomy is a recognised treatment, though the exact mechanism linking thymic abnormality to antibody production is still being defined.
Assessment findings that matter
Ocular symptoms are usually first: ptosis and diplopia that worsen as the day goes on. From there, weakness can spread to the muscles of chewing, swallowing, and speech, producing dysphagia and a voice that grows softer or more nasal with prolonged talking.
Respiratory muscle involvement is the finding that changes urgency. Assess forced vital capacity and negative inspiratory force at the bedside rather than waiting for oxygen saturation to drop, since desaturation is a late sign in neuromuscular weakness. Ask specifically whether weakness is worse toward the end of the day or after exertion and better after rest, since this activity-dependent pattern is what separates myasthenia gravis from most other causes of muscle weakness.
What the exam asks about this
Expect questions built around distinguishing myasthenic crisis from cholinergic crisis, since both present with worsening weakness but demand opposite responses. Myasthenic crisis, from too little acetylcholinesterase inhibitor or a triggering illness, improves with more medication. Cholinergic crisis, from too much, worsens with more medication and comes with muscarinic excess: salivation, lacrimation, urination, diarrhoea, GI upset, and emesis.
The Tensilon (edrophonium) test is the classic exam item for telling the two apart: improvement in strength points to myasthenic crisis, while no improvement or worsening symptoms points to cholinergic crisis. You may also see stems testing whether you know to hold anticholinesterase medication and prepare for possible intubation rather than simply administering another dose when the crisis type is unclear.
Nursing interventions in priority order
Airway and respiratory status come first, always. Have suction and emergency airway equipment at the bedside for any patient in crisis, and monitor forced vital capacity trends rather than a single reading.
Time activities and meals to the patient's medication schedule, scheduling the most demanding tasks, including eating, for peak drug effect, typically 45 to 60 minutes after an anticholinesterase dose. Assess swallowing before meals given aspiration risk from bulbar weakness, and space out care activities to conserve energy rather than clustering everything into one exhausting stretch.
Medications and monitoring
Pyridostigmine is the mainstay anticholinesterase, and timing doses consistently, roughly 30 minutes before meals, matters more here than with most medications because strength at mealtime depends on it. Corticosteroids and other immunosuppressants are used for longer-term control, and plasmapheresis or IVIG are options for acute exacerbation or crisis.
Watch drug interactions closely: several classes, including aminoglycosides, beta-blockers, and some anaesthetics, can worsen neuromuscular blockade and precipitate a crisis. Confirm every new medication order against this risk before it is given, and document the patient's baseline strength so that a decline has something concrete to be measured against.
When to escalate
Escalate immediately for any drop in forced vital capacity, new difficulty clearing secretions, or a subjective sense of breathlessness, since respiratory failure in myasthenic crisis can develop faster than vital signs suggest. Do not wait for oxygen saturation to fall.
Also escalate when it is unclear whether worsening weakness is myasthenic or cholinergic in origin. Giving more anticholinesterase to a patient in cholinergic crisis worsens the emergency, so when in doubt, hold the next dose, notify the provider, and prepare for the possibility of intubation rather than guessing.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our neurological practice questions are the closest set to what this page covers.
Common questions
What is the difference between myasthenic and cholinergic crisis?
Myasthenic crisis results from too little acetylcholinesterase inhibitor and improves with more medication. Cholinergic crisis results from too much and worsens with more, presenting with muscarinic symptoms like salivation, cramping and diarrhoea.
Why does myasthenia gravis weakness get worse throughout the day?
Each muscle contraction has fewer functioning acetylcholine receptors available due to antibody attack, so strength progressively fades with repeated use and recovers somewhat with rest.
What is the priority nursing assessment in myasthenia gravis?
Respiratory status, using forced vital capacity and negative inspiratory force rather than waiting for oxygen saturation to drop, since respiratory muscle weakness can progress to failure quickly.
When should pyridostigmine be given relative to meals?
Roughly 30 minutes before meals, so peak drug effect coincides with chewing and swallowing, reducing aspiration risk from bulbar weakness.
What does the Tensilon test show in myasthenia gravis?
Improved strength after edrophonium suggests myasthenic crisis; no improvement or worsening suggests cholinergic crisis. It helps distinguish which crisis type is occurring when symptoms overlap.