Clinical Presentation

Patients with myasthenic crisis present with:

• Acute worsening of muscle weakness in known myasthenia gravis patients
• New onset of severe generalized or bulbar weakness may be initial presentation in undiagnosed cases
• Symptoms often include dyspnea, dysphagia, dysarthria
• Physical exam shows severe weakness of respiratory muscles, bulbar muscles
• Respiratory insufficiency leading to hypercapnic failure requiring urgent intubation

Rapid recognition of respiratory muscle involvement is key to intervene urgently and prevent respiratory arrest.

Precipitating Factors

• Infection – especially pneumonia
• Medication changes – reducing MG therapy or medications exacerbating MG
• Emotional or physical stress
• Pregnancy
• Surgery or procedures

Medications that can precipitate myasthenic crisis:

• Aminoglycoside antibiotics – neuromuscular blockade
• Magnesium – neuromuscular blockade
• Quinolone antibiotics – may worsen neuromuscular transmission
• Anticholinesterase inhibitors – cholinergic crisis due to toxicity
• Beta-blockers – negatively impact muscle strength

Identifying precipitating factors like infections and high-risk medications enables targeted intervention.