A 35-year-old woman comes to the emergency department with progressively worsening dyspnea and generalized weakness. She has had a month of double vision and difficulty swallowing that are significantly worse toward the end of the day. Over the past 2 weeks, she has had difficulty raising her arms above her head and walking up and down stairs. The patient has no headache, speech difficulty, muscle aches, numbness, or paresthesias. She also has no rash, insect bites, recent travel, or illness.
On physical examination, the patient has fatigable horizontal binocular diplopia in the primary position and bilateral ptosis. Strength is 4 on a scale of 5 in the proximal muscles of the upper and lower extremities. Sensory examination and reflex testing are unremarkable.
Complete blood count, comprehensive metabolic panel, and chest x-ray are normal. Vital capacity obtained at the bedside is 500 mL. The patient's respiratory status decompensates, requiring endotracheal intubation and admission to the intensive care unit.
Which of the following therapies is the most appropriate for rapidly improving this patient's current condition?

Question

A 35-year-old woman comes to the emergency department with progressively worsening dyspnea and generalized weakness.  She has had a month of double vision and difficulty swallowing that are significantly worse toward the end of the day.  Over the past 2 weeks, she has had difficulty raising her arms above her head and walking up and down stairs.  The patient has no headache, speech difficulty, muscle aches, numbness, or paresthesias.  She also has no rash, insect bites, recent travel, or illness.
On physical examination, the patient has fatigable horizontal binocular diplopia in the primary position and bilateral ptosis.  Strength is 4 on a scale of 5 in the proximal muscles of the upper and lower extremities.  Sensory examination and reflex testing are unremarkable.
Complete blood count, comprehensive metabolic panel, and chest x-ray are normal.  Vital capacity obtained at the bedside is 500 mL.  The patient's respiratory status decompensates, requiring endotracheal intubation and admission to the intensive care unit.
Which of the following therapies is the most appropriate for rapidly improving this patient's current condition?

Quizplus · Accepted Answer

11ec193a_970a_87ca_853d_ebb1d9c4dde2_MD0002_00 This patient's presentation is consistent with myasthenic crisis, defined as severe weakness from myasthenia gravis (MG) requiring intubation. Patients in myasthenic crisis can have generalized weakness, respiratory symptoms, or severe oropharyngeal weakness that results in dysphagia and aspiration. Common precipitants include infection and surgery. Patients should be monitored in the intensive care unit, with respiratory status checks every 2-4 hours using vital capacity and maximal inspiratory force. Plasma exchange or intravenous immunoglobulin (IVIG) are mainstays in initial therapy due to their relatively rapid onset of action, although benefits are transient: These therapies exert their effects within days and have a maximal effect at 3 weeks. Glucocorticoids are added to provide longer-term symptom relief as their onset of action occurs later, at 2-3 weeks, with a peak effect at 5.5 months. However, treatment with high-dose glucocorticoids alone is associated with a transient worsening of MG symptoms and should be initiated only with plasma exchange or IVIG (Choice A). Patients who cannot tolerate glucocorticoids can be started on azathioprine, mycophenolate mofetil, or cyclosporine, although these drugs have a delayed time of onset compared with glucocorticoids. (Choice B) Trials for using methotrexate as a corticosteroid-sparing agent in generalized MG are ongoing. However, it is not indicated for myasthenic crisis. (Choice D) Anticholinesterase inhibitors (eg, pyridostigmine) should be stopped while the patient is on mechanical ventilation to minimize secretions and aspiration risk. They can be restarted after extubation. (Choice E) Rituximab is useful for refractory MG, especially in patients who have MG with muscle-specific tyrosine-kinase (MuSK) antibodies. However, it is not used in the management of myasthenic crisis. Educational objective: Treatment for patients with myasthenic crisis includes plasma exchange or intravenous immunoglobulin due to their rapid onset of action and peak effect. High-dose glucocorticoids are used to maintain symptom control, but onset is delayed; glucocorticoids alone are not recommended as they are associated with a transient worsening of symptoms. Acetylcholinesterase inhibitors (eg, pyridostigmine) should be stopped temporarily during mechanical ventilation to minimize oral secretions. __________ References: Progress in the treatment of myasthenia gravis. (http://www.ncbi.nlm.nih.gov/pubmed/21180568)

A 35-Year-Old Woman Comes to the Emergency Department with Progressively