Myasthenia Gravis: The Workup

Here’s a workup for suspected myasthenia gravis:

• Acetylcholine receptor antibody
• Muscle specific receptor tyrosine kinase (MuSK) antibody
• Chest CT (to look for thymoma)
• TSH (concomitant autoimmune thyroiditis is sometimes seen)
• Search for underlying infectious precipitants as guided by history (e.g., CBC, chest radiograph, urinalysis)
• Search for underlying concomitant metabolic derangements which may contribute to weakness (e.g., potassium, magnesium, phosphate)
• Electromyography (EMG, if the diagnosis is not obvious)
• Neostigmine test (edrophonium is no longer widely available)
• Forced vital capacity or net inspiratory flow monitoring (may help guide decision about when or whether to intubate)

 Reference

• Sabatine, Marc S., MD, Pocket Medicine, 5e (2014)