From the Guidelines
Treatment of myasthenia gravis exacerbation requires prompt intervention with both symptomatic management and immunomodulatory therapy, with the most recent guidelines recommending pyridostigmine starting at 30 mg PO three times a day, corticosteroids, and consideration of IVIG or plasmapheresis for severe cases 1.
Key Considerations
- For G2 symptoms (some symptoms interfering with ADLs, mild generalized weakness), hold immune checkpoint inhibitors (ICPi) and consider resuming if symptoms resolve, with neurology consultation and initiation of pyridostigmine and corticosteroids 1.
- For G3-4 symptoms (limiting self-care, weakness limiting walking, dysphagia, facial weakness, respiratory muscle weakness), permanently discontinue ICPi, admit patient, and initiate IVIG or plasmapheresis, with consideration of rituximab for refractory cases 1.
Symptomatic Management
- Pyridostigmine should be started at 30 mg PO three times a day and gradually increased to a maximum of 120 mg PO four times a day as tolerated and based on symptoms 1.
- Corticosteroids, such as prednisone, should be administered at 0.5 mg/kg orally daily, with weaning based on symptom improvement 1.
Immunomodulatory Therapy
- IVIG should be initiated at 2 G/kg IV over 5 days (0.4 G/kg/d) for severe cases, with consideration of plasmapheresis as an alternative 1.
- Rituximab may be considered for refractory cases, with frequent pulmonary function assessment and daily neurologic review 1.
Additional Considerations
- Avoid medications that can worsen myasthenia, such as β-blockers, IV magnesium, fluoroquinolones, aminoglycosides, and macrolides 1.
- Identify and address triggers for exacerbation, such as infections, surgery, or medications 1.
From the FDA Drug Label
Although controlled clinical trials have shown corticosteroids to be effective in speeding the resolution of acute exacerbations of multiple sclerosis, they do not show that they affect the ultimate outcome or natural history of the disease. An acute myopathy has been observed with the use of high doses of corticosteroids, most often occurring in patients with disorders of neuromuscular transmission (e.g., myasthenia gravis), or in patients receiving concomitant therapy with neuromuscular blocking drugs (e.g., pancuronium).
The treatment for myasthenia gravis (MG) exacerbation may involve corticosteroids, but high doses can cause acute myopathy.
- Concomitant use of anticholinesterase agents (e.g., neostigmine, pyridostigmine) and corticosteroids may produce severe weakness in patients with myasthenia gravis.
- If concomitant therapy must occur, it should take place under close supervision and the need for respiratory support should be anticipated 2
From the Research
Treatment for Myasthenia Gravis Exacerbation
The treatment for myasthenia gravis (MG) exacerbation includes several options, which can be categorized into symptomatic treatment, immunosuppressive/immunomodulatory treatment, and rapid acting short-term immunomodulation.
- Symptomatic treatment: Acetylcholinesterase inhibitors provide temporary, symptomatic treatment for all forms of myasthenia gravis 3.
- Immunosuppressive/immunomodulatory treatment: Options for immunosuppression include corticosteroids, azathioprine, mycophenolate mofetil, cyclosporine, tacrolimus, methotrexate, rituximab, cyclophosphchrome, eculizumab, intravenous immunoglobulin, subcutaneous immunoglobulin, plasmodesis, and thymectomy 4, 3, 5.
- Rapid acting short-term immunomodulation: Plasma exchange is used to achieve rapid improvement in patients with myasthenic crisis or exacerbation, to improve strength before a surgical procedure or thymectomy, and to minimize steroid-induced exacerbation in patients with oropharyngeal or respiratory muscle weakness 3. Intravenous immunoglobulin represents an alternative to plasma exchange in patients requiring relatively rapid short-term improvement in the setting of poor venous access 3, 6.
Specific Treatment Options
- Therapeutic plasma exchange (TPE) has been shown to be effective in treating MG exacerbation, with a higher response rate compared to intravenous immune globulin (IVIG) in acute MG patients and patients undergoing thymectomy 6.
- Periodic TPE has also been used to control symptoms in patients with moderate to severe MG who do not respond to immunosuppressive therapies, with good results and minimal side effects 7.
- Thymectomy is also considered as a treatment option, although its role in non-thymomatous MG is unclear, with evidence suggesting that it increases the probability for myasthenic remission or improvement 3.