From the Guidelines
Patients with Myasthenia Gravis (MG) should be managed based on the severity of their symptoms, with all grades warranting workup and intervention to prevent progressive MG and potential respiratory compromise. The management of MG, particularly in patients treated with immune checkpoint inhibitor therapy, has been updated in the 2021 ASCO guideline update 1.
Grading and Management
The guideline provides a grading system for MG management, which includes:
- All grades: warrant workup and intervention, with inpatient admission considered appropriate at all grades.
- G2: symptoms interfering with activities of daily living (ADLs), MGFA severity class I (ocular symptoms and findings only) and MGFA severity class II (mild generalized weakness), management includes holding immune checkpoint inhibitors (ICPi) and resuming only if symptoms resolve and steroid taper is completed, with neurology consultation and consideration of inpatient care.
- G3-4: limiting self-care, weakness limiting walking, ANY dysphagia, facial weakness, respiratory muscle weakness, or rapidly progressive symptoms, management includes permanently discontinuing ICPi, admitting the patient, and considering ICU-level monitoring, with initiation of IVIG or plasmapheresis and frequent pulmonary function assessment.
Treatment
Treatment for MG typically involves:
- Pyridostigmine, starting at 30 mg PO three times a day and gradually increasing to a maximum of 120 mg PO four times a day as tolerated and based on symptoms.
- Corticosteroids, such as prednisone, administered at 0.5 mg/kg orally daily, with tapering based on symptom improvement.
- IVIG, 2 G/kg IV over 5 days, or plasmapheresis, for severe cases.
- Consideration of rituximab for refractory cases.
Key Considerations
- All patients with MG should be closely monitored for symptom progression and potential respiratory compromise.
- Inpatient admission should be considered for all grades of MG, particularly for G3-4 patients who require close monitoring and potential ICU-level care.
- Neurology consultation is essential for managing MG, particularly for G2 patients who may require resumption of ICPi therapy.
- The goal of treatment is to improve symptoms, prevent progression, and minimize the risk of respiratory compromise, with a focus on individualized care based on symptom severity and response to treatment 1.
From the Research
Treatment Options for Myasthenia Gravis
- Symptomatic treatment: acetylcholinesterase inhibitors such as pyridostigmine 2, 3
- Immunosuppressive treatment: corticosteroids, azathioprine, mycophenolate mofetil, cyclosporine, tacrolimus, methotrexate, rituximab, cyclophosphamide 4, 5, 6, 3
- Rapid acting short-term immunomodulation: intravenous immunoglobulin, plasma exchange 6, 3
- Long-term immunomodulation: thymectomy 6, 3
Disease Management
- Treatment needs to be individualized based on disease subtype, severity, and patient co-morbidities 4, 5, 3
- Corticosteroids are the mainstay of immunosuppressive treatment in patients with more than mild MG 3
- Azathioprine is prescribed in addition to or instead of corticosteroids when background comorbidities preclude or restrict the use of steroids 3
- Rituximab has a role in refractory MG 3
- Plasmapheresis and immunoglobulin therapy are commonly prescribed to treat MG crisis and in some cases of refractory MG 3
Specific Considerations
- Ocular MG: early treatment with corticosteroids when ocular motility is abnormal and fails to respond to symptomatic treatment 3
- Older age-group: treatment needs to be individualized depending on specific comorbidities 3
- Younger age-groups: consideration must be given to the potential teratogenicity of certain therapies 3
- Fatigue and dysfunctional breathing: should be duly identified and managed with a combination of physical therapy and respiratory physiotherapy techniques 3