Myasthenia Gravis Treatment and Management

Clinical Immunology focuses on the immune system's health. Learn about the diagnosis and treatment of allergies, autoimmune diseases, and immunodeficiencies.

Myasthenia Gravis: Treatment and Care

Treatment for Myasthenia Gravis works well for most people. With the right mix of medicines and procedures, many patients get much stronger and can live normal lives. Treatment is personalized, aiming to relieve symptoms and control the immune system over the long term.

Cholinesterase Inhibitors

First-Line Symptomatic Therapy

Pyridostigmine (Mestinon) is typically the first medication prescribed. It is not a cure, but it provides temporary relief.

• Mechanism: It slows the breakdown of acetylcholine at the neuromuscular junction, allowing more of the chemical to remain available to stimulate the muscle receptors.
• Dosage: It is taken several times a day. The timing can be adjusted to peak during high-activity periods (e.g., before meals).
• Effectiveness: It works best for mild MG and ocular symptoms but is often insufficient as a standalone treatment for severe cases.
• Side Effects: Can include stomach cramps, diarrhea, muscle twitching, and increased salivation.

Extended Release Options

For patients who experience weakness upon waking, extended-release forms (Mestinon TS) can be taken at bedtime.

• Utility: Helps maintain strength throughout the night and early morning.

Caution: Absorption can be erratic, so it is usually used in conjunction with standard tablets.

Corticosteroids

When symptomatic treatment is not enough, corticosteroids (prednisone) are added to suppress the immune system.

• Action: They significantly reduce antibody production.
• Protocol: Often started at a lower dose and gradually increased to avoid a temporary worsening of weakness that can occur with high initial doses.
• Remission: Many patients achieve marked improvement or remission within a few months.
• Side Effects: Long-term use requires monitoring for weight gain, osteoporosis, diabetes, and hypertension.

Non-Steroidal Immunosuppressants

To avoid the long-term side effects of steroids, “steroid-sparing” agents are often used for maintenance.

• Azathioprine: Commonly used, effective, but takes 6-12 months to work fully.
• Mycophenolate Mofetil: Generally well-tolerated and works faster than azathioprine.
• Cyclosporine/Tacrolimus: Potent drugs used for more difficult cases, requiring monitoring of kidney function.
• Goal: These drugs allow the patient to taper off prednisone while maintaining remission.

Monoclonal Antibodies (Biologics)

Newer, targeted therapies are available for patients who do not respond to standard immunosuppression.

• Rituximab: Depletes B-cells (the cells that make antibodies). Effective for MuSK-positive MG.
• Eculizumab/Ravulizumab: Complement inhibitors used for AChR-positive generalized MG. They stop the immune system from damaging the neuromuscular junction.
• Efgartigimod: A neonatal Fc receptor blocker that reduces the levels of IgG antibodies (including the bad ones) in the blood.
• Administration: These are given via intravenous infusion.

Thymectomy (Surgical Care)

Removing the thymus gland is a cornerstone of treatment for many patients.

• Indication: Recommended for all patients with a thymoma. It is also recommended for non-thymoma patients under age 60 with moderate to severe generalized MG to improve long-term outcomes.
• Technique: Can be performed via sternotomy (opening the chest) or, more commonly now, via minimally invasive video-assisted thoracoscopic surgery (VATS) or robotic surgery.
• Outcome: Results are not immediate. It may take a year or more to see the benefits, including reduced need for medication and higher rates of remission.

Contraindication: Generally not recommended for purely ocular MG or MuSK-positive MG (unless a thymoma is present).

Acute Therapies (IVIG and PLEX)

For myasthenic crisis or severe worsening, rapid-acting therapies are used in the hospital setting.

• Plasmapheresis (PLEX): Filters the blood to remove the abnormal antibodies. It works quickly (days), but the effect is temporary (weeks).
• Intravenous Immunoglobulin (IVIG): Infusion of pooled antibodies from donors. It overwhelms the patient’s own immune system to stop the attack.
• Bridge Therapy: Often used before surgery to strengthen the patient or while waiting for oral immunosuppressants to take effect.

Crisis Management

Handling a myasthenic crisis requires intensive care.

• Ventilation: If breathing muscles fail, non-invasive ventilation (BiPAP) or intubation is necessary.
• Trigger Control: Treating the underlying infection or stopping the medication that caused the crisis.
• Medication Adjustment: Cholinesterase inhibitors are often temporarily stopped during intubation to reduce secretions.

Monitoring: Frequent checks of vital capacity and swallowing function.