What is the treatment for myasthenia gravis (Myasthenia Gravis, MG) with hypomagnesemia (low magnesium levels)?

From the Guidelines

The primary treatment for myasthenia gravis with hypomagnesemia involves addressing both conditions simultaneously, with a focus on administering acetylcholinesterase inhibitors and immunosuppressive therapy for myasthenia gravis, while avoiding IV magnesium due to potential worsening of myasthenia gravis symptoms, as suggested by 1. When managing myasthenia gravis with hypomagnesemia, it is essential to consider the following treatment approaches:

• For myasthenia gravis:
  • Administer acetylcholinesterase inhibitors, such as pyridostigmine (60-120 mg orally every 3-4 hours), as supported by 1.
  • Consider immunosuppressive therapy with prednisone (starting at 20-40 mg/day, gradually increasing) or azathioprine (2-3 mg/kg/day), as recommended by 1.
• For hypomagnesemia:
  • Provide magnesium supplementation, typically magnesium oxide (400-800 mg orally 1-3 times daily) or magnesium citrate (200-400 mg orally 1-3 times daily), while monitoring magnesium levels regularly and adjusting dosage as needed.
  • Avoid IV magnesium, as it may worsen myasthenia gravis symptoms, as cautioned by 1. It is crucial to prioritize the patient's overall outcome, focusing on minimizing morbidity, mortality, and improving quality of life, by carefully managing both conditions and avoiding potential exacerbating factors, such as certain medications, as highlighted by 1 and 1.

From the Research

Treatment for Myasthenia Gravis with Hypomagnesemia

• The treatment for myasthenia gravis (MG) with hypomagnesemia is not directly addressed in the provided studies, but the following information can be gathered:

Standard Treatment for Myasthenia Gravis

• Standard medical therapy for MG consists of symptomatic treatment with acetylcholinesterase inhibitors (e.g., pyridostigmine) 2
• Immunomodulating agents, such as corticosteroids, azathioprine, cyclosporine A, and cyclophosphamide, are also used 2

Considerations for Hypomagnesemia

• Magnesium replacement can worsen neuromuscular weakness in MG patients, as it inhibits the presynaptic release of acetylcholine and desensitizes the postsynaptic membrane 3
• There is no clear guidance on how to manage hypomagnesemia in MG patients, but it is essential to consider the potential effects of magnesium replacement on neuromuscular weakness

Emerging Therapies

• New strategies have been proposed for the treatment of MG, including complement blockade and neonatal Fc receptor antagonism 2
• Methotrexate has been shown to be effective as a steroid-sparing agent in MG treatment, with significant improvement in MG-Activity of Daily Living and Quantitative MG scores 4
• High-dose prednisolone and azathioprine have been used to treat MG, with a high percentage of patients achieving remission 5