Myasthenia Gravis (MG) in a geriatric patient

From the Guidelines

Geriatric patients with Myasthenia Gravis (MG) should be managed with pyridostigmine starting at 30 mg orally three times a day, with gradual increase to a maximum of 120 mg orally four times a day as tolerated and based on symptoms, and corticosteroids such as prednisone (1–1.5 mg/kg orally daily) if symptoms are severe, as recommended by the American Society of Clinical Oncology clinical practice guideline 1. When managing MG in geriatric patients, it is essential to consider the potential for progressive myasthenia gravis to lead to respiratory compromise, and therefore, all grades of symptoms warrant work-up and intervention.

• The management approach should be based on the severity of symptoms, with mild symptoms (MGFA severity class 1 and 2) being managed with pyridostigmine and corticosteroids, while more severe symptoms (MGFA severity class 3–4) requiring permanent discontinuation of immune checkpoint inhibitors, admission, and ICU-level monitoring, as well as initiation of IVIG or plasmapheresis 1.
• Frequent pulmonary function assessment and daily neurologic review are crucial in managing severe symptoms.
• The goal of treatment is to achieve symptom control while minimizing side effects, particularly in elderly patients who may be more susceptible to adverse effects of immunosuppressants.
• Regular follow-ups with a neurologist experienced in managing myasthenia gravis in elderly patients are crucial to adjust treatment as needed and provide supportive care, including physical therapy and occupational therapy, to maintain muscle strength and function.

From the FDA Drug Label

Although failure of patients to show clinical improvement may reflect underdosage, it can also be indicative of overdosage. As is true of all cholinergic drugs, overdosage of pyridostigmine bromide may result in cholinergic crisis, a state characterized by increasing muscle weakness which, through involvement of the muscles of respiration, may lead to death Myasthenic crisis due to an increase in the severity of the disease is also accompanied by extreme muscle weakness, and thus may be difficult to distinguish from cholinergic crisis on a symptomatic basis The treatment of the two conditions obviously differs radically. Whereas the presence of myasthenic crisis suggests the need for more intensive anticholinesterase therapy, the diagnosis of cholinergic crisis, according to Osserman and Genkins1, calls for the prompt withdrawal of all drugs of this type.

The management of Myasthenia Gravis (MG) in a geriatric patient using pyridostigmine requires careful consideration of the potential for cholinergic crisis versus myasthenic crisis.

• Cholinergic crisis is treated by prompt withdrawal of pyridostigmine and possible use of atropine.
• Myasthenic crisis may require more intensive anticholinesterase therapy. For detailed information on the management of patients with myasthenia gravis, the physician is referred to one of the excellent reviews such as those by Osserman and Genkins 2.

From the Research

Myasthenia Gravis (MG) in Geriatric Patients

• Myasthenia gravis is an auto-immune disease that results in muscle weakness caused by antibodies released against acetylcholine receptors at the presynaptic membrane 3.
• Treatment options for MG include acetylcholinesterase medications, such as pyridostigmine, which can cause a wide range of side-effects by increasing the concentration of acetylcholine at the synaptic cleft 3, 4.

Treatment Considerations in Geriatric Patients

• Pyridostigmine can precipitate myocardial ischemia by coronary vasogenic spasm or by its arrhythmogenic effect, particularly in elderly females 3.
• In geriatric patients, it is essential to be aware of the potential outcomes when starting treatment with anti-cholinesterase medications, such as pyridostigmine 3.
• Hyoscyamine, a muscarinic antagonist, can be used to block cholinergic side effects associated with pyridostigmine without reducing its efficacy at the neuromuscular junction 5.

Management of MG in Geriatric Patients

• Pyridostigmine is generally considered safe and suitable as a long-term treatment in patients with generalized non-progressive milder disease, and as an adjunctive therapy in patients with severe disease who are also receiving immunotherapy 4.
• Swallowing disturbances in patients with MG should not be attributed hastily to the disease, as they may also be a complication of therapy, such as Candida esophagitis 6.

Additional Treatment Options

• Tacrolimus has been used successfully to treat patients with intractable childhood-onset MG, but its use in geriatric patients is not well-documented 7.
• Other treatment options, such as methotrexate and prednisolone, may be used in combination with pyridostigmine to manage MG in geriatric patients 6.