Managing MG in Special Populations: Children, Pregnant People, and the Elderly

Key Takeaways:

• Pediatric patients demand careful diagnostic consideration and thoughtful medication adjustments to account for growth and development.
• Pregnant people necessitate a balance between maternal disease control and fetal safety, with specific attention to medication teratogenicity and the risk of neonatal myasthenia.
• In older people, comorbidities and the impact on quality of life drive therapeutic decisions, emphasizing low-dose strategies and careful monitoring.

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease characterized by fluctuating muscle weakness and fatigue. MG can affect people of any age. But its presentation, diagnosis, and management pose unique challenges in special populations, namely children, pregnant people, and the elderly.

Healthcare providers (HCPs) and caregivers must be acutely aware of these distinctions to ensure optimal care and improved quality of life.

Myasthenia gravis in children

Myasthenia gravis in children, often termed Juvenile Myasthenia Gravis (JMG), presents its own set of diagnostic hurdles and treatment considerations. The symptoms, though similar to adults, can be subtle and easily attributed to other conditions in children, which can delay diagnosis.¹

Problems with moving the eyes are frequently the first symptom in kids with MG. In many cases, JMG may remain localized to the eyes or go into remission within a few years.¹

Diagnosing MG in children can be tricky because their symptoms are often subtle and can mimic everyday childhood behaviors or other common illnesses. For example, a child might have a droopy eyelid (ptosis) or double vision, which can be easily dismissed as tiredness or just "being clumsy."¹

They might also experience weakness in their arms or legs, leading to falls or difficulty with activities. Parents or peers might attribute this to a growth spurt or being uncoordinated. Because children might not be able to clearly describe their symptoms or understand what they are feeling, and because the muscle weakness often comes and goes, it can be hard for parents and even doctors to pinpoint MG right away.¹

Treatment and considerations

The goal of MG treatment in kids is to help them manage their symptoms so they can play, learn, and live as normally as possible. This treatment can include:²

• Medicine – typically cholinesterase inhibitors, steroids, and immunosuppressants
• Thymectomy – removal of the thymus gland

For very sudden and severe weakness, treatments like IVIg (special antibodies given through an IV) or plasmapheresis (filtering the blood to remove harmful antibodies) can provide quick relief.²

Pregnancy and myasthenia gravis

MG can affect people of childbearing age, making pregnancy a significant consideration in disease management. The course of MG during pregnancy is highly variable. While some experience remission, others may have exacerbations, particularly in the first trimester and postpartum period.^3-5

Treatment and considerations

The primary goal is to maintain maternal well-being while minimizing fetal exposure to potentially harmful medications.^2-5

For example, intravenous anticholinesterase inhibitors should generally be avoided due to the risk of inducing uterine contractions. Rituximab is generally not recommended during pregnancy, particularly in the later stages. Mycophenolate mofetil, methotrexate, and cyclophosphamide can cause fetal abnormalities and are contraindicated during pregnancy.^3-5

The following treatment can be considered for people with MG who are pregnant:^3-5

• Pyridostigmine – Considered safe during pregnancy, although dose adjustments may be needed due to changes in blood volume and renal clearance.
• Corticosteroids – Prednisolone and prednisone are generally considered safe during pregnancy as they are largely inactivated by the placenta, limiting fetal exposure. However, there is a slightly increased risk of gestational diabetes, hypertension, and preterm delivery.
• Immunosuppressants – Azathioprine is often considered a safe steroid-sparing agent during pregnancy due to its metabolism to an inactive metabolite in the placenta.
• IVIg and plasmapheresis – Intravenous immunoglobulin (IVIg) and plasma exchange (PLEX) are safe and effective for managing acute exacerbations or severe weakness during pregnancy.

Delivery and postpartum

Vaginal delivery is generally recommended unless obstetric complications arise. While MG does not affect uterine muscles, the muscles involved in pushing during the second stage of labor can be affected, potentially increasing the need for instrumental delivery or C-section. Close monitoring of maternal respiratory function and a plan for potential myasthenic crisis are crucial.^3-5

About 10 to 20 percent of babies born to mothers with MG may develop transient neonatal myasthenia gravis (NMG) due to transplacental transfer of maternal antibodies. Symptoms include poor suck, feeding difficulties, and respiratory distress. This condition is temporary and typically resolves within a few weeks.^3,4

Myasthenia gravis in older people

MG after age 50 is considered late-onset MG. Diagnosing MG in the elderly can be challenging, as its symptoms may be mistaken for age-related decline or other neurological conditions common in this demographic.⁶

Treatment and considerations

Older patients often have multiple comorbidities – cardiovascular disease, diabetes, kidney problems, etc. – and take various medicines. These medicines can interact with MG treatments or worsen MG symptoms.^6,7

For example, certain antibiotics, beta-blockers, and calcium channel blockers can exacerbate MG. Also, thymectomy is generally not recommended in older patients (unless there is a thymoma) due to the increased surgical risks.6,7

The following medicines can be considered for older MG patients, with some considerations:^6,7

• Pyridostigmine – Generally well-tolerated, but side effects like gastrointestinal upset, urinary urgency, and muscle cramps can be more pronounced in the elderly. Starting with lower doses and titrating slowly is often recommended to minimize adverse effects.
• Corticosteroids – While effective, long-term steroid use in the elderly carries a higher risk of osteoporosis, cataracts, diabetes, hypertension, and infections. Steroid-sparing agents are often considered earlier in this population to reduce cumulative steroid exposure.
• Immunosuppressants – The choice of immunosuppressant should be guided by renal and hepatic function, potential drug interactions, and overall health status. Azathioprine may be a suitable option, but be sure to monitor liver function and blood counts.
• IVIg and plasmapheresis – These therapies are generally safe and effective in older patients for acute exacerbations or severe weakness. But be aware of fluid overload and potential strain on the heart.

Quality of life for elderly patients with MG

MG can profoundly impact the independence and quality of life in older adults, affecting mobility, speech, and swallowing. Regular assessment of functional status and tailored rehabilitation strategies are crucial.^6,7

When caring for your MG patients, take a nuanced approach

Managing myasthenia gravis in special populations requires a nuanced and individualized approach. By understanding these unique challenges and considerations, HCPs and caregivers can provide comprehensive, safe, and effective care, ultimately improving outcomes for all MG patients.