Causes of Myasthenia Gravis Explained

Myasthenia Gravis (MG) is a chronic autoimmune neuromuscular disorder that leads to varying degrees of skeletal muscle weakness. Understanding the causes of this condition is essential for proper diagnosis and treatment. The underlying reasons for MG can be broadly categorized into two groups: genetic factors and autoimmune responses.

Genetic and Hereditary Influences

In rare cases, Myasthenia Gravis can be linked to genetic predispositions. These inherited forms of the disease are extremely uncommon and are not associated with the more typical autoimmune mechanisms. Unlike the acquired form, congenital myasthenic syndromes result from genetic mutations that affect the structure and function of the neuromuscular junction.

Autoimmune Mechanisms

The majority of Myasthenia Gravis cases are classified as autoimmune disorders. While the exact trigger remains unknown, researchers believe that a combination of environmental factors, infections, and certain medications may contribute to the onset of the disease. In these cases, the body's immune system mistakenly attacks the receptors at the neuromuscular junction, leading to impaired signal transmission between nerves and muscles.

Common Symptoms and Patterns

Clinical manifestations of MG typically involve weakness and rapid fatigue of voluntary muscles. A hallmark characteristic is the fluctuation of symptoms throughout the day, often presenting as milder in the morning and worsening by evening. Patients may experience difficulties with speech, swallowing, eye movements, and even breathing in severe cases.

Connection with the Thymus Gland

There is a strong association between Myasthenia Gravis and abnormalities of the thymus gland. Approximately 65% to 80% of patients show signs of thymic hyperplasia, while 10% to 20% develop thymomas—tumors of the thymus. Due to this correlation, doctors often recommend a chest CT scan for patients suspected of having MG to evaluate the condition of the thymus and rule out potential complications.