Myasthenia Gravis: Understanding the Autoimmune Neuromuscular Disorder

Myasthenia gravis (MG) is a relatively common neuromuscular disorder that affects the communication between nerves and muscles. Classified as an autoimmune disease, it primarily targets the neuromuscular junction—the critical point where nerve cells transmit signals to muscles. This disruption leads to muscle weakness and rapid fatigue, especially during physical activity.

What Causes Myasthenia Gravis?

The root cause of myasthenia gravis lies in the immune system malfunction. In most cases, the body mistakenly produces antibodies that attack acetylcholine receptors at the neuromuscular junction. Acetylcholine is a vital neurotransmitter responsible for triggering muscle contraction. When these receptors are damaged or blocked, muscles cannot respond effectively to nerve signals, resulting in weakness.

Connection with Other Autoimmune Conditions

Myasthenia gravis often coexists with other autoimmune disorders, indicating a broader immune system dysfunction. Conditions such as hyperthyroidism, rheumatoid arthritis, and lupus may appear alongside MG. Additionally, approximately 10–15% of patients with myasthenia gravis have a thymoma (a tumor of the thymus gland), while others may experience thymic hyperplasia (enlargement of the thymus). The thymus plays a key role in immune regulation, and its abnormal function is believed to contribute to the development of the disease.

Symptoms and Impact on Daily Life

The hallmark symptom of myasthenia gravis is muscle weakness that worsens with activity and improves with rest. Commonly affected areas include the eyes (causing drooping eyelids or double vision), face, throat, and limbs. In severe cases, the respiratory muscles may be impacted, leading to a life-threatening condition known as a myasthenic crisis. Early diagnosis and treatment are essential to managing symptoms and maintaining quality of life.