Myasthenia Gravis

Myasthenia Gravis (MG) is a chronic autoimmune disease that causes weakness in the voluntary muscles, especially those that control the eyes, face, throat, and limbs. It happens when the body's immune system blocks or destroys the communication between nerves and muscles at the neuromuscular junction, preventing muscles from contracting properly.

Drooping eyelids (ptosis); Blurred or double vision (diplopia); Difficulty speaking (dysarthria) or swallowing (dysphagia); Weakness in arms, legs, neck, or facial muscles; Shortness of breath or difficulty breathing (in severe cases); Muscle weakness that worsens with activity and improves with rest.

Caused by autoantibodies that interfere with nerve-muscle communication. Most commonly, antibodies attack the acetylcholine receptors (AChR) on the muscle side of the neuromuscular junction. Some patients have antibodies against MuSK (muscle-specific kinase). The thymus gland is often involved - some people with MG have thymomas or an overactive thymus.

Blood tests for AChR and MuSK antibodies; Edrophonium (Tensilon) test - short-term improvement in muscle strength; EMG (electromyography) to test muscle response; CT or MRI of the chest to check for thymoma; Pulmonary function tests if breathing is affected.

Acetylcholinesterase inhibitors (e.g., pyridostigmine) - improve muscle communication; Corticosteroids and immunosuppressants (e.g., azathioprine, mycophenolate); Plasmapheresis or IVIG (used in crisis or flare); Thymectomy (surgical removal of the thymus) - may improve symptoms; Supportive therapies: speech, physical, or occupational therapy.

With treatment, most people can manage symptoms and lead normal or near-normal lives. Severe cases may require hospitalization during respiratory crises. Lifelong management is often necessary, but many improve with medication or thymectomy.

Affects approximately 20 per 100,000 people. Can occur at any age, but women are often diagnosed in their 20s-30s and men more often after age 60.