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Myasthenia Gravis
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Brain Nerves

Myasthenia Gravis

Myasthenia gravis is a chronic autoimmune disease that causes weakness in voluntary muscles by disrupting the communication between nerves and muscles.

Overview

Myasthenia gravis (MG) affects voluntary muscles, including those used for eye movement, facial expressions, talking, swallowing, and breathing. Weakness typically worsens with activity and improves with rest. It is an autoimmune disease where the immune system mistakenly attacks healthy cells.

Causes

The condition is caused by an error in nerve-to-muscle signaling. Normally, nerves release acetylcholine to trigger muscle contraction. In MG, the immune system produces antibodies that block acetylcholine from binding to muscle tissue. The thymus gland may also play a role, as it often remains large in adults with MG or may develop tumors known as thymomas.

Symptoms

  • Weakness of eye muscles
  • Drooping eyelids
  • Blurred or double vision
  • Changes in facial expressions
  • Trouble swallowing
  • Shortness of breath
  • Speech problems
  • Weakness in the arms, hands, fingers, legs, and neck

Severe weakness affecting breathing muscles is known as a myasthenic crisis, which is a life-threatening emergency.

Diagnosis & Treatment

Diagnosis involves a medical history review, physical and neurological exams, blood tests, imaging, and electromyography (EMG). While there is no cure, treatments include:

  • Anticholinesterase medicines: Improve nerve-to-muscle communication.
  • Immunosuppressive medicines: Decrease immune system responses.
  • Monoclonal antibodies: Help reduce immune system responses.
  • Plasmapheresis and intravenous immunoglobulin: Procedures to remove abnormal antibodies from the blood.
  • Thymectomy: Surgical removal of the thymus gland.

Lifestyle adjustments, such as gentle exercise and healthy eating, may also be recommended.

Frequently Asked Questions

myasthenic crisis is a life-threatening emergency characterized by severe weakness in the muscles that control breathing. Key warning signs include difficulty breathing while lying flat, the need to sleep propped up on pillows, shortness of breath after minimal exertion, or a change in voice that sounds weak or breathless. If you experience these symptoms, or if you have trouble clearing secretions from your throat, you must seek emergency medical attention immediately, as respiratory failure can occur rapidly.
Myasthenia gravis is generally not inherited in a direct genetic pattern, meaning it is not typically passed from parent to child. However, having a family member with an autoimmune disease may slightly increase the risk. The thymus gland plays a significant role because it is often abnormal in people with MG; it may be enlarged (thymic hyperplasia) or contain a tumor (thymoma). Removing the thymus gland (thymectomy) is often recommended, particularly for patients with thymomas or generalized MG, as it can improve symptoms and reduce the need for immunosuppressive medications.
nticholinesterase medications, such as pyridostigmine, improve nerve-to-muscle communication but can cause gastrointestinal side effects like nausea, diarrhea, abdominal cramps, and increased salivation. These symptoms are often dose-dependent. Patients should take the medication with food to reduce stomach upset and report any severe gastrointestinal distress to their doctor, as the dosage may need to be adjusted. It is important not to stop the medication abruptly without medical guidance, as this can lead to a sudden worsening of muscle weakness.
hallmark of myasthenia gravis is that muscle weakness worsens with repeated use and improves with rest. For example, a patient might have normal eye movement in the morning but develop double vision or drooping eyelids by late afternoon. Similarly, chewing may become difficult during a long meal. Recognizing this pattern helps patients plan their day by scheduling demanding tasks for when they are most rested and taking frequent breaks to prevent exhaustion.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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