Frequently asked questions about myasthenia gravis

Q: What parts of the body are affected by myasthenia gravis?

A: Myasthenia gravis affects your voluntary muscles, a category of muscles that you can control on your own will, such as your arms, legs and neck. Several types of the condition can appear, which are named after the parts it usually affects:

• Generalized myasthenia gravis — This type mostly affects the limbs, such as the legs and arms, as well as the torso.¹
• Ocular myasthenia gravis — Your eyelids experience muscle weakness, causing drooping eyelids and double vision.²
• Facial myasthenia gravis — Your facial muscles are affected, making it hard for you to eat, speak, swallow and create facial expressions.³
• Myasthenic crisis — This is a complication that weakens your breathing muscles, which can result in life-threatening situations. This requires immediate treatment.⁴

Q: Is myasthenia gravis hereditary?

A: There may be a hereditary component to myasthenia gravis.⁵ Children may develop congenital myasthenic syndrome due to genetic mutations of one or both parents.⁶

Q: What is the life expectancy of people diagnosed with myasthenia gravis?

A: The prognosis of myasthenia gravis is good. If you’re able to get treatment right away and follow a maintenance and prevention program, you’re expected to live a normal (or nearly normal) life. In some cases, the disease may even go in to remission. However, it’s important to be aware of your symptoms and maintain optimal health all the time, because the disease can appear again when you least expect it.⁷

Q: How is myasthenia gravis diagnosed?

A: Diagnosing myasthenia gravis can be hard, because it produces symptoms similar to other diseases that exhibit muscle weakness. Fortunately, there are several methods that can help confirm the presence of the disease:⁸

• Review of your medical history — Before conducting any kind of specialized test, your doctor will interview you and review your medical history for any specific pattern that may indicate myasthenia gravis. Afterward, they will conduct simple physical tests to examine your balance, coordination, muscle strength and reflexes.
• Edrophonium test — If muscle weakness is confirmed, your doctor will administer an edrophonium test, also known as a Tensilon test. You will be injected with edrophonium chloride to temporarily regain muscle control by blocking antibodies that disrupt your neurotransmitters. If the test shows positive results, it can indicate myasthenia gravis.⁹
• Electromyogram tests — Electromyogram (EMG) tests examine for functionality and any possible damage in your nervous system. Electrodes will be placed at the site of muscle weakness, and electrical impulses will be sent through them to the affected muscles. If the muscles do not respond well to the stimulation, you may likely have myasthenia gravis.
• Blood tests — There are several blood tests available to help confirm myasthenia gravis. The acetylcholine receptor antibody test, for example, looks for the presence of acetylcholine. An heightened amount of this antibody is found in approximately 75% of people with myasthenia gravis.¹⁰

You can visit the Tests for Myasthenia Gravis for more diagnostic methods and their in-depth explanations.