Multiple sclerosis (MS) and myasthenia gravis (MG) are both serious lifelong diseases. MS stems from faulty communication between your brain and the nerves that control your body. MG causes serious muscle weakness that can cause eyelids to droop, and the weakness can extend down to the rest of your face, arms, and legs.
Here are some other ways they’re alike, as well as how they differ.
Causes and Demographics
MS and MG happen when your immune system turns against your healthy organs, tissues, and cells. That disrupts the complex network of connections between your brain and your nerves and muscles.
With MS, the damage is in the myelin sheath that covers and protects your nerve fibers. With MG, your antibodies destroy the junction between your nerve and muscle cells.
Similarities. There’s no single proven factor that causes either MS or MG. Both conditions also:
- Often affect those under the age 40
- Are more common in females. For MS, women outnumber men 3 to 1. MG is much more common in younger women than in men.
- May be triggered by viral infections or other environmental risk factors
Differences. Some key contrasts include the fact that:
- MS can run in families. However MG is generally not considered a hereditary condition. Most cases of MG might be caused by too much of certain antibodies produced by the thymus gland. In rare cases, newborns may have MG temporarily after their birth if the mother has MG.
- White people are more likely to get MS than are Black or Asian American people. But Black women are more likely to get MG than Black men and white men and women.
- MS is more prevalent in areas such as North America with a moderate climate, compared with warmer regions. A pair of recent studies found higher rates of MG cases in urban areas than in rural ones.
Symptoms
MS and MG often mimic each other because they involve similar issues in your body. The main one is inflammation.
The key symptoms of MS include:
- Feeling exhausted all over
- Vision problems (optic neuritis, a condition that can decrease vision and cause eye pain)
- Trouble with balance and coordination
- Tingling or prickling sensation
- Difficulty with concentration or memory
Symptoms of MG include:
- Muscle weakness
- Fatigue that affects specific areas of your body
- Trouble moving your eyes or eyelids
- Double vision
- Difficulty swallowing, speaking, or making facial expressions due to muscle weakness
Many MG symptoms get worse with activity but may improve with rest.
Diagnosis and Prognosis
Both MS and MG tend to worsen over time. And each can have periods when symptoms go away for a while and then return, often called temporary remission.
MS is often diagnosed after your doctor has ruled out all other possible causes. They’ll check your muscle reflexes, your vision and other senses, and ask about your symptoms. Other tests for MS include:
- MRI
- Eye exam
- Blood screening
- Spinal fluid check
- Nerve test to check how quickly your brain responds to electrical stimuli
Tests for MG include:
- Blood test to check for specific antibodies common in people with MG
- Muscle reflex and strength
- Nerve stimulation
- Electromyogram to measure electrical activity in your muscles and nerves
Treatments
There is no cure for MS or MG. Treatments for both include certain prescription drugs or forms of physical therapy.
The main treatment goals for MS are to ease symptoms such as weakness and immobility and prevent or lessen the severity of relapses. Therapies for MG focus on strengthening muscles to improve the message connection between nerves and muscles.
Common therapies for MS include:
- Disease-modifying treatments to slow disease progression. The FDA has approved more than a dozen of this type of drug.
- Steroids to help with your attacks
- Relaxants to calm muscle spasms
- Medications to treat different side effects, including pain, itching, depression, tremors, and bladder problems
Treatments for MG include:
- Acetylcholinesterase inhibitor, a drug for MG that helps prevent enzymes that block nerve impulses
- Glucocorticoids and nonsteroidal immunosuppressant drugs to tamp down your faulty immune response
- Monoclonal antibodies, biologics, and receptor blockers, which are drugs that help fight attacks on your immune system
- Surgery (thymectomy) to remove your thymus gland
- IVIg, an infusion therapy that neutralizes and destroys damaging antibodies
MS and MG Together
Studies have found that, in rare cases, people can have both MS and MG. Usually, a person may start with symptoms of MG but later show signs that mimic MS. Or it can happen the other way. If your doctor suspects this may be the case for you, they can use several different tests to find out for sure.
