Myasthenia gravis (MG) is a rare autoimmune disease that affects how your nerves and your muscles function, and it can cause muscle weakness. This muscle weakness can be severe enough to interfere with your ability to participate in everyday activities.

Every individual’s experience with myasthenia gravis is unique, and you may experience symptoms differently from others. Your symptoms also may change over time. For example, you may notice your muscle weakness improves or worsens over the course of hours, days, or even months. Some people experience periods of remission (symptom relief) and exacerbations (worsening of symptoms).

What Causes Symptoms of Myasthenia Gravis?

When you want to move your arm or legs, your brain sends signals to your nerves and muscles for movement. The nerves and muscles communicate with one another in a space known as the neuromuscular junction (NMJ). Within this space, they send neurotransmitters (chemical messengers) to one another. Acetylcholine is a neurotransmitter that tells muscles when to contract for movement.

In myasthenia gravis, the body’s immune system mistakenly attacks the NMJ, preventing acetylcholine from working properly. Specifically, it creates immune system proteins known as antibodies that attack the acetylcholine receptors (AChRs) in the skeletal muscle. People with myasthenia gravis have fewer AChRs compared to those without the condition. This means that their muscles can’t respond to acetylcholine as well as before.

As a result, people with myasthenia gravis experience muscle weakness. In general, symptoms of MG usually appear suddenly. The specific symptoms depend on which muscle groups are affected. Symptoms can come and go but usually get progressively worse over time.

It’s also important to work together with your neurologist (nerve and muscle specialist) to identify what triggers your myasthenia gravis symptoms. For some, fatigue, stress, and taking certain medications can worsen them. Hot weather, infections, and menstruation can also worsen symptoms. By avoiding your triggers or limiting their risks, you can limit your MG symptoms and improve your quality of life.

Continue reading to learn about the different symptoms of myasthenia gravis.

1. Muscle Weakness

You can experience muscle weakness in different parts of your body when you’re living with myasthenia gravis. Your arms, legs, fingers, hands, and neck are common parts of the body affected by myasthenia gravis muscle weakness. If you have muscle weakness in any of these muscles, it can cause symptoms such as:

• Muscle aches
• Neck pain
• Weak arms, legs, and hands
• Difficulties walking long distances, standing up from a chair, climbing stairs, and lifting things

You may notice that you feel weaker and more fatigued during periods of activity and feel better after resting. This means that you might feel like you have more muscle strength in the morning and feel weaker at the end of the day.

With proper treatment, most people with myasthenia gravis don’t need to use a wheelchair full time due to muscle weakness.

2. Eye Problems

When myasthenia gravis affects the muscles in your eyes, you may experience problems with your eyes or vision. Problems with eyes and vision are common symptoms of MG. In fact, about 85 percent of people have what’s called extraocular (outside-of-the-eyeball) muscle weakness when they’re diagnosed with myasthenia gravis.

If your eye muscles are affected by myasthenia gravis, your symptoms may include:

• Ptosis (drooping eyelids)
• Diplopia (double vision)
• Blurry vision

Myasthenia gravis symptoms affecting your vision may come and go and can affect one or both eyes.

Although eye symptoms are typically some of the first symptoms of myasthenia gravis, most people will progress to have more general symptoms within two years. About 20 percent of people with MG have symptoms that primarily affect their eyes — known as ocular myasthenia gravis.

3. Heart Problems

In rare cases, myasthenia gravis can affect the cardiac (heart) muscles. Cardiac muscle is sometimes a target of the autoimmune process in MG, particularly in those who also have a thymoma (thymus gland tumor).

If myasthenia gravis affects your cardiac muscles, it can cause the following heart conditions:

• Heart failure — When your heart can’t pump enough blood to meet your body’s needs
• Arrhythmias — When your heart beats with an irregular rhythm
• Myocarditis — When there is inflammation in your heart muscle

4. Head, Neck, and Throat Problems

About 15 percent of people have symptoms involving their throat and neck when diagnosed with MG, according to StatPearls. If the muscles of your head, neck, and throat are affected, you may experience symptoms such as:

• Difficulty chewing
• Dysphagia (difficulty swallowing)
• Frequently choking on food
• Dysphonia (hoarse voice)
• Nasal voice
• Dysarthria (difficulty speaking)
• Difficulty making facial expressions
• Difficulty holding up your head

Muscle weakness in any of the muscles involved in holding your airway open can be serious if it causes breathing problems.

5. Difficulty Breathing

If myasthenia gravis affects the muscles in your chest or diaphragm that control breathing, you can experience respiratory (breathing) problems. Respiratory symptoms represent the most serious consequence of myasthenia gravis and can be life-threatening.

A myasthenic crisis can occur if your respiratory muscles are too weak to move enough air in and out of your lungs to meet your body’s needs. A machine called a ventilator may be necessary to help you breathe during a myasthenic crisis. Between 10 percent and 15 percent of people with myasthenia gravis experience a myasthenic crisis at least once that requires the use of a ventilator, according to the Journal of Neurology.

It’s important to keep track of your symptoms so you recognize when you need to contact your health care provider or go to the emergency department. Symptoms that may indicate a myasthenic crisis is coming on include:

• Shortness of breath
• Difficulty swallowing
• Increased weakness

6. Memory Problems

People with myasthenia gravis may have problems with their memory, such as:

• Forgetting words
• Memory loss
• Short attention span
• Slow information processing

Studies show that around 60 percent of people with myasthenia gravis experience some difficulties with their memory. Researchers think memory problems may be related to antibodies attacking AChRs in your central nervous system (brain and spinal cord). Memory problems could also be due to side effects of some MG treatments, such as corticosteroids.

7. Fatigue

Fatigue isn’t limited to your muscles in myasthenia gravis. You may also experience extreme tiredness or a lack of energy when you have the condition. Studies show that 42 percent to 82 percent of people with myasthenia gravis report symptoms of fatigue, such as:

• Difficulty with concentrating
• Lack of motivation
• Anxiety
• Irritability

Additionally, fatigue is associated with some of the same symptoms as MG, such as muscle pain and weakness.

Fatigue from myasthenia gravis can be severe enough to prevent you from participating in activities you enjoy, leading to stress and depression.

Find Your Team

On MGteam, the social network for people living with myasthenia gravis and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with MG.

What myasthenia gravis symptoms do you experience? How do you manage them? Share your experience in the comments below, or start a conversation by posting on your Activities page.