Myasthenia gravis

Myasthenia gravis is a long term (chronic) condition that causes muscle weakness and fatigue.

It's rare, and it most commonly affects the muscles that control:

• the eyes and eyelids
• the face
• speaking
• chewing
• swallowing

Other muscles in the body can be affected too. Myasthenia gravis can start at any age, but it's most often found in women under 40 and men over 60.

The first signs of myasthenia gravis are often droopy eyelids or double vision. The condition usually affects the eyes first, and it may then spread to other parts of the body. That spread can take weeks, months or years.

How severe the symptoms are differs from one person to another. Your symptoms are likely to get worse when you're tired, and they may improve after you rest.

Symptoms can affect different parts of your body and different body functions.

With myasthenia gravis, you might get droopy eyelids, in one eye or both, and double vision. In some people only the eye muscles are affected, which is called ocular myasthenia. In most people, though, the symptoms spread over time to other parts of the body.

With myasthenia gravis, you might notice:

• slurred speech
• difficulty swallowing
• difficulty making facial expressions like smiling
• problems with chewing
• a change in your voice
• choking or accidentally inhaling food, which can cause chest infections
• shortness of breath

In myasthenia gravis, muscle weakness can spread to other parts of the body, such as your arms, legs and neck.

You might notice:

• weakness in your arms, legs, neck or other parts of your body
• difficulty holding your head up
• aching muscles
• problems with tasks like climbing stairs or washing your hair

Some people with myasthenia gravis develop severe trouble with breathing and swallowing, and this needs treatment in hospital straight away. Doctors call it a myasthenic crisis.

A myasthenic crisis can happen even before you know you have myasthenia gravis.

If you have myasthenia gravis and are experiencing severe:

• breathing problems
• swallowing problems

You might need emergency hospital treatment.

If you have myasthenia gravis, stay away from activities that could turn dangerous if sudden weakness strikes, such as swimming alone.

Myasthenia gravis can be hard to diagnose. Your doctor will start by asking about your medical history and your symptoms.

Before a diagnosis is made, you may need several tests to rule out other possible causes of your symptoms.

A blood test can show whether you have a high level of antibodies (these are made by your immune system) that might be causing myasthenia gravis.

If your first blood test comes back normal but your symptoms keep getting worse, you might be offered another blood test later on.

Your doctor may suggest electromyography (also called an EMG) to check how your nerves and muscles are working.

For the test, small needles are put into your muscles to measure their electric activity. They're usually placed around your eyes, forehead or arms.

The test picks up the signals travelling from the nerves to the muscles. If it finds a disruption in those signals, this might be a sign of myasthenia gravis.

Your doctor may ask for a computerised tomography (CT) scan. It checks whether the thymus gland in your chest is bigger than it should be, or has grown abnormally (a thymoma).

The thymus gland is part of your immune system. Problems with it, such as inflammation (swelling), can be linked to myasthenia gravis.

You might also have a magnetic resonance imaging (MRI) scan. This can show whether your symptoms are coming from a problem in your brain.

If you notice your myasthenia gravis symptoms getting worse after certain things, try to stay away from those triggers as much as you can. Triggers might include:

• stress
• tiredness
• infections
• medicines
• surgery

There are treatments for myasthenia gravis that can help reduce the effects of your symptoms.

Your doctor might offer you medicine to help treat myasthenia gravis. This could be one of the following:

• pyridostigmine, which works by temporarily improving the way messages pass from nerve to muscle, so your muscles get stronger
• steroids, which reduce the activity of your immune system so it stops attacking the communication between your nerves and muscles
• other immunosuppressants, which also reduce the activity of your immune system

Your doctor might recommend surgery to remove the thymus gland (thymectomy) as a treatment for myasthenia gravis. After the operation, your symptoms should improve within the first few months, and they can keep improving for up to 2 years.

Surgery can reduce:

• the dose of steroids
• the need to take other immunosuppressants
• the chances of needing to go to hospital because of worsening symptoms

If you have a thymoma, surgery might not help your myasthenia symptoms. Your doctor might still recommend taking out the thymus gland, because it can cause problems if it keeps growing.

A thymectomy is usually done as keyhole surgery. The surgeon removes the thymus using instruments passed through small cuts (incisions) in the chest.

Plasma exchange and IVIG (intravenous immunoglobulin) can bring quick improvement, within a few days, if you're:

• very unwell
• having a myasthenic crisis

Plasma exchange is an emergency treatment that removes antibodies from your own blood. It's given in hospital, and the benefits can last around 6 weeks.

IVIG treatment is an injection of normal antibodies from donated blood. It temporarily changes the way your immune system works.

The two treatments are similar, and your doctors will decide which one suits you best. The benefits last only a few weeks, but that can buy time for the longer term treatments to take effect and help improve your symptoms.

Your myasthenia gravis may get worse during pregnancy or after you have had your baby. If you're planning a pregnancy or you become pregnant, speak to your doctor. Don't stop taking your medicines without speaking to your doctor first.