Myasthenia gravis (MG) can be difficult to diagnose because its symptoms overlap with other conditions. This means that, even if you have some of the most common symptoms of MG, it may take time to get a clear diagnosis.

Eye symptoms are often the first sign of myasthenia gravis. This is called ocular myasthenia gravis. These symptoms include ptosis, a droopy eyelid caused by muscle weakness in your eyelid. You might also experience diplopia (double vision). If you experience ptosis, your doctor might recommend an ice pack test to help diagnose myasthenia gravis. Here’s what you need to know about that test.

What Is the Ice Pack Test for Myasthenia Gravis?

The ice pack test for myasthenia gravis is simple and noninvasive. If one or both of your eyelids are drooping with no other clear cause, or if you have other symptoms of myasthenia gravis, your doctor may suggest this test.

With your permission, your doctor will place an ice pack on your closed eyelids for two to five minutes. To protect your skin and prevent cold burns, the ice pack will be wrapped in a cloth.

After the time is up, your doctor will remove the ice pack and ask you to open your eyelid. If you can lift your eyelid at least 2 millimeters higher than you could before you applied the ice pack, the test is considered positive for myasthenia gravis. If there’s no improvement, the test is negative, and your doctor will explore other causes for your symptoms.

The ice pack test is also useful for people in the hospital who can’t communicate easily, such as those with breathing tubes. The test is especially useful because it can be done at the bedside and doesn’t require the person to do anything other than tolerate the ice pack and try to open their eyes when asked.

Why Does the Ice Pack Test Work?

Myasthenia gravis is caused by a breakdown in communication between nerves and muscles. Researchers believe the ice pack test works because the chemicals involved in this communication don’t work as well at warmer temperatures.

Cooling the muscles that control your eyelids can temporarily improve their function. This may explain why your eyelids open more after being chilled.

While researchers know what chemicals are involved, based on what they know about the human body and myasthenia gravis, they’re still unsure exactly what happens in these muscles when they get cold.

What Does the Ice Pack Test Tell Your Doctors?

The ice pack test can help doctors determine a diagnosis of MG. While the test alone is not enough for a definitive diagnosis, it can help doctors decide what other tests to run and speed up the diagnostic process. The test correctly identifies people with myasthenia gravis about 80 percent of the time, though some studies suggest this number could be as high as 97 percent.

The ice pack test is usually done when doctors suspect that a person has myasthenia gravis and want to decide whether to investigate further. Because it’s quick, safe, and can be done in an office, it’s often a helpful first step in the diagnostic process.

If your ice pack test is positive, doctors may confirm the diagnosis with a few additional tests. They can check your blood for certain antibodies, which are proteins used by your immune system. These antibodies are called acetylcholine receptor antibodies. If you have them, this would confirm the diagnosis.

Doctors may also test how your nerves respond to certain types of stimulation. This is called repetitive nerve stimulation. If your nerves show a weaker response than normal, it could suggest a diagnosis of myasthenia gravis.

Another test measures how your eye muscles respond to electrical stimulation. This can provide additional information to help doctors confirm the diagnosis.

When considering a diagnosis of myasthenia gravis, your doctor may also recommend genetic testing. This test can check for genes linked to myasthenia gravis or other conditions with similar symptoms. It helps your doctor make a more accurate diagnosis of MG.

Talk to Your Doctor

If your eyelids start drooping and you don’t know why, talk to a doctor right away. Drooping eyelids aren’t normal and can affect your vision and quality of life. Some causes of a droopy eyelid are serious and need immediate treatment.

Your family doctor may refer you to an ophthalmologist (eye specialist). If they suspect myasthenia gravis, they may refer you to a neurologist (a specialist in conditions of the brain, spinal cord, and nerves).

Be sure to attend all appointments and follow-ups — they’re important for getting the right diagnosis and treatment.

Keep in mind that diagnosing myasthenia gravis can take time. Your ophthalmology or neurology may need to run several tests and it could take some time for them to analyze the results. If you’re not in a myasthenic crisis (a severe worsening of symptoms), let your doctors take the time they need. This ensures they can make the best diagnosis and recommend the most effective treatment for you.

Talk With Others Who Understand

MGteam is the social network for people 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 myasthenia gravis.

Have you had the ice pack test for myasthenia gravis? Did it help with your myasthenia gravis diagnosis? Share your experience in the comments below, or start a conversation by posting on your Activities page.