Myasthenia gravis

Also called MG

Myasthenia gravis is a rare long-term condition where the immune system disrupts the signals between nerves and muscles. It causes muscle weakness that gets worse with activity and improves with rest. It often affects the eyes and eyelids first, and can affect the face, throat, arms, legs and breathing muscles.

Last updated Nov 9, 2026

What it is

It is sometimes linked to a problem with the thymus gland, which may be removed.

Medicines that improve nerve signals and calm the immune system usually control symptoms well. Some medicines can make it worse, so check before starting new ones.

Common signs

  • Drooping eyelids
  • Double vision
  • Difficulty chewing, swallowing or speaking
  • Weak arms and legs that get worse with use
  • Shortness of breath

How it is usually diagnosed

  • Blood test for antibodies
  • Nerve tests and EMG
  • CT scan of the chest to check the thymus

Records worth keeping

Keeping these together makes each appointment easier, especially when you see a new doctor:

  • Antibody test results
  • EMG reports
  • Chest scan reports
  • Neurology letters and a list of medicines to avoid

Questions to ask your doctor

  • Which medicines should I avoid?
  • Would removing my thymus help?
  • What should I do if my symptoms suddenly get worse?

When to get help right away

Call 112 or go to the nearest emergency department if you have:

  • Difficulty breathing or swallowing: call 112, this may be a myasthenic crisis

This page is general information. It is not a diagnosis and does not replace a doctor who knows your history. Medfold keeps your records organised; it does not interpret them.

Sources