Myasthenia gravis (MG) does not have stages but classes. These classes describe the muscles the condition affects and the severity of muscle weakness, which can influence the treatments a doctor may recommend.
There are
| Description | |
|---|---|
| Class 1 | There is weakness only around the eyes. |
| Class 2 | There is mild weakness in muscles other than the eyes. A person may also experience eye muscle weakness. |
| Class 3 | There is moderate weakness in muscles other than around the eyes. A person may also have eye muscle weakness of any severity. |
| Class 4 | There is severe weakness of any muscles. The individual may have weakness in the ocular muscles of any severity. |
| Class 5 | This class is the most severe, affecting the muscles that control breathing to the extent that someone requires intubation, with or without ventilation from a machine. |
Classes 2 to 4 also each have two subclasses, which describe the specific muscles MG predominantly affects. This could be the:
- Limbs and axial muscles: Subclasses 2a, 3a, and 4a involve muscle weakness mainly in the limbs, the axial muscles in the back, or both. They may also have some mouth or throat weakness, but to a lesser extent.
- Mouth, throat, or respiratory muscles: Subclasses 2b, 3b, and 4b mainly affect the mouth and throat muscles, respiratory muscles, or both.
Doctors do not use stages for MG because this disease does not follow a step-by-step progression of stages over time.
The symptoms of MG can vary, sometimes even within hours or days. Factors that can temporarily worsen MG symptoms include:
- tiredness
- stress
- infections
- menstruation
- giving birth
Temporary symptoms may improve with rest, but people can also experience periods when symptoms flare up, which can be more severe. These flare-ups require medical supervision and treatment.
According to the Muscular Dystrophy Association, it takes around 1 to 3 years for symptoms to reach maximum severity.
Some people enter periods of remission. Usually, remissions are temporary, but they can be long term, particularly in those who undergo surgery to remove the thymus.
