Background + symptoms
It is estimated that there are roughly 20000-25000 people living with Mysthenia Gravis in the UK with the median age of onset being 63 years old. 78% of cases are in those over the age of 50. It is a rare autoimmune condition that can cause weakness in the limbs but the most common initial presentation is weakness in the facial muscles which may present as drooping of the eyelids (ptosis), double vision (diplopia), slurred speech (dysarthria and altered swallow (dysphagia). In more extreme circumstances where it isn’t caught early, people may have significant limb weakness and respiratory weakness which can be life threatening.
Pathophysiology
The abnormal autoimmune response causes the body to attack or block our own acetylcholine receptors. Acetylcholine is a neurotransmitter which essentially helps carry a message between different nerve cells. If these are damaged it can therefore prevent messages being carried to muscles telling them to contract which will cause weakness.
Treatment
There can be many treatments for Myasthenia Gravis but they aim to:
- Symptomatic treatment – Patients are often given acetylcholinesterase inhibitors which essentially slow the breakdown of acetylcholine. This increases the abundance of acetylcholine which allows for stronger muscle contractions
- Immunosuppressive therapy – These tend to reduce our antibody production which will in turn decrease the amount of acetylcholine being affected.
Physiotherapy goals/considerations:
It is advised to keep exercise low-moderate intensity for short durations
There is high fatiguability in muscles affected by Myasthenia Gravis so fatigue should be monitored and it’s advised to stop exercise before feeling fatigued.
Exercise ideally should be planned around medication timing and done when medications are at peak effectiveness
Respiratory function should be regularly monitored and provided with exercises if this is affected
