Myasthenia gravis is a condition affecting the neuromuscular junction. It is a relatively rare,also an auto immune disease. It is caused by antibodies blocking acetyl choline receptors. Thus it inhibits its effects.
It manifests as a generalized muscle weakness, may also affect respiration causing myasthenia crisis.
Clinical features of the disorder-
- specific muscle weakness, moreover frequently ocular symptoms.
- ptosis and diplopia (double vision).
- Generalised weakness may however be seen rarely
- fascial muscle weakness
- Weakness spreads from the ocular and facial and also to truncal and limb muscles.
- Weakness usually worsens as the day progresses.
- aggravted by exertion and alleviated by rest.
- Respiratory muscle weakness develop in up to 40% of patients. This thus may cause respiratory failure.
Classification of myasthenia-
- Early-onset seen in age group <50 years.
- Late-onset- above 50 years
- Presence of anti-MUSK antibodies.
- Ocular only
Class I: only ocular muscle weakness, possible ptosis.
II: Mild weakness apart from ocular muscless III: Moderate weakness affecting other than ocular muscles.
IV: Severe weakness affecting other than ocular muscles
There are four basic therapies which can be utilised for intervention of myasthenia gravis-
- Symptomatic treatment- this can be done with acetylcholinesterase inhibitors.
- plasmapheresis and intravenous immunoglobulin.
- glucocorticoids and other immunosuppressive drugs.
- Surgical treatment: thymectomy
Exercise interventions and patient education-
- Aim to strengthen large muscle groups.
- Advise patient to do the exercises at a time when they are not fatigued
- If on pyridostigmine, exercise 1.5 to 2 hours after dose
- Only moderate intensity exercises should be performed
- General aerobic exercise should also be performed.