Myasthenia Gravis Flashcards
What is Myasthenia Gravis?
Autoimmune neuromuscular condition where antibodies (AChR-Ab) attacks the acetylcholine receptors on the skeletal muscles (end motor plate)
2 main types of myasthenia gravis?
- Ocular MG
2. Generalised MG
Symptoms of ocular MG?
- ptosis (drooping eyelids)
- diplopia
- eye weakness/ophthalmoplegia
Main symptoms of generalised MG?
- Facial - expressionless and Myasthenic sneer of the lips
- Bulbar - dysphagia, dysarthria, fatiguable chewing
- Neck - Dropped head syndrome
- Respiratory - during myasthenia crisis
- Limbs - weakness especially in arms and proximal muscles
Commonest type of MG?
Ocular
How is the symptoms of MG classically described?
Fluctuating muscle weakness with fatiguability
Investigations for MG?
- Bedside: neuro exam, fundoscopy, Icepack test
- Bloods: FBC, haematinics, U&E, LFTs, bone profile, glucose/Hba1c, TFTs (Graves)
- Special test: serological testing (AChR-Ab), Repetitive Nerve Stimulation test
- Thymus assessment (CT)
- Rheumatological tests: ANA, CCP, RF (RF, SLE)
What is the Icepack test?
Put ice on the eye with ptsosis and it should provide temporary relief
What is the purpose of the thymus assessment?
To look for any thyoma or hyperplasia
1st line management for MG?
Acetylcholinesterase inhibitor - e.g, Pyridostigmine
2nd line management for MG when there is lack of control with AChE-i (Pyridostigmine)?
Whats the difference in starting doses for ocular and generlised?
- Add on Steroids (Prednisolone)
2. Initially 5mg for ocular and 10mg for generalised
3rd line management for MG?
Immunosuppressants (Azathioprine usually 1st line)
Precipitants of myasthenic crisis? (5)
- infection
- surgery
- warm weather
- medications
- stress
Common causes of morbidity in MS?
- aspiration
2. respiratory failure
Treatment of myasthenic crisis?
- IVIG
- Plasma exchange (if IVIG fails)
- Prednisolone (can be reinstated)
