Myasthenia Gravis

Question 1

What is myasthenia gravis.

Answer 1

An autoimmune conditions with antibodies directed against the acetylcholine receptors on the post-synaptic muscle membrane.

Question 2

What percentage of patients with myasthenia gravis have abnormal thymus glands. (3)

Answer 2

75%.
65% have hyperplastic thymus.
10% have thymic tumours.

Question 3

What is the prevalence of myasthenia gravis.

Answer 3

1 in 7,500.

Question 4

What is the ratio of women:men who have myasthenia gravis.

Answer 4

3:2.

Question 5

What are the clinical manifestations of myasthenia gravis. (8)

Answer 5

Weakness and fatiguability. 
Often affects cranial muscles early leading to:
Ptosis. 
Diplopia. 
Dysarthria. 
Dysphagia. 
Limb weakness is often proximal. 
If respiratory function is affected, this is a myasthenic crisis.