Myasthenia Gravis

Question 1

what type of condition is myasthenia gravis

Answer 1

autoimmune

Question 2

what is myasthenia gravis

Answer 2

chronic autoimmune disorder of the post-synaptic membrane at the neuromuscular junction in skeletal muscle

Question 3

what causes myasthenia gravis

Answer 3

autoimmune antibodies against nicotinic ACh receptors at the post synaptic membrane

therefore, there is limited muscle contraction

Question 4

what disease can present like myasthenia gravis but isnt

Answer 4

Lambert- Eaton syndrome

paraneoplastic subtype of myasthenia gravis caused by autoantibodies against pre-synaptic calcium channels, leading to impairment of acetylcholine release

Question 5

how does myasthenia gravis present

Answer 5

Patients present with weakness affecting limb muscles, extra-ocular muscles (drooping eyelids, diplopia), facial muscles (difficulty smiling or chewing), and bulbar muscles (change in speech or difficulty swallowing). Patients typically report the symptoms are worse after prolonged movement or at the end of the day.

On examination there may be fatigable muscle weakness, bilateral ptosis (worse on sustained upgaze), a myasthenic snarl (due to facial muscle weakness), head droop and bulbar features (such as nasal speech, dysarthria, or dysphagia).

Question 6

summary of symptoms of Myasthenia gravis

Answer 6

muscle fatiguability, ptosis, diplopia, dysphagia, dysarthria, facial paresis, proximal limb weakness

droopy eyelid, mouth, difficulty swallowing and speaking, double vision and unsteady walk (STANDARD SYMPTOMS)

Question 7

what investigations will be done in someone with suspected myasthenia gravis

Answer 7

bloods; serum AChR (acetylcholine receptor)
serum creatine kinase (to rule out myopathies)

pulmonary function tests

Question 8

treatment of myasthenia gravis

Answer 8

mechanical ventilation,

corticosteroids,

IV immunoglobulin or plasma exchange