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Flashcards in Neuromuscular Junction Disorders Deck (10):
1

Myasthenia Gravis

Autoimmune disorder of the postsynaptic NMJ
-T cells with help of B cells destroy AchR
-normal architecture and folding of post synaptic junction is lost

Occurs at any age

2

What factor plays an important role in the etiology of MG?

THYMUS gland
-most often glandular enlargement or hyperplasia less often tumor or thymoma

3

Symptoms of MG?

weakness and fatigue of skeletal muscles
when doing non strenuous activity

1. ptosis
2. diplopia
3. dysarthria
4. dysphagia

-asymmetric weakness is common
-muscle reflex, sensation, higher cortical function normal

4

ocular myasthenia

only visual symptoms
10-20% of patients

5

generalized myasthenia

more than just occular

6

neonatal myasthenia

healthy newborns of myasthenic mothers may have MG symptoms for a few days until mothers antibodies are out

7

myasthenic crisis

profound weakness may cause quadriplegia with the patient unable to speak swallow or breathe

Triggered by serious infection

8

What is the most specific test for MG?

serum AChR antibodies

9

Treatment of autoimmune MG

1. oral anticholinesterase drugs-pyridostigmine
-too high a dose will result in cholinergic crisis-weakness, sweatiness, salivation, diarrhea, excessive urination
2. immunosuppressants-corticosteriods(prednisone)
3. maybe thymectomy?

Crisis
1. IV immunoglobulin
2. plasmapheresis

10

Lambert-Eaton Myasthenic Syndrome

voltage gated calcium channels at the presynaptic membrane

-muscle fatigue and weakness but tend to disrupt proximal muscles of shoulders and hips and trunk
(symptoms do not usually involve the eyes, swallowing or speech)
-muscle stretch reflex may appear decreased but improved with isometric exercise

autonomic symptoms: dry, mouth, orthostatic hypotension, erectile dysfunction

Autoimmune related to SMALL CELL CARCINOMA OF THE LUNG

Treatment: drugs that enhance release of Ach-guanidine
-immunosuppressants and plasmapheresis
treatment not as effective as in MS