Approach to NMJ Disorders Flashcards
Which side of the synapse does Myasthenia Gravis affect?
Post-synaptic
Which side of the synapse does Lambert-Eaton Myasthenic Syndrome affect?
Pre-synaptic
Myasthenia Gravis involves autoantibodies to?
Ach Receptor
In what age/gender is Myasthenia Gravis more common?
Younger women
Older men
What type of weakness is seen with Myasthenia Gravis?
Fluctuating weakness = “excessive fatigability”
Where is the fluctuating weakness usually located with Myasthenia Gravis?
Ocular muscles – ptosis and diplopia
If AchR antibodies are not present with Myasthenia Gravis, what other antibodies may there be?
MUSK
LRP-4
With repetitive stimulation, what is the response on the EMG with Myasthenia Gravis?
Decremental response
What is a dangerous and no longer used drug injection that can be used to diagnose Myasthenia Gravis?
Tensilon (edrophonium)
What side effects can occur with the Tensilon (edrophonium) test?
Bradycardia, ventricular arrhythmias
What is the antidote for the Tensilon (edrophonium) test?
Atropine
What is a possible treatment for Myasthenia Gravis?
Acetylcholinesterase (-) = Mestinon
A Myasthenic crisis can present similarly to?
Cholinergic Crisis
MUSK Myasthenia Gravis response to Acetylcholinesterase (-)?
NO response
Lambert-Eaton Myasthenic Syndrome is due to?
Antibodies against voltage-gated calcium channels
– blocks Ach release
What are some symptoms of Lambert-Eaton Myasthenic Syndrome?
Weakness, dry mouth, loss of DTRs
After exercise/stimulation, what change will be seen in Lambert-Eaton Myasthenic Syndrome?
Strength INCREASES
(+) anti-VGCC?
LEMS
- Lambert-Eaton Myasthenic Syndrome
EMG response for LEMS with repetitive stimulation?
Incremental
LEMS is often associated with?
Cancer – look for malignancy
Where in the synapse does Botulism affect?
Pre-synaptic
Botulism blocks?
Pre-synaptic release of Ach
Treatment for Botulism?
ICU monitoring
Symptoms of Botulism?
Dry mouth, blurred vision, diplopia, N/V
How do Nerve gases like Sarin and VX work?
(-) Acetylcholinesterase to cause a cholinergic crisis
Nerve gases cause too much Ach to be around. What does that often cause to occur?
Seizures and increased secretions