Cholinergic vs. Myasthenic Crisis

[Dr. Edd P.]

Hello everyone, exams in 12 days, can somebody clarify these two for me pls?

And might anybody wanna pitch in some last days topics to cram, pls do so. Thanks

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[goodvibes27]

Cholinergic crisis:
When dose of AchE inhibitor inappropriately high -> excessive Ach in the synaptic cleft -> excessive stimulation of skeletal muscles -> refractory to future impulses, muscle weakness

(CHOLINERGIC crisis aka increased acetylCHOLINE)

Myasthenic crisis:
Suboptimal dose of AchE inhibitor -> not enough Ach available in the synaptic cleft -> myasthenic symptoms

(It's in the name again)

Tensilon test:
Infusion of edrophonium (short acting AchE inhibitor) -> increases neuromuscular transmission and temporarily improves symptoms in a myasthenic crisis ; no improvement in a cholinergic crisis as NMJ is already insensitive to the extra Ach

Hope that helps.


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[Dr. Edd P.]

Cholinergic crisis:
When dose of AchE inhibitor inappropriately high -> excessive Ach in the synaptic cleft -> excessive stimulation of skeletal muscles -> refractory to future impulses, muscle weakness

(CHOLINERGIC crisis aka increased acetylCHOLINE)

Myasthenic crisis:
Suboptimal dose of AchE inhibitor -> not enough Ach available in the synaptic cleft -> myasthenic symptoms

(It's in the name again)

Tensilon test:
Infusion of edrophonium (short acting AchE inhibitor) -> increases neuromuscular transmission and temporarily improves symptoms in a myasthenic crisis ; no improvement in a cholinergic crisis as NMJ is already insensitive to the extra Ach

Hope that helps.


Sent from my iPhone using SDN mobile

Thank you very much. Follow up question on that
1. Whats the management for Cholinergic crisis?
2. For myasthenic crisis, does it have a pharmacokinetic property that I have to be aware of? (Like if it is desensitization of nicotinic rc for cholinergic crisis)

 

[goodvibes27]

1. For the management of cholinergic crisis UW mentioned to discontinue the AchE inhibitors temporarily. I've read that atropine and respiratory support can be given.

2. I don't think so, but incase you come across anything let me know!


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[Dr. Edd P.]

1. For the management of cholinergic crisis UW mentioned to discontinue the AchE inhibitors temporarily. I've read that atropine and respiratory support can be given.

2. I don't think so, but incase you come across anything let me know!


Sent from my iPhone using SDN mobile

Will do tha again, thank you

 

[goodvibes27]

Will do tha again, thank you

No problem. And good luck for your exam!


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[iBS1972]

For myasthenic crisis, you can either give IVIG (synthetic antibodies) or plasmapheresis.