| Identifier |
botulinum_toxin_lee_novel |
| Title |
Botulinum Toxin |
| Creator |
Andrew G. Lee, MD; Stephanie Xiong |
| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (SX) Class of 2023, Baylor College of Medicine, Houston, Texas |
| Subject |
Botox; Hemifacial Spasm; Blepharospasm; Migraine; Strabismus |
| Description |
Summary: • Mechanism of botulinum toxin o Botox cleaves SNARE proteins, which are necessary for the release of acetylcholine containing vesicles in the pre-synaptic membrane o As a result, no acetylcholine will bind to the post-synaptic acetylcholine receptors • Uses of botulinum o Cosmetic > Often given for wrinkles, Botox is the widely used commercial botulinum toxin formulation o Medical > Hemifacial spasm, blepharospasm, migraine, and strabismus • Sites of botulism toxin injection and possible side-effects o Ptosis and ophthalmoplegia happen because the toxin diffuses to unintended sites o Glabella, may diffuse to medial rectus and cause diplopia o Latera, may diffuse to lateral rectus o Frontal, may cause ptosis • Always ask about botulinum injection when patient presents with diplopia o Be aware some patients may not readily admit because of embarrassment if you do not ask • Never give botulinum toxin to myasthenia gravis patient o Worsened ptosis and ophthalmoplegia; myasthenia crisis o Both pre and post-synaptic blockade. |
| Transcript |
So today we're gonna talk about botulinum toxin. But not as a treatment of disease, but rather a cause of neuro-ophthalmic disease. And as you know the commercially available Botox works at the pre-synaptic membrane. So before this synapse. And the post-synaptic is of course where the acetylcholine receptor is. And so in the pre-synaptic membrane, you have this vesicle, which is containing the packets of the acetylcholine, that has to interact with the SNARE proteins. And that interaction causes a fusion complex that will then allow the release of the acetylcholine to bind onto the post-synaptic acetylcholine receptor. And so when we give someone Botox, this is the normal scenario. The Botox, botulinum toxin, prevents the interaction because it is cleaving that protein and then the vesicle cannot bind to form the complex and therefore it cannot release the acetylcholine packets. And so this is how you end up with diplopia or double vision or ophthalmoplegia from receiving Botox because they are giving it to you to reduce wrinkles. So you might have wrinkles here in your forehead. And so a glabellar injection, or a frontal injection, or a peri-ocular injection for wrinkles with botulinum toxins that can diffuse right into the lid and cause a ptosis. Or it can diffuse into the muscles and cause an ophthalmoplegia. So that ophthalmoplegia can be anything. And so if we get a glabellar injection, it might diffuse to the medial rectus and cause diplopia because the medial rectus might not fire. If it's a lateral injection, it can diffuse into the lateral rectus muscle. Or if it's a frontal injection, it can cause the ptosis. So in any patient who presents with to us with diplopia, one of the questions you have to ask is, "have you received botulinum toxin injections"? Because they might not volunteer this, number one because they're a little bit embarrassed by receiving Botox, number two maybe the person that came with doesn't know that they're using Botox to achieve the look the way they're looking, and number three the patients often don't know that botulinum toxin could cause ptosis and diplopia. So it's particularly important that you ask about botulinum toxin exposure. It's very likely to be Botox if it's a combination of ptosis and a non third nerve pattern like ptosis plus esotropia. Esotropia is usually six nerve palsy. And the other important thing to recognize is if you have myasthenia gravis already, you already have a postsynaptic blockade; you already have post-synaptic acetylcholine receptor antibodies. It's dangerous to give the pre-synaptic botulinum toxin to someone who already has a post-synaptic problem because you could flip that person into full-blown myasthenic crisis or precipitate a worsened ptosis and ophthalmoplegia because you are giving someone who has myasthenia gravis botulinum toxin. And the reason that's important is botulinum toxin is given for other things, like hemifacial spasm and blepharospasm and also for migraine and also into muscles for strabismus. So we cannot just give people botulinum toxin without asking about the symptoms of myasthenia. And if we give someone botulinum toxin and they get a ptosis or ophthalmoplegia, we need to be aware that that could be from diffusion of the Botox to somewhere you don't want it to go. And so you need to know a little bit about botulinum toxin causing neuro-ophthalmic problems from iatrogenic, cosmetic, or other indications in and around the eye. |
| Date |
2021-04 |
| Language |
eng |
| Format |
video/mp4 |
| Type |
Image/MovingImage |
| Collection |
Neuro-Ophthalmology Virtual Education Library: Andrew G. Lee Collection: https://novel.utah.edu/Lee/ |
| Publisher |
North American Neuro-Ophthalmology Society |
| Holding Institution |
Spencer S. Eccles Health Sciences Library, University of Utah |
| Rights Management |
Copyright 2019. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright |
| ARK |
ark:/87278/s6xh5ns4 |
| Setname |
ehsl_novel_lee |
| ID |
1680589 |
| Reference URL |
https://collections.lib.utah.edu/ark:/87278/s6xh5ns4 |
