| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (ML) Class of 2021, Baylor College of Medicine, Houston, Texas |
| Transcript |
Today we're talking about Guillain-Barré syndrome. The Guillain-Barré syndrome is an acute inflammatory demyelinating polyneuropathy. And that means it is a polyneuropathy; it is both motor and sensory. It's usually an ascending polyneuropathy that occurs acutely to subacutely. It is demyelinating in the peripheral nervous system. It is inflammatory because there are antibodies that we can detect in the acute phase of the Guillain-Barré syndrome directed against components of myelin. And it's acute as opposed to the chronic form. The chronic form is called chronic inflammatory demyelinating polyneuropathy, also known as CIDP. We don't have time to talk about CIDP today. The AIDP has an ophthalmoplegia variant, which you can watch a video on, called the Miller Fisher variant. So when you have ophthalmoplegia and AIDP, we call it the Miller Fisher syndrome. So the key features are all A's in the clinical arena. We have an ascending polyneuropathy: sensory, motor. Ascending polyneuropathy. We have areflexia. We can have ataxia. And in the CSF, we're gonna be looking for albuminocytologic dissociation. And what that means is, we have few cells but high proteins in the CSF. The MRI scan in Guillain-Barré syndrome is typically normal, and the treatment, depending on severity, is IVIG or plasma exchange. We don't usually use steroids in this setting, even though you would think that it is an antibody, inflammatory-mediated disease that it would work. The antibody is anti-ganglioside antibody, and the prototype is GQ1b. And what this G stands for is ganglioside. As you know, a ganglioside is composed of side chains of sugars onto the core molecule for myelin, the ceramide and sphingomyelin core. And we call that a ganglioside, and the sugar that we're attaching is called N-acetylneuraminic acid, NANA. And that also goes by the name of sialic acid. So when we have 1 sialic acid attached onto the ganglioside, we call that GM, ganglioside monosialic acid. If we have 2, ganglioside disialic acid. If we have 3, ganglioside tri. And finally if we have 4, ganglioside quatrosialic acid. And it is this ganglioside quatrosialic acid, GQ1b, that is the antibody that causes the prototype Guillain-Barré syndrome, including the Miller Fisher variant, although the other anti-ganglioside antibodies should also be tested for. In patients who have anti-GQ1b antibody, they might have a pre-existing, pre-disposing trigger. Diarrhea, from Campylobacter jejuni, for example. And Campylobacter jejuni has something that is molecularly similar to GQ1b, and so your body is trying to attack Campylobacter jejuni, but instead is attacking you. An autoimmune, molecular mimicry event, triggered by a Campylobacter jejuni diarrhea leading to production of antibodies against gangliosides and producing an ascending polyneuropathy, ataxia, areflexia, and albuminocytological dissociation. This elevated protein is the CSF marker of blood-brain barrier breakdown from the attack, intrathecal production of immunoglobulin, and the condition we call Guillain-Barré syndrome. If you add the ophthalmoplegia, Miller Fisher variant, Guillain-Barré syndrome. |
