 So first off, I'm happy to see Dr. Hatch is here because today is National Signing Day for the recruits. And I thought he'd maybe, you know, researching what Utah is signing this year. The recruiting class doesn't look to be super great, but I think we're ranked like 70th right now. It's a down year for us. But anyways, our next presenter is Marilyn McCassan. She's also a PGY3 neurology resident. And like when we do our neuroophthalmology rotation, we have to do a certain number of grand rounds and presentations. They will hunt you down no matter if you're an ophthalmology or a neurology. She's finished her neuroophthalm rotation a couple months ago. They hunted her down to come back. So she's going to present chronic relapsing, inflammatory optic neuropathy. We'll be found. You cannot escape. Right, so yeah, I'm talking about chronic relapsing, inflammatory optic neuropathy. This also is a patient that I saw with Dr. Warner. So I'll talk about our case and then talk about the disease a little bit and then we'll just return to our case to see kind of where he is now. So our patient is a 48-year-old man. He presented a little over six months ago with right eye pain that was worse with eye movements. And that was followed shortly thereafter by complete vision loss in his right eye. On review of systems, he had a little bit of fatigue, but otherwise, that was about it. History of hypothyroidism and depression. He's had a couple of surgeries in the past. Nothing too remarkable on his social history. In his family history, his mother had hypothyroidism, so maybe a little bit of autoimmunity in pancreatic cancer and father just had hypertension. On his physical exam at his initial presentation, his visual acuity in his right eye was hand motion, but normal on the left. He had a very slightly elevated intraocular pressure on the right, normal on the left. He did have an afferent pupillary defect on his right eye. Extraocular movements were slightly limited just by pain, but otherwise were intact. He had impaired color vision on the right eye. And then on his anterior segment exam, he just had some mild blepharitis, maybe some trace cataracts, but then on his dilated fundoscopic exam, he did have some edema of the optic nerve on the right. These are his visual fields from when he first presented, and you can see that in his left eye looks pretty normal, but almost completely obliterated there on the right. And this is his initial MRI, and this is a contrast-enhanced MRI, and you can see there on the coronal view that on the right he has enhancement of his optic nerve, whereas we don't see that enhancement on the left eye, and you can see the same thing on the axial view there. And then, I mean, I don't have images looking at the rest of the brain, but his brain looked normal. So he had a pretty extensive laboratory workup that was mostly unremarkable. BMP and CBC were normal. He had aquapor in four antibodies tested, looking for NMO, and those were negative. They tested an ACE level, looking for sarcoidosis, which was normal. ANA was not detected. Lysosine was normal. RPR was non-reactive. ESR was normal. And then he also had West Nile virus titers that were negative. He had a lumbar puncture, and his CSF was normal. And he has a couple of labs that are pending right now testing for optic nerve antibodies, as well as CRMP5 antibodies, which are part of a perineoplastic syndrome that can affect the optic nerves. And then he also had a chest x-ray, again looking for changes that would suggest sarcoidosis, and that was also normal. So, yeah, like I said, his labs and imaging were pretty unrevealing, except for that optic nerve enhancement. So at this point, he really just has an isolated optic neuritis. He was treated then after this episode with methylprednisalone infusions for three days, followed by oral prednisone that was tapered over time. And with that, his pain resolved and his vision improved almost back to normal in that right eye. However, over the course of the next six months, he had two relapses of optic neuritis on his left eye and another relapse on the right eye. With each relapse, he was treated again with another IV course of steroids. And his vision, again, would return to normal almost normal. Each course of IV steroids was followed by oral prednisone, which was tapered over time. And it was noted that every time he would taper his oral prednisone down to either like zero to maybe about five milligrams daily is when he would have another relapse. And this just shows his visual fields on one of his return visits. And you can see that the right eye, which was the one that was initially affected, was almost returned to normal, and now the left eye is affected. So at this point, with so many relapses, he can be considered to have chronic relapsing inflammatory optic neuropathy. This is a really rare disease, and it's actually pretty new to the literature. So we've known about optic neuritis for a long time, and we've known that it can be its own isolated event, or it can eventually, over time, progress to multiple sclerosis or NMO, or it can be part of another systemic disease, like many of the things that this patient was tested for. But in some instances, we don't find any other disease, and these patients can just have relapses of optic neuritis, and that's when they get the diagnosis of cryon. So this was first described in 2003, so it hasn't really been around for that long, or at least that we've known about. In 2004, the NMO antibody was first described, or first discovered, I guess, and so at first people were saying, well, maybe cryon is part of NMO, but as this was studied more, it was found that these are really pretty separate entities. 95% of patients who present with optic neuritis are negative for the NMO antibody, and we also know that these diseases have different mechanisms of action, and with NMO, there's a complement activation that causes astrocytic necrosis, and there's a G-FAP biomarker that you can use to detect this process, and that is not detected in cryon, so that kind of helps to distinguish the two diseases as well. So, Petzel and Plant recently published a review of all of the 122 cases that have been reported in the literature since 2003. So really not something that we see very often, but from their review, they found that patients aged, or were aged anywhere from 14 to 69 years old with a mean of about 35 years, probably a little bit more prevalent in females, although in a 32% of the cases, the gender wasn't reported, so hard to know exactly. The etiology's certainly not understood, although it is thought to be some kind of autoimmune process because these patients do respond really well to immunosuppressive therapies, but we don't have any biomarkers for this disease, like we do, like for example, the NMO antibody that we have with NMO. So these patients present with either monocular or bilateral vision loss, which is usually severe, like we saw in our patients. The course of the disease and the prognosis is a little bit difficult to know right now with only a few cases in the literature and very variable time of follow-up with each of those cases, but the authors note that in their experience, the disease activity can settle over a decade or so. Anywhere from two to 18 episodes of relapse have been reported, although again it's hard to know because there's kind of a variety of lengths of follow-up. And most people do present with pain with their vision loss, like we would see with a typical optic neuritis. So when we evaluate these patients with optic neuritis, the differential is pretty broad. Usually these patients should get an MRI of their orbits and brain, as well as the spinal cord with and without contrast. For cryon, you should see optic nerve enhancement, but the MRI can also look for evidence of demyelinating lesions, which could make you think that maybe this is actually MS or NMO or some kind of compressive lesion affecting the optic nerve. But for cryon, there really shouldn't be any other MRI abnormalities that would explain the patient's symptoms. These patients should get an NMO antibody tested and usually should be negative, although approximately 5% of cases of cryon in the literature have a positive NMO antibody, which makes things a little bit confusing. Also on the differential is ischemic optic neuropathy, and you could think about this in somebody who has vascular risk factors. Maybe think about a temporal artery biopsy if you're worried about GCA. In someone with a family history, you could think about an hereditary optic neuropathy. And then testing for any of the systemic diseases that can cause optic neuritis, like diabetic papillitis, any of the toxicities or nutritional deficiencies that can cause this. There are several infections. Other autoimmune or inflammatory diseases like lupus. The authors of the Petzlilin Plant paper that at the review of all of these cases, they stress that they don't think that a lumbar puncture is needed to make this diagnosis, although of course it can be helpful if you have any reason to suspect MS or an infectious cause that a CSF analysis could help to differentiate. So the treatment can be broken down into three phases. In the acute phase, your goal is to restore the lost vision. Most people have used solumetrol or methylprednisolone for this. You can also use plasmapheresis. Once you've done that, you want to stabilize the vision. And this has usually been done with oral steroids. The authors of this review paper suggest using prednisone one meg per gig per day and then gradually tapering over time. Some patients are able to be tapered off with prednisone completely, but others will require oral steroids chronically in order to prevent relapses. And then in the long term, finding an immunomodulatory therapy that can allow the patient to come off of steroids is ideal, and a variety of things have been used for this even IVIG and plasmapheresis. So these authors proposed a set of diagnostic criteria for cryon. So they suggest that in the history, someone would have to have optic neuroritis with at least one relapse. They would have to have objective evidence for loss of visual function. They should have a negative NMO antibody ideally. MRIs should show contrast enhancement of the optic nerve, and these patients should respond to immunosuppressive therapies. So to follow up on our patients, when he was last seen, I think in January, his vision in his right eye was 2040, but 2020 on the left. And recently, he's been started on methotrexate in hopes to hopefully get him off of steroids. He had a recent MRI with maybe some faint optic nerve enhancement, but you can see here, this is his MRI, both optic nerves look pretty good, or at least closer to normal than his first MRI did. So I think that's it. Thank you.