Lecture: Idiopathic Intracranial Hypertension – Common Challenges and Misconceptions

During this live webinar, we will discuss radiographic signs of intracranial hypertension on MRI and their significance, review data on the surgical treatment of IIH including venous sinus stenting, understand what to do when papilledema improves but headaches do not, and examine the management of IIH in pregnancy. Participants will also be able to recognize fulminant IIH, understand how to approach IIH without papilledema, and recognize the association between IIH and skull base CSF leaks. Questions received from registration and during the webinar will be answered. (Level: Intermediate)

Lecturer: Dr. Devin D. Mackay, Ophthalmologist, Indiana University School of Medicine, USA


Hello everyone. Welcome to our webinar today. My name is Dr. Devin Mackay. I’m the director of neuro ophthalmology at Indiana University in the United States. We’re going to talk about idiopathic intracranial hypertension and common challenges and misconceptions. This is a condition that I see in my clinic and I see confusion out in the community on how to manage these patients and the best way to treat them. We’re going to be talking about that today. I have no relevant financial disclosures. The objectives today, one is to understand how the number of radiographic signs of intracranial hypertension that someone would find on an MRI influences the likelihood of finding papilledema. We’re going to talk about the data on the medical management of IIH and several surgical options including venous sinus stenting, which is relatively new. We’ll discuss what to do when a patient with IIH improves in every way except for headaches. Understanding how pregnancy planning impacts the management of IIH. Introduce idiopathic intracranial hypertension without papilledema and know what to do with those patients. And recognize fulminant IIH and be able to facilitate urgent management to save their vision. First, some of the systems that are typical for IIH. Headaches is the most common symptom and almost everyone has headaches, 94 percent of patients with IIH have headaches. The headaches may or may not be worse when lying down. If it’s worse when lying down, that can be a vote that high pressure is causing the headache. And the headache can be after a lumbar puncture. Pulsatile tinnitus is like a whooshing sound in the ears that is synchronous with the pulse. 58 aren’t of people have that. Transient visual obscurations are common in 68 percent of patients and that is in patients with moderate to severe papilledema. The way I ask patients about this, does your vision gray out or black out when you bend over, cough, or sneeze. Diplopia is less common, 38 percent of patients. Can happen from unilateral or bilateral sixth nerve palsies. Weight change, specifically rapid weight gain. And nausea and vomiting present in acutely severe elevated intracranial pressure. And, of course, some patients are asymptomatic. That happens as well. Papilledema is the most important finding when someone has IIH. And the higher the grade of papilledema that is found, the higher the risk is of permanent vision damage. Papilledema can be somewhat quantified on the grading scale to the right, the Frisen scale. I document that and I hope others do, too. It’s a nice way to quantify things in a way that is replicable and you can communicate between different people that way. Optic nerve structure and function with the most important things to monitor. Visual field testing is especially important and looking at the optic nerve head and seeing what the grade of papilledema is. Those are the two most important things. And then we check the color vision and visual acuity and other measures of optic nerve function. One of the pearls I wanted you to take from today is the higher opening pressure measurement does not automatically mean the patient has a higher reproduction of vision loss. The asbestos opening pressure does not have a determination of vision loss. What does determine that is how severe the papilledema is. Visual field progression. How does the visual field worsen in patients with IIH. That is worth knowing about. It progresses a lot like glaucoma from the outside in. Patients may not notice the vision loss is happening. Remember that central vision loss in IIH indicates severe vision dysfunction, it’s usually the last thing to go when someone has IIH. So here is a typical progression of visual field abnormalities with this condition. Enlargement of the blind spot is often the first thing we see. Followed by a nasal step. Visual field constriction. And then the center part of the vision. Central vision defects are very uncommon especially early in IIH. If you have a mild case where central vision loss is the predominant part of the presentation, we want to think about other diagnosis in that kind of case. One hot topic that has come up over the years is radiographic signs of intracranial hypertension. How often have you seen this phrase in your radiology reports? This was a report from an actual patient. Partially empty sella and bilateral transverse sinus narrowing. Correlation is advised and evaluate for papilledema. What do we do with this? Does this mean every patient that has that in their radiology report needs a lumbar puncture and we need to assume IIH? Not exactly. Let’s take a moment for a poll, I would love to know from each of you, how often are you referred patients because the radiologist read an MRI as showing signs of intracranial hypertension? Very frequently, fairly frequently, pretty rarely, or never. No one has every referred to you for that. I would love to hear your responses: We’ll give 30 seconds for everyone to respond and we’ll see what the results are. So we have people in the fairly frequently to rarely category as most common. And very frequently a few. And never a few. Okay. That’s really been our experience here as well. It’s good to see that appears elsewhere. To answer this question about how concerned do we need to be when patients have radiographic signs of intracranial hypertension? There is a study I want to call attention to published in Jama neurology in 2021. Looking at the prevalence of signs of intracranial hypertension on MRI and association with papilledema. For this study they took almost 300 patients that had MRIs for any reason at all. And they took them consecutively. And asked a neuro radiologist to look for ten different signs of hypertension. This one is distal transverse stenosis. Optic nerve protrusion into the globe. Increased CSF space around the optic nerve. The white ring around the optic nerve there. Empty sella turcica. Cerebellar tonsillar ectopia. Where the cerebellar tonsils descend below the foramen magnum. Here is the cerebellar tonsils. If they go below the line at the base of the skull, the foramen magnum, then that is cerebellar tonsillar ectopia. And posterior scleral flattening. If the posterior part of the globe is flat. And a few other signs as well. All of these patients underwent fundus photographic. And those without normal photographs were evaluated by a neuro ophthalmologist in person to confirm papilledema. And out of all these almost 300 patients they found 5 who had papilledema. And they looked at signs of intracranial hypertension and if someone had one sign of IH or more on MRI, about 2.8 percent of those patients had papilledema. That is not impressive. If someone had an empty sella, for example, their likelihood of papilledema was 3 percent. Quite low. If patients had more signs of intracranial hypertension, four or more of the ten signs, the prevalence went up quite a bit. So the most common sign in this series was an empty sella. A third of patients have an empty sella, that is amazing. For any reason at all. 300 MRIs done consecutively for any reason at all, about a third of those had an empty sella. It’s a common finding. Only five out of 300 had papilledema. There are a lot of patients with empty sellas that don’t have papilledema. Of the five, two had a known history of IIH, two had a structural lesion, a glioblastoma, and one with a temporal lobe encephalocele. If they had more radiographic signs of intracranial hypertension, they were more likely to have papilledema. Remember only 3 percent if they had one sign of intracranial hypertension had papilledema. It’s very unusual to diagnosis IIH just from the MRI and have that be a meaningful diagnosis. That is very, very rare. What did we learn from this? If someone has one sign of intracranial hypertension, it’s rare that is associated with papilledema. And looking for radiographic signs can be a factor in estimating how likely it is a patient may have papilledema but it doesn’t mean all of the patients have IIH. And those with papilledema were detected in this study with fundus photography without pupillary dilation. This is a photo of my own eye. This is the future of fundoscopy. Now direct ophthalmoscopy is useful and used in a lot of places and places that we can’t bring other equipment easily. But fundus photography with cameras like you see here are going to be part of the future. I typically teach others who are not ophthalmologists when they come across these findings on an MRI report, I have them ask the patient when was your last eye exam. If they had a recent exam that showed no papilledema, there is typically no cause for concern. If there was papilledema, they get evaluated as if they may have IIH or some other intracranial hypertension cause. Now shifting gears, let’s talk about the medical management of IIH. The best data we have for the medical management of IIH comes from the IIH treatment trial published in the journal of the American Medical Association, Jama in 2014. Let’s go over the results of the trial. They took 165 patients with IIH and mild visual loss and they randomized them to either a weight reduction, low sodium diet, plus acetazolamide or that diet plus placebo. The primary outcome was improvement in the visual field. I was happy about that. Visual field function is the most important outcome in IIH. So acetazolamide was better than placebo in improving visual fields, improving papilledema and improving vision related quality of life. There were some things that acetazolamide was not better at doing. That was improving headaches and improving visual acuity. The visual acuity part is not too surprising. These patients had mild vision loss, if you remember, central vision loss which is where visual acuity would be is uncommon in IIH unless it’s really advanced IIH. Acetazolamide has our best evidence for efficacy in IIH. How I usually prescribe it is in total daily doses up to 4,000 mg a day. I divide it twice daily. You can divide it more frequently like 3 or 4 times daily if the patient has difficulty tolerating the medication. That can be helpful change. In terms of a starting dose, about 500 mg twice daily. And I titrate if the patient has severe papilledema, I titrate up quickly to a higher dose. If they have minimal symptoms, I may stay there or go lower depending on the side effects. What are the side effects? Most patients describe a change in the taste of carbonated beverages. Sodas taste bitter to them. Tingling of the hands and feet is a common side effect. Most patients have that. And some patients have lethargy or other side effects. Now, weaker evidence exists for the use of topiramate. Class 2 evidence. A carbonic anhydride inhibitor similar to acetazolamide but it works a little differently. It has added benefits of serving as a prophylactic agent for migraine. So if you think a patient may have comorbid migraine, this can be a good choice. And there is a side effect of weight loss in patients that take topiramate. But the efficacy is not quite as good as acetazolamide. We have better evidence for acetazolamide. And some physicians use furosemide as well. It’s a poorly studied medication in IIH. Class 4 evidence. It can be helpful if someone wants to avoid surgery and everything else has failed. It can be a useful medication in some cases. Now what do we do with the side effect of nephrolithiasis or kidney stones? This was studied in the past and in this particular study they looked at the charts of 670 patients who had IIH. This was a case control study. They found that almost 3 percent, so 19 patients developed a kidney stone during acetazolamide treatment for IIH. That is a known side effect of IIH. What did we learn about that? About 90 percent of those who developed a kidney stone did so within the first year and a half of treatment. There was no association between the daily dose and stone development. In other words, if someone was on a higher dose of acetazolamide, that did not equal a higher risk of having kidney stones. Also, the longer you’re on the medication, so say five years you’re on the medicine versus a couple of years, there is not much difference there either because the first year and a half is the biggest risk for nephrolithiasis. If you gets it, it’s usually within the first year and a half. This has helped frame what I tell patients about the risk of kidney stones when they’re being medically treated. Most of the risk is the first year and a half and it doesn’t matter if they’re on 200 twice a day or 500 mg twice a day, there doesn’t appear to be a difference in the risk of nephrolithiasis. The other thing that came up in a few of my patients is a sulfa allergy. So as you know, there’s a moiety on acetazolamide that is, a sulfa moiety. There can be cross reactivity. It’s the thought with patients that have a sulfa allergy, they may also be allergic to acetazolamide. So does that mean we can’t use acetazolamide in patients with a sulfa allergy? Someone looked at this. Andy Lee and Michael Wall and a group in Iowa looked at this. They looked at 363 patients with IIH and found that almost 10 percent had a self-reported sulfa allergy. 34. 27 of those patients were treated with acetazolamide and 21 with furosemide and 14 with both. What I take home from this is it’s okay to use acetazolamide or furosemide in patients with a self-reported sulfa allergy if you need it. So I don’t let the self-reported sulfa allergy block me from trying the medication. I still convince most patients to take acetazolamide when necessary. If someone has a history of a very severe anaphylactic reaction to sulfa, that might make me think twice. But if it’s hive or a rash or GI intolerance, I push for acetazolamide because it’s the best medication that we have for the medical management or IIH. Weight loss is also a corner stone of the medical management of IIH. This study was fairly recently published in 2022 and looked at the amount of weight loss after bariatric surgery in patients with IIH. And seeing how much weight loss is enough in these patients. This looked at 66 women in the UK with IIH. Who had a BMI greater than 35. They randomized them to treatment with bariatric surgery or community weight loss management intervention. 23 of the 66 underwent bariatric surgery. And a loss of 24 of the body weight was associated with IIH remission. It went away when somebody lost weight in this study. Does that mean we need to recommend someone losing a quart over their body weight? That’s a lot. 60 pounds for a 250-pound person. It’s hard to get that kind of weight loss unless you’re doing bariatric surgery. And maybe 6 to 10 percent weight loss was previously suggested to make a difference with this condition. These data were for weight loss without acetazolamide use. So it can be different when someone is on acetazolamide. They maybe don’t have to lose quite as much weight. There is an amount of weight loss that is helpful for these patients. That exact amount is different for each patient and I never give a specific target number. We encourage them to work on weight loss as best they can at a rate of 1 to 2 pounds a week and try to keep it that way. Pregnancy planning and IIH. Oral contraceptives are not contraindicated in IIH. There has been an association between OCPs and IIH suggested by some case reports, however multiple studies have shown there is no increased risk of IIH from OCP use. OCPs with higher estrogen doses in the past were associated with weight gain and that may be a mechanism that IIH was more prevalent on patients from those OCPs in the past. The OCP estrogen levels are lower now and not associated with weight gain. This is a study out of the Mayo clinic. It’s a population-bailed study looking at the association between hormonal contraceptives including oral contraceptives and IIH. And they looked at patients with IIH diagnosed in this period. They have access to all of the patients with medical records in their county. They’re able to make population-based studies. And 53 had IIH. 21 percent used hormonal contraceptives within 30 days of diagnosis. And 31 percent of the control patients used hormonal contraceptive. The odds ratio, in other words the risk of OCP leading to IIH was 0.52. Much less than one. There was not an increased risk in patients on OCPs of developing IIH. This is mostly oral contraceptive pills but other contraceptives were included as well. OCPs do not lead to IIH. There is a myth out there that everyone need to be off of OCPs if they are at risk of IHH and the answer is no, that is not correct. If someone is pregnant and they have IHH and it’s confirmed and you need to treat them. Acetazolamide is listed as a pregnancy category C medication. That means that we don’t have data definitively proving it’s safe or harmful. There is studies showing class 4 evidence for acetazolamide as a safe treatment during pregnancy. One was an observational case study with 12 patients and they found no adverse pregnancy outcomes in those 12 patients. A larger survey of 158 pregnancies and 50 in the first trimester, showed no complications in women treated with acetazolamide. We asked in an informal setting at national meetings, has anyone had significant birth defect cases with IIH and there aren’t any. If the medication is necessary, then it is an option and I do use it routinely in patients with, who are pregnant and have IIH. Topiramate should not be used. It’s teratogenic. Don’t use topiramate during pregnancy. Now headaches. Your patients will come in with this and we need to figure out do I need to treat the IIH to get rid of the headache. Patients, so let’s examine a case here. A 25-year-old woman with IIH first diagnosed 2 years ago with papilledema and good visual function comes to see you. She initially had classic symptoms of headaches, pulsatile tinnitus and visual obscurations: Lost 10 percent of body weight and treated with acetazolamide at doses up to 2,000 mg device a day. High dose. And resolution of most of the symptoms. However, her headaches recently returned. Does that mean that her intracranial pressure went up again? Is that what happened? How do we know what to do with these patients. Let’s take a step back and understand the pathophysiology of headache in IIH. So the cerebral veins and meninges are the pain sensitive intracranial structures. Venous sinus stenosis and increased venous pressure present in many IIH patients may be a source of pain. Pressure on the meninges activates the release of nociceptor in meningeal blood vessels. This can lead to a cascade of events in the trigeminal vascular system and the projections which is similar to the pathophysiology of migraines. During the headache, the meningeal nociceptors and trigeminal system can become sensitized. Patients can have dysfunctional pain modulation as a resulted. And if that has happened, then lowering the ICP may have little effect on headache pain, even if initially it was from the pressure. This dysfunctional pain after chronic headache can sometimes change the effect if you were to lower the ICP again, maybe it won’t have the same beneficial effect. What do we do with patients who have headaches and IIH. There was a review in the journal of neuro ophthalmology in 2019 that went over this issue. 2/3 of IIH patients continue to have headaches even after the papilledema goes away and other symptoms of IIH resolve. Early in the course of IIH, CSF pressure lowering agents are the first line treatment for the headaches. And then adjunctive agents as needed. But after the resolution of the other signs and symptoms of IIH, the papilledema goes away and they’re doing well but the headaches are still there. It’s a headache-based strategy and it’s based on the phenotype of the headache. A migraine, a tension headache, treat it without regard to the intracranial. Someone’s headaches come back and automatically it’s assigned the IIH is the cause and it may not be. It may have been the initial cause but not the current cause. Those with just headache and nothing else, no papilledema, the patients need to be treated phenotypically for their headaches and that can be done with a neurologist. This summarizes what I just mentioned. So determine that headache phenotype and treat it as such. And again, that can be something that a neurologist can do. Take home message is treat according to the headache phenotype when someone has chronic headaches and IIH and the other signs and symptoms have gone away. Don’t try to lower the ICP as a treatment for that. What about IIH without papilledema? What do we do with those patients? Turns out this is a recognized entity and shares much of the same diagnostic criteria that are used for IIH with papilledema. With a notable exception of they either have to have one of two additional things. A sixth nerve palsy or 3 out of 4 imaging findings of ICP. The four that were chosen, empty sella, flattening of the posterior globe, distension of the optic nerve sheath or traverse sinus stenosis. Three out of four of those and the other criteria for IIH they meet the diagnostic criteria. Or a sixth nerve palsy. It’s not enough to have an opening pressure high on the lumbar puncture. You have to have the radiographic findings as well or a sixth nerve palsy. What do we do with these patients. If they don’t have papilledema, can they lose vision from IIH? The answer is no: They cannot. So that’s a very, very important detail. This has been studied in the past. So patients who do not have papilledema and they have a IIH, they are not at risk of vision loss. It’s an issue of headache management and controlling the symptoms. That can be done with acetazolamide and the other typical treatments but the issue is not vision risk. That is typically managed probably not by an ophthalmologist at that point. Why diagnosis that? Who cares if they can’t lose vision? Why do we care about IIH without papilledema. It clarifies ways to treat them for the high ICP symptoms. The pulsatile headaches or tinnitus if it’s from high pressure, we know how to treat that. There can be spontaneous CSF leaks if there is elevated intracranial pressure. It may be important to treat them to prevent CSF leaks but there is no data to confirm that yet. So it helps provide security of the patient having a diagnosis. That helps them have some security in knowing what to do to help symptoms. It motivates weight loss in many case and can be useful in that regard as well. What about fulminant idiopathic intracranial hypertension? That is I — a patient has intracranial hypertension with no secondary cause and they have severe vision loss within 4 weeks of vision onset. And that progression of vision loss develops over days. It’s a very, very severe case of IIH where the vision loss is presenting early and it’s swift. These patients we need to intervene on quickly. They need urgent treatment. They are at permanent risk for vision loss if we don’t treat them immediately. This is estimated to be 2 to 3 percent of patients with IIH have this fulminant variety. It’s worth knowing about them because we can help save their vision if we intervene quickly. So how do we recognize fulminant IIH when it happens? One series of 16 patients looked at what symptoms the patients present with. About 56 percent of the patients in that series presented with nausea with recurrent vomiting. That is not typical for IIH. If you have someone with severe vomiting as part of the IIH, that can tip you off this is a fulminant IIH case. And the majority of parents, 81 percent had subjective vision loss. They recognized their vision was going in the first few weeks. Neck stiffness is 25 percent. I hear about that in patients without fulminant IIH. If there is a prominent neck stiffness, you may want to think about fulminant IIH. And all of these parents should have severe papilledema. This should not be subtle papilledema. It’s severe sight- threatening papilledema. These patients should have neuro imaging performed quickly, an MRI. And a lumbar puncture to confirm the diagnosis and the puncture can provide a temporary decrease in the ICP. That does not last long. But sometimes it can be helpful in providing a little relief for the patient and time to plan for a surgical procedure if needed or starting aggressive medical management if it’s appropriate to do so. And fulminant IIH is managed with medical and surgical intervention combination. I start them on acetazolamide and get to a high dose quickly. That is a first step. We may want to consider urgent surgical intervention depending on the case. If we don’t have time for medical management to work because we’re losing vision quickly, we need to go to surgery in those cases. Some patients can be treated with IV methylprednisolone as a temporary measure while waiting for surgery and the pressure is getting bad. Sometimes IV methylprednisolone is an option. If the delay in surgery and they need surgery is more than 24-hour delay, you can consider a lumbar drain. That is a temporary shunt. A ventricular drain. Or serial lumbar punctures. I don’t advocate that unless they’re in the hospital and you’re literally waiting for surgery and can’t do a lumbar drain. Serial LPs are not the way to manage intracranial hypertension. Surgical options, there are three main options currently. CSF shunt, optic nerve, and venous sinus stent. These are the three that we choose from. How do you know which one to recommend? Well, let’s get a poll here first. I would love to hear from you about what surgical procedure have you most commonly recommended for IIH when necessary? Have you recommended a CSF shunt like a ventriculo peritoneal shunt or an optic nerve sheath fenestration or a venous sinus stent or bariatric surgery? Which have you recommended when needed most commonly. The vast majority are the shunt. Few for venous sinus stenting and bariatric surgery. Let’s talk about how to choose among those different options. First we need to understand how do we know when a patient needs surgery? How do you know when they need surgery? There are no universally agreed upon criteria. That’s the first thing to know. The most important thing is visual loss. That’s the most important criteria in deciding if someone needs surgery. Here are reasonable criteria for treatment of IIH. Surgically, what I would consider strong criteria is progressive vision loss despite medical therapy and significant vision loss on first presentation. Fulminant IIH are strong indications for surgery. Less strong, they have some vision loss but you can’t follow it for some reason. Maybe they have cognitive impairment or can’t do visual field testing and maybe they have severe papilledema. Or intractable headaches that respond to lumbar punctures even though the vision is okay. That is a more controversial indication. What are the surgical options? So one is doing a ventriculo peritoneal or LP shunt. That’s the most commonly recommended one in our group here today. And optic nerve sheath fenestration and venous sinus substantiating and bariatric surgery. Let’s talk about transverse venous sinus stenosis. This is one of the most reliable radiographic signs associated with IIH. And it’s sometimes hard for us to know does the transverse sinus stenosis cause high ICP or is high intracranial pressure causing transverse sinus stenosis or both? And so does one cause the other and they reinforce each other in a feed-forward cycle. So it may be that the second model is more accurate. And some people have speculated the venous sinus wall may be weaker in patients with IIH so it’s more susceptible to stenosis and that leads to high ICP and that causes more stenosis and it’s a cycle. How do we break the cycle? How do we break that cycle? So one way is to think about what if we took care of the venous sinus wall weakness by placing a metal scaffold in there like a stent. Some patients have a pressure gradient across their area of stenosis and so through catheter venography we measure the pressure before and after the stenosis and find a difference of 8 mm of mercury. That’s the support that says that venous sinus stenting may be indicated. Now, the surgical treatment of IIH, there was a trial that was designed to try to look at that and unfortunately, the trial was terminated due to low enrollment. The surgical IIH trial never happened. There is a trial that was possibly completed or may still be on going now that’s been going on for a few years looking at a prospective randomized control trial in patients that undergo monography, those with a trans-stenotic gradient of at least 8 mm of mercury, were randomized to one of two arms. Either a CSF shunt or venous sinus stenting. The primary outcome is vision related. This was supposed to have completed in January 2024, a few months ago, but I haven’t seen publications on this yet. We’re waiting to see what results may come from that trial in helping us know what is more helpful for these patients, shunts or stenting. The best data we have that compares the different surgical modalities for IIH comes from meta analyses. One was a review of 20 studies. The majority of those were retrospective. They had a varying number of patients, up to 52 and down to 6 in some studies. Median follow up was 18 months. Venous sinus stenting for the most part was quite safe with 474 patients, only 3 had subdural hematomas and one had a subarachnoid hemorrhage and they completely recovered. Overall, this supported a favorable safety profile for venous sinus stenting. 1.9 percent overall complication rate. Here is another meta analysis. This looked at over a thousand patients. 712 had ONSF and 435 with CSF shunt and 136 with venous sinus stenting. The highest major complication rate was seen in shunting. So shunting is not, certainly not benign. And the lowest major complication rate is optic nerve sheath fenestration but stenting was comparable. And minor complication rates, the lowest with stenting and significantly higher with the other two surgical modalities. And the efficacy of venous sinus stenting in IIH is looked at in these meta analysis. If we compare number, we find that papilledema improves in pretty much all of the forms of IIH surgery. But the best is with venous sinus stenting. 94 percent of the patients had improvement in papilledema. And only 70 percent with shunting and 80 percent with stenting. They got better with the pulsatile tinnitus. And their headaches got better. Optic nerve sheath fenestration is not a great treatment for headaches. Patients who were shunted, 43 percent needed another surgery at some point and with the stenting, about 12 percent. So what does this mean for venous sinus stenting? Should we recommend this more? It has a favorable safety profile. Improves the headaches, vision, and papilledema and pulsatile tinnitus. It can be that it’s comparable or superior to optic nerve SF and CSF diversion like shunting. The data that I just showed you are based on the pooling of heterogeneous data. This is retrospective. There is publication bias and other forms of bias. Cases with poor outcomes might not get published. So the long-term outcome of patients with stents is not clear. That is why we’re hoping for prospective trials to know if venous sinus stenting a good and comparable way to treat patients that need surgery for IIH. We’re looking for those trials to help inform us here. I used to not recommend venous sinus stenting at all but now I offer it as a treatment option. I discuss this data with them and allow them to make an informed decision on their own based on what we know from the data. What are the key points here today that I would like you to take home with you and really internalize from this webinar today? One is that the prevalence of papilledema in patients with at least one radiographic sign of intracranial hypertension is very low. Only about 3 percent of those patients with a partially empty sella for example from papilledema. So we want to suspect fulminant idiopathic intracranial hypertension if someone has rapidly declining vision, nausea and vomiting, papilledema, neck stiffness. These patients need urgent medical and surgical intervention after the diagnosis is confirmed. Confirm the diagnosis immediately and these patients needily need aggressive treatment. Vision is always the most important criteria when considering surgery for IIH. There may be other indications but vision is always the most important one. We talked about the surgical options. Most patients with sulfa allergies tolerate acetazolamide just fine. Don’t let a sulfa allergy talk you out of treating someone with IIH with acetazolamide if it’s indicated. A very important one is IIH patients cannot lose vision without papilledema. It’s safe to use acetazolamide in pregnant women with IIH when needed. Again, no reports of significant birth defects from acetazolamide. If headaches persist or worsen after other science of IIH signs and symptoms have resolved like papilledema, then the headache should be treated phenotypically. Don’t chase the pressure. Get them to someone that treats headaches and treat phenotypically. Hormonal birth control including ICP use does not increase the risk of IIH. That is an old myth. IIH without papilledema poses no risk to vision but it would be worth treating and diagnosing due to the other associated symptoms and it can help a patient feel better. The risk of vision loss correlates with papilledema severity and not the absolute opening pressure measurement. It doesn’t matter if the opening pressure is 45 or 27, it’s high. The important thing is how severe is the papilledema. If it’s more severe papilledema, they need aggressive treatment. If it’s less severe papilledema, less aggressive treatment. The risk of kidney stones does not depend on the dose. The highest risk is within the first year and a half of therapy. Don’t worry about keeping someone on therapy because of the risk of kidney stones. If they get the stones, it’s typically within the first year and a half. The amount of weight loss necessary for remission of IIH varies in studies from 6 percent up to 24 percent with the bariatric surgery in 2022. Regardless of how much the exact amount is necessary for remission of IIH, weight loss is a very important corner stone of the management of idiopathic intracranial hypertension. So those are some of the key points that I hope you take home with you today. There is a picture of my family who are very generous in supporting me to be here and do things like this today. I appreciate them. And now I’ll take time for questions. I’ll stop sharing and get to the questions. Is acetazolamide safe in pregnancy and breast-feeding? We talked about pregnancy, yes, it is safe in pregnancy. There is some that, there is some acetazolamide that turns up in breast milk as well. I haven’t had many patients who have been breast-feeding on it so I don’t have a lot of personal experience with that. I would say, I would still treat that the same way I would treat pregnancy as if we don’t need acetazolamide or it’s necessary. I would try to keep them on as low a dose as possible. If it’s a case with severe papilledema, that’s something that I would still want them on acetazolamide. So even having a child on acetazolamide wouldn’t be the end of the world for sure. So yes, I would still treat them with acetazolamide in that case. So question about who prescribes the Diamox. That is worked out on a case-by-case basis. You can or a neurologist can. There is no magic to it. It’s an easy medication to manage. I don’t monitor labs while someone is on it. I just keep them on it and adjust based on how bad the papilledema is and the side effects and symptoms. How frequently do I check potassium levels? I don’t check them at all. I’ve been fine that way. Some providers I know do check potassium levels and find them to be low at times. I never found any critically low levels or problems from hypokalemia on patients on acetazolamide. Similar question there. What do you tell the patient when they ask things about higher risk of developing kidney stones while on Diamox. The highest risk is within the first year and a half and it doesn’t matter what dose we’re on. I recommend they stay well hydrated and it’s a rare side effect. I haven’t had many patients that didn’t want to do the medication because of it but it should be factored into the discussion. So someone with kidney stones, would you change the medication or opt for decompression surgery. That can be a factor. One of the reasons to do surgery in patients with ICP is if they fail maximum medical therapy. If developing kidney stones prevents you from continuing the medication, that could be failure of maximum medical therapy. That can be an indication for surgery in the right patient. So here is a question about most patients come complaining mainly their headache affects quality of life. How do we manage that? You focus on the papilledema first. Get that managed. If they goes away and they still have headaches. Treat the headache phenotypically. Don’t chase the pressure. If you have to refer them to a headache specialist or a neurologist, so be it. The most important thing is to get the papilledema down and that will help preserve the vision. Do you use acetazolamide in the first trimester? Yes. I do. We don’t have any reports of any significant birth defects from acetazolamide use. That being said, I don’t indiscriminately use it. If someone is in the first trimester, I’m cautious about it and only do acetazolamide if necessary. If it’s possible to get through the first trimester without being on acetazolamide, I prefer that when possible. And how long should someone treat a patient with acetazolamide? That depends on their symptoms and their vision status and how severe their papilledema is. If someone has at least moderate papilledema, then they really need to be on acetazolamide or some treatment for IIH. If they have minimal, almost undetectable edema and no symptoms, I might not have them on acetazolamide at all. I might just observe clinically and if they get worse, I will add acetazolamide. But I have quite a few patients where they’re found to have minimal disk edema and they’re asymptomatic. And those patients I don’t treat with acetazolamide even if they have IIH. So the end point of treatment for IIH is really the papilledema for me. If the papilledema goes away, then that’s time to get off the medication. Is LP always need today diagnosis IIH? Yes, it’s part of the diagnostic criteria. However, there may be some patients if you’re not going to treat them anyway, you can get away with observation without an LP. That is only appropriate if they have no symptoms and very, very minimal edema. But those patients always need an MRI. You have to, have to, have to rule out a tumor or venous sinus thrombosis or other structural cause. If you’ve done that and they have minimal papilledema with no symptoms, sometimes you can get away with without a lumbar puncture. What are the endocrine risk factors for IIH? Well, the main thing is obesity but there’s growth hormone use as been associated with ICP. Is worsening of headache with posture a sign of raised ICP? Yes, it is. If the headache is worse when they lie down and better when they stand up, like immediately, that is a sign of high ICP. How aggressively do you treat patients with IIH with a bilateral sixth nerve palsy? Well, I, so it depends on how debilitating the symptoms are: If they are debilitated by the symptoms, we want that to go away. So that would involve treatment with acetazolamide. The same treatments that we use for IIH with papilledema. A lot of that is the same. Does the — go away, yes, when the patient is treated appropriately. I may titrate the medication up to help that go away or provide whatever medication is needed to get the ICP normal. The highest dose of acetazolamide that I feel safe prescribing is 2,000 mg twice a day. So 400 mg a day is the dose I go up to. In stable IIH patients who monitors and how often would a visual field be performed and what is the visual field test? For monitoring papilledema, that needs to be done by an eye doctor. Neurologists aren’t equipped for that part. The neurologists can help with prescribing the medication or treating the headaches if they’re uncoupled to the intracranial hypertension, But ophthalmologists really need to monitor the disc edema. So Goldman visual fields can done. That is fine. I don’t think it matters what visual field test you use. The key is you want to get a good sense of what their visual function is and if it’s worsening. The it’s worsening, you need more aggressive treatment. If it’s stabilizing, whatever you’re doing is fine. Doesn’t matter the field test, just do something reliable that you can interpret well and know if the patient is improving or not. What surgical options have the best outcomes? We talked about that in the webinar there. Is efficacy for all three of the different surgeries. So optic nerve sheath fenestration and shunting and venous sinus stenting. There are nuances that are different between them and you can refer back to the recording of the webinar. What kind of imaging should we do with patients with IIH? An MRI of the brain with and without contrast as a minimum. MRV, you can consider if your MRI does not show the veins well. The MRIs here we do at Indiana University include thin cuts with a venous sequence. That is like an MRV and it’s sufficient to rule out venous sinus thrombosis. If you don’t that have, you can do an MV venogram or if a patient has red flags for a clotting disorder or family history or personal history of clotting. Those can be reasoned to do a venogram as well. How frequently does IIH cause unilateral papilledema. I don’t have the numbers for that. What is rare is for it to be strictly unilateral. It can be asymmetric. More severe in one eye and less in the other. But severe in one eye and nothing in the other eye, I don’t think I’ve ever had that happen. What is the place for order steroids in the treatment. I never use oral steroids for the treatment of IIH. It may help with the disc edema but it causes too many other problems. Causes weight gain and irritability, sleep issues. Lots of side effects from steroids and there are better medications to treat than steroids: So I don’t use them. Topiramate I use if there is a contraindication to acetazolamide or they really need the weight loss help. Maybe they have a known history of migraine and that’s part of the reason so those are the reasons to use topiramate. Any options for drug induced papilledema? You treat that the same way. The only exception is you want to get them off the offending medication. If you can, great, if you cannot, you treat the same as any other case with medical management and surgical management if necessary. Can you talk about age and gender prevalence? 90 percent of IIH patients are women. And age, we typically consider it a condition of women in their childbearing years. That is teenage years, most commonly after puberty up to 40s or 50s for most women. There can be exceptions to that but that’s the typical age distribution that I see. Labs need to be monitored while on Diamox? No, I don’t monitor the labs. Some people do, I don’t. Patients commonly develop a metabolic acidosis while on Diamox. That doesn’t matter for me unless it’s a problem for another condition the patient has or they’re miserable from the symptoms of a metabolic acidosis. But I don’t monitor any labs. How often to do the visual field depends on how severe the papilledema is. If it’s really severe, you do them more frequently. If it’s less severe, less frequently is fine. You have to figure out what that frequency is for your clinic and practice. Can IIH occur below the age of 16? Yes. It can occur in children and prepubescent children. In that group, it doesn’t have to be associated with obesity. I met kids — before puberty. So, yes, that does happen. So someone asked about what to do with papilledema without — excuse me IIH without papilledema and if there is a progressive increase in nerve fibers on OCT. Then that means they have papilledema. So again, if they have papilledema without raised ICP, then I think you’re talking about something else, optic disc edema and other conditions. That is not IIH. Is it worth doing an LP on patient with resolved papilledema with resolved headaches? If it changes your management, yes. You may find the pressure is high and you can treat and see if the symptoms get better. If the papilledema is gone, I usually don’t repeat a lumbar puncture. At that point there is no risk to the vision. I would treat the headache phenotypically or send them to someone that can treat the headache phenotypically. The role of IC stenting was mentioned in the webinar. I refer you back to the webinar. Who performs optic nerve sheath fenestration? In Croatia there is, ophthalmologists are not trained in that. And neurosurgeons don’t do it either. It would be an ophthalmologist who would do it. At our institution, it’s a sub specialist in oculoplastic surgeon. If you don’t have that, you have CSF diversion like a shunt or stenting or bariatric surgery? You don’t have the optic nerve fenestration as an option. That is true at other institutions, you may not have all of the options. You do the best with the options you have. The definition of papilledema is optic disc edema from raised intracranial pressure. That is the definition of papilledema. Should we treat a kid with IIH, but asymptomatic without papilledema. I would not treat for ICP just based on that. A lot of these patients don’t have high ICP. Treat the ice tropia if applicable or if it’s changing or other signs of pressure, that is where a lumbar puncture might be indicated. Otherwise, no. How long can a patient be on acetazolamide? Indefinitely. As far as how I stop, I wean it off. There is not a huge like downside to stopping it kind of suddenly. Other than it’s possible for their disc edema to reoccur if they’re on a fairly high dose with minimal edema or no edema. If you stop it abruptly, the edema can come back. So I wean off over a couple of months. If it’s a very low dose, I do a very short taper. Have you seen a case of IIH progressing after a shunt. >> Yes. I have seen that. If you fail one modality, you have the other modalities. Drug induced IIH. Get them off the offending drug. If you can’t or even if you can and there is still IIH left over afterwards, you treat as you would any other case of IIH. Okay. And then a question in Spanish. Let’s see how I do with my Spanish. I think it’s about recommending contrast for radiographic studies. Yes, when I’m screening for structural causes of ICP, I recommend an MRI of the brain with and without contrast. That helps me see venous sinus stenosis better and in is a tumor or other abnormality that may be more difficult to pick up without contrast, the contrast helps me for that. The histologic changes of thin transverse sinus postmortem? I don’t know if that study has been done. Look in the literature for that. Opinion for VP shunting. It has its draw backs and advantages. One of the draw backs of CSF shunting is a higher complication rate and higher need for repeat surgery in the future. So you have to be careful with that. However, it’s very effective in a lot of cases and a lot of surgeons know how to do it and it’s a simple surgical procedure. It can be helpful if needed. But again, refer you back to the webinar for a more detailed discuss in how it compares. First line surgical management of shunt versus optic nerve sheath fenestration if both are available? Do they have headache? If they have a bad headache as part of the symptoms for IIH, then I will probably not do an optic nerve sheath fenestration. I would opt for a shunt. Mostly papilledema and no other symptoms, I prefer an optic nerve sheath fenestration. That’s the basic way I distinguish if I have the option of doing either one. So let’s see here, after IIH diagnosis is confirmed, medication of acetazolamide started and the follow up timeline schedule recommended? That’s really going to be dependent on everyone. I think you have to get a flavor for that yourself and I can’t tell you how often you need to see these patients. Many factors go into that. You check on symptoms, which can on visual acuity, optic nerve function, color vision, visual field testing and a funduscopic exam and see how severe the papilledema is. I like to use OCT as well if you have that as well. Very often papilledema doesn’t go away even with normalized ICP. If that’s the case, you maybe don’t have the right diagnosis. In the cases of IIH when the pressure goes to normal, the papilledema goes away. So that may be a different entity if it doesn’t go away. What is the recommended loading dose for methyl prednisolone. There is not data that answers that question. What I would do is 1,000 mg of IV methylprednisolone for a few days similar to optic neuritis flare or something like that. Let’s see here. What percent of development of multiple sclerosis from IIH? IIH is not related to multiple sclerosis nor does the risk of one of the conditions cause the other. In the case of daily vomiting, go with IV or oral? So yes, IV is hard because you have to be in a hospital or you have to have a PICC line or something like that in. If they’re vomiting is that bad, that might be a sign they need to be in patient. Why is this so bad? Because the ICP is super high. If so, maybe that’s something where we need to intervene more quickly on that patient especially if they have severe papilledema. So someone like that might need a surgical intervention. It’s hard to say just from the question. We have to take it in the context of the actual case-how often would one serialize the office appointments. That is up to each individual. I can’t give you an answer how often you need to see the patients. If the disc edema is mild, I might see them once every six months and they’re stable with minimal symptoms. If I’m worried about them, I might see them in a month or two or a number of weeks. You want to get enough time to pass so you know if your interventions are helping or not. But not enough time that if they’re worsening, you don’t have permanent damage. That’s how to determine how follow up should be. The role of visual evoke potential testing. I have not found that to be useful for this. It could be useful if you don’t have OCT and you don’t have, maybe if you didn’t have visual field testing for some reason but had VEP, it could be a specialized set of circumstances but I don’t use it. The role of intracranial venous sinus stenting. I refer you to the webinar. Special attention to treating IIH in children. Probably one of the most important things is kids are not as reliable with their symptoms. Part of that is because they don’t know how to articulate their symptoms. And so that can be tricky. So we have to be in tuned to that. Otherwise, the other principles are the same about the severity of the papilledema and the function of the vision and the visual field test and those things. If they can do them, those are going to play a role in how to treat the patient. If they’re so young you can’t test the vision, you have to go by the symptoms and how severe the papilledema is. Can enlarged cisterna magna be a radiologic sign of intracranial hypertension. In general, no, that is not something we look for as a sign of intracranial hypertension. Weight loss. There is metabolic research looking at different signaling factors and hormonal pathways and some of those have an intimate relationship with adipose tissue. So there is some reviews that have been published on that. Sinclair’s group is active in that. There are a few reviews done over the past years that talk more about that. If we see papilledema but the patient doesn’t have any symptoms is an LP mandatory? If it’s moderate papilledema, yes, it’s mandatory. If it’s minimal papilledema and no symptoms and you had an MRI that shows no tumor or serious structural cause, that kind of patient may be okay not doing a lumbar puncture. Topical steroids cause IIH? I have had a few patients where we think that topical isotretinoin use may have provoked IIH. I don’t think I’ve seen cases of topical steroids leading to IIH. Do you rely on retinal nerve fiber thinks for correlation. >> Yes. I use OCT and measure the nerve fiber thickness. It’s a helpful quantitative pressure that helps you follow someone’s severity of the disc edema. It has to be paired with the visual field exam, too. I do both. How often do you increase the Diamox? That is case by case and it really depends on how severe the optic disc edema is and how severe the symptoms are. Some patients I go up quickly over a week or two to whatever dose I think they need, sometimes a maximal dose. If it’s more mild, then I would just change it when I have a visit with them and if it seems to be worsening a bit, I go up a little bit. It’s like that. The highest dose is 2,000 mg twice a day is the highest when necessary. I reduce when the edema is getting better or if they’re having significant side effects. So if their edema is minimal, that’s usually when I feel comfortable going down on the medication. Prognosis of IIH, different in men and women? There has been a research that suggests the prognosis may be worse in men. Part of that may be for more advanced symptom presentations and more advanced vision loss on first presentation for men. That could be one of the reasons for the difference there. Lately seeing few cases of suspected IIH in young people prescribed large doses of vitamin A for acne. Yes, that is definitely an association. I ask that in any review of symptoms, I ask them if they’re on medications that may be a vitamin A derivative. Yes, that is associated with intracranial hypertension. How reliable is the LP opening pressure? I find it reliable if it’s done by a person that knows what they’re doing. I use it as one factor. If everything suggests the patient has IIH and the lumbar puncture wasn’t done properly, I won’t let that prevent me from treating the patient. But the LP opening pressure results should agree with the symptoms and the optic disc appearance and it should all make sense. So can LP be done together with methylprednisolone in fulminant IIH? Yes. What is the youngest and oldest patient. I don’t see children so I’m not good to ask about the youngest. I had patients in their 60s with IIH. I don’t remember if I had any in their 70s or 80s. I would have to look. Any relationship with systemic hypertension? Probably not directly. We haven’t found a good link between systemic hypertension and intracranial hypertension. As you know, systemic hypertension is exceptionally common and intracranial hypertension not as much. We haven’t seen a good link between those. Comment on a young female, 15 years old, tall and skinny with mild papilledema and headaches. LP. Anyone with papilledema needs neuro imaging. That is nonnegotiable. Everyone needs the imaging if you think they have papilledema. If it’s minimal and normal vision and no symptom, then the LP is optional. If you’re concerned it’s not IIT, maybe meningitis or something else, the LP is still indicated. Always be suspicious of someone not obese and you think has IIH. Could there be a secondary cause of intracranial hypertension in those patients. What signs to look for on OCT for IIH and papilledema. Thickening of the retinal nerve fiber layer. That is most important. Also look at the pattern of the thickening. The thickening should typically be nasal superior and inferior to start with. As it’s more severe it involves the temporal part. If we see edema and it’s thickening and it’s temporal and spares the other quad grants of the disc, that may make me think about other causes. How long does it take for papilledema to disappear after control of ICP? That’s a good question. It depends on the severity of the papilledema. If someone has severe papilledema, it takes a few weeks for it to go away. I had cases where it’s up to a month or two. If the papilledema is mild, then it can go very quickly, probably within a matter of days to weeks. And then spontaneous venous pulsations, can exclude high IP? Good question. There are studies looking at this. The answer is pretty much all patients, if they have an intracranial pressure greater than 30 cm of water, they will not have venous pulsations. There are some patients with an opening pressure on LP between 25 and 30 who may still have venous pulsations but they don’t have, they may have venous pulsations but they still have high pressure in the head. Those are the tricky ones and why venous pulsations are not perfect in predicting if someone has normal pressure or not. Let’s see here, the role of B scan for measuring optic nerve sheath diameter. I usually don’t use that. If you are proficient with ultrasound or someone you know is, then that might be helpful. Again, I wouldn’t use that though. OCT is much much better for getting the information we need. I don’t think you need to do anything else other than those two things and an eye exam with the basics. Relationship with PCOS. Polycystic ovarian syndrome. I have a lot of patients with PCOS and IIH. There appears to be a link between those. The etiological spectrum of pediatric IIH. Patients who are prepubescent, before puberty, they may not be obese. Also, the gender difference, there appears to be no gender difference in patients before puberty. Boys and girls are equally affected. The question is OCT angiography useful? I have not found a clinical use that is good for OCT angiography in IIH. What parameters does one look at with the OCT for IIH? I look at the retinal nerve fiber layer thickness in comparison with other exams. I look at the ganglion cell analysis. The ganglion cell analysis can sometimes give a clue there is damage that happened to the optic nerve even before it would show up on the retinal nerve fiber thickness. If you have swelling and say there is atrophy developing, the nerve fiber layer thickness is thick. You don’t know the atrophy is there unless you’re doing visual fields and can see the ganglion cells showing thinning. Then you know there is some atrophy developing there. Those are some wonderful questions. Thank you for joining the webinar. I look forward to seeing you on a future webinar.

Last Updated: May 15, 2024

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