Please BrainDump On Keeping/Regaining Smell After Brain Surgery

February 25, 2024 12:22 AM

I'm going to be having a benign brain tumour removed. I've been told I will almost certainly permanently lose my sense of smell. I want to do whatever I can to maximize that little bit of wiggle room it seems I have. Please come inside and read what I know and what I'm speculating. Please tell me what you know and what you can reasonably speculate based either on actual neurological knowledge or plausible speculation. I'm looking to develop a plan that "won't hurt; might help" so it doesn't have to be backed by rock solid science.

My tumour is a meningioma, 3cm, located "above the sinuses". It will be removed via my nose with endoscopic surgery. The surgeon said if it were a little farther front it would 100% result in losing my sense of smell but where it is now it will "almost" certainly result in permanent smell loss....later modified to "at least significant change". The student I saw initially estimated a 60% chance of permanent smell loss.

When speculating about smell the surgeon kind of moused over just in front of the tumour and mumbled something about "olfactory mucous" so i assume that's involved in the mechanism somehow.

But I'm thinking about all those people who lost their sense of smell to covid and how there are smelling protocols to help bring it back. I realize that's a completely different mechanism of losing one's sense of smell. Their mucous hasn't been physically disturbed which presumably mine will be. But I also know that people who physical brain lesions from strokes the brain figures out new ways to get the job done sometimes. So, I want to maximize the chance that my mucous regenerates or that my brain finds a way to get the job done.

So I've been looking at the covid thing and it seems like these are basically about smelling (or at least sniffing) lots of strongly smelling things frequently. I'm wondering if doing that soon after surgery and maybe even leading up to surgery (just to build up my stockpile of mucous?) might help. I started trying to read about olfactory mucous but it lead to a bunch of stuff about various neurological diseases and that's just going to give me hypochondria, so instead of reading that I'm turning to you all.

I'm wondering a bunch of related things:

1. What are the mechanisms, if known, associated with making/strengthening olfactory mucous? Like can I do anything now so I have plenty going into surgery? I have about 3 months.

2. The covid smell recovery protocols are all about smelling strong-smelling things. I wonder if it might make sense before surgery to practice distinguishing more subtle smells (as well? instead?). My thinking is that smelling the more subtle is probably more work requires my mucous/brain to be more on-the-ball and is just better exercise.

3. After surgery I assume I should start smelling essential oils as soon as possible (I'll ask surgeon if this is safe just in case it's somehow not), and that the sooner my brain gets to work on fixing this, the more successful it will be. I assume at this point strong smells are what I want until I can smell them right? then maybe consider more subtle smells? Or something else?

4. Are there any modifications to the covid smell-regaining advice that I should plausibly make because this is based on physical poking not on a disease process?

5. What about taste? Obviously while I can still taste now I'm trying to eat all the tastes I'll miss if I never get to taste them again. I'm something of a picky eater, but I'm wondering if maybe I should fill my diet with strong-tasting things in addition to trying to sniff strongly smelling things. What kinds of things would I eat here? I mean most things we think of as strong-tasting are either very bitter, very salty, very sweet, etc. etc. and those aren't the kinds of tastes I need to relearn how to perceive. What kinds of foods are "strongly tasting" in ways not perceived just by the tongue? Maybe licorice? Other things like that? Don't say cilantro. Cilantro is against my religion.

Again, while i would be thrilled if there's a neurologist specializing in smell who can come in and answer this, I'm open to speculation from people who have basic-educated-human levels of scientific knowledge and from anyone willing to do the google's that I'm avoiding because they would make me anxious. This is because I'm assuming that smelling and tasting a bunch of stuff might help but won't hurt. I'm not going to inject myself with smells or anything.

posted by anonymous to Health & Fitness (13 answers total)

If you want to work on the smell nuance thing, one of my favorite people on Twitter was (is?) Alyssa Harad, who wrote a book about perfume that I've always been meaning to read. In looking for it, I learned that there are a bunch of books on perfume and scents that look good. (Sorry this isn't that helpful, but I wanted to wish you the best by at least sharing what little info I had!)
posted by slidell at 1:44 AM on February 25

First, I would find out if there is anything your surgeon can do to minimize or mitigate the risk. Can they cut around it in a certain way that minimizes the risk? Do they just go and cut away without regard to affecting the sense of smell because it saves time (time is money?)? If it turns out the surgeon can take steps that might be outside of protocol or might take longer to do the surgery but can mitigate the risk, I would ask/beg them to do so. I might even offer them a bonus ($1000 cash?) if after the surgery you still have your sense of smell. I doubt the surgeon would take you up on the offer, but it will show them how serious and how much it means to you that you not lose your sense of smell.

On an equally speculative (and unusual?) note, while I have no scientific knowledge, it does not seem like the same issue as covid loss of smell. If they cut out the part that affects smell, it is no longer there to be retrained. If you are injured, say a traumatic brain injury, you can sometimes relearn to walk and regain the use of limbs. But if the spinal cord is severed, no amount of rehab will put it back together. But, having said all that, you are looking for ways to try that won't do any further damage so I imagine things you mentioned like practicing smelling now and trying to make your sense of smell keen before the operation cant hurt.

I have had hearing loss all my life. When I was in elementary school, I went to a speech therapist and learned to lip read. I still have hearing loss, but I learned to compensate by looking at the person speaking. When they are facing away from me, I don't "hear" as well. Is there some way to compensate for smell loss that still allows you to smell or at least taste? Probably. Maybe flash cards. Pictures of everyday items that one would normally smell like a flower or an onion or rotten eggs. I would try to remember the smell when the flash card came up without actually smelling the item. So, the next time you eat an onion, you don't actually taste it like someone without smell loss, but you remember the smell and taste and that satisfies your desire to know what you are eating or smelling. I don't think it would work if you cannot see the item like a blind taste test, but if you can see the apple and remember Grandma's apple pie, it might compensate.
posted by JohnnyGunn at 3:03 AM on February 25

This picture might help you understand what's going on. The yellow-orange stars are smell processing; the blue ones are taste processing.

The good news is that taste is handled elsewhere, so it's not going to change. However, a lot of what we call taste is really the sense of smell. The tongue directly registers sweet, salt, sour, bitter, and umami/savory; other receptors in the mouth detect cold, heat, and pain, which can be triggered by mint, hot pepper, and other things.

Sounds like the tumor is close to or mixed up with the olfactory bulb. I did some Googling so you don't have to: surgeons try very hard to remove only the tumor and no healthy tissue, but surgery is invasive and some damage can occur. Also, the brain can recover function to some extent, but maybe not fully.

Maybe ask your surgeon if they use image guidance, i.e. operating while looking at a live CT or MRI? This gives better results than just comparing to a pre-op scan.
posted by zompist at 3:46 AM on February 25

I might even offer them a bonus ($1000 cash?) if after the surgery you still have your sense of smell. I doubt the surgeon would take you up on the offer,

If the surgeon does take you up on the offer, find a different surgeon; bets or bribes on outcomes is such an astounding ethics violation it would be grounds for being fired at my institution. (Yes, I know, ability to pay does get you better results but we're not supposed to say the quiet part out loud, and anyway your spelling of "tumour" suggests you are in a slightly more advanced country than the US when it comes to healthcare.)

If the tumor is where you say it is, there doesn't seem to be any reasonable way to get at it without destroying the olfactory nerve itself. This is a little different than covid-related smell loss because it's structural not functional. Once the primary receptor structures are destroyed, that's it. Smell is a special sense like vision; if your optic nerve is severed or otherwise destroyed, that's it. The closest analogy I can think of is stroke rehab, but that presumes the primary sense receptor (motor/sensory fibers in the limbs) are intact and you're just trying to rejigger the brain wiring. But if your limbs are amputated, that's it.

You could ask for a second opinion from a different surgeon, or ask if a different surgical approach could spare your olfaction. You could also ask about watchful waiting; what are the risks of leaving the mening where it is? How quickly is it likely to grow, what symptoms will that growth cause? (Almost certainly it would alter your sense of smell anyway.)

Side note: most surgeons I know err on the side of pessimism because it's better to have a pleasant surprise than a nasty one. I'm not sure which side your surgeon falls on. But worth considering.
posted by basalganglia at 3:54 AM on February 25

Have you talked to Dr. Pablo Recinos at the Cleveland Clinic? One of the most prominent brain surgeons working today and also the nicest and most competent guy you'll ever meet and also he saved my life. I might schedule a video visit with him and get a second opinion. That's what I did (for starters) and he offered me a significantly better outcome than if I had had it done locally.

We only have five senses, so I encourage you to do all due diligence to secure yours.
posted by kbanas at 4:03 AM on February 25

I have a suggestion for you, should your worst-case scenario (loss of most smell and maybe taste) come to pass.

Roughly a century ago, a family member had a surgery that resulted in the outcome you fear: near-total loss of smell, with related impact on the taste of food. That was a hundred years ago, and of course much has changed since then. Even so, one thing he did after the surgery was to figure out what foods he could still smell/taste. He did this because, periodically and unpredictably, something would link up again and he could--for a short time, apparently with no ability to predict the duration--smell & taste a little bit more. He'd then head off as quickly as he could to the nearest grocery to acquire various foods that he knew from trial and error he was more likely to be able to smell and taste.

My suggestion here (n of 1!) is that, if things go poorly, you not lose hope entirely, and keep a "nose out" for temporary and/or partial return of your sense of smell.

Good luck.
posted by cupcakeninja at 6:29 AM on February 25

For a bit of “just in case” planning…My dad lost his sense of smell due to a brain injury. I’m his case, it didn’t come back. Just to reassure you, he still loves food a lot. He is careful about expiry dates. He has volunteered to help neighbours after sewage backup incidents, which he sees as a superpower. (His family may not be thrilled he offers to go into raw sewage but this is my dad.)

The one thing I would say is to invest in a natural gas detector (if you have natural gas in the home) -they come combined w/ carbon monoxide detectors. He also installed more smoke detectors and uses timers while cooking everything/em> (but he has other cognitive defects.)
posted by warriorqueen at 7:14 AM on February 25

To add what others are saying, I have a very poor sense of smell, which started at some point when I was a teenager. I still taste food, but I think I taste it a little differently than other people. I have much stronger impressions of textures and I suspect that the things I can smell have a higher impact (mint, orange, vanilla, etc.). I still love food.

Also, let me say, it's rare that people ask if you can smell something because it's a good smell. I can barely smell all of the bad smells in the world, while keeping the joys of beauty and music and textures. As warriorqueen said, you'd want a natural gas detector and I'd add needing a routine that makes sure you're wearing appropriate deodorant.

A worst case scenario might be less the loss of the things you love and more an opportunity to try things again and discover new things you can love. What might that thing you didn't like before taste like with what you dislike removed...?
posted by past unusual at 8:49 AM on February 25

I knew someone who had a cycling accident that resulted in his loss of smell. He liked lemonade because he could still taste sour and sweet.
posted by credulous at 11:20 AM on February 25

[Just a reminder to everyone that it’s important you comment with the intention of answering OP’s questions. Non-answers will be deleted moving forward.]
posted by travelingthyme at 12:14 PM on February 25

While it’s a small sub, you may find answers to some of your questions at r/braincancer (people with benign tumours are welcome).
posted by cotton dress sock at 10:09 PM on February 25

Please ask your surgeon for more information about why your sense of smell will be affected—I’m concerned these answers will sound irrelevant or confusing to you because they don’t have to do with “building up mucus,” which is the product of poor communication on your surgeon’s part. (This isn’t about mucus, but about nerves—the olfactory mucosa is a membrane containing the nerve endings that allow your sense of smell to function.) The nerves can recover from a certain amount of damage, and the sniffing-strong-smells therapy has to do with retraining your brain to recognize their signals. But, as everyone else is saying, there’s a level of nerve damage that will cut that signal off completely. Surgeons can be hard to talk to but I do recommend getting more information from a medical professional familiar with your case—they can clear up the mucus misconception and help you understand the likelihood of permanent nerve damage.
posted by babelfish at 7:02 AM on February 26

I would highly recommend a second opinion at the best facility you can practically manage. It is possible this is an "almost" unavoidable consequence, BUT top tier medical research facilities can be worlds of different sometimes offering totally different advice or practice. I think of it as they are doing medicine 10+ years in the future, before its been disseminated to the next generation of now student doctors, or even the next next generation of student doctors learning from today's student doctors.

Ask a medical professional if there are any treatments that increase likelihood of recovery. Whether the removed, or it sounds like nearby damaged, tissue there might be additional treatments, or at least speculation for treatments. Epothilones, gabapentinoids, baclofen, and even NSAIDs have been used to promote axon regeneration (the nerves finding their path back to their target) after being damaged. Guidance will have changed over time and for the particular damage that's occurring that results in anosmia (loss of smell), maybe your doctor can reach out to a doctor in an adjacent field for advice, or often if you identify a world expert in a topic then a good doctor will reach out to them upon your suggestion for advice.

Last, I can only offer the general advice of practice, practice, practice; and have reasonable expectations. The nervous system is remarkably plastic. You're still limited by reality, but you can still enhance what is there. An extreme example: there was some work awhile back about orgasm through the vagal nerve in women after a full spinal cord injury (typically orgasm occurs through connections in the spinal cord and these individuals "taught" themselves to orgasm using a neural pathway no one expected possible). If you have partial damage of the cranial nerve used for smell, or partial damage to tissue like the olfactory epithelium, it is still something to work with. Be patient and kind with yourself, but spend time really noting what smell (and taste) you have, describing it, giving it attention and developing it: when you eat, go for walks, at a grocery with a bulk spices and good produce section. Even if you lose some smell/tastes and cannot recover them, perhaps you'll discover alternate ways to experience those things and new preferences.

You're welcome to PM me to talk.
posted by rubatan at 12:38 PM on February 26