in this video i'm going to be doing a long needed update of one of my most popular and also one of my oldest videos the lysosomal storage diseases i actually up uploaded the original lysosomal storage disease video four years ago and wow time has flown and in that time we've learned a lot about new high-yield information that gets tested all the time on the lysosomal storage diseases so because of that i'm going to update the original lysosomal storage disease video and in this video we'll be doing the 2021 lysosomal storage disease update this is brought to you by dirty medicine before i get into today's video let me tell you about a new dirty medicine membership that i'm rolling out on my channel so as many of you saw i recently deleted my patreon page and on that page i was collecting financial support for the people that really wanted to give back to my channel and in lieu of patreon what i'm now doing is accepting members so if you want to become a dirty medicine member how that 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up are going to be able to vote so if you want your voice to be heard and to decide the topic of the next video or if you want to have the cool dirty medicine logo next to your name your username whenever you comment or if you're just looking for a way to give back and support my mission to provide quality free medical education for graduate health professionals in the across the world then please please please i humbly and respectfully implore you to sign up and support my channel now today's video is all about lysosomal storage diseases and i told you guys that i'm going to do a major update from the video that i uploaded four years ago so we're gonna go through these one at a time i'll tell you in in a very succinct way what the pathology is all the associated findings and then you'll get a one sentence mnemonic for all of these lysosomal storage diseases which will be the only thing you need to memorize to get 100 of these questions correct on usmle or comlex so let's get started we'll start with fabri disease now the way that this is going to work for all of these lysosomal storage diseases is that there's some type of enzyme deficiency and because that enzyme is absent or deficient there's an accumulating substrate and then there's clinical findings right or or histopathological findings and we're just going to list them like this so for fabri disease the enzyme deficiency is alpha galactosidase a because that enzyme is absent the accumulating substrate is ceramide trihexazide very very high yield findings include hypohydrosis angiokeratomas renal failure and peripheral neuropathy now the way to remember this is the following mnemonic my favorite activity is making a ceramic galaxy sorry to keep harping on it what does this tell you favorite or favorite if you will reminds you that we're talking about fabry disease ceramic is the cerama the in the ceramide trihexazine galaxy the gala part reminds you of alpha galactosidase and sorry to keep harping on it h-a-r-p should remind you of hypohidrosis angiokeratomas renal failure and peripheral neuropathy so my favorite activity is making a ceramic galaxy sorry to keep harping on it the next disease is gaucher disease in gaucher disease the enzyme deficiency is glucose cerebrosidase which causes the accumulation of glucose cerebroside not too bad the findings are osteoporosis you need to know that this is the most common lysosomal storage disease that you get a gross femoral head and you'll see why i'm phrasing it that way but that's an avascular necrotic femoral head and the presence of what are called gaucher cells or they might be phrased as lipin-laden tissue paper cytoplasm cells you might see either of those terms and what you see up in the corner of the slide is an image of the gaucher cell so these are cells that are said to have quote tissue paper cytoplasm and that's because there's just lipid deposits all over the cell now how do you remember this well the mnemonic is that in a crying voice you want to say oh my gosh he's such a bro now what does this tell you well first the reason that it's in a crying voice is because you need to remember that there's tissue paper cytoplasm so you use tissue paper or tissues to wipe your tears and that's why you say this mnemonic in a crying voice now oh my gosh omg or oh my gosh is there for a to remember about gaucher disease but the omg stands for the o in osteoporosis the m in most common lysosomal storage disease and then the g is just gosh as well as gross femoral head okay so that g doubles as gosh and gross femoral head which is another way of saying a vascular necrosis of the femoral head and then bro will remind you of the enzyme and the accumulation so glucosary bro cyadase and glucocerebroside all right so that's gaucher disease oh my gosh he's such a bro that's how you remember this one let's talk about tay sachs disease tay sachs disease is really high yield not necessarily because of the disease itself but because you need to differentiate it from neiman pick and they're very very similar clinically the enzyme deficiency for tay sachs is hexaze aminodace a the accumulating substrate is gm2 ganglioside the findings is that you're going to have a cherry red spot on the macula it's very high yield you have what's described as onion skinned lysosomes and there is no hepatosplenomegaly and that that at the absence of hepatosplenomegaly will be differentiated with neiman picks it's very important now how do you remember tay sachs disease well you want to remember a gang of six small jews and i know what you're thinking you're like why why jews well tay sachs disease disproportionately affects ashkenazi jews and that's just a high yield factoid that you need to know but as far as the rest of that mnemonic gang gang will tell you about gm2 ganglioside six is hex in hex aminodace a right hex the prefix has something to do with the number six and the reason that they're small jews is because the liver and the spleen are small because there's no hepatosplenomegaly now before i go to the next slide another thing that i just want to point out is that any disease with a hyphen in the name also features a cherry red macula because as you see cherry red is hyphenated tay sax is hyphenated so it's just an easy way to remember that now just like taste x is hyphenated so is neiman pick disease and as you'll see in just a second there's also a cherry red macula in neiman pick in neiman pick the enzyme deficiency is sphingomyelinase and the accumulating substrate is sphingomyelin the findings are that because it's hyphenated neiman pick has cherry red right so neiman pick has a hyphen cherry red has a hyphen so neiman pick disease features a cherry red spot on the macula neiman pick disease has what are referred to as foam cells or you might see it written as lipid lipid laden macrophages okay so lots of different cells to keep in mind for all of these different diseases but for neiman pick disease you'll get foam cells and the most high yield thing about neiman pick when you contrast it to taste sacs is that yes there's hepatosplenomegaly so the mnemonic for neiman pick disease is that you pick your nose with a big foamy finger right and instead of saying finger we're saying finger so pick reminds you of neiman pick disease you're picking your nose with a big because the liver and the spleen are big because there's hepatosplenomegaly big foamy because you have those foam cells or those macrophages that have lipids all over them and swinger for sphingomyelinase and sphingomyelin and finger sounds like finger and you pick your nose with your finger so pick your your nose with a big foamy swinger that's neiman pick disease and then again neiman pick hyphenated cherry red hyphenated all right next we've got crab disease crab disease has an enzyme deficiency of galacto cerebrosidase the accumulating substrate is galactose cerebroside findings are going to include globoid cells oligodendrocyte destruction and optic atrophy now a couple high yields here one you need to recognize the picture of a globoid cell and that's what it looks like but the mnemonic here is that the glob of gooey crab meat is out of this world right who doesn't love crabs who doesn't love crab meat and when you crack open those crab legs or the shells however you like to eat them you want to grab that big glob of crab meat you know anyone who's eaten crabs knows that sometimes you crack it open it's all that disgusting yellow crap that's not really good but you're looking for that glob you're looking for that globoid cell so the glob of gooey goo for globoid oligodendrocyte destruction and optic atrophy crab meat crab for crab disease is out of this world and world kind of reminds me of galaxy and the gala is galactocerebrosidase and galactose cerebroside so the glob of gooey crab meat is out of this world i'm gonna put the next two on the same slide because hunter and hurler syndrome have a lot in common and i think the way to approach this is just a color code to help you see the differences here so everything for hunter syndrome is in blue everything for hurler syndrome is in red and all of the features that they share or overlap are in purple so the enzyme deficiency for hunter syndrome it's iduronate ii sulfatase and for hurler syndrome it's alpha 2 hydronitase as you can see somewhat similar sounding but there is a subtle difference the accumulating substrate for both of these two syndromes is dermatin sulfate and heparin sulfate so it's both of those accumulating substances findings so for both you're going to see gargoylism and airway obstruction but in hurler syndrome you see corneal clouding and in hunter syndrome you see behavioral aggression okay so the way to to memorize this the mnemonic here is x marks the spot for the hunter so what does this tell you well a couple things one x reminds you that for hunter it's x-linked recessive and that's very very unique and you need to remember that it's high yield the other thing that you want to remember is that if you look at this image imagine this hunter putting that gun up against his skin or against his derm a tin sulfate right so it's just another stupid way to remember the accumulating substrate the other thing to remember is that hurler syndrome has corneal clouding but hunter syndrome has no corneal clouding which makes sense because if a hunter's cornea was clouded he wouldn't be able to hold that gun up to his eye and take aim so no corneal clouding for the hunter and just i guess by nature it should make sense to you that hunters are perhaps more aggressive people than non-hunters so in hunter syndrome you see behavioral aggression so that's hunter syndrome and hurler syndrome let's wrap up the updated lecture today with metachromatic leukodystrophy now four years ago when i up when i uploaded that original video i didn't include metachromatic leukodystrophy and the reason i didn't was because at the time it wasn't a really high yield lysosomal storage disease but i guess over time it has become one and you know i have to ponder for a second and wonder if maybe the test writers out there were checking out my channel and they said hey dirty you don't have this one here we're going to get those med students bastards all right so metachromatic glucodystrophy the enzyme deficiency is aryl sulfatase a the accumulating substrate is cerebroside sulfate and there's a couple unique findings one is demyelination and that occurs centrally as well as peripherally and then you'll have ataxia dementia you can get some psychotic symptoms in here you know neuropsychiatric symptoms is the way it'll be phrased but generally speaking it's demyelination ataxia and dementia now what's the mnemonic here well unfortunately or maybe fortunately if you're a huge nerd like i am this is actually a pokemon uh mnemonic so if you never watched or are familiar with pokemon then i apologize but the mnemonic here is that metapod is a real broken pokemon okay metapod the meta reminds you of metachromatic leukodystrophy and metapod is a real for aerosulfatase bro for cerebroside sulfate so metapod is a real broken pokemon but really the beautiful thing about this mnemonic is that i mean look at metapod he can't walk so he has ataxia he can literally only say his name if you've ever watched the pokemon show so he has dementia and what is demyelination demyelination is loss of the myelin sheath and metapod literally his only thing that he does is shed his skin and evolve into a beautiful butterfly so he literally demyelinates that's his role in pokemon life so the mnemonic here metapod is a real broken pokemon for metachromatic aerosulfatase cerebral side and then if you just think about all of the features of this stupid pokemon which i always wanted to get to level 10 as fast as possible he's just a toxic demented demyelinating little green guy but that's it for this update on the lysosomal storage diseases i want to just take a moment again to thank everybody who has supported and followed my channel over the past four years i had a chance to reflect on the growth of the channel since i'm doing my first update on a video that i uploaded four years ago this it's absolutely crazy but if you want to give back and support me because i'm going to be around for many many more years please consider joining my youtube membership to give back thank you and good luck