DIP Episode 90 - USMLE Step 1 Rapid Review Series 2 (Neuro)

Okay, welcome. My name is Divine. I am a PGI-1 transitional year resident going into radiology. This is episode 90 of the Divine Intervention Podcast and really in this podcast my main goal I guess plan is to rapidly review Neuro. So know that this is different from the longitudinal neurosurers I'm doing that's more detailed and will basically cover everything you need to know for step one neurology. Basically my plan with this is kind of like the micro rapid reviews to just go through things relatively quickly and highlight some key associations. So what if you get a question about a person that her needed after you corrected an electrolyte abnormality? Well I really hope you're thinking about hypernatrhypony and it's a rapid correction. I remember from high to low the person's brain will blow. Okay what if you get a question about a person that becomes quadriplegic after you rapidly correct it and electrolyte abnormality? Well I really hope you're thinking about again the rapid correction of hyponytrymia right? Remember from low to high the person's bones will die right? So if you have like central pontine myelinalysis some people call it the smudic dimylination syndrome. You can basically have knock out the entire corticospinal tract and obviously the person will be quadriplegic. Now what if you get a question about an 8-speed shend that has like stiff neck and has fevers right?

So kind of like meningitis in an 8-speed shend I really hope you're thinking about cryptococcal meningitis right? So remember cryptococcus in your formants it's an encapsulated bug and remember that it stings positive with India ink right? And the addition to staining positive with India ink it also has you can also detect it like a latex particle agglutinitia acid and I mean obviously if you want to treat you give the person amphoterosin and fluorosidosing. But after you do that treatment for like a year afterwards you need to place them on like I think it's it I believe it's fluorosidosing you place them on for a year but I'm not 100% on that. Now what if you get a question about you know an alcoholic that is kind of confused he has like a stagmus and he's sort of walking weird I really hope you're thinking about wernicis right? So that's like a triad right? So like confusion of thermoplesia and ataxia pretty easy there. Now what if you then make the leap to an alcoholic that is kind of making stuff up right? That's basically a confusion right? So where they're beginning to forget things right? So like both retrograde and tirade amnesia blah blah blah with that you know you're thinking about coarser coughs as psychosis and that's irreversible versus wernicis that's reversible and normally right you give a thiamine right? the IV thiamine to treat whernicis psychosis whernicis as syndrome yeah you give a IV thiamine remember that's vitamin B1 right?

Remember that's a cofacto for transketolis which is one of the which is actually the rate limiting enzyme of the if I'm not mistaken the non-oxidili phase of the pentosphosphate pathway. Okay now what if you get a question about a guy you know has an accident loses consciousness but after that you know he saw the prex backups that's talking for like two hours and then after a while he becomes some non-ent and then he dies right? I really hope you're thinking about an epidural hematoma right? Remember that's where you basically scrub the midomain ingel artery remember if you have like a temporal bone fracture that's a classic association there and remember the lens shaped the lens shape right on CT scale. Now what if you get a question about an old person you know has like burning on your nation and basically has trouble keeping up with an interview and the patient patient has like waxing and winning levels of consciousness. I really hope that's sort of getting you down towards a delirium. Remember UTI is one of the main causes of the lyrium in the elderly and another thing that also causes the lyrium in the elderly is a person taken an anticholinergic medication right? But the thing is if they give you like like Ben Stropin right? Boom everyone will get it right so they don't do that on exams. They'll give you something like Diphon hydramine right?

Basically they'll give you like some weird drug that has like a one-me mechanism of action like an anti-histamine but it also has like pothole anticholinergic effect. Diphon hydramine is the classic one on exams. Now what if you get a question about like a 40-year old like you know obese female has headache has like papillodema on exam and she tells you that oh she wakes up with this just terrible headaches in the mornings and she has like visual like vision changes I really hope you're thinking about a idiopathic intra-crenial hypertension right? That's what's known as a pseudo tumor cerebride. That pseudo tumor cerebride was the old name I-I-H is the more recent name. For that right? You want to do like a lumber puncture you'll see like very high opening pressures but in those C Ts kind of the head the ventricles will look perfectly fine right? And yeah lumber punctures are both diagnostic and therapeutic for this condition and remember those people should avoid like vitamin A containing products they should avoid like doxycycline for example because those things can always intra-crenial pressures and then if you're thinking about like treatment you can give them and you can give them a sederzolomide right? That's a carbonic and hydrism inhibitor. It sort of decreases the synthesis of CSF because carbonic and hydrism is actually one of the enzymes you need to make CSF.

Now what if you get a question about a 55-year-old female you know she has like difficulty chewing and she has a headache. Really you will be thinking about temporal arthritis under those circumstances right? Classically on exams the patients ESR CRP will be high. If they ask you for your next step in management right? You obviously want to go ahead and you want to go ahead and you know give them high-dose steroids and then at least within the span of 3 days try to do a temporal artery biopsy but never do the temporal artery biopsy first you need to go ahead and give steroids right? So the patient you don't you don't want to be doing a biopsy on a patient that's already blind right? That's why you go ahead and give a give a high-dose steroids. Now what if you get a question and you know like a histology question and you see like cox-screw fibers right? On histology in the childhood of brain tumor. Those are like the classic rosin thal fibers right? Remember those are pathonomonic for I mean you can find them in many other conditions but the big one you want to think about for NVME exams is a Pylocytic Astrocytoma right? Remember a Pylocytic Astrocytoma is probably one of the most common pediatric brain tumors and usually loves to shop in the in the cerebellum on exams. Now what if you get a question where you know histology is sort of showing like glial cells with like a friday appearance that's an oligodendroglioma right?

That's a I mean if it's a brain tumor question you'll be an oligodendroglioma but really like oligodendrocytes for the most part on histology look like fried eggs and don't forget this classic association oligodendrogliomas usually are found in the frontal loops on NVME exams right? So don't look for them in the temporal loops when the posterior force or any of that crop. Can they shop in those places? Absolutely they can but on NVM Es you really want to think of them as showing up in the frontal in the frontal loops. Now what if you get a question about you know a sex walker that's having seizures right? Sex walker having seizures sex walker having seizures. Well I mean maybe this is a little vague but let me add in some extra information. What if you get a question about a sex walker having seizures and then they you know they're like let's do a lumber puncture why not and then you say like 600 red blood cells right? I really hope you're thinking about like temporal lobe and cephalitis right from like he chase V just one of those classic things you want to keep in mind and those patients need IV cyclover if you don't give them IV cyclover they're gonna die okay the mortality from like herpes like meningitis or like encephalitis is almost a hundred percent out treatment bad bad bad situation. In fact if you have a patient in the hospital that has meningitis and you can't roll out herpes just go ahead and give them a cyclover you can always turn it off later.

No what if you get a question about a patient that you know keeps putting things in their mouth during an interview right? So let's see it's like a patient they're a fritter neurologist you know they keep putting things in their mouth and you know let's say like their partner says that man this this guy is just like a sex maniac he wants to have sex all the time right? I really hope you're thinking about a clover bucy syndrome right? So they have like hyperorality they want to put everything in their mouth think that for what you will I believe that's classically arises from a person that has like a lesion in their mechdala okay it's just again one of those high-ealth things you want to know for tests. Now what if you get a question about a patient you know that keeps having like flailing movements right or one of his arms during an interview right? That's a that's a sub-thalamic lesion right? So like a sub-thalamic nucleus lesion it's actually the contralateral sub-thalamic nucleus right? So this condition is what's known as a hemibalismus right? So on exams right you don't want to screw this up right? So if a patient has like hemibalismus of the right arm right that means their left-sort phalamic nucleus is all screwed up and I believe in a prior podcast I may have explained the mechanism behind hemibalismus white sort of like a hyper movement disorder if I've not explained it I will explain it in one of these upcoming neuro podcasts.

Now what if a patient you know has like let's say it's a 60-year-old guy has like neurologic deficits and you check the CSF and you see like increase the GFAP right? So like glial fibralary acidic protein on an exam right? If you see that I really hope you're thinking about GBM right? So like glial blastoma multi-formy again that's a non-specific presentation but on MDM is think of it as a very specific presentation right? And remember GBM right the classic video describing an exam is like a tumor right with a lot of like visogenic edema right? So a ton of edema with central necrosis that's another boss phrase and they tell you that it's crossing the corpus callusum if you see that you really want to think about a glial blastoma multi-forming as well. Offal awful awful awful disease most of people are dead in like months right? Less than a year. Now what if you you know check the CSF in a patient and you see like increase protein you see tons of neutrophils and you see low glucose what kind of meningitis is this right? I really hope you're thinking about a bacterial meningitis under those circumstances. Now what if you see you know increase protein a ton of lymphocytes but you see low glucose right? So notice it's not neutrophils this time it's lymphocytes I really hope that's pushing you more towards a fungal meningitis.

Now what if you you know do a CSF analysis you find like almost normal protein almost normal glucose you see tons of lymphocytes that's viral meningitis right? Although as specific scenario you may see is like 600 a thousand rib lot cells and a patient CSF and your suspect meningitis that's very specific for HSV usually HSV1 on NV Me exams. Now what if you get a question about you know 23-year-old female you know that has like hearing or incontinence you know she has visual problems that seem to come and go and really hope with that you're thinking about a multiple or they'll tell you this on NV Me exams if you see a female in her 30s it's usually in her 30s and has like non-descript neurologic deficits that sort of are not very localizable to any like part of the brains like right arm is screwed up left leg is screwed up and what not you really want to think about MS under those circumstances. Now what what if you get a question about you know like an anti-viral medication that you know increases dopamine release and you can actually use it to treat Parkinson's especially like early Parkinson's I really hope you're thinking about a man to Dean right a man to Dean is one of those drugs that I used to treat that the flu back in the day remember it's sort of inhibits like a proton pump but I won't use it anymore because there's like a hundred percent resistance these days people use them you're many days inhibitors like Oseltami vier and Zanami vier.

Now what's the cell type I guess that sort of on the goals hypertrophy when you have like non-specific breathing very like infarction or whatever those are your astrocytes remember your astrocytes that process is called like reactive glialysis remember your astrocytes they are like the sort of the half-foot processes that sort of help with the blood brain barrier and then they also help you maintain the extra cellulite environment around neurons in the brain.

Now what if you get a question this one don't get it wrong if you get it wrong on an exam after the exam go home and cry but if you get a question about a patient that you know sort of comes in complaining worst headache of their life you really want to think about right a sub-racidoid hemorrhage right that's that's uh that's a given on an exam but one crafty way your friends at the MBMME present that on a test is they may give you a question about a patient that you know sort of comes in um excuse me so patient comes in on the MBMME and they tell you that they have like a really bad headache and then they'll tell you the question that they won't put the boss phrase worst headache of the patient's life they can actually tell you that the patient has like no core rigidity right but it's usually the and actually believe it or not the patient can actually be fabriol so he may have like a fever right but it will be like a sudden onset fever, sudden onset headache, sudden onset no core rigidity right um if you see that you really want to think about a sub-racidoid hemorrhage especially if they then tell you that oh they do a number of puncturing you see like 6,000 or 7,000 rib blood cells if you see that that's not many anxiety right that's more of uh that's more of a sub-racidoid hemorrhage now what if you get a image right so you get a head CT and you see like a lenship lesion um that's an epiderohimatoma right um and remember if you contrast that with a crescent shaped lesion right on head CT that's a sub-derohimatoma um now what if a patient right that patient that presented a few questions ago was headache of their lives what if you sort of want to present like an ischemic stroke after this sub-racidoid hemorrhage hemorrhage stroke they just had um I really hope you're thinking about my Modepin remember my Modepin it's actually a dihydroperidina calcium channel blocke

r now what are the cells that make CSF right so an MDM is go ahead and pick a pendomal cell but that is technically not true the cells that actually make CSF acoroid plexus cells acoroid plexus cells they're kind of a pendomal cell they're derived from a pendomal cells the main job of an appendomal cell is actually to use its cilia to sort of like uh beat um CSF around right to sort of keep it moving okay uh but they're kind of one and the same so I guess that's okay for exams now what if you get a question about a patient you know that has like rapidly progressive paralysis and let's say like three days ago they had like bloody diarrhea I really hope you're thinking about Guillain-Barry syndrome right that's a Campylo-Bacter Gijunai um although on the MDM is the beginning to de-emphasize um um the what is it called they're beginning to de-emphasize the CG-Junai um bloody diarrhea they're not beginning to emphasize more like upper respiratory infections okay uh basically if you have an infection and then days later you start having like ascending paralysis that's symmetric you really want to think about a Guillain-Barry syndrome now what if you get a question about a patient that has like bilateral hearing loss on an MDM right just take a pick right just literally giving you all the information bilateral hearing loss on an MDM exam I really hope you're thinking about NF2 right neurofibromatosis type 2 and remember that's a chromosome 22 problem um and usually these people actually do not have a neurofibromus um they usually have more like the bilateral acoustic neuromus right those are schwannomas and classically you find them at the cerebellum pontina angle in fact a high-yodaggis a dendom question to that is the most common cause of a cerebellum pontina angle mass on MDM is a schwannoma the second most common cause if I'm not mistaken is a meningioma okay we really

want to think about schwannomas first in fact bilateral acoustic neuromus a diagnostic for neurofibromatosis type 2 now what if you get a question about you know patient he's like a 17-year-old guy um he's had liver problems for a while and then he's kind of acting psychotic um if you see that I really hope you're thinking about um well-since disease um well-since disease remember that arises from like an ATP7 B mutation and if you do like a diluted eye exam you can see those are classic chisaflisher rings right so they'll present it as a teenager that's having like psychiatric issues with liver problems if you see that combination you really want to think about a well-since disease that's like a copper metabolism in the solder you can treat the the well-since disease with a penicillamine right remember copper pennies or you can give the patient a triantine right that's another thing you mission exam because they know that many people have remembered copper pennies so they begin to deemphasize that on MDM is a now they are going after a triantine triantine is a copper key later that can be used in the treatment of well-since disease now what if you get a question about a patient you know they they recently began treatment for like MS and then they have like a like a viral meningitis and they die from that um and then let's say like they show you an MRI and they tell you that oh there's like dimylination seen like everywhere in the brain on MRI I really hope you're thinking about a progressive multi-focular look and sephalopathy um the classic MS drug that has that association is not a lysium app okay it's a monoclonal antibody against like alpha-4 integraine so you can see how that can be how they can basically integrate that with like that acute inflammation cascade that performance sort of discusses where you have like the margination and all that crap remember integ

rins are kind of involved in that process and a lysium app actually is a monoclonal antibody against alpha-4 integraine and it's associated with uh reactivation of the JC virus right so you can present as a progressive of a progressive a multi-focular look and sephalopathy now what if you get a question about a patient that is like hypothermic and they tell you that they have a CNS lesion that is causing that hypothermia I really hope you're thinking about the lesion to like the posterior nucleus of the hypothalamus um that's actually very high you to know for NVME exam so those hypothermic nuclei everyone basically sort of like this is them like uh who cares about the scrap no one really thinks about this on test believe it or not those things are like floridly high yield for NVME exams you definitely want to know them for your test now what if you get you know an analogous question CNS lesion on the patient is hypothermic so they are super super super super super warm right um I really hope you're thinking about lesion to the anterior nucleus of the hypothalamus right so probably an easy way to remember this is uh like there's this pneumonia kind of I'm studying for step one uh wow we need to even take step one this is what like 2016 wow it looks like so long ago but anyhow so um basically right so then the monica remember from back in the day right is like anterior cooling like AC right so like air conditioning so the anterior nucleus of the hypothalamus cools your body your body down so if you lesion that anterior nucleus your body will no longer be cooled down right so you sort of burn up right so you get hypothermia um and then you just remember that the other one is the other one right that's sort of like a nicely to remember that um remember you want to remember you want to learn the least amount of information that will help you control the most amount of kno

wledge right that's that's how people learn vast amounts of information you're like hmm how does it especially retain all the scrap in their head well that's how that's how now what's the hypotherlamic nucleus that sort of has connections to the retina well I really hope you think about your super chiasmatic nucleus right remember that sort of controls your your circadian rhythms now what if a patient has like uh you know they tell you that this patient has like tonal vision or bi-temperohemia nopsia and then they tell you that they do a CT scan of the patient's brain and it's a child right and then they see like a calcifications on a head CT and it's like a super-tentral mass or if they want to be a little nicer to you then you see like a super-cellar mass so like a mass above the cellar tersica right I really hope you're thinking about a craniofaring geoma right remember that's a tumor it's one of the most common supercellar tumors in kids um remember it arises from a ratkiss pouch that's a very nice embryology tie-in for an ambient exam and don't forget that um craniofaring geoma right classically if you sort of perform let's say like they say like oh on pathology you see like like colest like a motor oil fluid draining from the mass right that's like it's not actually like motor oil right I mean like no it's not motor oil it's actually like cholesterol and like tumor cells and all that crap okay now what if you get a question about a patient you know that has a brain tumor and let's say it's like a guy and he has like decrystal libido or it's a lady and she has like a gynecomastia I really hope you're thinking about a prolectinoma right remember uh prolectin sort of shuts down your HVG access so you basically become like non-reproductive okay now how do you treat a prolectinoma right if you want to treat a prolectinoma an nbm is you want to go after a dopamine ago

nist right like bromo cryptino carburegulin if they give you both as answer choices on an exam pick carburegulin okay pick carburegulin over bromo cryptin carburegulin I believe is longer acting and has fewer side effects than bromo cryptin and remember as a very nice a psychiatric association they remember that remember dopamine is also known as prolactin inhibiting factor right so if you have a high level of dopamine that will sort of shut down the release of prolactin um in fact that pathway I believe is known as the tubero um the tubero infantibular pathway okay that's a very nice way we can also integrate that on an nbm exam um let's see um what if you get a question about a patient that like a five-year-old a seven-year-old not doing well in school sort of like stairs off into space on exams I mean during lectures and whatnot I really hope you're thinking about um an absent seizure and how do you treat that how do you treat that right so you give ethosoxamide remember that's a tea type calcium channel blocker right and remember a classically on EEG if a patient has an absent seizure you see the three per second spike pattern right so like three hertz or whatever spike pattern I remember your EEG patterns are very high you to know for the US Emily step one right so if for example they give you a question about a patient that um has like a hypsi-rhythmian it's a kid and this kid has like multiple like tubers in the brain I really hope you're thinking about infantile spasms and like west syndrome remember that's associated with the hypsi-rhythmias on an EEG and really the way you treat that is with acth right um you can also use a vigabatrin if you don't see acth as an answer choice on on nbms now um what if they give you a question about a you know a patient that you know the sex worker has a four count is like 25 and um you know you're for some reason you obtain

a brain biopsy um and detail you that uh what would you expect right on a brain biopsy in that patient right I mean there are many things you can see right but really on an mbm exam the then I really want you to think about a like multi nucleated giant cells remember I believe I said this in probably like the first detail the the second detail the uh neuro step one podcast I said that uh remember that process of reactive gliosis that happens in HIV1 infection remember HIV loves to infect the microglia in the brain right so um if your microglia being infected by HIV um they sort of begin to gung up together to form like these giant giant cells remember microglia actually derived from uh from a misoder okay now what is the most common sight of an aneurysm in the circle of willis what is the most common sight of an aneurysm in the circle of willis uh remember A is the first letter in the alphabet right so anterior communicative artery right aneurysm is love to arise at a terabyte for occasion this kind of like a nice pro tip to uh sort of understand for exams there's a mechanism behind that what I want to keep this right this is literally a rapid review right so I want to sort of like keep this keep this short now um what if a patient you know has like uh they've basically lost like uh like higher order speech um and let's assume like they're trying to get you to pick like an artery as the artery that's been lesioned um I really hope you're thinking about like a middle-sabral artery lesion right um they basically lesioned uh one of the lesion the speech center remember a middle-sabral artery territory so that covers like your brokers and when it's area right but if you've lost speech right um you're thinking about like a model problem right like a broker's lesion that's an uh middle-sabral artery uh territory now what's the cranio nerve that's basically okay let's assume

a patient right has like cranio nerve deficits and again all these things out describe them in detail and describe like the mechanisms in the more detailed neuro podcasts um like again I promise like I really love neuro in fact I'm probably obsessed with neuro um I will finish up the neuro step one of podcasts but I want to sort of make this if you want to sort of get yourself going as you're studying for an exam uh because this is something I can basically like on the fly sort of like just sort of talk through uh it's short and sweet body covers a lot of information but what if you get a question about a patient you know that has like an aneurysm in the brain and in the setting of that aneurysm they're having like a down and out eye um I really hope you're thinking about like um the oculumurone nerve right so cranio-3 um remember cranio-3 does not do the superior liquid depresses the eye and the lateral rectus which AB ducts the eye right so the eye will literally be down and out right because the superior blick muscle and the lateral rectus muscle remember superior blick is cranio-4 that's your trochlear nerve lateral rectus is cranio-6 you have du sens nerve um those work on a pulse right so you have a down and out eye right so if you have an aneurysm of the posterior cerebral artery or an aneurysm of the superior cerebellar artery right um you can actually have a cranio-3 problem right because those cranio-3 basically cuts between those two arteries on its way to the to the eye now what if you have a question about like a 30-old guy you know he cannot smell and he's tried to have kids for years right I really hope you're thinking about common syndrome right remember uh basically the neurons that sort of secretion are each and the neurons that uh so they're like cranio-1 they sort of migrate together in embryology so they don't migrate well or something like weird

happens you can have common syndrome right so infertility plus not being able to smell that's common syndrome and remember right on exams right they can sort of try to mess up your head right you can say oh what kind of hypogonitis in those this person have remember if a patient has a problem up top at the level of the like the pituitary or the hypothalamus remember that'll be an example of a hypogonado tropic hypogonitis right because they basically have like the uh the gonado tropic not working right so it's a hypogonado tropic hypogonitis in contrast that would like a patient that has like um I don't know like toner syndrome and streak ovaries right the ovaries don't work right but they're gonna do tropines they're like oh crap why why do you why do I know estrogen right so they're gonna do tropines that sort of revved up revved up right so they'll have very high levels of gonado tropines but they will have like low levels of like a gonado hormones right so that'll be an example of a hyper gonado tropic hypogonitis in that's just one of those easy things that they try to present in a weird tough way on mba exams and I guess to sort of round this up so that I give this on the 30 minutes uh what's the most common cranial nerve that's kind of like you know in lesion in a carbonous sinus pathology um that's like the abducine nerve right that's uh that's a classic one to know for frame gaming exams and if a patient also has like high IC Ps uh the abducine nerve again can get into trouble there so I'm gonna stop here um and again as I round up remember I do offer one on one tutoring for uh the usml step one step two ck step two cs step three um med school preclinical exams med school shelf exams the internal medicine in training examined in the internal medicine board exams and again most of the people have tutoring have done extremely well on this test so um if you need

one or one tutoring for those or you really need like one or one tutoring for like organic chemistry or for like college physics or um what else do I even do um uh let's see um advising right so application advising for like um uh like if you're a med student applying for residency or your college student applying for med school like ERAS AMCA's applications and what not I do like help I help with like you know writing personal statements uh mocking interviews preparing an application so it's pristine um I mean like this last cycle like all but one person advice them matched um so take that for what you will and then if you're also interested in like a usml class right so if you're a group of like you know like three or five people and you sort of want like oh like say like over two three weeks sort of like rapidly review a lot of stuff relating to the usml that's something I also offer just reach out to me with your group and I'll sort of tell you what the guess group rate is so I wish you all the best I will see in the next podcast I will try to make as many as I can um this week um and well have a wonderful day God bless and I'll see you next time thank you

Confusion (encephalopathy), Ataxia, and Ocular abnormalities (nystagmus/ophthalmoplegia).

India ink stain (and Latex Particle Agglutination Assay).

Epidural hematomas are typically lens-shaped; Subarachnoid hemorrhages are crescent-shaped.

Neurofibromatosis Type 2 (NF2).

Anterior communicating artery (ACOM).

Oculomotor Nerve (CN III) palsy.

High protein, low glucose, and high neutrophils.

Thiamine (Vitamin B1), which is a cofactor for transketolase in the pentose phosphate pathway.

Papilledema, headache, and high opening pressure on lumbar puncture; normal ventricles/sulci on CT.

Pilocytic Astrocytoma.

Fungal meningitis (e.g., Cryptococcus).

GnRH/FSH/LH axis dysfunction; specifically, hypogonadotropic hypogonadism.

High protein, low glucose, and high neutrophils.

Thiamine (Vitamin B1), which is a cofactor for transketolase in the pentose phosphate pathway.

Papilledema, headache, and high opening pressure on lumbar puncture; normal ventricles/sulci on CT.

Pilocytic Astrocytoma.

Fungal meningitis (e.g., Cryptococcus).

GnRH/FSH/LH axis dysfunction; specifically, hypogonadotropic hypogonadism.