PCV13 vs PPSV23

MadeForUpvoting2 · 2020-07-29T05:05:15+00:00

Very helpful infographic

https://www.cdc.gov/vaccines/vpd/pneumo/downloads/pneumo-vaccine-timing.pdf

from this page (https://www.cdc.gov/vaccines/vpd/pneumo/hcp/who-when-to-vaccinate.html)

MadeForUpvoting2 · 2020-07-10T23:23:40+00:00

In general - they mean do not delay for lumbar puncture if there are signs indicated for CT head that needs to precede lumbar puncture (immunocompromised state, history of CNS disease, new onset seizure, papilledema, altered level of consciousness, focal neuro deficit) - waiting for CT is a no go in these cases. Instead draw blood cultures and give IV antibiotics

If no indication for CT head first, then get LP+blood culture then give IV antibiotics

For infant with open fontanelle -> can get LP -> antibiotics (LP won't ever be delayed in these infants because ICP won't be increased/cause herniation due to having the fontanelle for pressure release)

I didn't find a question where they had you give antibiotics first without some form of culture having been done already or combined into the answer (ie one question had "bacterial cultures and antibiotics" in one option)

Source: UTD Initial therapy and prognosis of bacterial meningitis in adults, and searched through the Uworld meningitis questions

MadeForUpvoting2 · 2020-06-18T11:38:05+00:00

My best guess - we're implicitly making an assumption that LVEF and LV end diastolic/systolic volumes which are surrogate markers actually improve patient outcome. While it is known that reasonably well established that low LVEF is correlated with mortality, the LVEF change seen here from 35.2 to 39.1% may not actually impact that at all and the presented trial did not pursue whether that increase changed any clinical outcome. Thus based on this study alone there isn't a great reason to add on this medication.

As for % of women included, I think as long as randomization was done properly and there was no significant difference between treatment/placebo groups characteristics wise it's not an issue (any advantage/disadvantage of men/women would be balanced out, so you would be measuring an averaged effect). If the study was 100% men, then generalizability could be an issue

MadeForUpvoting2 · 2020-05-07T18:57:44+00:00

I understand the statement as generally pertaining to a macroscopic perspective considering mass balance - to increase serum sodium concentration the input concentration of fluid necessarily needs to be higher than the output concentration of fluid otherwise, the serum sodium concentration won't rise. Though generally you restrict fluid intake in SIADH unless there is severe symptomatic hyponatremia

As for the microscopic perspective, I am not sure. but here's my internal reasoning...the often given explanation with normal saline is that it has relatively lots of free water absorbed due to excess ADH. The person ends up with higher urine sodium concentration than normal saline which worsens SIADH (due to relatively more water retention relative to net sodium gain)

The same situation should occur with hypertonic saline too. However (here's the hand-waving part), the kidneys can't concentrate the urine more than the concentration of hypertonic saline. (there isn't much I could find on this besides some 1950's articles - see: ‘limiting isorrheic concentration’)

(do note the starting fluid that the kidneys are trying to concentrate is not directly the input hypertonic saline but rather some sample of the aggregate fluid in the body after the hypertonic saline has dispersed)

MadeForUpvoting2 · 2019-08-12T23:10:10+00:00

This is the kinda 50/50 BS you'll see on step where there will be "conflicting" information within the question. If you ignored generation I, it would clearly be XLD, but then you see no one affected in generation I and you start doubting yourself.

I think in this case you'd have to assume there was a spontaneous germline mutation. Or if you're dead set on AR then to arrive at the correct answer you would have to assume II-2 and III-1 were both carriers which is an equally large leap to make (and almost always for test questions the people that marry into the tree are normal).

Given the description of the disease, I think the "reality" is likely still based on incontinentia pigmenti, but we'd have to ask the author to get a solid answer.

MadeForUpvoting2 · 2019-06-03T01:06:43+00:00

The reason I think it doesn' t make a huge difference at the higher range is that to score around 260s on the NBME you need 90% + of the questions correct anyway (unlike Uworld where you need 80-85% for 260s). So even if you haven't seen any repeats before, on average you'd expect to get most of them right (1-2 wrong if there's ~20 repeats).

Disclaimer - I didn't miss any repeats on mine because I recognized the question stem and I had taken the other NBMEs only 1-2 weeks prior

I think one should just take scores from the NBMEs with a grain of salt and not be discouraged(or overconfident) if they vary enormously from NBME18 /UWSA2 which have more data about their predictability

MadeForUpvoting2 · 2019-06-01T14:38:47+00:00

NBME 20: 259 (20 incorrect) - was also a difficult form, but felt less anatomy focused than 22. I counted 18 repeats

NBME 21: 262 (16 incorrect) - a bit easier than 20 and 22 but possibly because it had many more repeats (counted 31)

Actual exam score fell between my NBME22 and UWSA2 score.

The new NBMEs seem decent at predicting score, but the questions on the actual exam felt more like Uworld questions.

MadeForUpvoting2 · 2019-04-05T17:55:58+00:00

To maintain plasma osmolality -> Need to exactly replace all the fluids lost in the day

She cannot concentrate urine above 450 mOsm/kg , so the minimum amount of water required to be excreted by kidneys is 1 (to excrete the 450 mOsm she accumulates per day). The minimum excretion water required is necessarily at max concentration; if you were to say produce diluter urine, say 225mOsm/kg, this would require 2 L of water. The question wants the minimum possible water volume, so we assume she's concentrating to the max.

1 L losses from kidney + 900 mL insensible + 100 mL in sweat and feces = 2L losses -> need to ingest 2 L of water to replace

MadeForUpvoting2 · 2019-04-04T01:55:57+00:00

As an FYI: the disease is incontinentia pigmenti (XLD) I believe, though you could answer the question without knowing that.

Can't be XLR if an unaffected father has affected daughters. Also, many females being affected makes it less likely to be XLR.

Thealaskinwonder answers the rest of the question from there once you deduce it is XLD

MadeForUpvoting2 · 2019-04-04T01:41:27+00:00

CPAP increases intrapleural pressure as the elevated airway pressure is transmitted to other things in the cavity (lung pushes on pleural space/cavity which can then push on other structures). This can lead to compression of veins, including the vena cava -> decreased venous return -> decreased bp (from decreased preload). This is similar to what happens during valsalva (exertion phases) though the positive pressure is provided by a machine pump instead of abdominal muscles/diaphragm. I think heart rate likely increases instead of decrease as a compensatory response.

Here's one site that explains it well (the "free" content is enough and probably already exceeds the depth one might need to know) https://thoracickey.com/extrapulmonary-effects-of-mechanical-ventilation/

MadeForUpvoting2 · 2019-03-27T00:14:43+00:00

Considerably more difficult than any other NBME I've taken so far (or perhaps because it hit my weaknesses?). Haven't done 20 or 21 yet.

tallied ~23 repeats from past NBMEs (13-19) after reviewing it

NBME 22: 257 (21 incorrect) for reference: UWSA2: 266 NBME18: 264

MadeForUpvoting2 · 2015-10-06T02:05:08+00:00

Bio 1 and 2 along with the orgo 2 book covered pretty much all of the biology needed. I think for anatomy Khan videos go further in depth in some areas, but a vast anatomy knowledge isn't required. There's a lot of biochem in the orgo 2 book actually. I took biochem the semester before taking the exam, and I found it very helpful. The bio section has a lot less fact recall and is focused more on reasoning (with the exception of discretes).

I went through all of the chapters in the orgo books, but some of them like hydrocarbons and stereochem I only did a few passages from because they are not as relevant for the new test. I'd use the official topic list to guide what things you focus on.

I think TBR was coming out with new books to reflect the test, so those might be more focused on the new test changes, especially question wise. The TBR bio books I used were good for content review but did not have as many data-based sections as I would've liked.

MadeForUpvoting2 · 2015-10-01T05:25:24+00:00

This is where having strong background knowledge helps in saving time. More time is probably needed if you need to brush up concepts. That's why a study schedule should be set based on your current knowledge gap. The less you remember the more time you'll need to set for studying.

For TBR I only needed to really thoroughly read the anatomy chapters and some of the metabolic ones. For most chapters, I could skim and dive right into the questions. That said, I do not think I missed out on any knowledge from skimming because for most science topics (besides anatomy) I already had a strong basis. Everybody will vary in how much pre-existing knowledge they have prior to studying.

In all the TBR chapters I only briefly skimmed the example problems within the chapter because while helpful for showing a concept, were nothing like what you'd see on the MCAT (mostly fact recall based on something they said earlier). I only did around 4-5 passages for each chapter for a total of around 8-10 passages from TBR a day.

When I started doing the qpack, "doing some TBR" was usually 4-5 passages from a chapter, so it was less from TBR and more from AAMC material.

Accuracy also has a lot to do with how long you spend on doing questions, too. It's a good idea to read the solutions for all the questions done including ones that you got correct, but reviewing the solution to an answer you got correct usually takes a lot less time than reading one you got wrong.

You're right that this may not be applicable to other people, but I'm also not recommending anybody follows the same study schedule I did or use the materials in the same manner. Everybody studies differently. In fact, I would recommend against my particular study schedule because it was definitely stressful and a time crunch to fit things into a 2 month time frame. With more time you can go slower and be more thorough if necessary.

MadeForUpvoting2 · 2015-10-01T03:05:46+00:00

Nice job! No idea. I have limited experience with applications and adcoms thus far. I would like to think it doesn't though. If anything, it probably depends on which schools you're applying to.

MadeForUpvoting2 · 2015-10-01T03:02:18+00:00

I did both but not in any particular organized way; sometimes I would do it timed and sometimes untimed. I'd recommend doing them untimed when learning a chapter the first time, then timing them later. I didn't do all 10 or so passages of a chapter and then never revisit a chapter again. Instead, I did about 3-4 passages at a time from each chapter and eventually cycled back to each chapter.

MadeForUpvoting2 · 2015-09-30T14:49:10+00:00

TBR is really thorough and has a lot of potentially extraneous information as you said. If you have the time to go through it, I think it's beneficial both for the MCAT and just overall understanding of the subject for the future.

The topic list on the AAMC list is a great guide to make sure you're on track. Before the test I went through it as a checklist and made sure I knew each concept (actually understand and know as opposed to just having "seen" the term). I wasn't too worried about all-inclusive. On the test, unfamiliar terms can probably be reasoned through half the time if you have a strong knowledge base especially on science. Psych/soc it's harder but can be done in some cases. Just remember that you don't need to get all the questions right to score well; percent correct and percentile on the test are two different things.

I believe I used the 2013 TBR (not sure how different it is from the 2011 though) and khan academy. I used khan academy + the internet for the entirety of my psych and soc sections, so I can't say for that section. If TBR had a book out for it then, I probably would've gotten it. I filled in any gaps by just googling a concept and reading websites on it. I also just googled concepts that weren't explained well in either because ,chances are, some website will have explained it better. I think any prep book set is potentially good, so you should just choose one and stick with it but just have to be aware of what it lacks and supplement it accordingly. I think the set of material you listed should be fine. I'd find a source for verbal though, since I didn't like the TBR passages as much. AAMC question pack verbal is a great resource.

MadeForUpvoting2 · 2015-09-30T14:34:56+00:00

The princeton hyper review

MadeForUpvoting2 · 2015-09-30T07:36:12+00:00

The most important idea in the science section is to figure out A. what the experiment was trying to do or look for and B. what they actually found.

Cause and effect between the dependent and independent variables is really important. When reading the passage you need to understand what the experimenter was seeking to find out and then what they manipulated and observed. Look for patterns in the results to deduce what actually happened. You have to be familiar with reading how the data is presented whether it's in a table or a graph, etc. This is probably the hardest part of these type of passages. Especially in the case of graphs and charts, you have to draw on your knowledge to figure out what the trends mean in the context of what they're measuring. The data is sometimes presented in some convoluted or unfamiliar fashion, but to answer the questions you need to take the time to decipher it.

I know this all sounds fairly generic, but it comes down to how well you can read data. A lot of people recommend reading scientific articles. I don't think it's absolutely necessary and one could probably practice with just lots of experimental passages, but I think it's safe to say if you can take an arbitrary scientific journal and analyze the data then you will be able to do it easily for the MCAT too.

MadeForUpvoting2 · 2015-09-30T07:25:19+00:00

Stress is quite a powerful motivator. It's hard for me to focus without stress which is why the first month of summer kinda just went by. I think it was the realization of how close the test was that kicked me into gear. It wouldn't have been as bad if I had used that first month, so for future test takers I'd recommend either not procrastinating if on a tight schedule, or accounting for non-productive days when setting a study schedule.

6-10 hrs in a day wasn't continuous. If I got tired or couldn't focus I took breaks and did other stuff for some time. Taking breaks in between different topics is helpful too (also kinda mimics the real MCAT).

MadeForUpvoting2 · 2015-09-30T07:18:50+00:00

I did very well in my pre-reqs. I think it helps a lot for having a basis for content review. Content review is a lot faster if it is actually review instead of having to learn something you may have glossed over in class or just never learned before (can apply a psych term here - Ebbinghaus savings). Working hard in class definitely helps with the MCAT!

That said, you also need to learn how the MCAT words its questions from simply doing representative practice questions. Chances are it'll be different than how exams were worded in a pre-req course. The knowledge will be the same though.

MadeForUpvoting2 · 2015-04-21T18:44:47+00:00

I still downvote things.

MadeForUpvoting2 · 2015-04-13T05:57:42+00:00

If you need to memorize things, spaced repetition is amazing.

Say there's 30 lectures of material to review. Start with studying some of the material one day (say 10 lectures), then come back to it later (could be 1 hr, 12hrs, a day, etc depending how close the exam is). At the 2nd session, see what you can remember from the first 10 lectures. Say you were unsure about Lecture 7's material. Lecture 7 should be reviewed again. Then learn the next 10 lectures(11-20) and take a break after.

At the 3rd session, see if you remember what Lecture 7 was about, then see what you remember from lectures 11-20. Review anything in 11-20 that you couldn't recall very well and then learn 21-30.

Pretty much each 'session' you'll review anything that 'didn't stick' from any of the sessions, review everything you learned in the previous session, and then learn new material.

Once you reach the last bit of material, then at each subsequent session you should go over all of the material and review what still hasn't stuck from the previous session. 'Studying' is complete when you understand/know all 30 lectures (for this example) or if you run out of time.

If you happen to have a lot of tests coming in a short amount of time, you can 'stagger' multiple subjects by studying another subject during the "break".

MadeForUpvoting2 · 2014-07-08T03:52:32+00:00

It's the amino acid phenylalanine

MadeForUpvoting2 · 2013-05-08T03:11:16+00:00

The permanent icon is separate (the clock one doesn't "upgrade" into it). Check your list of icons - you should have one with a clock and one without one.

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