Why vancomycin is not the answer

As I tutor of medical students I have noticed a few trends. I wanted to share just one of them today. Specifically I want to talk about a very specific antibiotic that many students think is the answer for so many infectious disease questions. That antibiotic is vancomycin. Now, just to clarify, I am not shaming anyone for not knowing. On the contrary, I want to help you to understand the right times to use vancomycin, so that you can get those pesky MCQ questions correct. More importantly this knowledge will help you when making decisions on how to help your patients. We need to start with answering the question, what is vancomycin?

Vancomycin is a renally excreted inhibitor of peptidoglycan synthesis which is used to build the bacterial cell wall. Without this the bacteria dies which by definition makes vancomycin bactericidal. It accomplishes this by stopping D-Ala-D-Ala groups from attaching to the growing chain; however, gram negative bacteria cell walls are thick. Gram negative bacteria, such as E. coli, have porin proteins that act as tunneled highways by letting small molecules in and are too small to allow bulky molecules such as vancomycin through. If you remember back to molecular biology class 70% of UTIs are caused by E. coli. That being said is the first point is vancomycin is not used to treat UTIs unless the organism involved is gram positive AND you do not have other options.

Now you may be saying that vancomycin has activity against MRSA and you would be right. Vancomycin is used in cases of suspected or confirmed MRSA infection as well as serious skin/bone (osteomyelitis) infections caused by staphylococci; however, have you ever noticed that for sepsis and endocarditis the guidelines say to switch to a synthetic penicillin (PCN) if culture results show MSSA infection or a non-staphylococci infection? This is partly to stop cross resistance from developing as well as the fact that vancomycin is not as effective as synthetic penicillins, but also because vancomycin is very toxic. Red man syndrome is one toxicity that leads to an IgE independent mast cell degranulation. This causes wheals and urticaria primarily on the upper torso, neck, and arms. Rarely this can cause angioedema. The risk of this can be reduced by anti-histamine prophylaxis and decreasing the infusion rate. Drug fever is another possible problem that complicates the clinical course, but nowhere near as much as the feared neutropenia.

Vancomycin also does a great job of working synergistically with aminoglycosides to create help destroy the patient’s ears and kidneys (ototoxicity and nephrotoxicity). Again you might say, but a patient can live without their kidneys on dialysis right? If we ignore the fact that lifelong dialysis is life changing to say the least then yes you can survive on dialysis; although, vancomycin is not removed by dialysis. One dose is enough for 7 days while on dialysis. This is important as many of the toxicities, and the benefits, are dose dependent.

The route of entry is also important to consider. Vancomycin is used IV, but is not released into the colon this way. For moderate/severe C. difficile infection or previous C. difficile infection you should give vancomycin orally. Watch for trick questions that will have both IV and oral (PO) as possible answers. This also adds the duality that vancomycin given IV does not alter the gut flora and does not cause diarrhea. With this being said there is one other area where vancomycin is important and that is when GBS treatment is required in a pregnant woman allergic to PCN.

That is all for this post, so if you want a free and non-obligatory consult on how to study for the USMLE, NBME exams, or MCCEE or any other medical exam check out http://www.mcceetutoringservices.com/contact and send me an email! If you liked this article just say so in the comments below!


Golan, D. E., Tashjian, A. H., & Armstrong, E. a. (2012). Prinicples of Pharmocology: The Pathophysiologic Basis of Drug Therapy Third Edition. Philadelphia, PA: Lippincott Williams and Wilkins.

Is that a normal EKG tracing?

When I was studying for the Step 1 I remember how much time I spent on memorizing pathology, biochemistry, and genetics. I spent hardly any time on minor areas such as biostatistics, EKGs (Electrocardiograms), and heart sounds. Now I did make the socially isolating decision early in university to minor in math, so I always felt comfortable with statistics. When it came to EKGs I was more looking for all those First Aid buzzwords like “saw tooth waves.” EKG’s are important not only for the USMLE Step 1, but also the Step 2 CK, and the Canadian exams such as the NAC OSCE.

Many of you have probably been handed many an EKG by an attending and asked to interpret it. This may lead to you staring at the sheet hoping the answer will pop out like the image on an autostereogram in Figure 1. (you know those pictures you stare at cross eyed to make a 3d image). Even if you have not started rotations yet, the importance of understanding an EKG for all USMLE exams cannot be overstated. This is similar to my blog about biostatistics, learning how to read an EKG is lost in the shuffle while studying pathology or general medicine. Subjects like biostatistics, EKGs, and hearts sounds alone will not give you the score you want, but what they will do is increase your score from say a 230 to a 240 if you had not put any time into them.


Why can these smaller subjects change your marks so much? You are guaranteed questions from these small subjects. Let me reinforce that point. You are guaranteed to receive several questions that have EKGs, hearts sounds, and biostatistics. Remember there are only so many questions on the exam and although I cannot say an exact number, over a half dozen questions are used in these subject areas. Are you really going to leave the answers to those all up to chance just so you can learn another obscure pathology concept that will likely not be on the test?

In my previous blog entry I wrote about how to get better with biostatistics. The next question you may have is how do I master reading an EKG? First you will need to develop a systemic method of the reading the EKG just like with X-rays. You can do this by reading: https://www.amazon.ca/Rapid-Interpretation-EKGs-Methodology-Understanding/dp/0912912065. This book is the Bible of reading EKGs. It is also interactive with practice EKGs to read. The second thing you need to do is get as much practice as you can by looking at EKGs and try and figure out what the tracing suggests.

After you have mastered EKGs you should try your hand with the tracing below and tell me what you think the diagnosis is in the comments below. This is a more complicated strip (ie. will not exactly be on the exam, but will happen in real life), so use a systematic approach to it.


That is all for this post, so if you want a free and non-obligatory consult on how to study for the USMLE, NBME exams, or MCCEE or any other medical exam check out http://www.mcceetutoringservices.com/contact and send me an email! If you liked this article just say so in the comments below!

USMLE Exams and the Importance of Biostatistics

Medical students in the US, particularly IMGs (International Medical Graduates) and pre-IMGs, know the importance of achieving a first time pass and high score on the USMLE (United States Medical Licensing Examination) Step 1. It is long and intense and everyone is always happy when it is finally over. The majority of the questions come from the section “Internal Medicine” so it would seem like an easy way to get a high score is to make sure you memorize everything internal medicine. In practice this is difficult because internal medicine is a gateway to many different topics such as nephrology, cardiology, pulmonology which makes it difficult to fully memorize. I would suggest first to learn the six disciplines as best as you can, but also know a few smaller sections very well. In this post I want to focus on the neglected discipline of medicine: statistics.

Before I dive right into the main part of this post, I wanted to introduce a bit of my background prior starting medical school. Many years ago I realized I wanted to become a doctor and I started working my way down the path of science. I had, and still have, a great love of math and science which propelled me to major in biochemistry. After one year I found the course load of biochemistry to be not socially isolating enough and added a math minor. This is where my passion for math started to grow. It is a very great tool for science, but now I see many medical students and doctors do not fully understand statistics.

Statistics is a branch of math, so most people would normally choose swallowing a pack of batteries than try to learn it. The most common thing I hear people say is, “Why do I need to learn this? I am not going into research!” This may be true, but you do have to read journal papers, understand them, and critique them. Statistics helps you decide if there are any sources of bias and evaluate the likelihood of a type I error (rejecting the null hypothesis when it is actually true) without even having any knowledge of the medical content of the paper. This will come into play in rotations and will continue throughout your medical career.

If gaining valuable critiquing skills for journal articles is not enough for you then I will give you a very strong reason. You will have biostatistics questions on the USMLE Step 1 and Step 2 CK exams. There will be several of them. On an exam of 322 questions you cannot afford to lose four to five guaranteed marks. A few of these questions will center on tiny articles you have to read, while others will be straight forward providing that you study for this.

I guess I did say that many people find studying for biostatistics about as exciting as watching paint dry, so is there an easy way to learn the material? Of course there is! I would not have written this article otherwise. I have an interactive e-book out complete with USMLE and MCCEE style practice questions. It makes the process much less painful and is more effective at helping you remember the content. I have shown a couple of example pages and a question below. The bold text is the answers to the blanks which is the interactive component.


Question: According to a shingles prevention study the live attenuated Herpes zoster vaccine decreased the incidence of shingles over a three year period by 50% in an at risk group. The difference was 3.3% for the placebo group and 1.6% for the treatment group. How many people need to receive treatment in order for one person to not get shingles?

  1. 1
  2. 43
  3. 2
  4. 59
  5. 14


You do not have to just take my word for it you can check out the reviews on Amazon at https://www.amazon.ca/Medical-School-Statistics-Rx-MCCEE-ebook/dp/B01M3Q9868/ref=sr_1_1?ie=UTF8&qid=1483653731&sr=8-1&keywords=statistics+rx

That is all for this post, so if you want a free and non-obligatory consult on how to study for the USMLE, NBME exams, or MCCEE or any other medical exam check out http://www.mcceetutoringservices.com/contact and send me an email! If you liked this article just say so in the comments below!

Is it possible to study for the MCCEE?

The Medical Council of Canada Evaluating Exam (MCCEE) is a must for any foreign trained medical student who desires a residency in Canada. In 2018 the format is changing, but currently, it consists of 180 multiple choice questions (MCQ) with 30, or about 1 out of 6 questions, being experimental. There are 30 questions from each of the major subject areas: pediatrics, psychiatry, surgery, population health and ethics, medicine, and OB/GYN. The questions are all in a case, or vignette, format like the USMLE exams, but they are much shorter. Sometimes the questions are only a couple of sentences. This would mean it is easier right?

Doing a quick Google search refutes this claim. You will see many people complaining about the exam being random and impossible to study for. The main complaint I hear is that the questions are too vague and you do not have enough information to solve them. Does this remind you of a certain profession? It should. Being a doctor in the real world means you have to use probability to push you in the right direction and wait for any test results to come in. This means that doctors go with the demographics and symptoms presented and ask what is the most likely diagnosis and differential?

Just like a doctor in the real life and unlike the USMLE, the MCCEE does not give you enough information to solve the case outright. Instead it relies on you to know what the most likely cause is and how to manage the patient. This means it is not random, but instead makes you think from an epidemiologic perspective. This is what I call the science of generalizing. Being much shorter the MCCEE is also not the marathon the USMLE Step 2 CK is and gives you more time to think your answer through. If you think in the same way that a student would taking the USMLE exams you will find the exam frustrating and random. Please do not misinterpret this though. You still need to have all of the medical knowledge for the USMLE Step 1 and 2 CK, you just need to apply it in a different way. There will also be a few, “…out there” questions to quote one of my students. Just pray those are the experimental ones. There will also be health maintenance questions that are very straightforward.

That brings us to the initial question which was can you study for the MCCEE? Yes you can, but you need take the above information into consideration and study appropriately.

If you want a free and non-obligatory consult on how to study for the MCCEE or any other medical exam check out http://www.mcceetutoringservices.com/contact and send me an email! If you liked this article just say so in the comments below!

MCC, NBME, and USMLE Study Guide

This post will cover exam studying strategies. There are many exam taking strategies out there, but I want to add some much needed clarity.

1) Get the most out of your rotations

As long as your rotation is not just a pure observership and you are allowed to take part in diagnostic process you can quickly assimilate information necessary for your exams. I put this higher on the list than even question banks because of how powerful putting a face to a disease/condition is. Follow up by checking peer reviewed sources, such as UpToDate, so you can double check what you saw and get a good differential. This serves the double purpose of fact checking your diagnosis.

2) Use question banks… correctly

Question banks are great and you need to start them AS EARLY AS POSSIBLE. Do not wait to start them as they are a learning tool not an assessment tool. They primarily act as an interactive textbook and studies have shown they increase your retention of material; however, Qbanks like UWorld are PACKED with information meaning you must make notes AND study from them. Many students of mine forget the second part at first. Time consuming, but worth it. Be sure to use the timed mode and go through all unused questions first, before doing the question bank again.

3) Do not get discouraged

Remember that making mistakes and getting questions wrong is not just a part of the learning process, it is the primary component. You will always learn more from making mistakes. Anytime you feel like giving up or not studying just remember this post.

4) Get a tutor early if you need help

 A good tutor will help you in more ways than one. To keep this article short, I will mention the important part. Exams test you on content and your ability to deal with questions you could not have studied for (ie. interpretation questions). A good tutor will help you in both of those areas. You can send me a message if you would like to know more on how MCCEE Tutoring Services achieves this goal.

5) Remember to have fun!

Medicine may be what you love and will take a lot of work, but remember to find healthy ways to reduce stress. Exercise, go out with friends, or go for hikes in places with more green than concrete and tell people if you are beginning to feel depressed/overwhelmed. The key is to prevent burn out.

Have any other suggestions? Let me know in the comments below and be sure to check out http://www.mcceetutoringservices.com/ for other tools to help you on your exams!