Most medical students use the same resources to study for board exams. By the end of dedicated studying, most students will have the same knowledge base. So, what differentiates those who score a 230 vs a 250 on step 1? I truly believe that it’s not knowledge. Instead, it’s the critical thinking skills and ability to apply knowledge to new scenarios. These skills are used in what I call “question interpretation.” This means applying what you already know to understand each sentence, in context, of the given scenario. This is not taught in medical school, but I think it’s crucial for doing well on boards! In this post, I will show you ane example of how I used question interpretation to crush my board exams!
A few fundamental rules:
1. Know that every sentence has a purpose. Even in vignettes that are 10-12 sentences long, understanding the role of EACH sentence will help you in getting the right answer. Ask yourself, “why did the test writer include this?”
2. Rephrase each sentence in your own words and within the context of the scenario.
3. Most importantly, rephrase the question in your own words. Board exams typically have a complex way of asking very simply questions!
First, start by reading and analyzing this question yourself. (You’ll understand much better if you try it yourself first).
A 34 year-old woman presents to the emergency department with a 6-month history of recurrent epistaxis and easy bruising. She has experienced approximately two to three epistaxis episodes per month during this period, and the bleeds eventually stops following packing of the anterior nares. She has no past medical or surgical history and takes no medications. She has never been pregnant but notes that her menstrual periods have been “more heavy than usual” during the same 6 months. She denies headaches or changes in vision. On examination, she is afebrile, has a pulse of 78 beats/minute and a blood pressure of 119/82. On dermatologic examination, she has diffuse areas of petechiae under her tongue, on the extensor surfaces of her forearms, and on her posterior thighs bilaterally, none of which are elevated or palpable. Abdominal exam is negative for splenomegaly. Laboratory examination shows: BUN 13 mg/dL Creatinine 0.8 mg/dL WBC 8,000 cells/mm3 Platelets 24,000 platelets/mm3 Hemoglobin 14.1 mg/dL Hematocrit 42% PT 14 seconds (normal 11-15 seconds) aPTT 27 seconds (normal 25-40 seconds) Bleeding time 11 minutes (normal 2-7 minutes) What is the most likely diagnosis for this patient’s condition?
Let’s break it down
Sentence 1: 34 year-old woman. This is a young female. 6-month history tells you that this is a chronic, not an acute issue. Recurrent epistaxis and easy bruising, tells you that she has some issue in the clotting or coagulation pathway. At this point, my mind is formulating some differential diagnoses. This includes von Willebrand disease (vWD), hemophilia, hemolytic uremic syndrome (HUS), idiopathic thrombolytic purpura (ITP), and thrombotic thrombocytopenic purpura (TTP), heparin-induced thrombocytopenia (HIT), disseminated intravascular coagulation (DIC), and malignancy (such as leukemia/lymphoma). Of note, hemophilia would be less likely given her gender.
Sentence 2: Two to three epistaxis episodes per month during this period, and the bleeds eventually stops following packing of the anterior nares. This information gives you an idea of the severity. You now know that this bleeding is not life-threatening (DIC) since it stops after she packs it.
Sentence 3: She has no past medical or surgical history and takes no medications. Great, you know that her bleeding isn’t due to being hyper anti-coagulated from medications such as warfarin. You also can rule out HIT since she’s not on heparin.
Sentence 4: She has never been pregnant but notes that her menstrual periods have been “more heavy than usual” during the same 6 months. This confirms that you have a more chronic issue, so it’s less likely HUS. Also, heavy menstrual bleeding makes me think of vWD. However, I’d still like to consider other diseases on my differential.
Sentence 5: She denies headaches or changes in vision. This information helps you rule out, TTP, where patients usually present with neurological symptoms.
Sentence 6: On examination, she is afebrile, has a pulse of 78 beats/minute and a blood pressure of 119/82. Her vitals are good, so again this confirms that she isn’t having severe blood loss (such as in DIC).
Sentence 7: On dermatologic examination, she has diffuse areas of petechiae under her tongue, on the extensor surfaces of her forearms, and on her posterior thighs bilaterally, none of which are elevated or palpable. Peteachie tells you that she has low platelets. It’s not palpable which rules out a vasculitis.
Sentence 8: Abdominal exam is negative for splenomegaly. Splenomegaly in the setting of coagulopathy could be associated with malignancy such as chronic lymphocytic leukemia (CML) or non-Hodgkin lymphoma. Now, we know that she is less likely to have cancer.
Sentence 9: Laboratory examination shows: BUN 13 mg/dL Creatinine 0.8 mg/dL WBC 8,000 cells/mm3 Platelets 24,000 platelets/mm3 Hemoglobin 14.1 mg/dL Hematocrit 42% PT 14 seconds (normal 11-15 seconds) aPTT 27 seconds (normal 25-40 seconds) Bleeding time 11 minutes (normal 2-7 minutes). Her normal kidney function rule out HUS. Her normal white count rules out leukemia/lymphoma. Note that her platelets are extremely low. Her PT/PTT are normal, but BT is prolonged. Her normal PT/PTT rule out any issue in the coagulation cascade (hemophilia). Bleeding time tells you that this an issue with her platelets or vWF. Now, my top two diagnoses are ITP and vWD. In vWD, you should expect prolonged PTT because vWF stabilizes Factor VIII. Therefore, this patient most likely has ITP!
Question: What is the most likely diagnosis for this patient’s condition?
The most likely diagnosis for this patient’s condition is ITP.
A quick review: the pathophysiology of ITP involves the formation of IgG antibodies against the patient’s own platelet glycoprotein antigens. Antibody-mediated opsonization of platelets leads to phagocytosis by macrophages and subsequent platelet sequestration in the spleen, leading to a decrease in platelet number. In addition, megakaryocyte maturation can also be affected by antibody binding, leading to decreased ability of the bone marrow to produce new platelets. The combination of these two factors causes easy bleeding as well as the formation of petechiae, which are punctate areas of bleeding caused by the failure of platelet plug formation.
Again, laboratory examination shows both normal PT/PTT with a prolonged bleeding time, indicating an intact coagulation cascade and either a qualitative or quantitative platelet defect.
Question interpretation requires a good understanding of the material. However, once you have a basic understanding of the content, focus on mastering this way of answering questions will help you excel on board exams. Your ultimate goal should be to understand the purpose of each sentence. Break each sentence down. What is the author trying to tell you with this sentence?
It is not easy, but it will improve with practice. Keep in mind that this clinical reasoning skill is also what is used throughout third and fourth year of medical school, and as an actual doctor. So, force yourself to analyze information this way early on in your learning!
Lastly, remember that USMLE exam writers typically ask simple questions, but in a convoluted way. In this example, we didn’t have to decode the question, but in general, they can typically be translated to straightforward questions such as “what is the cause of this patient’s condition?” or “what is the diagnosis?” Overall, the more you can decode the vignette, the higher your chances of getting the question right!
Good luck studying! Leave any questions or comments below!
This was very very helpful. Glad I signed up for your email list. Thank you for helping us med students. I appreciate it!
Thanks for the feedback!:)