There is more to the USMLE than the requisite volume of knowledge, and you can take the test efficiently by acknowledging outright the things your subconscious probably already knows. This is a somewhat randomly chosen question from the official 2013 USMLE Step 1 information booklet:
A previously healthy 48-year-old man comes to the physician because of fever and cough for 2 days. He attended a convention 10 days ago, and two of his friends who stayed in the same hotel have similar symptoms. His temperature is 38.3°C (101°F), pulse is 76/min, respirations are 20/min, and blood pressure is 130/70 mmHg. Crackles are heard over the right lung base. A chest x-ray shows a patchy infiltrate in the right lower lobe. A Gram stain of sputum shows segmented neutrophils and small gram-negative rods that stain poorly. A sputum culture grows opal-like colonies on yeast extract. Which of the following is the most likely causal organism?
(A) Campylobacter jejuni
(B) Eikenella corrodens
(C) Legionella pneumophila
(D) Proteus mirabilis
(E) Pseudomonas aeruginosa
Once you’ve done enough Step questions, you will already know the most likely answer at the word “convention” (it’s C). Not every question can come as a knee-jerk reaction, but one key to Step preparation is not just overall knowledge but rather pattern-recognition and memorization.
What separates the massive scores from the excellent scores boils down to intrinsic genius, test-taking voodoo, and tons of studying. The first you can’t change; the third you have to do (and should do efficiently). The second you need to be clever about (and doing questions is key). You can lay a strong foundation by making questions like the one above comically easy. Knowing the key phrases and patterns can allow you to literally “feel” the right answer even without having conscious knowledge. If you can get in the head of the question writer and know the tip-offs, you can often make a reasonable guess even if you don’t actually know the “basic science” details the question is supposedly trying to test.
Rid Yourself of Your MCAT Bias
Start by acknowledging that the USMLE is different from the MCAT. Knowledge during the MCAT is a foundation that allows you to reason through a question to arrive at an answer. Knowledge in the USMLE is frequently the answer itself. There is minimal critical thinking involved. The slight exception is physiology, which requires knowing more complex relationships (this goes up; this and that go down; the other thing stays the same), which can also be memorized (though it is more cumbersome to memorize than to intuit). Most of the test, however, is the straightforward application of memorization dressed in the clothing of painfully verbose question-writing and enough length to exhaust your sympathetic reserves.
MCAT and USMLE scores do correlate (of course they do). Know, however, that there are people who perform very poorly on the MCAT that end up with massive Step scores. This is because you can brute force your way to a solid score with questions, while it’s very difficult to improve your verbal subscore on the MCAT.
Use the Force
The “test-taking” skill itself comes into play only in knowing when they’re trying to play you for a fool. Inexperienced test-takers will second-guess themselves out of the correct answer or hinge their guesses on irrelevant “clues.” Good test-takers get in the head of the question writer. Another official example:
A 24-year-old primigravid woman at 28 weeks’ gestation has had nagging headaches, a puffy looking face, and swollen legs for the past week. Her blood pressure is 180/95 mm Hg; it was within normal limits earlier in the pregnancy. Urinalysis shows a protein concentration of 0.6 g/dL. Which of the following is the most likely diagnosis?
(A) Acute glomerulonephritis
(B) Congestive heart failure
(D) Nephrotic syndrome
The answer is E. This is classic preeclampsia, and the question goes out of its way to list an almost comical number of criteria. That said, it’s a question about a pregnant patient with a seemingly pregnancy-related problem. Only two of the five choices is specific to pregnancy. Question writers very rarely include totally extraneous details, so you should be looking for a pregnancy problem first and foremost before believing the voice on your shoulder telling you that they’re trying to mislead you. So, ask yourself: if you didn’t know anything at all about the actual criteria, which answer would you guess? You should be guessing E (C requires a seizure).
USMLE questions are “single best answer.” That doesn’t mean the other answers are 100% wrong or that they aren’t even reasonable. They’re just not the best. People find elements in the stem that support other choices, and these force them to reconsider their gut (and usually correct) feeling. Your feelings (except for that miasma of anxiety) matter, so don’t ignore them.
In the above question, edema supports CHF and nephrotic syndrome. Proteinuria supports GN, and if it were of a larger amount, nephrotic syndrome. These answer choices having true elements doesn’t take away from the fact that preeclampsia explains all of them.
But even if you don’t know anything, your goal when guessing is to narrow down answer choices. Think about the body systems involved, the time courses, acquired versus congenital, viral vs bacterial, drug reactions, any answer choices you do recognize that you know can’t be it. Cross stuff out.
One more from the official packet:
An 18-year-old female athlete reports easy fatigability and weakness. Physical examination shows no abnormalities. Laboratory studies show:
Na+ 141 mEq/L
Cl− 85 mEq/L
K+ 2.1 mEq/L
HCO3− 35 mEq/L
Na+ 80 mEq/24 h
K+ 170 mEq/24 h
Which of the following is the most likely diagnosis?
(A) Aldosterone deficiency
(B) Anxiety reaction with hyperventilation
(C) Diabetic ketoacidosis
(D) Ingestion of anabolic steroids
(E) Surreptitious use of diuretics
“Female athlete” is a code word for “eating disorder” (the answer is E). If the question mentioned a boxer, wrestler, or other sport with weigh-ins, ditto. Board questions reflect an extremely judgmental worldview with heavy-handed generalizations about race, sex, and a wide variety of stereotypes. African-American females in their 30-40s have sarcoidosis. If a woman takes oral contraceptive pills, the question is nearly always implying that she doesn’t use barrier protection and has contracted an STD. People who have recently immigrated from another country with cough have tuberculosis. If it’s a child who has recently immigrated, then they have a vaccine-preventable illness.
Often, in order to allow you to reasonably pick an obscure or rare illness with a set of non-specific symptoms, these giveaways make sense. Sometimes they just make the question easier. Other times, it’s a second-order question and simply knowing the diagnosis isn’t enough anyway. But always look for a question’s internal clues to help you guess, give you the answer, or boost your confidence. You can’t learn every fact, and sometimes you don’t have to. When picking facts to learn from a long list of tidbits, pick the ones that help distinguish a diagnosis from other likely/related answer choices.
Dealing with irritating clinical science questions
Which of the following is the most appropriate next step in management?
Which of the following is the most appropriate next step in diagnosis?
These question styles can make you question yourself and frustrate you in times when you otherwise could have sworn you knew the answer. Here are a couple of takeaways using examples from the official Step 2 CK information booklet:
In emergencies/unstable patients, your “go to” answer is whichever one prevents death or most stabilizes the patient. So, in the trauma setting, follow your ABCs (where “C” essentially always means fluid resuscitation). For example, if tension pneumothorax is a possibility, then needle decompression must be performed without delay. Always follow an algorithmic approach with the goal of stabilization and prevention of avoidable complications. The “definitive” management is almost always available as an answer choice and usually must be avoided for this style of question. In real life, many things happen simultaneously, but while studying, always think about which thing is the most crucial to perform.
A 22-year-old man is brought to the emergency department 30 minutes after he sustained a gunshot wound to the abdomen. His pulse is 120/min, respirations are 28/min, and blood pressure is 70/40 mm Hg. Breath sounds are normal on the right and decreased on the left. Abdominal examination shows an entrance wound in the left upper quadrant at the midclavicular line below the left costal margin. There is an exit wound laterally in the left axillary line at the 4th rib. Intravenous fluid resuscitation is begun. Which of the following is the most appropriate next step in management?
(A) Upright x-ray of the chest
(B) CT scan of the chest
(C) Intubation and mechanical ventilation
(D) Peritoneal lavage
(E) Left tube thoracostomy
This gentleman has a GSW to the abdomen extending to the thorax with ipsilateral respiratory compromise from a hemothorax. You may remember from your studying that all GSWs to the abdomen will go for exploratory laparotomy. But first things first, he has earned himself a chest tube (choice E). After all, B comes before C in ABC. Now, if he were stable after the tube is in, he might get a CT before going to the OR (B). He will certainly be intubated for surgery (C). But never forget your ABCs. Don’t get excited. Even if exploratory laparotomy or thoracotomy were answer choices, they would also be wrong.
When patients are stable, the “next best step/most appropriate test” is that which is most likely to make the diagnosis (always know the test of choice, especially for imaging studies) or rule out a less-likely but potentially life-threatening diagnosis. If the diagnosis is already made, treat the problem (there may be two or more treatments, but one is more important). Other tests may be reasonable and performed concurrently in real life, but there is typically one test that is geared towards the most likely diagnosis based on presentation. That’s the one you want. You should have some knee-jerk associations for complaints (e.g. LLQ pain and fever – diverticulitis – CT scan of the abdomen with contrast; RUQ pain and fever – cholecystitis – RUQ abdominal sonogram). When given a classic but non-acute disease presentation, always think about how to prevent catastrophic consequences.
42-year-old woman comes to the physician because of a 1-year history of vaginal bleeding for 2 to 5 days every 2 weeks. The flow varies from light to heavy with passage of clots. Menses previously occurred at regular 25- to 29-day intervals and lasted for 5 days with normal flow. She has no history of serious illness and takes no medications. She is sexually active with one male partner, and they use condoms inconsistently. Her mother died of colon cancer, and her maternal grandmother died of breast cancer. She is 163 cm (5 ft 4 in) tall and weighs 77 kg (170 lb); BMI is 29 kg/m2. Her temperature is 36.6°C (97.8°F), pulse is 90/min, respirations are 12/min, and blood pressure is 100/60 mm Hg. The uterus is normal sized. The ovaries cannot be palpated. The remainder of the examination shows no abnormalities. Test of the stool for occult blood is negative. Which of the following is the most appropriate next step in diagnosis?
(A) Barium enema
(B) Progesterone challenge test
(E) Endometrial biopsy
Now, there is a rule about abnormal vaginal bleeding in women over 35, but let’s say you didn’t know that. Ask yourself, what would be the worst thing to cause non-acute bleeding? What would you want to rule out? Cancer. Could it be that she has amenorrhea and that a progesterone challenge test could answer our question? Absolutely. But we must rule out the life-threatening cause. The answer is E.
- Stabilize if necessary — ABCs, even for non-trauma patients
- Diagnose if necessary — Test of choice to make the diagnosis or the test that will rule out a potentially life-threatening cause
- Treat — If there are multiple appropriate options, which one is the most crucial?
Ultimately, most questions are fair. That said, every once in a while, the question is actually terrible. If after all is said and done, it makes no sense, don’t extrapolate too much from it for your general test-taking skills.
There are always miserably hard questions on NBME Shelf and USMLE Step exams, and that’s okay. It’s not realistically possible to get them all right. The nature of the test is such that a ball of doubt will form deep in the core of your body, growing with each question you waver on. And, the test is designed to make you waver over that second answer choice which doesn’t feel right (but you can’t explain why it’s wrong). Allow yourself to approach the tests with an air of dispassion and nonchalance. Your nerves don’t help you. Your instincts do.
Stay awake. Stay focused. Use what they give you to make your life easier. When you don’t know an answer, try to narrow it down based on internal characteristics, guess, and move on. If you go back to change an answer, you must know why and have a good reason. Never change an answer arbitrarily because of feelings.
If you’ve made it this far, you’d probably also be interested in the sequel, “How I read NBME/USMLE questions.”