Explanations for the 2020-2022 Official Step 2 CK Practice Questions

Update: The March 2021 pdf is identical outside of some minor formatting changes.

Update: The April 2022 pdf also seems to be unchanged.

The NBME released a completely new set of questions in March 2020, which was the first major update since basically 2015.

The 2019 set, which is completely different, is available and explained here for more free questions!

These are in the order of the PDF linked above.


Block 1

  1. C – While you may have initially been thinking of alcohol withdrawal, the case presents you with signs/symptoms of decompensated cirrhosis including hepatic encephalopathy from hyperammonemia (AMS, asterixis). Treatment is oral lactulose, which helps clear ammonia via the power of horrible diarrhea.
  2. F – Keep in mind that “not all that wheezes is asthma.” Wheezing is a sign of obstructive lung disease, not a diagnostic feature, so consider asthma alternatives in adults. Hemoptysis and fever help change the game. Eosinophilic granulomatosis with polyangiitis (Churg-Strauss) and granulomatosis with polyangiitis (née Wegener’s) both cause lung disease, but did you know they can also cause peripheral neuropathy? The former over the latter more commonly has neuropathy and presents with asthma, but the latter can easily do the same. ANCA can be positive in both and helps confirm the diagnosis of systemic vasculitis as a unifying cause.
  3. D – Urinary retention due to pelvic organ prolapse. Multiple vaginal deliveries are the risk factor/cause.
  4. D – This patient has neutropenic fever. Methimazole can cause agranulocytosis.
  5. A – Concerning for meningitis. Yes, even with abdominal pain, which can be so severe that it can mimic appendicitis. Remember that splenectomy status predisposes to infection with encapsulated organisms such as meningococcus. This may also be purposefully vague, as in real life this could also certainly be an abdominal process like actual appendicitis, for which you might get an appendix ultrasound or CT of the abdomen/pelvis in addition to the key testing point of starting empiric antibiotics in an asplenic patient, but that’s not an answer choice.*
  6. A – Also meningitis. There’s a vaccine for that, which everyone in college is supposed to get.
  7. D – Every pregnant patient gets tested for HIV during routine initial prenatal workup/testing as well as again during the third trimester.
  8. E – Quitters gonna quit.
  9. C – When old men stop peeing so well, consider the poorly designed straw-crusher, the prostate. Chronic outlet obstruction isn’t so great, but it also predisposes to acute prostatitis which in turn can further worsen said obstruction when the gland swells. First thing to do is see how much the gentlemen is backed up, which in turn tells us if he has earned catheterization. Old people and UTIs go together like [insert your own clever comparison].
  10. E – That’s a septic joint, not just RA (RA is a risk factor). Full-blown fever and intraarticular pus.
  11. C – We have event rates of 35% for EST and 15% for EPCS, and the number needed to treat (NNT) is the inverse of the absolute risk reduction or 1/ARR. ARR = Control event rate minus experiment event rate. So, we have ARR = 0.35 – 0.15 = 0.2, and therefore NNT = 1/0.2 = 5. Boom, math.
  12. B – This is a great RCT. The issue is that EPCS is a specialized treatment not as widely and emergently available as the usual GI-doc on call.
  13. B – It works. P < 0.001 for that parameter.
  14. A – With treatment adherence, most HIV-positive individuals will die of the same things as the rest of us: the American way of life.
  15. A – Initial treatment for inadequate sleep and various types of “insomnia” is sleep hygiene modification. Certainly, her smoking and nicotine activation aren’t helping, but there’s no such therapy as “setting a date for smoking cessation.” Americans are terrible with sleep, and many who struggle are doing all the wrong things like using electronic devices late in the evening, dealing with neverending light pollution, caffeine and cigarettes too late in the day, going to bed too late, blah blah blah.
  16. B – Rapidly progressive dementia (with or without personality changes, psychiatric disturbances, and sudden/jerky movements) raises the possibility of Creutzfeldt-Jakob disease, for which CSF protein 14-3-3 is an important marker.
  17. C – Slow submersion warming is key when dealing with frostbite. Air and towels/dressings are poor conductors of temperature.
  18. D – She has thrombocytopenia, likely related to a lupus flare given underlying SLE as well as evidence of active arthritis with joint effusions. Thrombocytopenia in lupus can occur via an ITP-like autoantibody phenomenon. In fact, some patients with lupus initially present with immune thrombocytopenic purpura (ITP) prior to developing other lupus symptoms. Whether a lupus flare or true ITP in the setting of other autoimmune conditions, the initial treatment of an active bout is prednisone. Refractory cases of ITP can be treated by splenectomy.
  19. B – Mitral regurgitation explains the soft S1 and holosystolic murmur loudest at the apex. Acute heart failure with pulmonary edema. In the context of a recent URI, this is most concerning for viral myocarditis. Rheumatic fever can also present with carditis, but in this case, the patient has otherwise recovered from other symptoms.
  20. E – Bilious vomiting in the newborn includes the full differential (duodenal atresia, midgut malrotation and volvulus, jejunoileal atresia, meconium ileus and necrotizing enterocolitis), but rapidly-ill bilious vomiting combined with fever, distension, and tenderness after a  few days to a week or so is most concerning for midgut volvulus. Most other causes present soon after birth with the exception of necrotizing enterocolitis, usually affecting premature babies within a couple of weeks after birth. Diagnosis with upper GI.
  21. A – Using the most expensive things isn’t always a great use of limited resources. In a very elderly patient with dementia and multiple medical comorbidities, you probably don’t need the most long-lasting most-expensive stents when the long-term survival prospects of the patient are dismal.
  22. A – This is a potentially fatal decision. Patients can choose to deny care, but when someone is making the “wrong” choice, it’s important to make sure they have the capacity to do so: do they understand their situation, their options, and the possible consequences of their actions? If so, that’s fine.
  23. E – The banana bag! You might be thinking of Flumazenil to reverse his benzo use, but be wary of using in an otherwise stable chronic user as this can precipitate seizures. He’s also probably drunk, but that we’ll just wait out. In this case, he’s awake and protecting his airway but he’s encephalopathic. When an alcoholic is encephalopathic, think Wernicke’s and give thiamine. Even if they’re just plain ole drunk you’re not going to hurt them.
  24. B – These are the signs and symptoms of testicular torsion, a surgical emergency.
  25. C – This is a diffuse pontine glioma, a death sentence. You don’t really need to know that, because the stem tells you of the poor prognosis. Whenever someone is presented with a serious diagnosis, any treatment discussion starts with establishing a baseline understanding of the disease process and then discussing goals of care.
  26. B – We have a middle-aged black female as the setup. Pulmonary disease with CXR showing bilateral hilar adenopathy. She has cutaneous involvement of the face. Cutaneous involvement is present in 1/3 of systemic cases but can have a variety of appearances.
  27. E – Statin-myopathy is assessed laboratorily with serum CK.
  28. C – Source control followed by symptomatic relief. Have you seriously ever heard of anyone doing any of that other crazy stuff?
  29. A – ECT works. It works really well, and it works really fast. This gentleman is wasting away and is unable to care for himself.
  30. E – USPSTF recommends clinicians screen all adults aged 18-79 for hepatitis C infection.
  31. D – Serum sickness-like reaction, relatively common with penicillin. If someone has an antibiotic allergy/complication, just use another antibiotic.
  32. B – People low on the totem pole aren’t going to feel comfortable speaking up unless encouraged.
  33. D – If you thought that looked like a squamous cell carcinoma, that’s because it is. A keratoacanthoma is the name of the erupting-volcano variant, though some keratoacanthomas will resolve spontaneously and others progress to invasive cancer.
  34. D – USPSTF recommends all men 35 and older (women 45 and older) are screened for lipid disorders, and age 20+ for those with increased risk of CAD.
  35. C – Routine imaging for pyelonephritis at presentation is not generally helpful. But CT imaging for those who do not respond to antibiotics is indicated to evaluate for complicating factors like renal abscess or nephrolithiasis that cannot be treated with antibiotics alone.
  36. D – We can simplify this with the general framework that if significant hypotension doesn’t resolve with volume repletion, then we move on to pressors.
  37. A – She is currently prediabetic. But not for long.
  38. D – No lying.
  39. C – Acute kidney injury with volume overload, presumably from the ACE-inhibitor.
  40. C – Hereditary weak bones, mobile joints, and hearing loss are a good fit for osteogenesis imperfecta. Scoliosis and short stature are also common, particularly in more severe cases.

Block 2

  1. B – The goal is to hopefully make sure she is safe (and if she is at-risk for partner abuse to provide her with resources). On a related note, unlike for children and elders, there is no reporting mechanism for partner abuse.
  2. B – He’s got a cyanosis-level from an aortic embolism. His floppy, akinetic LV is the risk factor for thrombus generation, which was subsequently squeezed out and lodged distally. The other choices would not result in isolated symmetric lower body symptoms.
  3. B – This is all to say he has chronic lung disease. He has findings of possible fibrosis on CXR and a history certainly concerning for smoking-related lung disease. HRCT will tell us if he has a pattern characteristic of UIP (e.g. idiopathic pulmonary fibrosis) or something potentially more treatable like NSIP or just run-of-the-mill COPD.
  4. B – Recurrent vomiting results in a hypokalemic hypochloremic metabolic alkalosis (i.e. you lose acid and keep having to make more).
  5. C – CTs evaluate the kidneys, but they do a very poor job evaluating the bladder. Direct cystoscopy is needed to clear the lower urinary tract of an underlying bleeding mass. Smokers are at increased risk of bladder cancer.
  6. E – “Bone broke must fix.”
  7. D – Hypertension is the number 1 risk factor for stroke. Additionally, while smoking cessation is also important, it takes years for the deleterious vascular effects of smoking to normalize. Antihypertension therapy is needed right now and has a much higher likelihood of success than stopping someone’s habit of a lifetime.
  8. B – They are presumably trying to demonstrate that she has an acute viral-type syndrome given the flu-like illness with fever, muscle aches, and generalized misery. COVID-19 wasn’t an answer choice. Note the CXR says “interstitial infiltrates,” which is the Step code phrase for atypical infection (as opposed to consolidative pneumonia).
  9. D – Dyslexia is one of several different learning disorders.
  10. C – Inflamed painful infected external auditory canal is consistent with otitis externa. Earplugs are a risk factor, both from microabrasion trauma and/or from contact dermatitis.
  11. C – Most acute sinusitis is viral, not bacterial. Most antibiotic use for sinusitis is futile. Nasal irrigation and decongestant therapy are the hallmark treatments to relieve drainage pathway obstruction and give the body the ability to drain secretions properly.
  12. D – Children with VATER often have tracheomalacia (part of the T), which can be associated with TEF and esophageal atresia. Tracheomalacia results in dynamic airway obstruction due to airway collapse on expiration (greater when forced).
  13. D – Chest pain in the setting of a recent URI and with the low-grade ST elevation in multiple leads is the classic setting for pericarditis. The scratchy sound is the “pericardial rub.” Echo will assess for a pericardial effusion (and its size/significance), pericardial thickening, as well as assess for overall cardiac function.
  14. B – Idiopathic and viral pericarditis treatment is anti-inflammatory. Data show that Colchicine is a useful NSAID adjunct for all pericarditis treatment, not just recurrent or prolonged cases as was once commonly assumed.
  15. D – He is not safe, you have enough information to act.
  16. E – She has multiple sclerosis. Clinically, neurologic lesions/deficits separated in time and space. MRI can show us evidence of demyelination in the brain to go along with her optic neuritis. These features are more important than oligoclonal bands in the CSF.
  17. E – She has no significant cognitive deficits and is thus still normal enough to not require a dementia workup. In real life, I have plenty of evidence she’d get that MRI.
  18. D – Serotonin syndrome. The most important next step is to remove the offending serotonergic agents.
  19. E – He would seem to be psychotic. While people with schizophrenia or delusional disorders are on average no more dangerous than other folks, safety is paramount. Danger to self or others and all that.
  20. A – Vesicular rash in the immune-compromised is a common scenario for Varicella-Zoster reactivation. Visceral zoster involvement can result in severe pain that can be mistaken for an acute abdomen. Treatment with acyclovir or valacyclovir.
  21. E – Vulvar cancer is rarer than cervical cancer but has many of the same risk factors including HPV. Another risk factor worth knowing is lichen sclerosis, which results in thin itchy vulvar skin.
  22. E – Thyroid nodules are best evaluated by thyroid ultrasound. While larger nodules (>1.5 cm) are more likely to be malignant, there are plenty of very large completely benign nodules that would be inappropriate to biopsy.
  23. E – AZT monotherapy during the intrapartum and postpartum period (in addition to maternal therapy throughout pregnancy) is recommended for all neonates of HIV-positive mothers to reduce transmission and is very effective (less than 1%) for mothers who achieved viral suppression. Presumptive HIV therapy is recommended for infants whose mothers didn’t or who had their primary infection during pregnancy or while nursing.
  24. B – Prolactinomas (pituitary adenomas that secrete prolactin and as a result can cause amenorrhea/infertility/lactation) can be treated with dopamine agonists like cabergoline. This is because dopamine normally inhibits pituitary prolactin production. In many cases, tumors can completely involute with pharmacologic therapy alone.
  25. E – This constellation of symptoms in a premature infant by around two weeks of life is concerning for NEC. The diagnosis is commonly made with abdominal radiographs, which can demonstrate bowel dilation and pneumatosis (and when more severe, frank pneumoperitoneum).
  26. E – You can’t turf out emergency care that you are equipped to perform just because a patient can’t pay. Dumping is why EMTALA was created in the first place.
  27. E – Pseudoseizures are diagnosed in EMUs with video EEG. You match the behavior with the EEG to see if there are epileptiform discharges that correspond to the episodes. While this is clearly absurd for an epileptic seizure (impossible movements, insane duration, and no postictal period), there are plenty of cases of bizarre seizure patterns that are VEEG proven.
  28. D – Pleurisy (or potentially costochondritis) secondary associated with a URI, either way, treat with NSAIDs.
  29. B – This person recently had normal cycles, essentially excluding A and C. We have no reason to suspect D. And the normal prolactin excludes E. Hypothalamic hypogonadism can have many causes, among them chronic stress and anxiety, as seen in patients with eating disorders, sufferers of PTSD, etc.
  30. B – Menopause. Elevated FSH and no period for over a year confirm.
  31. E – Penicillin prophylaxes is indicated in all children with sickle cell younger than 5 to prevent severe pneumococcal infection.
  32. B – Jaundice in the newborn. When unconjugated, typically “physiologic,” with two common causes breastfeeding jaundice (due to insufficient intake) and breast-milk jaundice. In this case, however, the bilirubinemia is conjugated (“direct”), which suggests cholestasis. Ultrasound is needed to evaluate the liver and biliary system.
  33. D – Relentless dry cough is a common reaction to ACE inhibitor therapy.
  34. E – Opioids result in floppy babies who don’t breathe well, just like they do in adults.
  35. D – Obstructive sleep apnea can result in ADHD-like symptoms, irritability, and poor growth. The snoring is a tip-off, and tonsil/adenoid enlargement is the main cause of intermittent airway obstruction during sleep in children.
  36. D – Lisfranc (tarso-metastarsal) dislocations in the setting of Charcot arthropathy (diabetic neuropathic joint). Initial treatment for acute Charcot joint is immobilization to prevent progressive deformity.
  37. C – Parents don’t get to withhold lifesaving emergency treatment from their children, religion or not.
  38. C – Cyanotic newborn with a single S2 is suggestive of a truncus arteriosis congenital heart defect (a VSD combined with a single ventricular outflow track comprising both the pulmonary and systemic circulation). The pulmonary circulation is thus torrential resulting in pulmonary edema. Like other CHD that result in early cyanosis, these patients are ductus-dependent for oxygenation mixing and should receive prostaglandin to maintain a PDA.
  39. A – Vasospastic angina (formerly known as Prinzmetal angina). Rest angina/chest pain rapidly relieved by nitrates in a patient without coronary disease. Commonly treated with calcium channel blockers. An alternative possibility that would also yield the correct answer is esophageal spasm, but there’s been no workup to support that etiology save for the presence of non-CAD-related chest pain.
  40. D – There is AV concordance (all QRS have a preceding P wave), but we have intermittent dropped beats consistent with a second-degree AV block. The PR-interval of the conducted beats is always the same, so we have Mobitz 2. Progressively lengthening PR-interval prior to a dropped QRS is Mobitz 1 (Wenkebach).

Block 3

  1. B – You know people make mistakes of all types after a few drinks.
  2. A – Help her feel better. That’s the point of hospice.
  3. D – With family members with both primary hyperparathyroidism and an “adrenal tumor” (let’s guess pheochromocytoma), we have two out of the MEN2A triad. The third is medullary thyroid cancer.
  4. A – People with CVID are at increased risk of lymphoma. B-symptoms like fever, weight loss, and night sweats combined with lymphadenopathy are highly concerning.
  5. E – I think the description here is a little odd, but a helpful reader suggested cigarette burns, which I think is probably correct. Alternatives could be a blistering burn secondary to intentional hot water submersion or really serious spanking, potentially with a welt-causing object. Either way, not an accidental/expected pattern. Whenever the story doesn’t make sense or there are any concerning physical exam findings, it is critical to work up for nonaccidental trauma.
  6. E – History is clearly gallbladder (“biliary colic”). Now cholecystitis, so evaluate with ultrasound. Minimal lipase bumps can be seen with other GI and biliary issues, but also note that gallstones can also cause pancreatitis, so it’s certainly possible for her to also have that brewing. If you suspect gallbladder/biliary issues, always start with US.
  7. B – Tracing shows a prolonged severe fetal bradycardia. This is bad. Causes include cord prolapse, placental abruption, uterine rupture, and uterine tachysystole. Umbilical cord prolapse is particularly common after AROM, where rapid descent of the fetal head compresses the umbilical cord, limiting blood flow as it’s squeezed inferiorly by the contracting uterus. Vertex station doesn’t actually matter as once previously thought, but a nondilated cervix (less than 6 cm) is a risk factor.
  8. F – How many people with sats in the 80s have you seen not getting O2?
  9. A – Ulcerative colitis is a risk factor for colon cancer. The skin lesions are a description of erythema nodosum.
  10. A – Trauma and critical illness can cause acute insulin resistance.
  11. A – Don’t be a dick.
  12. C – Hyperaldosteronism = hypertension + hypokalemia. Adrenal adenomas are a common cause of primary hyperaldosteronism.
  13. F – Necrotizing fasciitis = looks like bad cellulitis but then you add skin breakdown and necrotic goo.
  14. D – The key to dealing with occupational exposures is safe practices. That means anything producing a particle or fume needs a respirator. You can’t fix the damage already done.
  15. D – Spironolactone helps reduce ascites production and is the diuretic of choice for the initial treatment of portal hypertensive ascites.
  16. C – Severe hypertriglyceridemia is an important risk factor for/cause of pancreatitis. Fibrates remain the drug of choice for severe HTG (TGs > 500 mg/dL).
  17. B – Cirrhotic wanderer, completely disoriented. While potentially just intoxicated or suffering from hepatic encephalopathy, the question is again probably getting at Wernicke’s encephalopathy. Treatment is thiamine. It’s harmless, and that’s why lots of drunks get the banana bag.
  18. B – Algorithmic standard approaches that reduce variability are the hallmark of high-quality care. Not everyone can receive heparin, but everyone needs to have a DVT prophylaxis plan so they don’t fall through the cracks.
  19. A – Subtraction.
  20. C – Stop. Wrong-sided surgery is a big no-no. Everyone on the team should feel empowered to stop a surgery or procedure if something in the preprocedural checklist is amiss.
  21. E – PEEP is like cowbell. Okay not really but when gas exchange is insufficient with increased FiO2, PEEP will help open alveoli and increase the functional area available for ventilation.
  22. A – TCA overdoses are potentially fatal due to the drugs’ cardiac effects. The most dangerous is that fast sodium channel blockage can lengthen the QRS and result in fatal ventricular arrhythmias.
  23. C – The test of choice for AAA screening is ultrasound. Cheap and radiation-free.
  24. A – Back pain, normocytic anemia, fatigue, and hypercalcemia. These are concerning for a hematopoietic process, particularly multiple myeloma. Serum protein electrophoresis will demonstrate the M-spike.
  25. D – The decreasing and irregular periods coupled with high FSH suggest early menopause. Estrogen helps with bone strength. The lack predisposes to osteoporosis.
  26. E – Increased bleeding with normal labs (or an isolated mildly prolonged PTT) is always a good picture for von Willebrand disease, the most common bleeding disorder. Yes, the PTT is slightly elevated (which can happen), but that’s also why they probably gave you boy and girl siblings to help you not pick hemophilia.
  27. E – Colon cancer is a surgical disease.
  28. B – Part of the DSM-V criteria for generalized anxiety disorder: “Excessive anxiety and worry (apprehensive expectation), occurring more days than not for at least 6 months, about a number of events or activities (such as work or school performance).”
  29. A – Ascites with a neutrophil count higher than 250 is consistent with spontaneous bacterial peritonitis. Treatment of choice is a third-gen cephalosporin like cefotaxime or ceftriaxone.
  30. E – AED-induced bone disease is a problem with long-term therapy. Carbamazepine and phenobarbital both induce CYP450 and can cause vitamin D deficiency.
  31. A – Write it out. Abbreviations are like assumptions.
  32. D – When it comes to development questions, always make sure before you pick something other than normal if offered. Tanner stages are available for review here.
  33. D – Implantable birth control is much more effective than methods that require active effort.
  34. F – Malignant pleural effusion. Cancer is full of protein.
  35. E – Ah, ye old “inconsistent condoms” code phrase for STDs.
  36. B – Externally normally developed female with a 46XY male karyotype, elevated testosterone, and no internal sex organs is consistent with complete androgen insensitivity syndrome. While somewhat controversial particularly with regards to timing, gonadecotmy is recommended to remove the undescended gonads to prevent cancer. In this case, she’s already gone through puberty. If gonadectomy is performed earlier in childhood, then puberty will need to be induced with HRT.
  37. C – HCTZ (and other symporter and loop diuretics) can result in diuretic-induced hyperuricemia and cause or worsen gout.
  38. D – This is the MSG symptom complex, sometimes historically and pejoratively called “Chinese Restaurant Syndrome.” While MSG gets a bad wrap, real MSG sensitivity is rare.
  39. C – Don’t be a dick. But you don’t have to entirely give up either: she may come around after her crazy simmers for a while.
  40. F – Sciatica.


Corrections, clarifications, copy/paste errors etc can be made/asked/mocked in the comments below.


Cory G 06.21.20 Reply

I just did the free 120 (6/21/20) and I don’t see how these match.

Ben 06.22.20 Reply

You probably did the 2019 set that I linked to above. The NBME itself released this new 2020 PDF earlier this year but then subsequently reverted back to the 2019 set on their usmle.org site (but they kept both the 2019 and 2020 links active). From what I’ve gathered, I believe most Prometric centers are offering this new set. Either way, it’s just more free questions.

obtunded 06.23.20 Reply

for questions 114. Why isn’t A correct if we assume this is a neoplastic effusion ? according to uworld neoplastic effusions lead to low glucose.

Ben 06.24.20 Reply

That is a much less consistent relationship than protein. Malignant effusions are typically exudative, not transudative, which is what we’re getting at here.

On a test, a low glucose would be more commonly used to reflect infection like empyema or a process like RA and Lupus.

Stephen 06.26.20 Reply

Thanks for this! Very helpful.

Naz 06.27.20 Reply

Pheochromocytoma, hyperparathyroidism and medullary thyroid cancer are MEN2A
MEN2B would be pheo, medullary, and mucosal neuromas

Ben 06.27.20 Reply

Typo, thanks, fixed.

Emma 06.27.20 Reply

Thank you for this! For your explanation for 83 – I believe it’s describing MEN2A syndrome not MEN2B (which is associated with mucosal neuromas, MEN2A is associated with parathyroid hyperplasia). MEN2A and 2B are both associated with pheos and medullary thyroid cancer so it doesn’t change the answer, but wanted to make sure people didn’t get confused!

Ben 06.27.20 Reply

Errata, thanks for the comment. I thought I’d caught most of them on review but I’m sure there are more. Keep ’em coming people. If there are pages of them in First Aid there will always be a few on my little site!

MY 06.28.20 Reply

This was super helpful, but geeeez why is this exam so much more difficult than the old free 120? My test is in a few days – I did great on the old free 120, but not good on this one. I’m so confused as to how/why they can make this new one so drastically harder. I was feeling good after the old free 120, but I’m a bit concerned now.

Ben 06.28.20 Reply

That’s the general consensus. I don’t believe the overall difficulty is necessarily that well calibrated, which could even be a factor in why the current set online reverted back to 2019. Don’t sweat it!

Sista 07.06.20 Reply

I dont agree with 116. I know the NBME said its B. But if you look at the literature, They suggest delaying gonadectomy until after pubertal growth. They recommend giving leuprolide to prevent undesired virilization and then recommend counselling regarding gender dysphoria or and their assigned gender. If they want to become male they keep the gonad

Ben 07.06.20 Reply

I think you’re confusing complete gonadal dysgenesis in 46XY (Swyer Syndrome), where the phenotype is completely female, and partial gonadal dysgenesis, where varying degrees of residual gonadal function and virilization can occur. In CGD, gonadectomy is performed as soon as possible as malignancy can occur early in childhood.

In complete AIS though, normal external pubertal development occurs, and the timing of gonadectomy depends only on whether puberty occurs naturally first or whether supported by hormone replacement therapy. Given the low risk of malignancy in this setting, delayed gonadectomy is more common.

Andrew 09.17.20 Reply

I think you are referring to androgen insensitivity syndrome – where you wait until after puberty to remove gonads. But AIS patient would have no hair, while this patient does. This patient has Swyer, due to SRY gene mutation.

Ben 06.15.21

They actually don’t mention pubic hair in this question.

Tim Cras 07.13.20 Reply

Why is 96 not apheresis? According to UWorld, if a patient has an acute pancreatitis with normal glucose and high triglycerides, you should do aphaeresis.

Ben 07.13.20 Reply

Best next step. I don’t know that there’s good head to head data that is should completely replace fibrate therapy. Plasmapheresis is invasive, requires special IV access, expensive, takes time to set up and complete, and is not available at all centers. Fibrates are a pill and can be administered instantaneously. Keep in mind that the definitive therapy and the “next best step” aren’t always the same (or it may just be a bad question).

Sara Parkinson 11.08.20

Acording to uptodate:

Initial management of patients with HTGP includes treatment of acute pancreatitis and reduction of serum triglyceride levels to 1000mg/dL plus lipase >3 times the upper limit of normal) and signs of hypocalcemia, lactic acidosis, signs of worsening systemic inflammation or organ dysfunction, or multi-organ failure, we suggest treatment with apheresis, and specifically therapeutic plasma exchange (Grade 2C). Triglyceride levels should be monitored every cycle of apheresis. We continue apheresis until triglyceride levels are below <500 mg/dL (5.6 mmol/L).

•In patients without worrisome features, we suggest initiating therapy with intravenous (IV) regular insulin (Grade 2C). We administer insulin at a rate of 0.1 to 0.3 units/kg/hour. In patients with blood sugar levels between 150 and 200 mg/dL, we administer IV glucose supplementation with a separate 5 percent dextrose infusion to prevent hypoglycemia. Triglyceride levels should be monitored every 12 hours. Serum glucose should be measured every hour and the insulin/5 percent dextrose infusion should be adjusted accordingly. Intravenous insulin should be stopped when triglyceride levels are <500 mg/dL (5.6 mmol/L).

Once triglyceride levels are <500 mg/dL (5.6 mmol/L), patients with HTGP require long-term therapy to prevent recurrent pancreatitis and to prevent other complications of HTG. This consists of both pharmacologic therapy (eg, oral gemfibrozil 600 mg twice daily) and dietary modification (eg, fat- and simple sugar-restricted diet). Other nonpharmacologic interventions include weight loss in obese patients, aerobic exercise, avoidance of concentrated sugars and medications that raise serum triglyceride levels, and strict glycemic control in diabetics.

Ben 11.08.20

Yes, I’ve seen the uptodate article. That recommendation is considered 2C evidence, and many hospitals do not have 24h (or any meaningful) plasmapheresis capacity. This is presumably why the NBME question is graded that way, though I agree it’s probably not a great question.

Austin 07.14.20 Reply

For number 2, first aide says that peripheral neuropathy is common in Churg-Strauss disease and not Wegners. Which normally an eosinophils and serum IgE is collected. But since the patient is asthmatic they could already be hight, making Serum ANCA assay the best choice.

Ben 07.15.20 Reply

I think perhaps the idea here is probably that ANCA is positive in both and suggests/confirms the unifying underlying process of systemic vasculitis.

Denzel 05.29.21 Reply

I want to add in here that the reason why mesenteric angiography is an answer choice is that mononeuritis multiplex, which is defined by 2+ lesions of non-contiguous peripheral nerves (e.g. numbness in the left leg and right arm), is seen in either polyarteritis nodosa or Churg-Strauss. PAN would present with renal involvement (HTN), increased MI risk (due to vasculitis of the coronary artery), and vasculitis of the mesenteric arteries. Importantly, PAN spares the lungs, while Churg-Strauss involves the lungs.


A.S 07.14.20 Reply

this is an awesome effort thank you so much i really appreciated. so informative and helpful.

JC 07.17.20 Reply

Really appreciate this. You’re the best.

Ben 07.17.20 Reply


ARR 07.19.20 Reply

I have a question… so I was reading your explanations and I noticed that a few questions I was like wtf I knew this why I didn’t think about this at the moment? but when I am doing the questions with time I tend to forget and not make the connection at the moment until I read an explanation… and its things I know I am just not applying it very well while doing the questions.. what approach do you use? for example, should I start looking at the answers first and go one by one ruling out? or should I start with the question?

#92 has me a little confused… sodium is normal… so why its C? also, cant hypothyroidism cause hypertension also?

#47 I had a question a while back that smoking cessation was the strongest factor of stroke, or that only when the patient doesn’t have hypertension?

#64 Shouldn’t we do surgery since there are compression symptoms?

#65 Why not D(M. tuberculosis)?

Also, how can we distinguish a person with alcoholic cirrhosis and having an alcohol withdrawal VS encephalopathy like in question #1? in question #23 the answer is vitamin B1 (thiamine) if the option lactulose was there also what it would’ve been? lactulose?

Sorry for so many questions. Thank you in advance.

Ben 07.19.20 Reply

I have two posts that deal with my approach:


47. It’s hypertension overall. Sometimes it’ll be smoking when it’s described as a behavioral or modifiable risk factor or another phrase like that.
64. Medical therapy is basically always appropriate for a hormone-producing prolactinoma in the absence of active vision problems requiring optic chiasm decompression. They respond well and it’s safe. Surgery has risks, and the larger the tumor the more challenging the surgery.
65. I think you’re referring to a different question?

Tremor in alcohol withdrawal is not the same as the flapping seen with asterixis from hepatic encephalopathy. The time course of alcohol withdrawal will likely be provided if relevant. They will often provide you with elevated ammonia for encephalopathy or other laboratory evidence of decompensated cirrhosis like elevated bilirubin.

DL 07.20.20 Reply

For Question 85, I don’t think it is spanking as much as it is referring to intentional submersion/dipping the baby into hot water causing burns.

Ben 07.20.20 Reply

One of the two would seem likely; but really, just not accidental.

AK 07.24.20

I would warrant that those burns are from cigarettes being put out, multiple, presumably round partial thickness burns on an erythematous base would give you flaccid bullae.

Ben 07.24.20

That’s a really good thought. I think regardless the clear issue here is that it’s not an injury pattern that can happen accidentally and therefore is super suspicious for NAT.

ufy 11.08.20

i think the tip off for me was the fact the mother said she didnt even notice the blisters on the buttocks. that is unususal for a mother that has a child with a peeling bum.

Ben 11.21.20

Also a good point.

sophie 05.09.21 Reply

Another point is that the baby is 9 months old, and definitely still wearing diapers, a mother would see those wounds while changing a diaper with out a doubt. Her denying she ever saw them shows shes hiding something.

Ben 05.29.21

Indeed, definitely not a subtle question.

kayleigh jin 08.03.20 Reply

For 103, why screen for triple A when he doesn’t meet the screening guidelines? Confused about this.

Ben 08.04.20 Reply

He does. USPSTF recommends screening in all men 65-75 who have ever smoked. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/abdominal-aortic-aneurysm-screening

AA 08.06.20 Reply

Thanks a lot. Your explanations were very helpful!

Sal 08.27.20 Reply

for number 87, how would you explain the loss of decent from vertex at -3 to vertex at -2?

I thought that would be indicative of Uterine rupture

Ben 08.27.20 Reply

That’s not loss of descent, that’s just descent. It goes from minus to positive as you progress in labor. https://fpnotebook.com/ob/exam/FtlStn.htm

Amna 08.29.20 Reply

Thank you so much for the explanations. Some of them were hilarious, which is deeply appreciated. Things can get dark during dedicated

Ben 08.31.20 Reply

You’re welcome!

MT 09.20.20 Reply

I think #79 is actually describing Diffuse Esophogeal Spasm, not Vasospastic Angina. They’re treatments and reaction to Nitrates are practically the same, but Vasospastic Angina shows ST-elevations not depressions.

Ben 09.20.20 Reply

It may be that they’re trying to make it unclear purposefully because the correct answer is the same regardless, acknowledging that reality is complicated.

In the question, we’ve done all the cardiac workup necessary for vasospastic angina by excluding CAD. We have done zero workup for DES, for which manometry remains gold standard. ST elevations are definitely more common and are the “classic” presentation of variant angina, but depressions can also occur do not exclude it. Likewise, not all cases of DES or nutcracker esophagus result in ST changes. ECG changes are not a diagnostic criteria.

HDCG 09.23.20 Reply

I just did this test today (sept 23 2020) and question 102 (22 from block 3) has changed into a media-type question. Pretty straight forward anyway, but would be good to get your insight on it.

Ben 09.24.20 Reply

I use the PDF for numbering so I didn’t do the multimedia questions. Flash is blocked so I can’t see the actual cardiac exam, but based on the question text the baby is totally normal/healthy. In a non-cyanotic baby with a murmur at 2 days of age, I’m going to go out on a limb and guess they’re demonstrating a normal ductus arteriosus, which typically closes by 2-3 days.

Arslan A Khan 10.11.20

Not sure about this but another plausible answer could be a VSD murmur (Even though an Echo might be the best next step to that, which was not given in the options). I say this based on the fact that the murmur was loudest at the left lower sternal border and the mitral area (as opposed to a PDA murmur which would be loudest in the left Infraclavicular area or close to that). Just a thought

Ben 10.11.20

VSD would require an echo for workup, so that’s not it.

Stephen 11.11.20 Reply

What’s the answer to the heart sounds question, I encountered 1 in the latest free 120 at Prometric….Aortic insufficiency, aortic stenosis, mitral stenosis, and some stem related to the patient having a vague memory of rheumatic fever

Sidra 08.13.22 Reply

It’s question 38 on block 2. It says the answer is aortic stenosis the man is now 77 yo. It is a systolic murmur when you listen and in the stem it says there is a systolic thrill.

Stephen 11.13.20 Reply

Why is 68 not pertussis?

Ben 11.13.20 Reply

The question should never be why not. It’s why is something the best answer? So, knowing that, what about a presumably vaccinated adult having a random URI makes you want to assume pertussis?

Michael 11.17.20 Reply

This is absolutely fantastic. It’s frustrating how NBME doesn’t even attempt to explain the answers. I’m going into DR and had my first interview yesterday, and I think it went well! Taking CK on Friday.

Vineeth 11.21.20 Reply

For #9, the old man with the UTI and chronic obstruction, why not FIRST go for the TMP-SMX therapy, and then do the measurement of the postvoidal residual volume afterwards? My question is why not D? Thanks!

Ben 11.21.20 Reply

We have no idea how obstructed he is. He could be sitting there with over a liter in the bladder working his way toward autonomic instability. He could already be in postrenal AKI. We need source control. The antibiotic isn’t going to do anything in the 5 minutes it takes to cath someone.

Lastly (but importantly), you always want your fluid (in this case urine) sample before initiating empiric antibiotics when practical.

Vineeth 11.22.20 Reply

Thanks for answering my previous Q! Just a couple more quick ones

On #68, why not do an ECG first (Choice C) to rule out a possible viral pericarditis? She had pleuritic chest pain so it seemed like a solid next step.

Also, any idea why they threw in the bit about her having “recurrent aphthous ulcers”? Like what were they trying to imply there? Just curious. Thanks so much! :)

Ben 11.23.20 Reply

Because this is super common and doesn’t require work-up.

Not sure about the latter; a very common condition that can also have a large number of associated conditions including various mucocutaneous disorders (e.g. IBD, SLE, etc etc).

They could be trying to get at MAGIC syndrome (mouth and genital ulcers with inflamed cartilage), which can be treated with NSAIDS, but I think that’s very very unlikely the point of the question.

Ayesha 12.21.20 Reply

This is a variable deceleration. Two causes for which are
1) cord compression
2) cord prolapse.
We differentiate these 2 by knowing that In cord compression, we have an abrupt compression followed by relaxation of cord.. seen as abrubt, variable decel with return to baseline when compression relieves.
In cord prolapse, the compression on umb cord is persistent hence no return to baseline.

tli 02.20.21 Reply

for 64, I’m wondering how we for sure know the mass is a prolactinoma vs a nonfunctional pituitary adenoma. I’ve seen Uworld questions in which the prolactin is elevated but not high enough to be a prolactinoma, which i think the number threshold they go by is 200 (other sources also say >5x the upper limit of normal). And in nonfunctional adenomas females also have amenorrhea, compressive sxs, and nipple discharge. thoughts?

Ben 02.20.21 Reply

The normal range provided by this test is <25, and the patient's is 100. Milky discharge is not a sign that one should attribute to a nonfunctioning adenoma.

The lab rationale you mentioned is flipped. It’s that super high prolactin, more than 150-200, is almost always a prolactinoma (as opposed to another cause), not that all prolactinomas have levels that high (and thus lower levels should entertain other possibilities). A moderately elevated prolactin level does not argue against a prolactinoma. In her case, elevated prolactin and galactorrhea in the setting of a pituitary mass make it clear even if amenorrhea is +/-.

I read scans every day for prolactinomas producing two-digit hormone levels.

Joyce 03.18.23

Milky discharge could be caused by the nonfunctioning adenoma due to the disruption of hypothalamus dopamine pathway?

tli 02.20.21 Reply


Arooj Mohammed 04.23.21 Reply

For the question with 76 year old woman receiving home hospice care with dyspnea, why wouldn’t admitting patient to the hospital be correct, especially if suspecting a pulmonary embolism given her hypercoagulable state? Is iv morphine the correct answer bc this is hospice? I just don’t see that patient is in pain, it seems that dyspnea and low O2 sat is the issue. Thanks, if someone can help me understand this?

Ben 04.25.21 Reply

Morphine treats not just pain but also air hunger, which is the important use in this scenario.

We often don’t treat life-threatening issues in hospice because they by definition are expected to pass in the near future, and there’s rarely a benefit to bringing someone into the hospital if they have adequate treatment with the hospice team. Hospice is about being comfortable with the time you have left, not about herculean measures. When someone is dying in hospice, that is an anticipated outcome: you help them transition comfortably.

Yelaine Bartolome Sierra 05.02.21 Reply

Great and helpful explanation! thank you!

Denzel 05.28.21 Reply

I disagree, this is not a variable decel. Its a change in baseline to fetal bradycardia, of which causes include: cord prolapse, placental abruption, uterine rupture, and uterine tachysystole. (1) This is the reason why uterine rupture and uterine hyperstimulation are provided as answers in Q87. A deceleration by definition would involve a return to baseline. The defining characteristic of a variable deceleration is an abrupt change in FHR >60 BPM, which appears as a abrupt downward line rather than the smooth slope of the early/late deceleration.

The classic presentation of cord compression is prolonged fetal bradycardia in a patient with a previously normal tracing. Other causes of fetal bradycardia involve vaginal bleeding (vasa previa) or presenting fetal parts (uterine rupture); in prolapse, often the FHT is the only clinical manifestation. The diagnosis is C/x (although TVUS can be helpful in visualizing the prolapsed cord), and the treatment is emergent C/S. (2)

I just want to let everyone know that I also got this question wrong/was really confused but digging through the UpToDate article on uterine cord prolapse really cleared things up (2). I suggest reading it if you want to get more background on this topic. Dr. Paul Bolin has some good youtube videos on OB in general if this is a content topic you need more help in. (3)

1. Section: “Fetal bradycardia/prolonged deceleration without loss of variability”. https://www.uptodate.com/contents/intrapartum-category-i-ii-and-iii-fetal-heart-rate-tracings-management?sectionName=Fetal%20bradycardia%2Fprolonged%20deceleration%20without%20loss%20of%20variability&search=prolonged%20deceleration&topicRef=418&anchor=H11184021&source=see_link#H11184021
2. https://www.uptodate.com/contents/umbilical-cord-prolapse?search=prolonged%20deceleration&topicRef=16663&source=see_link#H6
3. https://www.youtube.com/watch?v=C8ICa9hpaOk&list=PLVMC6VenuLZTcuhCYRLnufy9AseFNvksU

Ben 05.29.21 Reply

You’ve convinced me, nice work.

RS 07.10.21 Reply

Its not any type of decel – the baby is crashing!
First thing I thought when I saw the FHT was vasa previa or something to do with cord circulation getting cut. Could also happen with uterine rupture, but they didn’t mention pain + baby reaching through the belly.

Ibrahim Khalil 07.27.21 Reply

Thank you very much for the explanations, I thoroughly enjoyed them as well as learnt from them. There are a few explanations missing from the 2021 version that I did yesterday, which I think is due to 2-3 different questions, Do you have a link for that?

Mani 08.23.21 Reply

I just LOVE your explanations. They are succinct and hits the point of confusion. Thank you so much this useful resource!!!

Daniel Johnson 08.29.21 Reply

Thank you so much for these! For 56, how do you choose MS instead of Lyme disease? I got suckered into choosing Lyme given the sxs and the trip to northeastern USA. I can’t figure out how I would pick MS instead on the real exam if we had this picture. These sxs seem to match both diseases pretty well to me. Thoughts?

Ben 08.30.21 Reply

While the manifestations of both diseases are legion, neurologic Lyme disease tends to show up most commonly as cranial neuritis (typically *facial* nerve palsy), peripheral neuritis (causing painful radiculopathy), and meningitis.

Optic neuritis, while described with Lyme, is much, much, much more typical of multiple sclerosis. It is the presenting feature of MS in ~20% of cases and present in around 50%.

Emily 03.15.22

thank you so much for these, really helpful!
just one quick Q, why is #56 not GBS? the miller fisher syndrome type? it has signs similar to it and MFS type includes eye signs too. just confused, or maybe overthinking exam in a week :(

Ben 03.20.22

GBS is monophasic with ascending paralysis (and less commonly sensory symptoms), and MFS variant has a cranial nerve involvement (though not typically optic neuritis, keeping in mind that CN2 is really an extension of the telencephalon and not a typical nerve). This is a pretty classic multiple lesions with disparate jumbled symptoms separated in time. So while a good disease to know about I’d say overall overthinking it.

Abby 09.02.21 Reply

Part 3 #5 (85) is not cigarette burns, those would be small and usually on the extremities with the surrounding skin being relatively normal. Flaccid bullae on the buttock with a surrounding area of erythema are areas of blisters from second degree burns on a larger area of first degree skin burns. The location of the buttocks makes it very likely that the child was dunked in hot water. A nine month old can’t walk, and small kids who fall into hot water are top heavy and fall head first. But dunking will be the buttocks (they raise their feet and legs up out of the way to avoid touching the water).

Lani H 10.28.21 Reply

thanks a million for your answers. when it comes down to 2 possible choices, your explanation helps clarify why usmle.org is correct &/or conceptually driven. also, you’ve kept me from having to deliberate over the validity of other online info.

about your comment to #91 – is this similar to saying, “what would jesus do?”

Ben 10.28.21 Reply

It’s the sassy version of the golden rule: treat others as you would want to be treated. :)

Fred 03.20.22 Reply

Hey Dr. White,
Quick update–Block 2, Q48 is now a different auscultation question re an older gentleman with AS. Block 3, Q22 is also an auscultation question now (not about TCA overdose) about a 2-day-old infant with PDA.
Thanks for your help; your explantations give me life!

Ben 03.21.22 Reply

Yeah these are all from the PDF version, I didn’t go through and pick the handful of multimedia ones.

KB 06.02.22 Reply

Thank you for the great explanations. This was a very helpful resource during dedicated and the humor was much appreciated.

JH 06.20.22 Reply

Ditto on the humor. Laughed several times during my review. Thanks for a great resource Dr. White!

Taking Step2 tmr 06.29.22 Reply

thank you for this!!! this helped a lot.

Lil 07.08.22 Reply

For #5 I think the choice is empiric antibiotics not so much due to whether the vague symptoms are meningitis or appendicitis, but rather the principle that any signs of infection in an asplenic patient should be treated immediately with empiric antibiotics.
Thanks for the explanations!

Joseph HQ 07.20.22 Reply

For block 1 question 10,

the WBC count is significantly elevated indicating septic joint, but why is there no organisms? Is vancomycin the right choice for organisms?

Ben 07.22.22 Reply

Very common to not see organisms on gram stain. They may show up later via culture, but you can’t wait for culture growth to start therapy. Vancomycin is the choice in order to cover MRSA, the most common causative organism.

Vinod Kamath 07.31.22 Reply

do you have explanation for NBME free 120 Step 1, 2022 questions please?

Ben 08.01.22 Reply

I’m working on them, but it’s slow going with some other priorities taking precedence at the moment.

Neal Hall 08.06.22 Reply

Thanks Dr. White, this was awesome! I take Step 2 on Monday then fly to Dallas next weekend to do a sub-I with you guys for 2 weeks.

Deano 08.16.22 Reply

For question 88, I thought we didnt give active smokers O2? I understand his sats are low, but I thought they included active smoking to trick us

SS 10.02.22 Reply

Thank you very much! very helpful!!

I see some of the questions are revised, could you please update them?
What I noticed were
#78, #85, #102.

Thanks again.

SS 10.02.22 Reply

Self resolved. This is the difference between the problem with PDF and interactive testing. My apologies.

luke 11.12.22 Reply

could 31 be DRESS or is delayed allergy better?

Fever, rash, eos, lymphadenopathy

or do you need more signs of internal organ involvement

Ben 11.13.22 Reply

DRESS is a form of delayed-type IVb hypersensitivity reaction.

Joyce 03.18.23 Reply

From uptodate: In both drug reaction with eosinophilia and systemic symptoms (DRESS) and serum sickness, fever and rash are characteristic, and lymphadenopathy may be prominent. The typical urticarial rash of serum sickness is not seen in DRESS. A morbilliform rash present in the early phases of DRESS may be similar to the morbilliform pattern sometimes seen in serum sickness, but the rash of DRESS usually becomes confluent and very red and results in sloughing and peeling that are not seen in serum sickness. Arthralgias, typical of serum sickness, are not seen in DRESS. The prominent eosinophilia and elevated transaminases that are characteristic of DRESS are not seen in serum sickness.
So I feel the question stem is a little bit confused but more like serum sickness. Uptodate also says eosiniphilia may be present but not prominent in serum sickness, so you could see eosiniphilia. Another important thing is penecillin is more likely to cause serum sickness-like reaction rather than DRESS (ADE, vanco more common)

es 12.13.22 Reply

110: AED..
literally an explanation later..

“111: write it out, abbreviations are like assumptions”

Ben 12.13.22 Reply

I could argue that referencing something already described in words with an abbreviation later is very different than using one spontaneously where the meaning would otherwise be unclear, but yes, the unintended irony of my writing there is pretty thick.

Andrea 12.31.22 Reply

Thanks so much for posting this! Just a few clarifications, not sure if anyone has made note of these yet:
#31 is serum sickness-like reaction, commonly triggered by PCN.
#63: AZT is required for all neonates born to pregnant people with viral load 1000.
Thanks again!

Andrea 12.31.22 Reply

oops, i don’t know what happened to my comment but the above was supposed to say this:
#63: AZT is required for all neonates born to pregnant people with viral load LESS THAN 1000, whereas multi-drug ART is required for those born to pregnant people with viral loads GREATER THAN 1000.

K 06.01.23 Reply

#78 you mentioned it’s C because it’s truncus arteriosus… however, I think it might be more likely tetralogy of fallot?

SK 07.11.23 Reply

The link in “The NBME released a completely new set of questions in March 2020, which was the first major update since basically 2015.” directs you to a pdf which says it was updated in July 2023 and has a totally different set of questions. Can you please post the answers to the new set?

Ben 07.12.23 Reply

They’ve just updated the set and changed the PDF. I’ve updated the link here to point to the original version that was available before this week. I don’t know if I’ll be able to get to the new set at this point, especially if it’s entirely new.

LK 07.12.23 Reply


For those looking for more comprehensive explanations.

Ben 07.12.23 Reply

Those are still the old set.

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