Free 120 Step 2 CK Block 1 covers items 1–40 of the official USMLE Step 2 CK practice set. This page gives you the answer key for all 40 items, then a full explanation of each one: the reasoning that leads to the correct answer, why every distractor is wrong, and the educational objective the item is testing. Work through the official booklet first, then read these explanations alongside it.
Recall Mastery is not affiliated with the NBME, FSMB or the USMLE program. The official USMLE Step 2 CK Sample Test Questions booklet is available free from usmle.org. The questions are not reproduced here — these are our own explanations, written to be read alongside the official booklet. Item, block and page numbers match the July 2023 edition.
What Block 1 actually tests
Block 1 of the Free 120 covers items 1–40. Here is how those 40 questions break down by subject — useful for spotting which systems cost you the most marks:
| System | Items in this block |
|---|---|
| Cardiovascular | 4 |
| Biostatistics & Prevention | 4 |
| Psychiatry | 3 |
| Neurology | 3 |
| Respiratory | 3 |
| Ethics | 3 |
| Gastrointestinal | 3 |
| Renal | 2 |
| ENT & Ophthalmology | 2 |
| Immunology | 2 |
| Infectious Disease | 2 |
| Endocrine | 2 |
| Quality & Safety | 2 |
| Musculoskeletal | 1 |
| Obstetrics & Gynecology | 1 |
| Heme/Onc | 1 |
| Dermatology | 1 |
| Reproductive | 1 |
Answer key — Free 120 Step 2 CK Block 1 (items 1–40)
Score yourself first, then read the explanation for anything you missed or guessed.
| Item | Answer | System |
|---|---|---|
| Item 1 | A — Agoraphobia | Psychiatry |
| Item 2 | E — Echocardiography with bubble study | Neurology |
| Item 3 | A — Amiodarone | Respiratory |
| Item 4 | A — Audiography | Musculoskeletal |
| Item 5 | E — Son | Ethics |
| Item 6 | C — Echocardiography | Cardiovascular |
| Item 7 | B — Serum albumin concentration | Renal |
| Item 8 | B — start a daily low-dose inhaled corticosteroid (fluticasone by spacer) | Respiratory |
| Item 9 | B — Fasting serum lipid studies | Biostatistics & Prevention |
| Item 10 | F — Vitamin B12 (cyanocobalamin) supplementation | Neurology |
| Item 11 | B — Surgical biopsy of the oral lesion | ENT & Ophthalmology |
| Item 12 | B — Dilated cardiomyopathy | Cardiovascular |
| Item 13 | B — Physical therapy | Neurology |
| Item 14 | D — Learning disorder | Psychiatry |
| Item 15 | C — Administration of epinephrine | Immunology |
| Item 16 | B — Washing hands thoroughly with soap and water | Infectious Disease |
| Item 17 | E — efficacy at these doses cannot be distinguished | Biostatistics & Prevention |
| Item 18 | E — inclusion of trials lasting only 2 weeks | Biostatistics & Prevention |
| Item 19 | C — positive trials are more likely to reach publication | Biostatistics & Prevention |
| Item 20 | B — Contact the organ bank for potential donation | Ethics |
| Item 21 | C — Expectant management | Obstetrics & Gynecology |
| Item 22 | E — Monthly immune globulin replacement therapy | Immunology |
| Item 23 | C — Hepatocellular carcinoma | Gastrointestinal |
| Item 24 | B — Factor VIII concentrate | Heme/Onc |
| Item 25 | D — Macular degeneration | ENT & Ophthalmology |
| Item 26 | A — a central eschar over the wound | Dermatology |
| Item 27 | C — DASH diet | Cardiovascular |
| Item 28 | B — Insulin therapy | Endocrine |
| Item 29 | A — Administer a bolus of intravenous 3% saline | Renal |
| Item 30 | B — Cat-scratch disease | Infectious Disease |
| Item 31 | B — tell her now, in age-appropriate terms | Psychiatry |
| Item 32 | A — ask frontline clinicians what they believe drives failure to remove central lines | Quality & Safety |
| Item 33 | B — Endoscopy | Gastrointestinal |
| Item 34 | A — Albuterol therapy | Respiratory |
| Item 35 | C — explain to patient and family that the operation cannot help | Ethics |
| Item 36 | E — Thyrotoxicosis | Endocrine |
| Item 37 | D — Smoking cessation | Gastrointestinal |
| Item 38 | D — Pericardiocentesis | Cardiovascular |
| Item 39 | C — stop, and take her out of the operating room | Quality & Safety |
| Item 40 | A — take a history of alcohol use, smoking and stress | Reproductive |
Free 120 Step 2 CK Block 1 explanations: items 1–40
Item 1 — Agoraphobia [Psychiatry]
Answer: A — Agoraphobia
Recurrent panic attacks followed by avoidance of public places and progressive restriction of life is agoraphobia. His abrupt episodes of chest pain, palpitations, sweating, nausea, and fear of dying are panic attacks; the decisive feature is his persistent fear of having another attack where escape or help may be difficult, leading him to remain at home and withdraw from social activities.
Agoraphobia commonly accompanies panic disorder but is diagnosed separately. The feared consequence here is not embarrassment under social scrutiny—it is being caught in public during another incapacitating episode.
- B) Generalized anxiety disorder causes excessive, difficult-to-control worry across multiple domains, typically with symptoms such as restlessness, poor concentration, muscle tension, and sleep disturbance. It does not present as discrete, rapidly peaking attacks with situational avoidance.
- C) Illness anxiety disorder involves persistent fear of having or acquiring a serious disease despite minimal or absent somatic symptoms. He fears recurrent panic episodes, not an undiagnosed medical illness.
- D) Social anxiety disorder centers on fear of negative evaluation, humiliation, or scrutiny. His avoidance is driven by concern about having a panic attack in public.
- E) Somatic symptom disorder requires excessive thoughts, anxiety, or behavior focused on distressing physical symptoms. His chest pain occurs within brief panic attacks rather than as a persistent somatic preoccupation.
Educational objective: When panic attacks produce fear of being outside the home or in places where escape or help may be difficult, think agoraphobia. Fear of the attack favors agoraphobia; fear of others’ judgment favors social anxiety disorder.
Item 2 — Echocardiography with bubble study [Neurology]
Answer: E — Echocardiography with bubble study
A young patient with an embolic MCA stroke, a normal carotid evaluation, and signs of lower-extremity DVT needs evaluation for paradoxical embolism through a patent foramen ovale. Weightlifting transiently raises right atrial pressure through a Valsalva-like maneuver, allowing venous thrombus to cross a right-to-left intracardiac shunt and enter the arterial circulation.
Agitated saline echocardiography is the appropriate diagnostic study. Bubbles normally remain in the right heart because they are filtered by the pulmonary circulation; their appearance in the left heart after injection, especially during Valsalva, demonstrates a right-to-left shunt. Routine color Doppler can miss a PFO because its flap remains closed during much of the cardiac cycle.
- A) Adenosine stress testing evaluates inducible myocardial ischemia. It does not identify the embolic conduit suggested by concurrent DVT and cryptogenic stroke.
- B) Cardiac catheterization is invasive and is not the initial test for a suspected PFO or paradoxical embolism.
- C) Cardiac MRI can assess ventricular thrombus and structural cardiac disease, but bubble-contrast echocardiography is the preferred study for detecting a transient right-to-left shunt.
- D) CT angiography evaluates intracranial and cervical arteries and is useful for large-vessel occlusion or arterial dissection. The absence of head or neck pain, normal carotid ultrasonography, and evidence of DVT favor paradoxical embolism.
Educational objective: When a young patient has a cryptogenic arterial stroke plus evidence of venous thrombosis, think paradoxical embolism through a PFO. Confirm the right-to-left shunt with agitated saline echocardiography, ideally with a Valsalva maneuver.
Item 3 — Amiodarone [Respiratory]
Answer: A — Amiodarone
Progressive exertional dyspnea, a persistent nonproductive cough, and diffuse fine inspiratory crackles indicate interstitial lung disease from chronic amiodarone therapy. Amiodarone accumulates in tissues with prolonged use and can cause pneumonitis that progresses to pulmonary fibrosis, its most serious chronic adverse effect. Preexisting lung disease, as in this patient with COPD, increases susceptibility.
The absence of fever or infectious exposure argues against pneumonia, while the lack of jugular venous distention makes cardiogenic pulmonary edema less compelling. The pulmonary toxicity can occur even at the lower maintenance doses used for atrial fibrillation.
- B) Lisinopril can cause a dry cough through bradykinin accumulation, but it does not account for progressive exertional dyspnea with diffuse fine crackles from interstitial fibrosis.
- C) Propranolol may worsen COPD through β2 blockade and bronchoconstriction; wheezing rather than fine crackles would be expected.
- D) Tiotropium is a long-acting muscarinic antagonist used to improve COPD symptoms. Its adverse effects are predominantly anticholinergic, such as dry mouth and urinary retention.
- E) Warfarin can cause pulmonary hemorrhage when anticoagulation is excessive, typically producing acute dyspnea, hemoptysis, anemia, and diffuse alveolar opacities.
Educational objective: When chronic amiodarone use is followed by progressive exertional dyspnea, dry cough, and fine inspiratory crackles, think amiodarone-induced interstitial pneumonitis and pulmonary fibrosis.
Item 4 — Audiography [Musculoskeletal]
Answer: A — Audiography
Recurrent fractures after trivial trauma, blue sclerae, normal fracture healing, and an affected parent identify osteogenesis imperfecta, particularly the mild autosomal dominant phenotype. The underlying type I collagen defect affects extraskeletal tissues as well as bone.
Progressive hearing loss is an important complication, arising from abnormalities of the middle-ear ossicles and/or inner ear. Because it may develop despite an otherwise mild skeletal phenotype, regular audiographic screening is appropriate.
- B) DEXA scan measures bone mineral density and may help monitor selected patients or treatment response, but it does not screen for the major extraskeletal complication targeted here.
- C) Echocardiography is reserved for suspected valvular or aortic involvement; routine serial screening is less central than hearing surveillance in this presentation.
- D) Retinal detachment is associated with some type II collagen disorders, not the type I collagen defect causing osteogenesis imperfecta.
- E) Calcium and vitamin D deficiency causes defective mineralization, whereas osteogenesis imperfecta is a structural collagen disorder; serum concentrations are not the primary surveillance test.
Educational objective: When recurrent low-impact fractures coexist with blue sclerae and normal fracture healing, think osteogenesis imperfecta. Remember to screen these patients regularly for hearing loss with audiography.
Item 5 — Son [Ethics]
Answer: E — Son
The adult son should serve as surrogate because the patient lacks decision-making capacity and has not appointed a health care proxy. When no advance directive or designated proxy exists, statutory surrogate hierarchies generally prioritize legal next of kin; an adult child takes precedence over an unmarried partner or friend.
The son should base decisions first on the patient’s known values and previously expressed preferences—substituted judgment. If these are unknown, he should choose according to her best interests by weighing the benefits and burdens of treatment.
- A) Boyfriend: His long-term caregiving role makes him an important source of the patient’s values, but an unmarried partner does not take priority over an available adult child in the standard surrogate hierarchy.
- B) Neighbor: Close involvement in medical care does not confer legal decision-making authority without formal designation as health care proxy.
- C) Patient: She cannot understand her prognosis, indicating impaired capacity for this medical decision. A diagnosis of dementia alone is insufficient, but her inability to appreciate the situation is decisive here.
- D) Physician: The physician assesses capacity and advises the surrogate but does not replace an available authorized family surrogate.
Educational objective: When a patient lacks decision-making capacity and has no designated proxy, use the statutory next-of-kin hierarchy. An available adult child takes priority over an unmarried partner or friend.
Item 6 — Echocardiography [Cardiovascular]
Answer: C — Echocardiography
Recent cardiac surgery + abrupt low-output shock + marked respiratory variation in the arterial pressure waveform indicates postoperative pericardial tamponade. The waveform represents pulsus paradoxus, while cool extremities, delayed capillary refill, and oliguria reflect obstructive shock from impaired ventricular filling.
Urgent bedside echocardiography is the initial investigation because it rapidly identifies pericardial fluid and its hemodynamic consequences. Relevant findings include right atrial or right ventricular diastolic collapse and exaggerated respiratory variation in transvalvular Doppler flow. If tamponade is confirmed in this unstable infant, immediate pericardial drainage is required.
- A) Cardiac catheterization can define residual shunts or postoperative pressure abnormalities, but it is invasive and delays diagnosis of suspected tamponade.
- B) CT angiography offers excellent anatomic assessment and may detect a loculated collection missed on echocardiography. It is not the initial bedside study in a hemodynamically unstable infant.
- D) Electrophysiology study is used to characterize or treat arrhythmias. The rhythm strip shows sinus tachycardia rather than an arrhythmia causing the shock.
- E) Cardiac MRI can characterize the pericardium and complex effusions but is too slow and logistically unsuitable for acute instability.
Educational objective: After cardiac surgery, sudden obstructive shock with pulsus paradoxus should trigger immediate bedside echocardiography for cardiac tamponade. Remember: echocardiography is the initial test; hemodynamically significant tamponade requires urgent drainage.
Item 7 — Serum albumin concentration [Renal]
Answer: B — Serum albumin concentration
Generalized edema plus heavy proteinuria in a 6-year-old is nephrotic syndrome, with minimal change disease as the standard pediatric diagnosis. Urinary loss of albumin produces hypoalbuminemia, lowering plasma oncotic pressure and shifting fluid into the interstitium; this explains the periorbital edema, dependent pitting edema, and abdominal distension.
The recent upper respiratory illness is a common antecedent to minimal change disease. Complement levels remain normal, while hepatic compensation for reduced oncotic pressure increases lipoprotein synthesis, producing hyperlipidemia rather than reduced triglycerides.
- A) Hemoglobin is not characteristically reduced in nephrotic syndrome; intravascular volume contraction may even cause relative hemoconcentration.
- C) Low C3 and C4 suggest immune complex disease such as lupus nephritis. Minimal change disease does not consume complement.
- D) Serum triglycerides increase because the liver enhances lipoprotein synthesis and lipid clearance is impaired.
- E) Serum urea nitrogen is usually normal but may rise if severe intravascular volume depletion reduces renal perfusion; a decrease is not expected.
Educational objective: When a child has periorbital and dependent edema with heavy proteinuria, think nephrotic syndrome: hypoalbuminemia causes the edema, hyperlipidemia accompanies it, and complement is normal in minimal change disease.
Item 8 — start a daily low-dose inhaled corticosteroid (fluticasone by spacer) [Respiratory]
Answer: B — start a daily low-dose inhaled corticosteroid (fluticasone by spacer)
Weekly nocturnal awakening plus exercise-related activity limitation means persistent asthma, despite infrequent reported albuterol use and a normal examination. She therefore needs Step 2 controller therapy with a daily low-dose inhaled corticosteroid such as fluticasone; albuterol remains the rescue medication.
Asthma severity is determined by the most severe impairment or risk feature—not by auscultation findings or rescue-inhaler use alone. Inhaled corticosteroids suppress airway inflammation, improve symptom control, and reduce exacerbations and systemic corticosteroid exposure.
- A) Theophylline has a narrow therapeutic index and is not preferred initial controller therapy when a low-dose inhaled corticosteroid is appropriate.
- C) Salmeterol should not be used as LABA monotherapy in asthma. An ICS/LABA combination is used for asthma inadequately controlled with ICS alone or for more severe persistent disease.
- D) Oral prednisone is reserved for significant acute exacerbations; she has no respiratory distress, tachypnea, or current airflow symptoms.
- E) Continuing albuterol alone would undertreat persistent airway inflammation, as shown by nocturnal symptoms and exercise limitation.
Educational objective: When a child with asthma has recurrent nocturnal awakening or activity limitation, classify and treat based on that impairment even if albuterol use is infrequent. Mild persistent asthma requires an ICS-containing controller, typically daily low-dose ICS.
Item 9 — Fasting serum lipid studies [Biostatistics & Prevention]
Answer: B — Fasting serum lipid studies
Premature myocardial infarction in a first-degree relative plus smoking and excess weight warrants assessment for dyslipidemia now. A fasting lipid panel identifies a major modifiable ASCVD risk factor and provides total cholesterol, LDL-C, HDL-C, and triglycerides for risk assessment and preventive planning.
His father’s infarction at age 48 qualifies as premature coronary disease and should prompt a search for treatable risk factors rather than waiting for the routine age-based screening threshold. Smoking further amplifies the cardiovascular risk associated with elevated cholesterol.
- A) ECG is not a screening test for coronary atherosclerosis in an asymptomatic young adult; a normal tracing would neither exclude CAD nor meaningfully refine his risk.
- C) A nonspecific serum chemistry profile is not the best study for assessing his principal risk. Diabetes screening, when indicated, should use fasting plasma glucose or HbA1c rather than an unspecified chemistry panel.
- D) Screening is indicated because he has multiple ASCVD risk factors, particularly a first-degree family history of premature myocardial infarction.
Educational objective: When a young adult has a family history of premature ASCVD, assess modifiable cardiovascular risk factors early—especially with a lipid panel. Resting ECG does not screen asymptomatic patients for coronary atherosclerosis.
Item 10 — Vitamin B12 (cyanocobalamin) supplementation [Neurology]
Answer: F — Vitamin B12 (cyanocobalamin) supplementation
Severe loss of vibration and proprioception with absent ankle reflexes indicates a large-fiber sensory neuropathy from vitamin B12 deficiency. Cobalamin deficiency affects peripheral nerves and posterior columns; corticospinal signs such as hyperreflexia and Babinski responses may be absent, particularly early in the disease.
Advanced age is itself a major clue because food-cobalamin malabsorption commonly occurs in older adults, even without an obvious gastrointestinal disorder or macrocytic anemia. Prompt B12 replacement prevents further neurologic injury, although established deficits may not fully reverse.
- A) Alcohol cessation would be central if there were alcohol-related malnutrition or a nonspecific painful sensorimotor polyneuropathy. Two glasses of wine nightly does not explain the preferential loss of vibration and position sense as well as cobalamin deficiency.
- B) Calcium carbonate is not a recognized cause of this large-fiber neuropathy; discontinuation would not arrest the neurologic process.
- C) Folate can correct megaloblastic anemia but does not treat cobalamin-related neurologic injury and may allow it to progress.
- D) Niacin deficiency causes pellagra, with photosensitive dermatitis, diarrhea, and neuropsychiatric manifestations, usually in severe malnutrition.
- E) Thiamine deficiency produces a length-dependent axonal sensorimotor neuropathy, often with burning pain and weakness, rather than preferential posterior-column-type sensory loss.
Educational objective: When vibration and joint-position sensation are disproportionately impaired with absent ankle reflexes, think vitamin B12 deficiency—even without anemia, macrocytosis, or Babinski signs. Early replacement stops progression but may not reverse established damage.
Item 11 — Surgical biopsy of the oral lesion [ENT & Ophthalmology]
Answer: B — Surgical biopsy of the oral lesion
A persistent white buccal lesion in a 50-year-old smokeless-tobacco user is oral leukoplakia and requires biopsy. Leukoplakia is a clinical diagnosis that may histologically represent hyperplasia, dysplasia, carcinoma in situ, or invasive squamous cell carcinoma; visual appearance and absence of lymphadenopathy cannot exclude malignant change.
Histopathologic evaluation is therefore the appropriate next step. Because this lesion is small, surgical biopsy can establish the diagnosis while potentially removing the entire lesion. Tobacco cessation remains essential but does not replace tissue diagnosis.
- A) Oral nystatin treats candidiasis, which typically produces removable, curdlike plaques over a raw or bleeding surface and usually occurs with predisposing factors such as immunosuppression, antibiotics, or glucocorticoids.
- C) Exfoliative or brush cytology lacks sufficient sensitivity for a suspicious oral lesion. Formal tissue biopsy is required to assess epithelial architecture, dysplasia, and invasion.
- D) Observation is inappropriate because tobacco-associated leukoplakia is potentially premalignant. Waiting for regression after cessation risks delaying diagnosis of dysplasia or carcinoma.
Educational objective: When an adult tobacco user has a persistent nonremovable white oral patch, think leukoplakia and obtain a biopsy. A normal neck examination does not eliminate early oral squamous neoplasia.
Item 12 — Dilated cardiomyopathy [Cardiovascular]
Answer: B — Dilated cardiomyopathy
Six weeks of severe exertional intolerance, weight gain, pulmonary crackles, S3, peripheral edema, and hypotension describes advanced biventricular systolic heart failure. Echocardiography will show dilated cardiac chambers—particularly increased left ventricular dimensions—with global hypokinesis and reduced ejection fraction.
His long-term heavy alcohol use is an important toxic exposure because alcohol is the most common toxin associated with chronic dilated cardiomyopathy. The absence of a murmur, known hypertension, or a focal ischemic presentation further supports global myocardial dysfunction rather than valvular, hypertensive, or regional ischemic disease.
- A) A large pericardial effusion can cause hypotension, but tamponade produces elevated jugular venous pressure and muffled heart sounds; extensive pulmonary crackles are less typical because left-sided filling is restricted.
- C) Left ventricular hypertrophy suggests chronic pressure overload, usually from hypertension or aortic stenosis. This patient has neither a hypertension history nor an outflow murmur.
- D) Paradoxical septal motion occurs with conditions such as right ventricular volume overload, left bundle branch block, or after cardiac surgery. It does not explain this global congestive syndrome.
- E) A regional wall motion abnormality supports focal myocardial ischemia or prior infarction. Dilated cardiomyopathy instead causes global ventricular systolic dysfunction.
Educational objective: When progressive dyspnea and fatigue accompany an S3, pulmonary congestion, dependent edema, and chronic heavy alcohol exposure, think dilated cardiomyopathy. Echocardiography shows ventricular dilation with globally reduced systolic function.
Item 13 — Physical therapy [Neurology]
Answer: B — Physical therapy
Backward falls, instability while turning, and failure to recover after a backward pull indicate postural instability from Parkinson disease. This impaired postural reflex is a major fall-risk feature and often responds poorly to further dopaminergic escalation.
Physical therapy addresses the functional deficit through balance training, lower-extremity strengthening, gait and turning practice, and instruction in compensatory strategies. Assistive-device assessment and a structured home exercise program can further reduce fall risk. Given his recurrent falls and prior fracture, rehabilitation is the appropriate intervention rather than adding another dopamine agonist.
- A) Biofeedback may supplement selected rehabilitation programs, but it is not the standard primary intervention for Parkinson-related postural instability and recurrent falls.
- C) Pramipexole can improve motor symptoms such as rigidity and bradykinesia, but dopamine agonists do not reliably correct impaired postural reflexes and may cause orthostatic hypotension or somnolence.
- D) Ropinirole is another dopamine agonist with the same limitations; escalating dopaminergic therapy does not directly address this patient’s balance and turning deficits.
- E) Rotigotine provides continuous transdermal dopaminergic stimulation, useful for motor fluctuations, but it is not the preferred fall-prevention intervention for established postural instability.
Educational objective: When a patient with Parkinson disease has recurrent falls, backward instability, and an abnormal pull test, think physical therapy focused on gait, strength, balance, turning strategies, and assistive-device assessment.
Item 14 — Learning disorder [Psychiatry]
Answer: D — Learning disorder
An isolated inability to read despite average receptive intelligence, preserved basic mathematics, and age-appropriate adaptive functioning indicates a specific learning disorder with impairment in reading.
His slow acquisition of English is understandable after international adoption, but he also cannot read in Russian despite prior schooling. The deficit is therefore academic and domain-specific rather than a global language, cognitive, or adaptive impairment. His shyness is context-appropriate: he makes eye contact, answers questions, expresses positive emotion, plays well with siblings, and has formed a comfortable relationship with his adoptive parents.
- A) Autism spectrum disorder requires persistent social-communication deficits with restricted or repetitive behaviors. Reciprocal interaction, emotional expression, and sibling attachment are preserved here.
- B) Fetal alcohol syndrome would be supported by prenatal alcohol exposure, characteristic facial abnormalities, growth restriction, and neurobehavioral impairment. Mildly low growth percentiles alone are insufficient.
- C) Intellectual developmental disorder causes deficits in both intellectual functioning and adaptive functioning. His average receptive IQ and age-appropriate daily living skills argue against it.
- E) Post-traumatic stress disorder requires trauma-related intrusion, avoidance, negative mood or cognition changes, and hyperarousal. None are described.
- F) Reactive attachment disorder presents with emotionally withdrawn behavior toward caregivers and minimal seeking or accepting comfort after severe neglect. He has become comfortable with his adoptive parents and shows appropriate emotional reciprocity.
Educational objective: When a child has a specific academic deficit despite preserved intelligence and adaptive functioning, think specific learning disorder. Global cognitive and daily-living impairment instead suggests intellectual developmental disorder.
Item 15 — Administration of epinephrine [Immunology]
Answer: C — Administration of epinephrine
Acute urticaria plus respiratory distress and hypotension after amoxicillin is anaphylaxis. Give intramuscular epinephrine immediately; diagnostic testing must not delay treatment.
Epinephrine addresses the lethal components simultaneously: α1-mediated vasoconstriction raises blood pressure and reduces mucosal edema, while β2 stimulation causes bronchodilation and limits further mediator release. Antihistamines and bronchodilators are adjuncts only after epinephrine and hemodynamic stabilization. Airway assessment, oxygen, IV access, and rapid isotonic fluid resuscitation should proceed concurrently.
- A) Albuterol treats bronchospasm but does not reverse vasodilation, increased vascular permeability, or hypotension. It may be added for persistent wheezing after epinephrine.
- B) Diphenhydramine improves pruritus and urticaria but acts too slowly and does not adequately treat airway compromise or shock.
- D) A complete blood count has no role in immediate management; anaphylaxis is diagnosed clinically and requires prompt treatment.
- E) Observation alone is unsafe in a patient with respiratory distress and hypotension, both signs of severe systemic anaphylaxis.
Educational objective: When acute urticaria is accompanied by respiratory compromise or hypotension after allergen exposure, think anaphylaxis and give intramuscular epinephrine immediately. Antihistamines and albuterol are adjuncts, not substitutes.
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Item 16 — Washing hands thoroughly with soap and water [Infectious Disease]
Answer: B — Washing hands thoroughly with soap and water
Recent C difficile colitis with ongoing diarrhea requires contact precautions: a clean gown, gloves for patient or environmental contact, and handwashing with soap and water. C difficile forms hardy spores that persist on skin, surfaces, and equipment and are readily transmitted by healthcare personnel.
Alcohol-based hand gel does not reliably kill these spores. Soap-and-water washing is preferred because it mechanically removes them from the hands.
- A) Alcohol gel is suitable for routine hand hygiene against many pathogens but is not sporicidal and therefore is inadequate here.
- C) A surgical mask is used for droplet protection or during procedures with splash risk; C difficile spreads predominantly through the fecal-oral route via spores.
- D) Sterile gloves and chlorhexidine skin preparation are unnecessary for routine staple removal. Clean gloves are appropriate, but chlorhexidine does not replace C difficile-specific hand hygiene.
- E) Ongoing diarrhea after recently treated C difficile infection warrants continued contact precautions rather than standard precautions alone.
Educational objective: When caring for a patient with suspected or confirmed C difficile diarrhea, use contact precautions and wash hands with soap and water. Remember: alcohol gel does not kill C difficile spores.
Item 17 — efficacy at these doses cannot be distinguished [Biostatistics & Prevention]
Answer: E — efficacy at these doses cannot be distinguished
At medium and high doses, the confidence intervals cross the null value, so treatment retention does not differ significantly between buprenorphine and methadone. The reported relative reductions of 13% and 21% are point estimates, not proof that buprenorphine is less effective.
This is a precision issue: medium-dose BMT versus MMT had a 95% CI of −10% to 31%, while high-dose BMT versus MMT had a 95% CI of −216% to 20%. Both intervals include no difference and allow effects in either direction. Therefore, superiority of either drug cannot be established at these doses.
- A) The 13% and 21% values ignore their confidence intervals. Neither comparison reached statistical significance.
- B) Buprenorphine and methadone did not differ in benzodiazepine use. Her nonprescribed benzodiazepine use requires separate counseling because combining sedatives with opioid agonists increases toxicity risk.
- C) Methadone had significantly better retention with flexible and low-dose regimens, not with the medium- or high-dose comparisons asked here.
- D) Buprenorphine improved retention compared with placebo at low, medium, and high doses.
Educational objective: Remember: a point estimate does not establish a treatment difference when its 95% confidence interval includes the null. For relative benefit or risk reduction, the null value is 0%.
Item 18 — inclusion of trials lasting only 2 weeks [Biostatistics & Prevention]
Answer: E — inclusion of trials lasting only 2 weeks
A 2-week intervention is too brief to evaluate maintenance therapy for a chronic, relapsing opioid use disorder. Treatment retention and sustained suppression of illicit opioid use are time-dependent outcomes; studies lasting only a few weeks may capture induction or early dropout rather than the durable efficacy expected from maintenance treatment. Combining such short trials with studies lasting up to 52 weeks introduces substantial clinical heterogeneity and weakens confidence in the pooled conclusion.
Longer treatment—at least several months—is associated with more meaningful reductions in illicit drug use and relapse. Maintenance programs are generally more effective when continued long term rather than evaluated over detoxification-length intervals.
- A) Excluding detoxification-only studies appropriately preserves the review’s focus on maintenance therapy; acute detoxification answers a different clinical question.
- B) Excluding pregnant patients limits generalizability to pregnancy but does not undermine the conclusion for the defined nonpregnant population.
- C) Restriction to randomized controlled trials strengthens internal validity by reducing confounding and selection bias.
- D) Placebo-controlled trials appropriately establish whether buprenorphine is efficacious; methadone-controlled trials separately assess comparative efficacy.
- F) Urinalysis was used to confirm morphine, cocaine, and benzodiazepine use—not to determine treatment retention. It provides a more objective substance-use outcome than self-report.
Educational objective: When assessing maintenance therapy for a chronic relapsing disorder, scrutinize follow-up duration. Very short trials may measure induction-phase outcomes rather than sustained retention and relapse prevention.
Item 19 — positive trials are more likely to reach publication [Biostatistics & Prevention]
Answer: C — positive trials are more likely to reach publication
Preferential publication of trials with positive or statistically significant findings creates publication bias. A meta-analysis restricted mainly to published studies can therefore overestimate treatment benefit because negative or inconclusive trials remain unavailable.
Although this review searched trial registries, conference proceedings, ongoing-trial databases, and other gray literature—and contacted authors—these measures reduce publication bias but cannot guarantee its elimination. The underlying tendency for positive trials to reach publication remains the principal threat listed.
- A) Earlier recognition of relapse could produce detection bias, but relapse was assessed using objective urinalysis-confirmed drug use; no differential timing of diagnosis is described.
- B) Excluding pregnancy and detoxification-only studies appropriately narrows the review to maintenance therapy. This limits generalizability rather than inherently biasing the comparative estimate.
- D) Government funding is disclosed, but funding source alone does not establish systematic distortion of results.
- E) Variation in sample size affects study precision and weighting, not the direction of results by itself. Smaller studies receive less weight in appropriately conducted meta-analysis.
Educational objective: Remember: meta-analyses are vulnerable to publication bias when positive studies are more likely to be published than negative or null studies. Searching trial registries and gray literature reduces—but does not abolish—this bias.
Item 20 — Contact the organ bank for potential donation [Ethics]
Answer: B — Contact the organ bank for potential donation
A catastrophic, irreversible intracranial hemorrhage with coma and absent oculocephalic, corneal, and oculovestibular responses raises concern for brain death. After stabilization, the appropriate next step is referral to the organ procurement organization through the organ bank, which coordinates donor evaluation, authorization, organ suitability, allocation, and retrieval while formal brain-death determination proceeds according to protocol.
The wife’s report of his wish to donate is sufficient reason to initiate referral; a written advance directive is not required. Organ eligibility is assessed individually, and treated hypertension alone does not exclude donation.
- A) Ethics consultation is reserved for genuine conflict or uncertainty regarding goals, consent, or decision-making authority. No ethical dispute is present here.
- C) Clinicians do not search within their own hospital for recipients. Organ allocation is handled through the regulated transplant network based on compatibility, urgency, and allocation policy.
- D) Lack of an advance directive does not disqualify donation; authorization can be established through the legally appropriate surrogate and donor registry processes.
- E) Hypertension may influence evaluation of individual organs but is not an automatic exclusion from organ donation.
Educational objective: When a patient with devastating irreversible neurologic injury is a potential organ donor, contact the organ procurement organization promptly. Donor eligibility and recipient allocation are determined by the transplant system, not by the bedside team.
Item 21 — Expectant management [Obstetrics & Gynecology]
Answer: C — Expectant management
The tracing shows early decelerations: gradual, symmetric decreases in fetal heart rate whose onset, nadir, and recovery mirror the uterine contractions. These result from fetal head compression during descent, causing a vagal response; preserved variability and recovery to baseline indicate no fetal hypoxia.
Labor is progressing rapidly, but the cervix is still 9 cm dilated, so she remains in the first stage. Continue fetal monitoring and allow complete cervical dilation before pushing. No intrauterine resuscitation or expedited delivery is indicated for benign early decelerations with normal baseline variability.
- A) Pushing begins after complete cervical dilation. Starting at 9 cm risks cervical edema or laceration and provides no fetal benefit.
- B) Amnioinfusion is used for recurrent variable decelerations caused by umbilical cord compression, especially with oligohydramnios. This tracing has smooth, contraction-mirroring early decelerations.
- D) Forceps delivery requires complete dilation, ruptured membranes, an engaged head, and an appropriate maternal or fetal indication. She has not yet entered the second stage.
- E) Immediate cesarean delivery is reserved for fetal compromise or another obstetric indication. Moderate variability with benign early decelerations does not justify operative delivery.
Educational objective: When a gradual fetal heart rate deceleration mirrors the uterine contraction, think early deceleration from fetal head compression. It is benign; continue labor unless another maternal or fetal indication requires intervention.
Item 22 — Monthly immune globulin replacement therapy [Immunology]
Answer: E — Monthly immune globulin replacement therapy
Recurrent bacterial sinus and pulmonary infections with low IgG, IgA, and IgM indicate common variable immunodeficiency. The broad reduction in immunoglobulin classes distinguishes CVID from selective IgA deficiency, where IgG and IgM remain normal.
Immune globulin replacement supplies functional IgG antibodies against respiratory pathogens, reducing recurrent sinopulmonary infections and preventing complications such as bronchiectasis and chronic lung disease. Because infused IgG has a half-life of approximately 3–4 weeks, intravenous replacement is typically repeated monthly. Antibiotics treat individual infections; immunoglobulin replacement addresses the underlying antibody deficiency.
- A) Inhaled tobramycin is used for chronic airway infection with Pseudomonas, particularly in cystic fibrosis or established bronchiectasis. Neither condition is demonstrated here.
- B) Intranasal glucocorticoids reduce inflammation in allergic rhinitis or chronic rhinosinusitis but do not correct hypogammaglobulinemia.
- C) Antibiotic prophylaxis may be considered in selected patients, but daily trimethoprim-sulfamethoxazole does not replace the missing broad antibody protection and is not preferred over immunoglobulin replacement in symptomatic CVID.
- D) Intranasal live-attenuated influenza vaccine provides pathogen-specific active immunization, not broad protection against recurrent bacterial infections. Live vaccines are also generally avoided in clinically significant immunodeficiency.
Educational objective: When an adult has recurrent sinopulmonary bacterial infections plus reduced IgG with low IgA and/or IgM, think CVID. Symptomatic antibody deficiency is treated with regular immune globulin replacement to reduce infections and prevent chronic lung damage.
Item 23 — Hepatocellular carcinoma [Gastrointestinal]
Answer: C — Hepatocellular carcinoma
HBsAg positivity with IgG anti-HBc and absent anti-HBs identifies chronic hepatitis B infection. His persistent fatigue and modest aminotransferase elevation support ongoing chronic hepatitis, while immigration from an HBV-endemic region raises the likelihood of infection acquired early in life and prolonged viral carriage.
Untreated chronic HBV can progress through chronic hepatic inflammation and fibrosis to cirrhosis and hepatocellular carcinoma. Importantly, HBV also has direct oncogenic effects, so hepatocellular carcinoma may develop even without established cirrhosis. Among the listed outcomes, this is the major long-term complication.
- A) Amyloidosis occurs with sustained inflammatory disorders or plasma-cell dyscrasias; it is not a characteristic consequence of chronic HBV infection.
- B) Essential mixed cryoglobulinemia is strongly associated with chronic HCV infection. This patient is anti-HCV negative.
- D) Membranoproliferative glomerulonephritis can occur through viral antigen–antibody complex deposition, but the normal creatinine and absence of renal findings make it less likely than the major long-term malignant complication.
- E) Polyarteritis nodosa is an uncommon immune-complex complication of HBV and would present with systemic vasculitic features rather than isolated fatigue and transaminitis.
- F) Sjögren syndrome causes autoimmune exocrine gland dysfunction, particularly dry eyes and dry mouth; it is not a typical sequela of chronic HBV.
Educational objective: When HBsAg is positive, anti-HBs is absent, and IgG anti-HBc is present, think chronic HBV infection. Remember: chronic HBV carries a major risk of hepatocellular carcinoma, which can arise even without cirrhosis.
Item 24 — Factor VIII concentrate [Heme/Onc]
Answer: B — Factor VIII concentrate
A warm, swollen, painful knee with restricted movement in a child with hemophilia A is an acute hemarthrosis. Treatment is immediate replacement of the deficient factor—factor VIII—at the first sign of joint bleeding. Prompt infusion achieves hemostasis, limits ongoing intra-articular blood accumulation, and reduces subsequent synovial damage and hemophilic arthropathy.
The joint may also be rested and splinted in a comfortable position, with analgesia that does not impair platelet function. Factor replacement should not be delayed for imaging or aspiration in this stable, afebrile child.
- A) ADH (vasopressin) is not used to treat hemophilia. Desmopressin, an ADH analog, can raise endogenous factor VIII in selected patients with mild hemophilia A who are known responders, but factor VIII concentrate is the standard treatment for an acute hemarthrosis.
- C) Factor IX concentrate treats hemophilia B, not factor VIII deficiency.
- D) Ferrous sulfate treats iron deficiency and does not control an acute joint bleed.
- E) Fresh frozen plasma contains factor VIII but requires large-volume infusion and is reserved for emergencies when specific factor concentrate is unavailable.
Educational objective: When a patient with hemophilia develops a warm, swollen, painful joint, treat acute hemarthrosis immediately with the deficient clotting factor: factor VIII for hemophilia A and factor IX for hemophilia B.
Item 25 — Macular degeneration [ENT & Ophthalmology]
Answer: D — Macular degeneration
An elderly patient with painless central visual loss and metamorphopsia—straight lines appearing curved or wavy—has age-related macular degeneration. Macular distortion disrupts the spatial arrangement of central photoreceptors, producing difficulty with reading and the characteristic wavy-line complaint.
The relatively rapid change over 3 weeks raises concern for neovascular (“wet”) AMD, in which choroidal neovascularization causes subretinal fluid, hemorrhage, and retinal elevation. Clear lenses and preserved red reflex shift the lesion away from the ocular media and toward the retina.
- A) Cataracts cause progressive painless blurring, glare, lens opacity, and an impaired red reflex. They do not characteristically produce metamorphopsia, and the lenses are clear here.
- B) Central retinal artery occlusion causes sudden, profound, painless monocular visual loss, typically developing over seconds rather than 3 weeks.
- C) Closed-angle glaucoma presents with severe ocular pain, headache, halos, a red eye, corneal edema, and a poorly reactive mid-dilated pupil. This patient has painless visual distortion and reactive pupils.
- E) Temporal arteritis can cause abrupt ischemic visual loss, often with headache, scalp tenderness, jaw claudication, or polymyalgia rheumatica. Wavy central vision is a macular symptom, not the typical ischemic pattern.
Educational objective: When an older adult reports that straight lines look bent or wavy, think macular pathology—particularly age-related macular degeneration. Rapidly progressive metamorphopsia suggests the neovascular form.
Item 26 — a central eschar over the wound [Dermatology]
Answer: A — a central eschar over the wound
A witnessed spider bite while putting on clothing, followed by severe localized pain and central violaceous necrosis, identifies cutaneous loxoscelism from a brown recluse spider. These spiders hide in dark, undisturbed areas and folds of clothing; their sphingomyelinase D–containing venom causes local ischemia and dermonecrosis.
The lesion evolves from erythema and induration to blistering, hemorrhagic necrosis, ulceration, and a central black eschar. The surrounding pale ischemic rim with peripheral erythema produces the characteristic “red, white, and blue” pattern.
- B) Distal limb gangrene would suggest major arterial occlusion or extensive invasive soft-tissue infection, not localized recluse envenomation.
- C) Generalized upper-extremity edema is more compatible with a major local allergic reaction or extensive inflammation; this lesion instead progresses toward focal necrosis.
- D) Palpable purpura indicates small-vessel vasculitis. Systemic loxoscelism may cause a diffuse rash, hemolysis, and coagulopathy, but this patient has isolated cutaneous disease.
- E) Rapidly spreading erythema suggests cellulitis or necrotizing soft-tissue infection. Recluse bites may have an expanding erythematous rim, but central ischemic necrosis and eschar formation dominate the evolution shown here.
- F) Tender erythematous streaks toward regional nodes indicate lymphangitis, usually from a bacterial skin infection.
Educational objective: When a painful bite sustained from clothing develops a pale ischemic zone, violaceous center, and surrounding erythema, think brown recluse envenomation. Expect central necrosis followed by black eschar formation.
Item 27 — DASH diet [Cardiovascular]
Answer: C — DASH diet
Repeated blood pressures of 136–138/85–87 mm Hg place this asymptomatic, obese man in stage 1 hypertension. With no cardiovascular disease, diabetes, kidney disease, or other evidence of high ASCVD risk, management begins with nonpharmacologic intervention rather than antihypertensive medication.
Along with weight loss, the DASH diet is the best-supported dietary intervention for lowering blood pressure and cardiovascular risk. It emphasizes fruits, vegetables, whole grains, and low-fat dairy while limiting saturated fat and cholesterol. In patients without established hypertension, good adherence can lower systolic pressure by approximately 2–3 mm Hg.
- A) ACE inhibitors are appropriate when stage 1 hypertension coexists with cardiovascular disease or high ASCVD risk, or for more advanced hypertension. Neither indication is present here.
- B) Calcium supplementation is not a standard intervention for preventing hypertension or cardiovascular morbidity in this setting.
- D) Fish oil may lower triglycerides in selected patients but is not first-line therapy for mildly elevated blood pressure.
- E) Thiazide diuretics are effective antihypertensives, but pharmacotherapy is unnecessary for a low-risk patient with stage 1 hypertension before a trial of lifestyle modification.
Educational objective: When a low-risk adult has stage 1 hypertension, begin with weight loss and evidence-based lifestyle measures such as the DASH diet. Add medication when hypertension is more severe or stage 1 hypertension accompanies established cardiovascular disease or high ASCVD risk.
Item 28 — Insulin therapy [Endocrine]
Answer: B — Insulin therapy
Glucose 578 mg/dL with polyuria, polydipsia, and 15-lb weight loss requires insulin—this is severe symptomatic hyperglycemia with a catabolic phenotype.
Oral monotherapy will not correct this degree of hyperglycemia rapidly enough. Insulin promptly reverses glucose toxicity, suppresses ongoing catabolism, and restores metabolic control. His age does not exclude autoimmune type 1 diabetes; adult-onset type 1 disease is frequently mistaken for type 2, and his lean habitus and weight loss increase that concern. Insulin may later be adjusted or discontinued if evaluation and clinical response establish type 2 diabetes with recovered endogenous insulin secretion.
- A) Glyburide increases endogenous insulin secretion but is inappropriate for severe symptomatic hyperglycemia and may cause hypoglycemia.
- C) Metformin is standard initial therapy for uncomplicated type 2 diabetes with mild-to-moderate hyperglycemia. It is insufficient alone at a glucose of 578 mg/dL with catabolic weight loss.
- D) Pioglitazone improves insulin sensitivity but has a slow onset and commonly causes weight gain and fluid retention; it cannot provide rapid control here.
- E) Sitagliptin has modest glucose-lowering efficacy and is unsuitable as initial monotherapy for marked symptomatic hyperglycemia.
Educational objective: When severe hyperglycemia is accompanied by polyuria, polydipsia, or catabolic weight loss, initiate insulin rather than oral monotherapy. Adult age does not rule out type 1 diabetes.
Item 29 — Administer a bolus of intravenous 3% saline [Renal]
Answer: A — Administer a bolus of intravenous 3% saline
Seizure plus drowsiness with serum sodium of 122 mEq/L is symptomatic acute hyponatremia with cerebral edema. The immediate priority is hypertonic 3% saline to raise sodium enough to reverse neurologic symptoms and prevent cerebral herniation.
Recent head injury, surgery, pain, and physiologic stress can promote inappropriate ADH release and acute water retention. Normal glucose and calcium make other metabolic seizure triggers unlikely, while the nonfocal examination argues against a structural lesion as the immediate cause. Sodium must be monitored closely during treatment; correction should stop once neurologic symptoms improve and must remain controlled to avoid osmotic demyelination.
- B) Vasopressin increases renal water reabsorption and would aggravate dilutional hyponatremia. It is used in selected cases of central diabetes insipidus, which produces hypernatremia and dilute polyuria.
- C) Fosphenytoin is not the primary treatment for an acute provoked seizure caused by hyponatremia. Correcting the electrolyte disturbance treats the seizure mechanism.
- D) Excess isotonic maintenance fluid does not provide sufficiently rapid sodium correction and may worsen water excess when ADH activity is elevated.
- E) EEG may be considered for recurrent or unexplained seizures, but it must not delay correction of symptomatic hyponatremia.
- F) Neuroimaging is appropriate if structural intracranial pathology remains suspected, particularly with focal deficits or deterioration, but metabolic stabilization comes first here.
Educational objective: When hyponatremia presents with seizure, coma, or significant altered mental status, treat immediately with intravenous 3% saline. Neurologic symptoms—not the sodium value alone—define the emergency.
Item 30 — Cat-scratch disease [Infectious Disease]
Answer: B — Cat-scratch disease
Cat exposure followed by subacute, tender axillary and epitrochlear lymphadenopathy is cat-scratch disease due to Bartonella henselae. These nodes drain an inoculation site on the upper extremity; the primary papule or scratch is often small or no longer visible by presentation.
The 2-week course, mobile tender nodes with overlying erythema, and well appearance without fever, weight loss, or hepatosplenomegaly favor localized infectious lymphadenitis over lymphoma or tuberculosis. Axillary and epitrochlear involvement is particularly characteristic.
- A) Castleman disease causes unicentric or multicentric lymphoproliferative disease. A tender regional nodal chain temporally associated with cat exposure does not fit.
- C) Hidradenitis suppurativa produces recurrent painful axillary nodules, abscesses, sinus tracts, and scarring—not a discrete mobile axillary node with epitrochlear lymphadenopathy.
- D) T-cell lymphoma more often causes persistent, usually nontender lymphadenopathy and may be accompanied by constitutional symptoms, extranodal disease, or hepatosplenomegaly.
- E) Tuberculous lymphadenitis is typically chronic, painless, and may produce matted nodes or draining sinuses. This acute tender regional pattern is inconsistent with tuberculosis.
Educational objective: When cat contact is followed within weeks by tender regional lymphadenopathy—especially axillary or epitrochlear—think cat-scratch disease, even when no inoculation papule is visible.
Item 31 — tell her now, in age-appropriate terms [Psychiatry]
Answer: B — tell her now, in age-appropriate terms
Adoption should become part of the child’s life narrative from the toddler years, not a delayed revelation. Parents should discuss it openly, repeatedly, and in developmentally appropriate language; the child does not need to understand its full meaning during the first conversation.
Early disclosure allows understanding to mature naturally as cognition develops and avoids the loss of trust that can follow accidental or late discovery. At age 2, simple language, stories, photographs, or a “lifebook” can introduce the adoption narrative, with more detail added over time.
- A) Waiting until age 18 unnecessarily turns adoption into a concealed secret and risks damaging trust if the child learns earlier from another source.
- C) Disclosure should not depend on access to sealed records. Parents can explain adoption even when information about the biologic family is incomplete.
- D) Kindergarten enrollment is an arbitrary milestone. Adoption conversations should begin earlier and continue throughout childhood and adolescence.
- E) Waiting until the child discovers a lack of biologic relationship makes disclosure reactive and potentially distressing. The parents should establish the narrative themselves before such discovery occurs.
Educational objective: When parents ask when to disclose adoption, advise early, open, repeated, and developmentally tailored communication beginning in the toddler years. Adoption should be integrated into the child’s identity rather than revealed as a later secret.
Item 32 — ask frontline clinicians what they believe drives failure to remove central lines [Quality & Safety]
Answer: A — ask frontline clinicians what they believe drives failure to remove central lines
The next step is to define the current process and identify why unnecessary catheters remain in place. Frontline clinicians can reveal practical barriers—unclear responsibility for removal, failure to discuss line necessity during rounds, or concern about future access—that aggregate infection data cannot explain.
Quality improvement begins by understanding the local system before selecting an intervention. Once the causes are identified, the team can introduce a targeted change, measure catheter-days and infection outcomes, and refine the intervention through rapid improvement cycles. This matters because infection risk rises with catheter duration, making timely removal a core preventive measure.
- B) Routine replacement every 5 days does not address whether the catheter is still needed and adds insertion-related risks. The goal is prompt removal, not scheduled exchange.
- C) Door stickers are a proposed intervention, but choosing one before identifying local barriers is premature and may have little effect.
- D) A randomized controlled trial determines efficacy under research conditions. This is a local process-improvement problem better addressed through targeted, measured, rapid-cycle testing.
Educational objective: When a quality gap is identified, first characterize the existing process and engage frontline staff to identify its causes; only then design, test, and measure a targeted intervention.
Repeating themes across blocks? The topics that recur exam after exam are collected in Step 2 CK chronic repeats.
Item 33 — Endoscopy [Gastrointestinal]
Answer: B — Endoscopy
Persistent epigastric pain related to meals raises concern for acid-peptic disease, and esophagogastroduodenoscopy confirms it by directly visualizing the esophageal, gastric, and duodenal mucosa. It can identify gastritis or an ulcer and permits gastric and duodenal biopsies for histology and H. pylori testing.
The brief, self-limited episode of watery diarrhea three weeks earlier does not explain three months of meal-related epigastric pain. Stool testing is useful for ongoing or recurrent infectious diarrhea, not for confirming upper gastrointestinal mucosal disease.
- A) CT scan of the abdomen evaluates pancreatic, hepatobiliary, mass, and other extraluminal pathology, but it is insensitive for uncomplicated mucosal ulcers or gastritis.
- C) Stool examination for ova and parasites is appropriate for persistent diarrhea, particularly with travel or exposure risks. A resolved 2-day diarrheal illness does not support parasitic infection.
- D) Stool culture is used for suspected bacterial enterocolitis with active diarrhea, fever, blood, or relevant exposure history.
- E) An upper gastrointestinal series can demonstrate an ulcer radiographically but is less sensitive than endoscopy and cannot obtain a biopsy.
Educational objective: When persistent meal-related epigastric pain requires confirmation of acid-peptic disease, use upper endoscopy: it directly visualizes mucosal lesions and allows biopsy for histology and H. pylori.
Item 34 — Albuterol therapy [Respiratory]
Answer: A — Albuterol therapy
Sudden cough and diffuse wheezing immediately after inhaling acetic acid mixed with cleaning agents indicate acute irritant-induced bronchospasm, or reactive airways dysfunction syndrome. Mild hyperinflation supports airflow obstruction, while normal vital signs, preserved mentation, and absence of accessory-muscle use indicate a nonsevere presentation.
The initial treatment is inhaled albuterol, a short-acting β2-agonist that increases cAMP in bronchial smooth muscle and produces rapid bronchodilation. His mild hypoxemia warrants monitoring and supplemental oxygen as needed, but there is no evidence of respiratory failure requiring airway intervention. A near-normal PCO2 becomes ominous in a patient with severe respiratory distress; here, the reassuring clinical examination makes that interpretation inappropriate.
- B) Bronchoscopy is used for suspected foreign-body aspiration, particulate aspiration, or mucus-plug obstruction. Diffuse bilateral wheezing after chemical exposure reflects generalized bronchospasm, not focal airway obstruction.
- C) CT of the chest may evaluate unexplained structural or parenchymal disease but would delay treatment of clinically apparent bronchospasm.
- D) Intubation is reserved for impending respiratory failure, such as exhaustion, altered mental status, silent chest, or worsening gas exchange. None is present here.
- E) Systemic methylprednisolone is added for moderate-to-severe obstruction or inadequate response to initial bronchodilator therapy; it does not provide the immediate bronchodilation needed first.
Educational objective: When abrupt cough and diffuse wheezing follow a high-level irritant exposure, think reactive airways dysfunction syndrome. Manage the acute bronchospasm like an asthma exacerbation: inhaled short-acting β2-agonist first, with systemic glucocorticoids added when severity or response warrants.
Item 35 — explain to patient and family that the operation cannot help [Ethics]
Answer: C — explain to patient and family that the operation cannot help
Diffuse peritoneal carcinomatosis, ascites, recurrent obstruction despite a prior bypass, and a previous laparotomy documenting no further surgical options make another operation nonbeneficial. Patient autonomy permits refusal among medically appropriate treatments; it does not obligate a physician to perform an operation that cannot achieve its intended goal and carries substantial morbidity and mortality.
The next step is a candid, compassionate discussion explaining why laparotomy cannot provide durable relief and may worsen his remaining quality of life. With no peritoneal signs or evidence of strangulation, symptom-directed management is appropriate: nasogastric decompression initially and a venting gastrostomy for ongoing palliation of nausea and vomiting.
- A) The patient’s preferences should guide care among reasonable options, but neither the patient nor family can require futile surgery.
- B) Changing systemic chemotherapy will not provide timely relief of a mechanical jejunal obstruction caused by extensive carcinomatosis.
- D) Transfer may be considered if disagreement persists and another qualified team is willing to evaluate him, but the immediate step is transparent discussion of the operation’s lack of benefit.
- E) External beam radiation may palliate localized tumor-related bleeding or pain; diffuse peritoneal disease causing small-bowel obstruction is not an appropriate target.
Educational objective: Remember: autonomy does not create an obligation to provide medically futile treatment. In unresectable malignant bowel obstruction without ischemia or perforation, prioritize decompression and symptom palliation rather than nonbeneficial laparotomy.
Item 36 — Thyrotoxicosis [Endocrine]
Answer: E — Thyrotoxicosis
Weight loss despite systemic hyperactivity, frequent stools, tremor, atrial fibrillation, and widened pulse pressure establish thyrotoxicosis. The diffuse goiter with a thyroid bruit indicates marked glandular hypervascularity, while widened palpebral fissures and pretibial peau d’orange thickening are Graves-specific ophthalmopathy and infiltrative dermopathy.
The nail separation is onycholysis, also called Plummer nails in hyperthyroidism. In an older patient, atrial fibrillation may be a prominent cardiovascular presentation even without striking tachycardia.
- A) Addison disease causes weight loss, hyperpigmentation, hypotension, and often hyponatremia or hyperkalemia. It does not produce a hypervascular diffuse goiter, ophthalmopathy, or pretibial myxedema.
- B) Carcinoid syndrome causes episodic flushing, secretory diarrhea, bronchospasm, and right-sided valvular disease. The thyroid bruit and Graves-specific skin and eye findings exclude it.
- C) Cushing syndrome produces central obesity, proximal muscle weakness, wide violaceous striae, bruising, and hypertension—not weight loss with tremor and diffuse goiter.
- D) Pheochromocytoma typically causes episodic headache, sweating, palpitations, and severe or labile hypertension. It does not explain the thyroid, ocular, and pretibial findings.
Educational objective: When diffuse goiter with a bruit occurs alongside ophthalmopathy or pretibial peau d’orange dermopathy, think Graves disease causing thyrotoxicosis. In older adults, new atrial fibrillation may be the dominant clue.
Item 37 — Smoking cessation [Gastrointestinal]
Answer: D — Smoking cessation
Ileal ulceration with intervening normal mucosa—skip lesions—identifies Crohn disease. Cigarette smoking increases the risk of Crohn disease and, unlike its association with ulcerative colitis, worsens disease activity after diagnosis. At two packs daily, smoking is a major modifiable driver of future flares and complications; cessation is therefore an essential part of management, with benefits on disease activity comparable to medical therapy.
He should receive a firm cessation recommendation, assessment of readiness to quit, counseling, and pharmacologic support such as nicotine replacement or varenicline if acceptable.
- A) Annual screening for lymphoproliferative disorders is not routinely indicated at diagnosis. Lymphoma risk becomes relevant particularly with certain immunosuppressive therapies, but there is no standard annual screening program.
- B) Citalopram need not be discontinued; the endoscopic pattern supports Crohn disease rather than a medication-induced diarrheal syndrome.
- C) Prophylactic colectomy has no role in Crohn disease. Surgery is reserved for complications or medically refractory disease and is not curative because inflammation may recur elsewhere in the gastrointestinal tract.
Educational objective: When ileal skip lesions indicate Crohn disease, actively recommend smoking cessation. Remember: smoking worsens Crohn disease but has a contrasting protective association with ulcerative colitis.
Item 38 — Pericardiocentesis [Cardiovascular]
Answer: D — Pericardiocentesis
A precordial stab wound followed by abrupt hypotension, tachycardia, and jugular venous distention is acute cardiac tamponade. FAST will demonstrate pericardial fluid, confirming hemopericardium causing obstructive shock by restricting diastolic filling.
In this unstable patient, pericardial decompression cannot wait for advanced imaging. Pericardiocentesis provides immediate, potentially lifesaving relief while resuscitation and definitive surgical exploration with repair of the cardiac injury are arranged. Penetrating cardiac trauma ultimately requires operative management because needle drainage may be incomplete when the pericardium contains clotted blood.
Why the other options are wrong
- A) Contrast CT is appropriate only after hemodynamic stabilization. Transferring a patient with obstructive shock to the scanner dangerously delays decompression.
- B) Exploratory laparotomy treats intra-abdominal hemorrhage, which would produce intraperitoneal free fluid and usually flat neck veins rather than jugular venous distention.
- C) Needle decompression followed by chest tube placement treats tension pneumothorax. That diagnosis is supported by unilateral absent breath sounds, hyperresonance, and tracheal deviation, not pericardial fluid on FAST.
- E) Diagnostic peritoneal lavage evaluates intraperitoneal bleeding when FAST is unavailable or equivocal; it neither diagnoses nor relieves cardiac tamponade.
Educational objective: When penetrating precordial trauma is followed by hypotension, tachycardia, jugular venous distention, and pericardial fluid on FAST, think traumatic cardiac tamponade. Immediate decompression is lifesaving, but definitive treatment requires surgical drainage and repair.
Item 39 — stop, and take her out of the operating room [Quality & Safety]
Answer: C — stop, and take her out of the operating room
The operation must stop because the preincision verification has failed: neither the operative consent nor the marked surgical site can be confirmed. The universal protocol requires verification of the correct patient, procedure, and site before incision; the surgeon’s memory cannot substitute for documented consent and site confirmation.
This is elective surgery, and sedation has temporarily impaired the patient’s capacity to provide fresh informed consent. She should be removed from the operating room, allowed to recover capacity, and the consent and site-verification process completed properly before rescheduling or proceeding.
- A) Asking a sedated patient whether she recalls signing a form neither establishes current decision-making capacity nor replaces the missing documentation and site verification.
- B) A new consent obtained after sedation is invalid if the medication impairs comprehension or voluntariness. Consent should be obtained after capacity returns.
- D) Her husband cannot replace the decision of a competent adult merely because she has been temporarily sedated. There is no emergency requiring surrogate authorization.
- E) Proceeding despite a failed surgical pause violates the safety protocol and creates an avoidable risk of wrong-site surgery.
Educational objective: When an elective procedure fails preincision verification—especially due to absent consent documentation or unconfirmed surgical site—stop the procedure. Temporary incapacity from sedation is not a reason to bypass consent; postpone until the patient regains capacity and verification is complete.
Item 40 — take a history of alcohol use, smoking and stress [Reproductive]
Answer: A — take a history of alcohol use, smoking and stress
The first move in oligospermia is a detailed history for reversible contributors to impaired spermatogenesis. Heavy alcohol use can reduce testosterone through testicular and hypothalamic-pituitary effects; smoking, psychosocial stress, medications, recreational drugs, prior infections, and occupational exposures also need assessment before escalating treatment.
A single abnormal semen analysis may require confirmation because sperm concentration varies between samples. Subsequent evaluation is guided by severity and includes repeat semen analysis, examination, and endocrine testing with FSH, LH, prolactin, and TSH.
- B) Advancing age can affect reproductive function, but age-related counseling neither identifies the cause nor addresses a potentially reversible factor in this 30-year-old.
- C) Phosphodiesterase inhibitors treat erectile dysfunction. The stem describes impaired sperm concentration, not difficulty achieving or maintaining an erection.
- D) Exogenous testosterone suppresses LH and FSH, reducing intratesticular testosterone and spermatogenesis; it can worsen oligospermia despite raising serum testosterone.
- E) IVF, often with ICSI, is reserved for severe male-factor infertility or failure of less invasive approaches. Severity and reversible causes must be assessed first.
Educational objective: When evaluating male infertility, begin with a detailed reproductive, medication, substance-use, occupational, and lifestyle history. Remember: exogenous testosterone is contraceptive to the testes—it suppresses gonadotropins and sperm production.
Continue with the rest of the Free 120
- Block 1 (items 1–40)
- Block 2 (items 41–80)
- Block 3 (items 81–120)
- What does my Free 120 score mean? Score-to-readiness guide
- Free 120 hub: format, timing and how to take it
Last reviewed for the 2026 exam window. Spotted an error? Tell us and we will correct it — accuracy matters more to us than being first.