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ABIM Internal Medicine practice questions

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Question 1Allergy and Immunology

A 27-year-old man develops flushing, diffuse urticaria, wheezing, and hypotension within minutes of eating a peanut-containing dessert. Which of the following is the most appropriate initial pharmacologic treatment?

  1. Oral prednisone with observation
  2. Nebulized albuterol and oxygen
  3. Intravenous diphenhydramine and fluids
  4. Intramuscular epinephrine in thigh Correct answer.

Explanation

Intramuscular epinephrine into the anterolateral thigh is the first-line treatment for anaphylaxis and should be given immediately, because it reverses mast-cell mediator effects on vasculature and airway. Antihistamines, corticosteroids, and bronchodilators are adjuncts that do not reverse shock or airway edema and must never delay epinephrine.

Question 2Allergy and Immunology

A 28-year-old woman has a 6-year history of recurrent episodes of facial and hand swelling and severe abdominal cramping, each lasting 2 to 3 days. Urticaria never occurs. Complement C4 is low both during and between attacks, and C1 inhibitor level is reduced. Which of the following is the most appropriate acute therapy for an attack?

  1. Intramuscular epinephrine at home
  2. C1 esterase inhibitor concentrate Correct answer.
  3. A short course of oral corticosteroids
  4. Scheduled high-dose oral antihistamines

Explanation

Hereditary angioedema results from C1 inhibitor deficiency and is bradykinin-mediated, so attacks respond to agents that restore or block the kallikrein-bradykinin pathway, such as C1 inhibitor concentrate, icatibant, or ecallantide. Antihistamines, epinephrine, and corticosteroids act on histamine-driven pathways and are ineffective for bradykinin angioedema.

Question 3Allergy and Immunology

A 45-year-old woman developed a pruritic maculopapular rash without mucosal involvement, blistering, or systemic symptoms on day 4 of amoxicillin therapy for sinusitis; the rash resolved after the drug was stopped. She now requires antibiotic therapy and asks about her penicillin allergy. Which of the following is the most appropriate next step?

  1. Permanently avoid all beta-lactams, including carbapenems
  2. Give a full 10-day course of oral amoxicillin immediately
  3. Perform penicillin skin testing to guide future use Correct answer.
  4. Obtain a serum tryptase level at the next reaction

Explanation

A benign delayed maculopapular eruption is a low-risk reaction, and penicillin skin testing followed by an observed graded challenge when indicated safely clarifies whether the patient can use beta-lactams. This avoids unnecessary use of broad-spectrum alternatives and reduces antimicrobial resistance, whereas labeling the patient as permanently allergic to all beta-lactams is unjustified.

Question 4Allergy and Immunology

A 19-year-old man has had two episodes of disseminated Neisseria meningitidis infection within 3 years despite appropriate treatment. Testing shows an undetectable total hemolytic complement (CH50), a normal alternative pathway hemolytic assay (AH50), and normal C3 and C4 levels. Which of the following best explains his susceptibility?

  1. Terminal complement deficiency Correct answer.
  2. Properdin deficiency
  3. C3 deficiency
  4. C1 esterase inhibitor deficiency

Explanation

An undetectable CH50 with a normal AH50 and normal C3/C4 localizes the defect to the terminal membrane attack complex (C5 through C9), which is required for serum killing of Neisseria species. Patients with terminal complement deficiency also warrant meningococcal vaccination and may benefit from prophylactic antibiotics.

Question 5Cardiovascular Disease

A 58-year-old man presents 40 minutes after the onset of substernal chest pressure. ECG shows 3 mm of ST elevation in leads V2 through V4, and the catheterization laboratory is available. What is the maximum recommended time from first medical contact to device activation (wire crossing) for primary percutaneous coronary intervention?

  1. 24 hours
  2. 30 minutes
  3. 90 minutes Correct answer.
  4. 150 minutes

Explanation

Primary PCI is the preferred reperfusion strategy for STEMI when it can be performed promptly, and the accepted goal is a first-medical-contact-to-device time of 90 minutes or less (120 minutes when transfer is required). Fibrinolysis is considered when PCI cannot be delivered within that window and symptoms began within 12 hours.

Question 6Cardiovascular Disease

A 70-year-old man with hypertension and diabetes mellitus has new nonvalvular atrial fibrillation. His CHA2DS2-VASc score is 2. Which management is most appropriate?

  1. Clopidogrel monotherapy
  2. Oral anticoagulation Correct answer.
  3. No antithrombotic therapy
  4. Aspirin 81 mg daily alone

Explanation

In nonvalvular atrial fibrillation, a CHA2DS2-VASc score of 2 or more in men (3 or more in women) is a clear indication for oral anticoagulation, which substantially reduces stroke risk. Aspirin and P2Y12 inhibitors are not adequate substitutes because they provide far less stroke protection.

Question 7Cardiovascular Disease

Which auscultatory finding is most characteristic of severe aortic stenosis?

  1. Crescendo–decrescendo systolic murmur radiating to the carotids Correct answer.
  2. Mid-diastolic rumble heard at the apex with an opening snap
  3. Holosystolic murmur at the apex radiating to the axilla
  4. Early diastolic decrescendo murmur along the left sternal border that worsens with handgrip

Explanation

Aortic stenosis produces a harsh crescendo–decrescendo systolic ejection murmur best heard at the right upper sternal border, with radiation to the carotids and a delayed, diminished carotid upstroke. The second heart sound is often paradoxically split and the murmur peaks later as stenosis worsens.

Question 8Cardiovascular Disease

A 32-year-old man has sharp pleuritic chest pain that worsens with inspiration and is relieved by sitting forward. ECG shows diffuse ST-segment elevation and PR-segment depression. Which treatment is most appropriate?

  1. Colchicine alone without anti-inflammatory therapy
  2. Pericardiocentesis
  3. Emergency coronary angiography
  4. Ibuprofen plus colchicine Correct answer.

Explanation

Acute viral or idiopathic pericarditis is treated with an NSAID plus colchicine, which reduces symptoms and recurrence. Colchicine is added to, not substituted for, anti-inflammatory therapy, and aspirin or an NSAID is the mainstay in most patients.

Question 9Cardiovascular Disease

A 55-year-old Black man with no diabetes and no chronic kidney disease has stage 2 hypertension. Which initial antihypertensive therapy is recommended?

  1. Thiazide diuretic or calcium channel blocker Correct answer.
  2. ACE inhibitor monotherapy in the absence of proteinuria
  3. Alpha-1 blocker monotherapy for initial blood pressure control
  4. Beta blocker as the preferred first-line agent in all patients

Explanation

For Black adults without CKD or diabetes, a thiazide-type diuretic or a dihydropyridine calcium channel blocker is the preferred initial therapy because renin-angiotensin blockade is less effective in this population. Two-drug combination therapy is often used when blood pressure is 20/10 mm Hg or more above goal.

Question 10Cardiovascular Disease

Which medication has been shown to reduce all-cause mortality in heart failure with reduced ejection fraction?

  1. Digoxin
  2. Furosemide
  3. Sacubitril–valsartan Correct answer.
  4. Amlodipine

Explanation

Sacubitril–valsartan is part of guideline-directed medical therapy for HFrEF and reduces cardiovascular death and heart failure hospitalization compared with enalapril. Beta blockers, mineralocorticoid receptor antagonists, and SGLT2 inhibitors similarly confer mortality benefit.

Question 11Cardiovascular Disease

A 62-year-old woman with a prior myocardial infarction has an LDL cholesterol of 130 mg/dL and takes no lipid-lowering therapy. What is the most appropriate regimen?

  1. No therapy because the LDL is below 160 mg/dL
  2. Ezetimibe monotherapy
  3. Moderate-intensity statin with a goal LDL below 100 mg/dL
  4. High-intensity statin with a goal LDL below 70 mg/dL Correct answer.

Explanation

Established ASCVD places the patient in the very-high-risk category, for which high-intensity statin therapy targeting an LDL-C reduction of at least 50% and an LDL-C level below 70 mg/dL is recommended. Ezetimibe or a PCSK9 inhibitor is added if LDL remains above goal.

Question 12Cardiovascular Disease

A 60-year-old man with hypertension has sudden tearing chest pain radiating to the back, with a blood pressure of 190/110 mm Hg in the right arm and 140/80 mm Hg in the left. Which is the most appropriate initial therapy?

  1. IV hydralazine to lower blood pressure rapidly as monotherapy
  2. IV beta blocker to lower heart rate and dP/dt Correct answer.
  3. Immediate thrombolysis
  4. IV heparin infusion

Explanation

In acute aortic dissection, an intravenous beta blocker is started first to reduce heart rate and the rate of pressure rise (dP/dt), followed by a vasodilator to bring systolic pressure to roughly 100–120 mm Hg. Anticoagulation and thrombolysis are contraindicated because they promote propagation and bleeding into the false lumen.

Question 13Cardiovascular Disease

A 25-year-old man has a systolic murmur that increases in intensity with the Valsalva maneuver and decreases with squatting. Which diagnosis is most likely?

  1. Ventricular septal defect
  2. Hypertrophic cardiomyopathy Correct answer.
  3. Mitral regurgitation
  4. Aortic regurgitation

Explanation

Dynamic left ventricular outflow tract obstruction in hypertrophic cardiomyopathy worsens when preload and afterload fall, so the murmur intensifies with Valsalva and standing and softens with squatting or handgrip. The murmur is typically harsh and heard at the left lower sternal border without radiation to the carotids.

Question 14Cardiovascular Disease

Which maneuver increases the intensity of a holosystolic murmur at the apex that radiates to the axilla?

  1. Isometric handgrip Correct answer.
  2. Valsalva maneuver
  3. Standing from a squatting position
  4. Amyl nitrite inhalation

Explanation

Mitral regurgitation is a systolic murmur that intensifies when afterload rises, as with isometric handgrip, because more blood is driven backward through the incompetent valve. Maneuvers that reduce preload, such as Valsalva and standing, soften the murmur.

Question 15Cardiovascular Disease

A 78-year-old woman is evaluated for syncope. ECG shows a ventricular rate of 38/min, P waves at 90/min with no consistent PR relationship, and a wide QRS complex. Which long-term therapy is most appropriate?

  1. Oral theophylline
  2. Atropine infusion
  3. Isoproterenol infusion
  4. Permanent pacemaker implantation Correct answer.

Explanation

Third-degree (complete) atrioventricular block with syncope is an indication for permanent pacing, which is the only definitive therapy. Chronotropic drugs are used only as temporary bridging measures while pacing is arranged.

Question 16Cardiovascular Disease

A hospitalized patient with a QTc of 560 ms develops polymorphic ventricular tachycardia with a twisting axis and hypotension. Which intravenous therapy is indicated?

  1. Diltiazem
  2. Magnesium sulfate Correct answer.
  3. Amiodarone
  4. Digoxin

Explanation

Torsades de pointes is treated with intravenous magnesium sulfate, correction of electrolyte deficits, and removal of QT-prolonging drugs; overdrive pacing or isoproterenol is used for recurrence. Drugs that further prolong the QT interval must be avoided.

Question 17Cardiovascular Disease

An 80-year-old woman taking digoxin presents with nausea and visual disturbance. The serum digoxin level is 4.0 ng/mL, potassium is 6.2 mEq/L, and she is hemodynamically unstable. Which therapy is most appropriate?

  1. Hemodialysis as the sole therapy
  2. Intravenous calcium gluconate
  3. Digoxin-specific Fab fragments Correct answer.
  4. Oral potassium binder alone

Explanation

Life-threatening digoxin toxicity with hyperkalemia and hemodynamic compromise is treated with digoxin-specific antibody fragments, which bind and neutralize the drug. Hyperkalemia in this setting reflects sodium-potassium ATPase inhibition and usually resolves with antidote therapy.

Question 18Cardiovascular Disease

Which physical finding is most consistent with cardiac tamponade?

  1. Pulsus paradoxus Correct answer.
  2. Pulsus bisferiens
  3. Wide pulse pressure
  4. Dicrotic pulse

Explanation

Pulsus paradoxus, an inspiratory decline in systolic pressure of more than 10 mm Hg, reflects exaggerated ventricular interdependence in tamponade. Other features include elevated jugular venous pressure, tachycardia, and muffled heart sounds.

Question 19Cardiovascular Disease

Which condition warrants antibiotic prophylaxis before dental procedures?

  1. Mitral valve prolapse with mild regurgitation
  2. Bicuspid aortic valve without stenosis
  3. Coronary artery bypass grafting
  4. Prosthetic aortic valve Correct answer.

Explanation

Prophylaxis before dental procedures is recommended for patients with prosthetic valves or prosthetic material used for valve repair, prior infective endocarditis, unrepaired cyanotic congenital heart disease, and repaired congenital defects with residual material. Most native valve lesions, including mild prolapse and bicuspid valves without significant disease, do not qualify.

Question 20Cardiovascular Disease

A patient presents with chest pain, and high-sensitivity troponin demonstrates a rise and fall with at least one value above the 99th percentile upper reference limit, accompanied by new ischemic ST-segment changes. Which diagnosis does this establish?

  1. Stable angina
  2. Acute myocardial infarction Correct answer.
  3. Musculoskeletal chest pain
  4. Gastroesophageal reflux disease

Explanation

The universal definition of myocardial infarction requires detection of a rise or fall in cardiac troponin with at least one value above the 99th percentile plus evidence of ischemia, such as ischemic symptoms, ECG changes, or imaging findings. A single static elevation without a dynamic pattern is less specific.

Question 21Cardiovascular Disease

A 45-year-old man has resistant hypertension while taking three agents including a diuretic, along with unprovoked hypokalemia. Which screening test is most appropriate?

  1. Renal artery duplex ultrasonography
  2. 24-hour urinary metanephrines
  3. Overnight dexamethasone suppression test
  4. Aldosterone-to-renin ratio Correct answer.

Explanation

Resistant hypertension with spontaneous or diuretic-induced hypokalemia should prompt screening for primary aldosteronism with a plasma aldosterone concentration and plasma renin activity ratio. An elevated aldosterone with suppressed renin is the hallmark, followed by confirmatory testing.

Question 22Cardiovascular Disease

Which finding is most characteristic of chronic severe aortic regurgitation?

  1. Systolic murmur that increases with Valsalva
  2. Wide pulse pressure with a water-hammer pulse Correct answer.
  3. Narrowed pulse pressure
  4. Pulsus parvus et tardus

Explanation

Chronic aortic regurgitation produces a large stroke volume ejected rapidly into the aorta and a low diastolic pressure from runoff, yielding a wide pulse pressure with a bounding, water-hammer pulse. Associated signs include head bobbing and an early diastolic decrescendo murmur.

Question 23Cardiovascular Disease

Which corrected QT interval on the ECG is associated with a markedly increased risk of torsades de pointes?

  1. 380 ms
  2. 500 ms Correct answer.
  3. 420 ms
  4. 340 ms

Explanation

A QTc above roughly 500 ms confers a substantially elevated risk of torsades de pointes, particularly when the interval prolongs further during therapy. Values in the 340–440 ms range are within the normal range for most adults.

Question 24Cardiovascular Disease

A 40-year-old woman with rheumatic mitral stenosis develops atrial fibrillation. Her CHA2DS2-VASc score is 1. Which management is most appropriate?

  1. Aspirin alone
  2. No antithrombotic therapy
  3. Long-term oral anticoagulation Correct answer.
  4. Anticoagulation only if she develops heart failure

Explanation

Moderate-to-severe rheumatic mitral stenosis is itself a risk factor that justifies long-term anticoagulation once atrial fibrillation develops, independent of the CHA2DS2-VASc score. Stroke risk in this setting is high, and antiplatelet therapy is inadequate.

Question 25Cardiovascular Disease

A 74-year-old man with dyspnea has an aortic valve area of 0.8 cm², a mean gradient of 22 mm Hg, and a left ventricular ejection fraction of 30%. Which test best distinguishes true severe aortic stenosis from pseudosevere stenosis?

  1. Dobutamine stress echocardiography Correct answer.
  2. Transesophageal echocardiography at rest
  3. Coronary angiography
  4. Cardiac MRI with late gadolinium enhancement and T2 mapping

Explanation

In low-flow, low-gradient aortic stenosis with reduced ejection fraction, dobutamine stress echocardiography assesses contractile reserve; if stroke volume and gradient rise while valve area remains small, stenosis is truly severe, whereas an increase in calculated valve area indicates pseudosevere stenosis. Patients without contractile reserve have a poor prognosis and require careful individualized decisions.

Question 26Cardiovascular Disease

A patient with a prior myocardial infarction has a wide-complex tachycardia at 170/min and is hemodynamically stable. The ECG shows AV dissociation and fusion beats. Which management is most appropriate?

  1. Vagal maneuvers
  2. Intravenous amiodarone Correct answer.
  3. Intravenous diltiazem
  4. Adenosine 6 mg IV push

Explanation

AV dissociation, fusion beats, and capture beats identify ventricular tachycardia, which in a stable patient is treated with intravenous amiodarone or another antiarrhythmic and preparation for synchronized cardioversion if instability develops. Verapamil and diltiazem are contraindicated because they can precipitate hemodynamic collapse in ventricular tachycardia.

Question 27Cardiovascular Disease

An 80-year-old man has heart failure with preserved ejection fraction, low-voltage limb leads on ECG despite 16 mm left ventricular wall thickness on echocardiography, and an apical-sparing longitudinal strain pattern. Which test is most useful to confirm the diagnosis?

  1. Cardiac MRI with late gadolinium enhancement and T2 mapping
  2. Coronary CT angiography
  3. Serum troponin and B-type natriuretic peptide levels
  4. 99mTc-pyrophosphate scintigraphy Correct answer.

Explanation

The combination of increased wall thickness with low-voltage ECG and apical-sparing strain suggests transthyretin cardiac amyloidosis, which can be confirmed noninvasively with technetium-99m pyrophosphate scintigraphy when a monoclonal protein has been excluded. Cardiac MRI with late gadolinium enhancement is supportive but less specific.

Question 28Cardiovascular Disease

A patient with prior mediastinal radiation has right-sided heart failure, a positive Kussmaul sign, and a pericardial knock. Echocardiography shows a septal bounce and prominent respiratory variation in mitral inflow velocities. Which diagnosis is most likely?

  1. Restrictive cardiomyopathy from amyloidosis
  2. Severe tricuspid regurgitation
  3. Right ventricular infarction
  4. Constrictive pericarditis Correct answer.

Explanation

Constrictive pericarditis classically follows mediastinal radiation or cardiac surgery and produces a pericardial knock, Kussmaul sign, septal bounce, and exaggerated ventricular interdependence with respiratory variation in inflow velocities. Imaging may show pericardial thickening or calcification.

Question 29Cardiovascular Disease

Which medication has been shown to reduce the combined risk of cardiovascular death or heart failure hospitalization in heart failure with preserved ejection fraction?

  1. Sacubitril–valsartan
  2. Empagliflozin Correct answer.
  3. Ivabradine
  4. Digoxin

Explanation

SGLT2 inhibitors such as empagliflozin and dapagliflozin reduce the composite of cardiovascular death or heart failure hospitalization in heart failure with preserved ejection fraction. They are now part of guideline-directed therapy across the spectrum of ejection fraction.

Question 30Cardiovascular Disease

Which electrocardiographic finding is most characteristic of acute pericarditis?

  1. New left bundle branch block with QRS duration greater than 140 ms
  2. Diffuse ST-segment elevation with PR-segment depression Correct answer.
  3. Peaked T waves with a shortened QT interval
  4. ST-segment elevation limited to the anterior leads with reciprocal inferior depression

Explanation

Acute pericarditis produces diffuse inflammation of the epicardium, so ST elevation appears in multiple, noncontiguous lead territories rather than in a single coronary distribution. Reciprocal PR-segment depression (and ST depression in aVR/V1) reflects atrial involvement. Coronary territory ST changes or new conduction block suggest ischemia instead.

Question 31Cardiovascular Disease

A 58-year-old man with an inferior ST-elevation myocardial infarction has a blood pressure of 82/54 mm Hg, an elevated jugular venous pressure, clear lung fields, and no pulsus paradoxus. Which is the most appropriate initial management?

  1. Intravenous isotonic saline bolus Correct answer.
  2. Emergent pericardiocentesis
  3. High-dose intravenous furosemide
  4. Sublingual nitroglycerin

Explanation

Hypotension with raised jugular venous pressure and clear lungs after an inferior infarction indicates right ventricular involvement, in which the right ventricle is preload dependent. Volume loading with isotonic saline supports cardiac output until reperfusion is achieved. Nitrates and diuretics reduce preload and can precipitate profound hypotension in this setting.

Question 32Cardiovascular Disease

A 52-year-old woman with HER2-positive breast cancer has received trastuzumab for four months. She develops progressive dyspnea, and echocardiography shows a left ventricular ejection fraction of 40%, decreased from 62% before therapy; there is no evidence of ischemia. Which is the most appropriate next step in management?

  1. Discontinue trastuzumab permanently without further cardiac therapy
  2. Hold trastuzumab and begin an ACE inhibitor with a beta blocker Correct answer.
  3. Continue trastuzumab and add a loop diuretic
  4. Reduce the trastuzumab dose and repeat a surveillance echocardiogram in six months

Explanation

Trastuzumab causes a typically reversible, non-ischemic cardiomyopathy, so the standard approach is to interrupt the drug and start guideline-directed heart failure therapy with an ACE inhibitor or ARB plus a beta blocker. Most patients recover ventricular function and can be rechallenged with trastuzumab under cardiac monitoring. Continuing the drug without heart failure therapy risks further decline.

Question 33Endocrinology, Diabetes, and Metabolism

A 24-year-old man with type 1 diabetes presents with nausea, vomiting, and abdominal pain. Glucose is 486 mg/dL, arterial pH is 7.12, serum bicarbonate is 9 mEq/L, and serum ketones are positive. Which of the following is the most appropriate initial intravenous fluid?

  1. 0.45% sodium chloride
  2. 5% dextrose in water
  3. 0.9% sodium chloride Correct answer.
  4. Sodium bicarbonate solution

Explanation

Patients in diabetic ketoacidosis are profoundly volume depleted, and isotonic saline is the fluid of choice for initial resuscitation because it restores intravascular volume and improves tissue perfusion while glucose falls. Dextrose-containing fluids are added only once the glucose has fallen to roughly 200 to 250 mg/dL, so that insulin can be continued without causing hypoglycemia. Bicarbonate is reserved for extreme acidemia and is not given routinely.

Question 34Endocrinology, Diabetes, and Metabolism

Using a standardized assay in a nonpregnant adult, which hemoglobin A1c value establishes the diagnosis of diabetes mellitus?

  1. 7.0%
  2. 8.0%
  3. 6.5% Correct answer.
  4. 5.7%

Explanation

An A1c of 6.5% or greater on a standardized assay is one of the accepted diagnostic criteria for diabetes, along with fasting glucose of 126 mg/dL or greater, a 2-hour glucose of 200 mg/dL or greater during an oral glucose tolerance test, or a random glucose of 200 mg/dL or greater with classic symptoms. An A1c between 5.7% and 6.4% defines prediabetes rather than diabetes.

Question 35Endocrinology, Diabetes, and Metabolism

A 45-year-old woman with primary hypothyroidism is starting levothyroxine. Which instruction about administration is most appropriate?

  1. Take it every other day to avoid overtreatment
  2. Take it at bedtime with a glass of milk
  3. Take it on an empty stomach before breakfast Correct answer.
  4. Take it with breakfast to improve absorption

Explanation

Levothyroxine absorption is reduced by food, calcium, iron, and fiber, so it is taken on an empty stomach 30 to 60 minutes before the morning meal or at bedtime several hours after the last meal. Daily dosing is required because the drug has a long half-life but must be given consistently to maintain euthyroidism. Consistent timing is also important because a change in administration alters the effective dose.

Question 36Endocrinology, Diabetes, and Metabolism

Which combination of laboratory findings is most consistent with the syndrome of inappropriate antidiuretic hormone secretion (SIADH)?

  1. Serum osmolality 300 mOsm/kg, urine osmolality 600 mOsm/kg, urine sodium 60 mEq/L
  2. Serum osmolality 250 mOsm/kg, urine osmolality 100 mOsm/kg, urine sodium 10 mEq/L
  3. Serum osmolality 250 mOsm/kg, urine osmolality 600 mOsm/kg, urine sodium 60 mEq/L Correct answer.
  4. Serum osmolality 300 mOsm/kg, urine osmolality 100 mOsm/kg, urine sodium 10 mEq/L

Explanation

SIADH causes hypotonic, euvolemic hyponatremia in which the urine is inappropriately concentrated (urine osmolality typically above 100 mOsm/kg and often above 300) and urinary sodium is high (usually above 30 mEq/L) because of continued renal sodium handling plus volume expansion. A low serum osmolality with a dilute urine instead suggests primary polydipsia or another cause of water excess with appropriate antidiuretic hormone suppression.

Question 37Endocrinology, Diabetes, and Metabolism

A 55-year-old asymptomatic man is newly diagnosed with type 2 diabetes; A1c is 7.6%, estimated glomerular filtration rate is 75 mL/min/1.73 m2, and he has no symptoms of hyperglycemia. Which is the most appropriate initial pharmacologic therapy?

  1. Metformin Correct answer.
  2. Pioglitazone
  3. Glipizide
  4. Insulin glargine

Explanation

Metformin is the preferred first-line agent for most patients with newly diagnosed type 2 diabetes because it is effective, weight-neutral, inexpensive, and not associated with hypoglycemia when used alone. It should be accompanied by lifestyle counseling. Insulin is generally reserved for patients with marked hyperglycemia, catabolic symptoms, or suspected type 1 diabetes.

Question 38Endocrinology, Diabetes, and Metabolism

A 30-year-old woman with type 1 diabetes is treated for diabetic ketoacidosis. Glucose is 520 mg/dL, pH 7.10, bicarbonate 8 mEq/L, and potassium 3.1 mEq/L. Which is the most appropriate next step in management?

  1. Give 50% dextrose and repeat the glucose in 1 hour
  2. Hold insulin and give intravenous potassium chloride Correct answer.
  3. Begin an insulin infusion now and recheck potassium in 4 hours
  4. Give intravenous sodium bicarbonate to correct the acidosis

Explanation

Total body potassium is depleted in ketoacidosis, and insulin shifts potassium into cells, so starting insulin when the serum potassium is below about 3.3 mEq/L can precipitate dangerous hypokalemia and cardiac arrhythmia. Insulin should be withheld until potassium has been repleted. Once potassium is above roughly 3.3 mEq/L, insulin and further potassium replacement proceed together.

Question 39Endocrinology, Diabetes, and Metabolism

A 42-year-old woman is found to have a 1.8-cm solid thyroid nodule that is hypoechoic on ultrasonography. She is asymptomatic, and her thyroid-stimulating hormone level is normal. Which is the most appropriate next step?

  1. Referral for total thyroidectomy
  2. Repeat ultrasonography in 12 months
  3. Radioiodine uptake scanning
  4. Fine-needle aspiration biopsy Correct answer.

Explanation

When the thyroid-stimulating hormone level is normal or high, a solid nodule of this size meets criteria for cytologic evaluation by fine-needle aspiration, which is the definitive test for malignancy risk. Radionuclide scanning is reserved for nodules accompanied by a suppressed thyroid-stimulating hormone level, where it distinguishes an autonomously functioning nodule from other causes of thyrotoxicosis.

Question 40Endocrinology, Diabetes, and Metabolism

Which of the following patients is the most appropriate candidate for screening for primary aldosteronism?

  1. A 55-year-old with well-controlled hypertension on a single agent
  2. A 45-year-old with hypertension and high plasma renin activity
  3. A 30-year-old with stage 1 hypertension and a normal serum potassium
  4. A 50-year-old with resistant hypertension and unprovoked hypokalemia Correct answer.

Explanation

Primary aldosteronism is screened for with a paired aldosterone and renin measurement in patients with resistant hypertension, spontaneous or diuretic-induced hypokalemia, an adrenal incidentaloma, obstructive sleep apnea, or a family history of early-onset hypertension. The characteristic pattern is a high aldosterone concentration with suppressed renin, giving an elevated aldosterone-to-renin ratio.

Question 41Endocrinology, Diabetes, and Metabolism

A 38-year-old woman presents with weight gain, plethoric facies, easy bruising, and proximal muscle weakness. Which is the most appropriate initial test to establish cortisol excess?

  1. Adrenal computed tomography
  2. Plasma ACTH concentration
  3. Pituitary magnetic resonance imaging
  4. 24-hour urine free cortisol Correct answer.

Explanation

Suspected Cushing syndrome is first evaluated with one of three confirmatory tests of cortisol excess: 24-hour urine free cortisol, late-night salivary cortisol, or the 1-mg overnight dexamethasone suppression test. Measurement of ACTH and imaging of the adrenal or pituitary glands are performed only after hypercortisolism has been biochemically confirmed, because they are used to determine the cause rather than to establish the diagnosis.

Question 42Endocrinology, Diabetes, and Metabolism

A 62-year-old woman has a serum calcium of 11.4 mg/dL, phosphate of 3.0 mg/dL, albumin of 4.0 g/dL, and a parathyroid hormone level of 110 pg/mL (normal 15 to 65). Which is the most likely diagnosis?

  1. Familial hypocalciuric hypercalcemia
  2. Primary hyperparathyroidism Correct answer.
  3. Hypercalcemia of malignancy
  4. Vitamin D intoxication

Explanation

Hypercalcemia accompanied by an elevated or inappropriately normal parathyroid hormone level indicates a parathyroid-dependent process, and primary hyperparathyroidism is by far the most common cause in outpatients. Malignancy and vitamin D excess raise calcium through parathyroid-independent mechanisms and suppress parathyroid hormone to the low end of the reference range.

Question 43Endocrinology, Diabetes, and Metabolism

A 28-year-old woman who is 8 weeks pregnant is newly diagnosed with Graves disease. Which medication is most appropriate?

  1. Radioactive iodine ablation
  2. Methimazole
  3. Observation alone until delivery
  4. Propylthiouracil Correct answer.

Explanation

Propylthiouracil is preferred during the first trimester because methimazole in early pregnancy is associated with a characteristic embryopathy that includes aplasia cutis and choanal or esophageal atresia. Many clinicians switch to methimazole after the first trimester to reduce the risk of propylthiouracil-related hepatotoxicity. Radioactive iodine is absolutely contraindicated during pregnancy.

Question 44Endocrinology, Diabetes, and Metabolism

A 64-year-old man with type 2 diabetes, heart failure with reduced ejection fraction (30%), and chronic kidney disease stage 3b (estimated glomerular filtration rate 35 mL/min/1.73 m2) has an A1c of 8.2% on metformin. Which addition would most reduce heart failure hospitalization and progression of kidney disease?

  1. Empagliflozin Correct answer.
  2. Glimepiride
  3. Sitagliptin
  4. Insulin degludec

Explanation

Sodium-glucose cotransporter-2 inhibitors reduce heart failure hospitalizations and slow progression of albuminuric chronic kidney disease independently of glycemic control, making them the preferred add-on in this patient with both heart failure and chronic kidney disease. Their benefit persists at reduced estimated glomerular filtration rates, although glucose-lowering efficacy declines.

Question 45Endocrinology, Diabetes, and Metabolism

A 55-year-old woman with primary hyperparathyroidism caused by a large adenoma undergoes parathyroidectomy. On the second postoperative day she reports perioral numbness and has carpopedal spasm with a serum calcium of 7.2 mg/dL. Which mechanism best explains her hypocalcemia?

  1. Rapid skeletal calcium uptake after prolonged PTH excess Correct answer.
  2. Reduced intestinal calcium absorption caused by a fall in phosphate
  3. Ischemic injury to the remaining glands that is usually permanent
  4. Fat saponification from postoperative acute pancreatitis

Explanation

After removal of a long-standing parathyroid adenoma, bone that has been chronically demineralized rapidly takes up calcium and phosphate, producing hungry bone syndrome with profound and sometimes prolonged hypocalcemia. Risk is greatest with large adenomas, elevated alkaline phosphatase, and marked preoperative bone disease, and treatment is oral or intravenous calcium plus calcitriol.

Question 46Endocrinology, Diabetes, and Metabolism

A 34-year-old man reports headaches and progressive loss of peripheral vision. Prolactin is 2,400 ng/mL and magnetic resonance imaging shows a 2.5-cm pituitary macroadenoma with suprasellar extension. Which is the most appropriate initial treatment?

  1. Octreotide
  2. Transsphenoidal surgical resection
  3. Cabergoline Correct answer.
  4. External beam radiation therapy

Explanation

Dopamine agonists such as cabergoline are first-line therapy for prolactinomas, including macroadenomas, because they shrink tumor volume and restore visual fields in most patients while normalizing prolactin. Surgery is reserved for intolerance or resistance to dopamine agonists, for apoplexy, or for residual tumor after medical therapy.

Question 47Endocrinology, Diabetes, and Metabolism

A 70-year-old woman with chronic hyponatremia from SIADH has a serum sodium of 108 mEq/L. During the first 12 hours of therapy, her sodium rises to 122 mEq/L. Which is the most appropriate management?

  1. Give oral sodium chloride tablets to complete the correction
  2. Start furosemide to increase free water clearance
  3. Continue current therapy and recheck the sodium in 24 hours
  4. Give desmopressin with free water to re-lower the sodium Correct answer.

Explanation

Correction of chronic hyponatremia should not exceed about 8 to 10 mEq/L in 24 hours, because a faster rise risks osmotic demyelination. When the limit is exceeded, the sodium is deliberately re-lowered by administering desmopressin to stop free water clearance together with free water (typically 5% dextrose) before the overcorrection is allowed to persist.

Question 48Endocrinology, Diabetes, and Metabolism

A 48-year-old woman has recurrent episodes of fasting hypoglycemia. During a supervised fast, glucose is 38 mg/dL with insulin 60 microU/mL, C-peptide 0.1 ng/mL, and low proinsulin. Which is the most likely cause?

  1. Adrenal insufficiency
  2. Sulfonylurea overdose
  3. Surreptitious insulin injection Correct answer.
  4. Insulinoma

Explanation

Exogenous insulin produces hypoglycemia with a high insulin level but suppressed endogenous secretion, reflected by a low C-peptide and low proinsulin. Endogenous hyperinsulinism, whether from an insulinoma or a sulfonylurea, raises both insulin and C-peptide because the beta cell secretes them together.

Question 49Endocrinology, Diabetes, and Metabolism

A 68-year-old man has an isolated alkaline phosphatase of 240 U/L with normal calcium, phosphate, and 25-hydroxyvitamin D. Radiographs show coarse trabeculae and cortical thickening of the pelvis. Which is the most appropriate treatment?

  1. Zoledronic acid Correct answer.
  2. Teriparatide
  3. Observation without therapy
  4. Calcitriol

Explanation

The findings are typical of Paget disease of bone, in which isolated alkaline phosphatase elevation with coarse trabeculae and cortical thickening reflects increased osteoclastic and osteoblastic activity. A potent intravenous bisphosphonate such as zoledronic acid is the treatment of choice for symptoms, involvement of weight-bearing bones or the skull, or preparation for surgery, and it normalizes bone turnover.

Question 50Endocrinology, Diabetes, and Metabolism

A 40-year-old woman presents with fatigue, weight loss, and generalized hyperpigmentation. Serum sodium is 128 mEq/L, potassium is 5.6 mEq/L, and glucose is 60 mg/dL. Which test is most appropriate to confirm the diagnosis?

  1. 1-mg overnight dexamethasone suppression test
  2. Midnight salivary cortisol
  3. Plasma renin activity
  4. Cosyntropin stimulation test Correct answer.

Explanation

Hyponatremia, hyperkalemia, hypoglycemia, and hyperpigmentation point to primary adrenal insufficiency, in which cortisol and aldosterone deficiency remove feedback inhibition of ACTH and melanocyte-stimulating hormone. The diagnosis is confirmed by a cosyntropin stimulation test showing a subnormal cortisol response, reflecting depleted adrenal reserve.