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Question 3301Question →

A 64-year-old man presents to the clinic for a health maintenance examination. He feels well and has no history of cardiovascular disease, chest pain, shortness of breath, or transient ischemic attacks. His medical history includes hypertension, hyperlipidemia, and type 2 diabetes mellitus. Current medications include lisinopril, metformin, and atorvastatin. Blood pressure is 128/78 mm Hg, and heart rate is 72/min. Recent laboratory studies show a hemoglobin A1c of 7.1% and an LDL cholesterol of 85 mg/dL. His calculated 10-year atherosclerotic cardiovascular disease (ASCVD) risk is 14%. The patient read a health newsletter recommending daily aspirin to prevent heart attacks and asks if he should start taking it. Which of the following is the most appropriate recommendation regarding antiplatelet therapy for this patient?

Show answer & explanation

Answer: Advise against initiating any antiplatelet therapy

Answer

Advise against initiating any antiplatelet therapy.
The correct recommendation is to advise against initiating any antiplatelet therapy. According to the updated 2022 United States Preventive Services Task Force (USPSTF) guidelines, initiating low-dose aspirin for the primary prevention of cardiovascular disease is not recommended in adults aged 60 years or older (Grade D recommendation). Although this patient has multiple risk factors (diabetes, hypertension) and a 10-year ASCVD risk greater than 10%, current evidence shows that for patients in this age group without established cardiovascular disease, the increased risk of significant bleeding (such as gastrointestinal bleeding and intracranial hemorrhage) cancels out or outweighs the potential cardiovascular benefit. He is already appropriately managed with a statin, ACE inhibitor, and metformin.

Step-by-Step Solution

1
Determine the indication for aspirin in this patient.
The patient has no history of cardiovascular disease, so the indication would be primary prevention.
Secondary prevention (e.g., prior MI or stroke) always requires antiplatelet therapy, while primary prevention depends on specific risk-benefit profiles.
2
Evaluate the patient's age and risk factors against current evidence-based guidelines.
The patient is 64 years old with a 14% ASCVD risk.
Age is the primary determining factor in the updated 2022 USPSTF guidelines for aspirin initiation.
3
Apply the guideline recommendation.
The USPSTF recommends against initiating low-dose aspirin for the primary prevention of cardiovascular disease in adults 60 years or older.
In this age cohort, the risk of serious bleeding (gastrointestinal and intracranial) outweighs the potential cardiovascular benefits of initiation.
4
Select the corresponding management step.
Advise against initiating any antiplatelet therapy.
Withholding aspirin is the guideline-concordant, evidence-based next step.

Key Concept

The USPSTF recommends against initiating low-dose aspirin use for the primary prevention of cardiovascular disease in adults 60 years or older due to bleeding risks outweighing benefits.
Question 3302Question →

A 59-year-old woman is admitted to the hospital with a 4-day history of worsening abdominal distention, increased lethargy, and confusion. She has a history of cirrhosis secondary to nonalcoholic steatohepatitis.

Home medications:
Spironolactone 100 mg100\text{ mg} daily
Furosemide 40 mg40\text{ mg} daily
Nadolol 40 mg40\text{ mg} daily

Vitals:
Temperature: 38.1∘C38.1^\circ\text{C} (100.6∘F100.6^\circ\text{F})
Blood pressure: 96/54 mmHg96/54\text{ mmHg}
Pulse: 108/min108/\text{min}
Respirations: 18/min18/\text{min}

Physical examination reveals scleral icterus and a distended abdomen with shifting dullness and diffuse mild tenderness to palpation. Neurologic examination is notable for lethargy, disorientation to time and place, and a bilateral flapping tremor of the hands when the wrists are extended.

Laboratory results:
Hemoglobin: 10.2 g/dL10.2\text{ g/dL}
Platelet count: 78,000/mm378,000/\text{mm}^3
Leukocyte count: 11,500/mm311,500/\text{mm}^3
Sodium: 131 mEq/L131\text{ mEq/L}
Potassium: 3.4 mEq/L3.4\text{ mEq/L}
Blood urea nitrogen: 38 mg/dL38\text{ mg/dL}
Creatinine: 1.8 mg/dL1.8\text{ mg/dL} (baseline 0.9 mg/dL0.9\text{ mg/dL})
Total bilirubin: 4.2 mg/dL4.2\text{ mg/dL}
International normalized ratio (INR): 1.91.9

Diagnostic paracentesis is performed, yielding cloudy yellow fluid. Ascitic fluid analysis reveals an absolute neutrophil count of 450/mm3450/\text{mm}^3.

Which of the following pharmacologic interventions should be initiated in this patient? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Intravenous cefotaxime; Intravenous albumin; Oral lactulose

Answer

The correct interventions are intravenous cefotaxime, intravenous albumin, and oral lactulose.
The correct options comprise the standard multi-modal therapy for this patient's decompensated cirrhosis. The ascitic fluid absolute neutrophil count of 450/mm3450/\text{mm}^3 confirms spontaneous bacterial peritonitis (SBP), which requires immediate empiric treatment with a third-generation cephalosporin, such as intravenous cefotaxime. Additionally, patients with SBP are at high risk for developing hepatorenal syndrome due to splanchnic vasodilation and effective arterial blood volume depletion. Intravenous albumin is indicated to prevent this complication in SBP patients who meet specific high-risk criteria (creatinine >1.0 mg/dL> 1.0\text{ mg/dL}, BUN >30 mg/dL> 30\text{ mg/dL}, or total bilirubin >4.0 mg/dL> 4.0\text{ mg/dL}); this patient meets all three. Finally, the patient's confusion, lethargy, and asterixis (flapping tremor) indicate concurrent hepatic encephalopathy, which is often precipitated by infections like SBP. Oral lactulose is the first-line pharmacologic intervention to reduce intestinal ammonia absorption and improve neurologic status.

Step-by-Step Solution

1
Evaluate the clinical presentation and laboratory findings to identify all acute complications of cirrhosis.
The patient has spontaneous bacterial peritonitis (ascitic neutrophil count ≥250/mm3\ge 250/\text{mm}^3), hepatic encephalopathy (asterixis, lethargy), and acute kidney injury (creatinine increased to 1.8 mg/dL1.8\text{ mg/dL} from a baseline of 0.9 mg/dL0.9\text{ mg/dL}).
Accurate diagnosis of concurrent complications is required to select appropriate multi-modal pharmacologic therapy.
2
Select the appropriate pharmacologic intervention for spontaneous bacterial peritonitis (SBP).
Intravenous cefotaxime is indicated.
Third-generation cephalosporins are the recommended first-line empiric antimicrobial therapy for SBP.
3
Assess the need for adjuvant therapy to prevent hepatorenal syndrome in the setting of SBP.
Intravenous albumin is indicated.
Guidelines strongly recommend albumin infusion for SBP patients who meet specific high-risk criteria (creatinine >1.0 mg/dL> 1.0\text{ mg/dL}, BUN >30 mg/dL> 30\text{ mg/dL}, or total bilirubin >4.0 mg/dL> 4.0\text{ mg/dL}). This patient meets all three criteria.
4
Select the appropriate pharmacologic intervention for hepatic encephalopathy.
Oral lactulose is indicated.
Lactulose reduces intestinal ammonia production and absorption, serving as the first-line medical treatment for hepatic encephalopathy.
5
Identify and exclude contraindicated or inappropriate interventions.
Furosemide and fresh frozen plasma should not be initiated.
Diuretics will worsen the acute kidney injury and hypoperfusion. Fresh frozen plasma is unnecessary for an isolated elevated INR without active bleeding.

Key Concept

Pharmacologic management of decompensated cirrhosis with spontaneous bacterial peritonitis (SBP) requires immediate empiric antibiotics (e.g., cefotaxime), intravenous albumin for renal protection, and lactulose for concurrent hepatic encephalopathy, while avoiding medications that exacerbate renal hypoperfusion.
Estimated Time:2m 0s
Question 3303Question →

A 72-year-old woman is brought to the emergency department by her daughter due to a 2-day history of persistent nausea, vomiting, and profound generalized weakness. The patient also reports seeing "yellow halos" around lights in her home. Her medical history includes heart failure with reduced ejection fraction, atrial fibrillation, and hypertension. Her daily medications are digoxin, furosemide, lisinopril, and rivaroxaban. Vital signs show a heart rate of 48/min and blood pressure of 105/65 mm Hg. Physical examination reveals a lethargic woman with dry mucous membranes.

Laboratory studies reveal:
TestResult
Sodium134 mEq/L
Potassium3.0 mEq/L
Chloride98 mEq/L
Bicarbonate26 mEq/L
Blood urea nitrogen42 mg/dL
Creatinine1.9 mg/dL (baseline 1.1 mg/dL)

Which of the following are appropriate next steps in the evaluation and management of this patient? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Obtain a 12-lead electrocardiogram; Measure serum digoxin concentration

Answer

The appropriate next steps are to obtain a 12-lead electrocardiogram and measure the serum digoxin concentration.
The patient's presentation of nausea, vomiting, lethargy, visual changes ('yellow halos'), and significant bradycardia is highly suspicious for digoxin toxicity. This toxicity is likely precipitated by acute kidney injury (which reduces digoxin clearance) and concurrent hypokalemia from furosemide use (which increases myocardial sensitivity to digoxin). The most critical initial steps in evaluating and monitoring this patient are to obtain a serum digoxin concentration to definitively confirm the diagnosis, and a 12-lead electrocardiogram to evaluate for potentially life-threatening arrhythmias (such as advanced atrioventricular block or ventricular tachycardia). Additionally, potassium should be carefully but promptly repleted, as hypokalemia exacerbates the toxicity.

Step-by-Step Solution

1
Identify the primary clinical syndrome
The patient presents with gastrointestinal symptoms, specific visual disturbances ('yellow halos'), and bradycardia in the setting of digoxin use.
These findings represent the classic presentation of acute-on-chronic digoxin toxicity.
2
Analyze contributing laboratory factors
The patient has hypokalemia (3.0 mEq/L) and acute kidney injury (creatinine 1.9 mg/dL).
Acute kidney injury decreases digoxin renal clearance, leading to accumulation. Hypokalemia increases digoxin binding to the Na+/K+-ATPase pump, severely exacerbating its toxic effects.
3
Determine immediate monitoring and management steps
Order a 12-lead ECG and a serum digoxin level.
An ECG is mandatory to assess for life-threatening arrhythmias (such as atrioventricular block or ventricular arrhythmias). Serum levels confirm the diagnosis and help determine if digoxin-specific antibody fragments are indicated.

Key Concept

The initial evaluation and monitoring of digoxin toxicity involves confirming serum levels, assessing for arrhythmias with an electrocardiogram, and aggressively correcting exacerbating electrolyte abnormalities such as hypokalemia.
Estimated Time:1m 30s
Question 3304Question →

A 6868-year-old man is evaluated on hospital day 33 for acute decompensated heart failure. On admission, he had severe dyspnea, orthopnea, and 3+3+ bilateral lower extremity edema. He was initiated on intravenous bumetanide. Over the past 4848 hours, his total urine output has been 6,500 mL6,500\text{ mL}, and his weight has decreased from 92 kg92\text{ kg} to 86 kg86\text{ kg}. Today, the patient reports significant improvement in his breathing and is able to lie flat comfortably. Physical examination shows clear lungs bilaterally and trace lower extremity edema. Vital signs are temperature 37.0∘C37.0^\circ\text{C} (98.6∘F98.6^\circ\text{F}), blood pressure 112/70 mmHg112/70\text{ mmHg}, and heart rate 82/min82/\text{min}.

Laboratory studies today:
Blood urea nitrogen: 54 mg/dL54\text{ mg/dL} (baseline 24 mg/dL24\text{ mg/dL})
Serum creatinine: 2.3 mg/dL2.3\text{ mg/dL} (baseline 1.2 mg/dL1.2\text{ mg/dL})

Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Hold intravenous bumetanide and monitor renal function

Answer

The correct answer is to hold intravenous bumetanide and monitor renal function.
The patient has experienced significant diuresis, evidenced by a 6 kg6\text{ kg} weight loss, 6,500 mL6,500\text{ mL} urine output, and resolution of his heart failure symptoms. However, his new laboratory findings show an acute rise in blood urea nitrogen and serum creatinine, with a BUN-to-creatinine ratio greater than 20:120:1. This pattern clearly indicates prerenal acute kidney injury secondary to intravascular volume depletion from aggressive diuresis. Because the patient is clinically euvolemic (clear lungs, breathing comfortably flat), the most appropriate next step in treatment evaluation is to hold the loop diuretic. This approach prevents further volume depletion and allows renal perfusion to recover, while strictly observing the patient to ensure he does not slip back into volume overload.

Step-by-Step Solution

1
Assess the patient's clinical volume status based on symptoms and physical exam.
The patient can lie flat comfortably, has clear lungs, and has trace edema, indicating successful resolution of volume overload.
Clinical assessment is the primary driver for determining if ongoing diuresis is necessary.
2
Evaluate the new laboratory findings in the context of recent therapy.
BUN has increased to 54 mg/dL54\text{ mg/dL} and creatinine to 2.3 mg/dL2.3\text{ mg/dL} (BUN:Cr ratio >20:1> 20:1).
To identify any adverse effects of aggressive diuresis, specifically prerenal acute kidney injury.
3
Determine the safest and most appropriate intervention to address the acute kidney injury.
Hold the intravenous loop diuretic and monitor the patient.
The patient is clinically euvolemic, and pausing the diuretic allows intravascular volume to equilibrate and renal perfusion to recover without risking recurrent heart failure.

Key Concept

In patients receiving aggressive diuresis for heart failure, the development of prerenal acute kidney injury (elevated BUN and creatinine) with clinical euvolemia indicates overdiuresis, and the appropriate management is to hold the diuretic rather than administer intravenous fluids.
Estimated Time:1m 15s
Question 3305Question →

A 74-year-old man is brought to the clinic by his son for a routine health maintenance visit. The patient has a history of severe chronic obstructive pulmonary disease requiring continuous home oxygen, New York Heart Association class IV heart failure, and stage 4 chronic kidney disease. Over the past 12 months, he has been hospitalized four times for cardiopulmonary exacerbations. He is wheelchair-bound and requires assistance with most activities of daily living. He has a 55 pack-year smoking history and continues to smoke several cigarettes daily. His most recent preventive screenings included a normal colonoscopy at age 64 and a negative low-dose chest computed tomography scan 2 years ago. The son asks which cancer screenings his father should undergo today. Which of the following is the most appropriate recommendation?

Show answer & explanation

Answer: Advise that no routine cancer screenings are indicated at this time

Answer

Advise that no routine cancer screenings are indicated at this time.
The correct action is to discontinue routine cancer screening. While this patient's age (74) and smoking history (55 pack-years, active smoker) place him in the demographic that typically requires lung and colorectal cancer screening, preventive care must always be contextualized to the individual patient's overall prognosis. The USPSTF guidelines for lung cancer screening explicitly state that screening should be discontinued if a patient develops a health problem that substantially limits life expectancy or the ability and willingness to undergo curative lung surgery. Similarly, colorectal cancer screening is generally not recommended when life expectancy is less than 10 years, as the time to realize a mortality benefit from removing a pre-malignant polyp exceeds the patient's projected lifespan. Given this patient's oxygen-dependent COPD, NYHA class IV heart failure, and stage 4 CKD, his life expectancy is severely truncated, and he would not be a candidate for surgical resection. Therefore, the potential harms of screening (anxiety, procedural complications, overdiagnosis) far outweigh any possible benefits.

Step-by-Step Solution

1
Assess the patient's age and baseline risk factors for cancer.
The patient is 74 years old with a heavy smoking history, which mechanically qualifies him for lung and colorectal cancer screening based on age and exposure alone.
To determine baseline guideline applicability before adjusting for individual clinical factors.
2
Evaluate the patient's overall health status, life expectancy, and ability to undergo curative treatment.
The patient has end-stage COPD, severe heart failure, CKD stage 4, and poor functional status, indicating a severely limited life expectancy (likely less than 1-2 years) and an inability to tolerate major surgery.
Cancer screening guidelines (such as those from the USPSTF) include critical caveats regarding life expectancy and surgical candidacy.
3
Synthesize risk factors with the patient's prognosis to determine the appropriate screening plan.
Routine screening should be discontinued because the harms of screening (including follow-up testing and potential procedures) outweigh the benefits in a patient with a severely limited life expectancy.
The goal of screening is to decrease long-term mortality, which is impossible if the patient will likely succumb to other severe comorbidities before a cancer would become clinically significant.

Key Concept

Discontinuation of cancer screening based on limited life expectancy and severe comorbidities
Estimated Time:1m 15s
Question 3306Question →

A 5858-year-old man presents to the emergency department with a 22-day history of nausea, vomiting, abdominal pain, and poor oral intake. He has a history of type 2 diabetes mellitus, hypertension, and hyperlipidemia. His medications include metformin, dapagliflozin, lisinopril, and atorvastatin.

Temperature is 37.1∘37.1^\circ C (98.8∘98.8^\circ F), blood pressure is 102/64102/64 mmHg, pulse is 112112/min, and respirations are 2424/min. Physical examination shows dry mucous membranes and diffuse mild abdominal tenderness without rebound or guarding.

Laboratory studies show:
Na +^+: 132132 mEq/L
K +^+: 4.84.8 mEq/L
Cl −^-: 9898 mEq/L
HCO 3−_3^-: 1414 mEq/L
Urea nitrogen (BUN): 3838 mg/dL
Creatinine: 1.61.6 mg/dL
Glucose: 185185 mg/dL
Ketones: Positive

Arterial blood gas on room air:
pH: 7.247.24
pCO 2_2: 2828 mmHg
pO 2_2: 9595 mmHg

Which of the following intravenous regimens is the most appropriate pharmacologic management for this patient?

Show answer & explanation

Answer: Continuous regular insulin, 5%5\% dextrose, and normal saline

Answer

Continuous regular insulin, 5%5\% dextrose, and normal saline
The patient presents with a high anion gap metabolic acidosis, ketonemia, and a relatively normal blood glucose level (185185 mg/dL) in the setting of recent poor oral intake and use of an SGLT2 inhibitor (dapagliflozin). This is classic for euglycemic diabetic ketoacidosis (DKA). SGLT2 inhibitors cause significant urinary glucose loss, lowering serum glucose and subsequently decreasing endogenous insulin secretion while increasing glucagon secretion. This hormonal shift stimulates lipolysis and ketogenesis, leading to DKA without marked hyperglycemia. The cornerstone of DKA management is fluid resuscitation and continuous intravenous regular insulin to halt ketogenesis. However, because the patient's blood glucose is already below the typical 200200-250250 mg/dL threshold, initiating insulin without concurrent dextrose will precipitate severe hypoglycemia. Therefore, the most appropriate pharmacologic regimen must simultaneously include continuous intravenous regular insulin, normal saline for volume expansion, and 5%5\% dextrose to maintain euglycemia while the insulin clears the ketones.

Step-by-Step Solution

1
Calculate the anion gap and identify the primary acid-base disorder.
Anion gap = 132−(98+14)=20132 - (98 + 14) = 20 mEq/L. Combined with pH 7.247.24, this indicates a high anion gap metabolic acidosis.
Determining the acid-base disorder is the first step in diagnosing the cause of the patient's presentation.
2
Correlate the metabolic acidosis with the clinical history and medication list.
The presence of positive ketones, use of dapagliflozin, and blood glucose <250< 250 mg/dL establishes the diagnosis of euglycemic diabetic ketoacidosis (DKA).
SGLT2 inhibitors are a known trigger for euglycemic DKA, particularly during periods of decreased oral intake or acute illness.
3
Select the appropriate fluid and insulin regimen based on the patient's blood glucose level.
Because the blood glucose is 185185 mg/dL (below the typical 200200-250250 mg/dL threshold), the regimen must include dextrose alongside continuous IV insulin and normal saline.
Insulin is required to suppress ketogenesis, but dextrose is necessary to prevent insulin-induced hypoglycemia.

Key Concept

Euglycemic Diabetic Ketoacidosis (DKA) Management
Estimated Time:2m 0s
Question 3307Question →

For each patient presenting to the ambulatory primary care clinic for a health maintenance examination, select the most appropriate guideline-concordant preventive screening or intervention.

Click a left item, then click its matching right item

Items

A 21-year-old asymptomatic woman who is sexually active with a new male partner.
A 38-year-old asymptomatic woman whose mother was diagnosed with advanced colorectal cancer at age 48.
A 68-year-old man with a history of hypertension, active smoking, and an estimated 10-year ASCVD risk of 14%.
A 28-year-old healthy man who reports having unprotected insertive and receptive anal intercourse with multiple male partners.

Matches

Show answer & explanation

Answer

The clinical scenarios correctly match with their specific preventive interventions based on USPSTF and specialty society guidelines regarding patient age, family history, and sexual risk factors.
Each match accurately reflects current evidence-based guidelines. The 21-year-old woman falls into the <25 sexually active cohort requiring annual CT/GC screening. The 38-year-old woman meets criteria for early colorectal screening due to a first-degree relative diagnosed at 48. The 68-year-old man meets ASCVD threshold (>10%) and age criteria for statin initiation. The 28-year-old MSM requires comprehensive, multi-site STI testing due to high-risk exposures.

Step-by-Step Solution

1
Evaluate the 21-year-old woman's demographic profile and sexual history.
She is a sexually active woman under the age of 25.
This categorizes her into the universally recommended annual screening population for Chlamydia and Gonorrhea.
2
Analyze the 38-year-old woman's family history of colorectal cancer.
She has a first-degree relative diagnosed before age 60 (at age 48).
High-risk familial colorectal cancer requires screening at age 40 or 10 years before the relative's diagnosis (age 38), prompting immediate colonoscopy.
3
Assess the 68-year-old man's cardiovascular risk.
He is between 40-75 years old, has CVD risk factors, and an ASCVD risk >10%.
These criteria satisfy the Grade B USPSTF recommendation to initiate a low- to moderate-intensity statin.
4
Review the 28-year-old man's sexual exposure history.
He is an MSM engaging in unprotected receptive and insertive anal intercourse.
Standard urine/genital STI screening is insufficient; comprehensive screening including extragenital (pharyngeal/rectal) sites and blood-borne pathogens (HIV, Syphilis) is mandatory.

Key Concept

Application of tailored preventive care and screening guidelines based on age, sex, family history, and specific clinical risk factors.
Question 3308Question →

A 42-year-old woman is brought to the emergency department by her husband due to severe confusion, agitation, and recurrent vomiting for the past 24 hours. She was diagnosed with Graves disease two years ago but has not taken any medications for the past six months. Temperature is 39.8°C (103.6°F), blood pressure is 155/65 mm Hg, pulse is 152/min and irregular, and respirations are 26/min. Physical examination shows a confused, diaphoretic woman with a diffusely enlarged, non-tender thyroid gland, bilateral proptosis, and severe fine resting tremor. ECG shows atrial fibrillation with rapid ventricular response. A diagnosis of thyroid storm is made, and the patient is admitted to the intensive care unit.

Arrange the following pharmacologic interventions in the most appropriate chronological order of administration for this patient's comprehensive management, from initial acute stabilization to long-term definitive therapy.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological sequence is: Intravenous propranolol, followed by Oral propylthiouracil (PTU), then Oral potassium iodide, and finally Radioactive iodine ablation.
The management of thyroid storm requires a strict sequence of pharmacologic blockade targeting different pathophysiological steps. First, peripheral adrenergic effects are controlled immediately with a beta-blocker (propranolol). Second, new hormone synthesis is blocked with a thioamide (PTU). Third, the release of preformed hormone is blocked with iodine (potassium iodide), which must be given at least 1 hour after the thioamide to prevent it from being used as a substrate for new hormone synthesis. Finally, after the acute crisis resolves and the patient is euthyroid (often weeks later), definitive therapy with radioactive iodine ablation or surgery is performed.

Step-by-Step Solution

1
Administer intravenous propranolol.
Heart rate decreases and adrenergic symptoms are controlled.
Immediate life-threatening cardiovascular and sympathetic manifestations must be managed first to prevent hemodynamic collapse.
2
Administer oral propylthiouracil (PTU).
Thyroid hormone synthesis is halted at the follicular level.
PTU blocks thyroid peroxidase and prevents synthesis of new hormone. It also blocks peripheral T4 to T3 conversion. It must be in the system before introducing exogenous iodine.
3
Administer oral potassium iodide.
Release of preformed thyroid hormone from the gland is blocked.
Must be given at least 1 hour after PTU to prevent the iodine from being utilized as a substrate for new hormone synthesis, exploiting the Wolff-Chaikoff effect safely.
4
Perform radioactive iodine ablation.
Definitive destruction of the hyperactive thyroid tissue is achieved.
Only safe to perform on an outpatient basis weeks later once the patient is euthyroid, to prevent radiation-induced thyroiditis from triggering another thyrotoxic crisis.

Key Concept

Chronological pharmacologic management of thyroid storm
Question 3309Question →

A 48-year-old man comes to the clinic for a routine follow-up examination. Three months ago, he was diagnosed with type 2 diabetes mellitus and started on metformin. He reports that he has been adherent to his medication and has started a structured exercise program. He has no other medical conditions. He does not use tobacco or illicit drugs, and drinks alcohol occasionally. His blood pressure is 126/78 mm Hg, pulse is 76/min, and BMI is 29 kg/m2. Recent laboratory studies show a hemoglobin A1c of 6.8%. His vaccination records indicate that he received all standard childhood vaccines, a tetanus-diphtheria-acellular pertussis (Tdap) booster 3 years ago, a hepatitis B vaccine series in his twenties, and the seasonal influenza vaccine 1 month ago. He has never received a pneumococcal vaccine. Which of the following is the most appropriate recommendation regarding pneumococcal immunization for this patient?

Show answer & explanation

Answer: Administer a single dose of the 20-valent pneumococcal conjugate vaccine (PCV20)

Answer

Administer a single dose of the 20-valent pneumococcal conjugate vaccine (PCV20)
The correct answer is to administer a single dose of the 20-valent pneumococcal conjugate vaccine (PCV20). According to current Advisory Committee on Immunization Practices (ACIP) guidelines, adults aged 19 to 64 years with specific underlying medical conditions (including diabetes mellitus, chronic heart, liver, or lung disease, alcoholism, and cigarette smoking) are at increased risk for invasive pneumococcal disease. If they have not previously received a pneumococcal vaccine, they should receive either a single dose of PCV20 OR a single dose of PCV15 followed by a dose of PPSV23 at least one year later. Because this 48-year-old patient has newly diagnosed type 2 diabetes and is pneumococcal vaccine-naïve, a single dose of PCV20 is the most appropriate next step in his preventive care.

Step-by-Step Solution

1
Identify the patient's age and clinical risk factors for vaccine-preventable diseases.
The patient is a 48-year-old adult with a recent diagnosis of type 2 diabetes mellitus.
Age and specific comorbid conditions dictate the indications and timing for adult immunizations.
2
Determine the patient's previous pneumococcal vaccination history.
The patient has never received any pneumococcal vaccine.
Vaccination history determines whether an initial series or follow-up booster doses are required.
3
Apply current ACIP guidelines for pneumococcal vaccination in at-risk adults.
Adults aged 19-64 with diabetes who are pneumococcal vaccine-naïve should receive either a single dose of PCV20 or a single dose of PCV15 followed by PPSV23.
Diabetes places the patient at higher risk for invasive pneumococcal disease, necessitating early immunization with current higher-valent vaccines.

Key Concept

Adults aged 19-64 years with specific underlying medical conditions (such as diabetes mellitus) should receive either a single dose of PCV20 OR a dose of PCV15 followed by PPSV23 at least one year later.
Question 3310Question →

An emergency medical services team transports a 72-year-old male resident of an assisted living facility to the hospital for evaluation of worsening confusion, productive cough, and subjective fevers over the last 72 hours. His medical history includes paroxysmal atrial fibrillation, heart failure with preserved ejection fraction, and type 2 diabetes mellitus. His prescribed medications are amiodarone, apixaban, empagliflozin, and metformin. He has no known drug allergies and has not required antimicrobial therapy or hospitalization in the past twelve months.

Upon assessment in the emergency department, his temperature is 38.8°C (101.8°F), blood pressure is 112/68 mm Hg, heart rate is 108/min and irregularly irregular, respiratory rate is 24/min, and oxygen saturation is 92% on 2 L/min of supplemental oxygen via nasal cannula. Auscultation of the lungs reveals bronchial breath sounds and crackles over the left lower lung zones.

Pertinent laboratory values include:
Leukocyte count: 15,500/mm³
Serum creatinine: 1.1 mg/dL
Blood urea nitrogen: 28 mg/dL

A chest radiograph confirms a left lower lobe consolidation. A 12-lead electrocardiogram demonstrates atrial fibrillation with a ventricular rate of 105/min and a corrected QT (QTc) interval of 535 msec. The patient is admitted to the general medical ward for the treatment of community-acquired pneumonia. Which of the following is the most appropriate empiric antimicrobial regimen for this patient?

Show answer & explanation

Answer: Ceftriaxone and doxycycline

Answer

Ceftriaxone and doxycycline is the most appropriate empiric antimicrobial regimen because it provides complete coverage for community-acquired pneumonia pathogens while avoiding medications that prolong the QTc interval.
The correct answer combines a beta-lactam (ceftriaxone) with doxycycline. This patient is admitted with community-acquired pneumonia (CAP) and requires empiric coverage for both typical and atypical pathogens. The standard of care for inpatient, non-severe CAP is a beta-lactam plus a macrolide, or a respiratory fluoroquinolone. However, this patient has a baseline QTc interval of 535 msec (normal is less than 440 msec in men) and is on amiodarone, a known QTc-prolonging agent. Both macrolides (e.g., azithromycin) and fluoroquinolones (e.g., levofloxacin) prolong the QTc interval and can precipitate Torsades de pointes. Doxycycline provides excellent atypical coverage and does not affect the QTc interval, making this combination the safest and most effective choice.

Step-by-Step Solution

1
Diagnose the clinical syndrome and determine the required setting of care.
The patient has community-acquired pneumonia requiring inpatient admission to the general medical ward.
The patient presents with fever, productive cough, left lower lobe consolidation, and confusion.
2
Identify the standard empiric antimicrobial regimens for this condition.
Standard inpatient regimens include a beta-lactam plus a macrolide (e.g., ceftriaxone and azithromycin) or a respiratory fluoroquinolone (e.g., levofloxacin).
Coverage for both typical (S. pneumoniae, H. influenzae) and atypical (Mycoplasma, Legionella, Chlamydia) pathogens is necessary.
3
Evaluate the patient for specific contraindications to standard therapies.
The patient has a severely prolonged QTc interval (535 msec) and takes amiodarone.
Both macrolides and fluoroquinolones prolong the QTc interval, putting the patient at high risk for fatal arrhythmias such as Torsades de pointes.
4
Select the safest alternative regimen that provides the necessary microbiological coverage.
Ceftriaxone combined with doxycycline.
Doxycycline covers atypical pathogens but does not prolong the QTc interval, making it the safest choice for this specific patient.

Key Concept

In patients hospitalized with community-acquired pneumonia who have a prolonged QTc interval or are taking QTc-prolonging medications, a beta-lactam combined with doxycycline is the preferred empiric regimen to cover atypical pathogens while minimizing the risk of Torsades de pointes.
Question 3311Question →

A 34-year-old man is evaluated in the psychiatric clinic for a routine follow-up visit. He has a 10-year history of schizophrenia. Over the past several years, he has continued to experience frequent auditory hallucinations, profound negative symptoms, and persecutory delusions despite documented medication adherence and adequate therapeutic trials of olanzapine, risperidone, and haloperidol. The physician and patient agree to initiate clozapine therapy.

As part of this patient's long-term management, which of the following laboratory parameters require routine ongoing monitoring? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Absolute neutrophil count; Fasting blood glucose; Fasting lipid panel

Answer

The parameters that require routine ongoing monitoring for a patient on clozapine are the absolute neutrophil count, fasting blood glucose, and fasting lipid panel.
The correct options reflect the major risks associated with clozapine therapy: severe neutropenia and metabolic syndrome. To mitigate the risk of potentially fatal agranulocytosis, absolute neutrophil count monitoring is strictly mandated by the national REMS program. Furthermore, clozapine is highly obesogenic and carries a substantial risk of inducing diabetes and dyslipidemia. This necessitates routine ongoing monitoring of both fasting blood glucose and a fasting lipid panel to ensure timely intervention if metabolic derangements occur.

Step-by-Step Solution

1
Identify the indication and newly prescribed medication.
The patient has treatment-resistant schizophrenia and is starting clozapine.
Establishing the specific pharmacotherapy is necessary to determine the appropriate monitoring protocol.
2
Recall the unique adverse effect profile of the prescribed medication.
Clozapine is highly effective but carries a boxed warning for severe neutropenia (agranulocytosis) and has a high propensity for causing metabolic syndrome.
Monitoring requirements are directly derived from the drug's known, high-risk safety profile.
3
Determine the required evidence-based laboratory monitoring parameters.
The REMS program mandates regular monitoring of the absolute neutrophil count. Furthermore, clinical guidelines require longitudinal tracking of metabolic parameters, specifically fasting blood glucose and a fasting lipid panel.
Adherence to these monitoring guidelines prevents life-threatening hematologic complications and manages long-term cardiovascular risk.

Key Concept

Patients prescribed clozapine require mandatory routine monitoring of their absolute neutrophil count to prevent agranulocytosis, as well as periodic assessment of fasting blood glucose and lipids due to a significantly elevated risk of metabolic syndrome.
Question 3312Question →

A 6868-year-old woman is evaluated in the emergency department for a 33-day history of fever, chills, right flank pain, and dysuria. Her medical history is significant for type 22 diabetes mellitus, essential hypertension, and stage 3a3\text{a} chronic kidney disease with a baseline serum creatinine of 1.4 mg/dL1.4 \text{ mg/dL}. Her daily home medications include metformin, lisinopril, empagliflozin, and atorvastatin.

Vital signs show a temperature of 38.9∘C38.9^\circ\text{C} (102.0∘F102.0^\circ\text{F}), blood pressure of 92/58 mmHg92/58 \text{ mmHg}, pulse of 112/min112/\text{min}, and respiratory rate of 18/min18/\text{min}. Physical examination reveals dry mucous membranes and marked right costovertebral angle tenderness.

Laboratory studies show:
Leukocyte count: 16,500/mm316,500/\text{mm}^3
Serum sodium: 138 mEq/L138 \text{ mEq/L}
Serum potassium: 4.8 mEq/L4.8 \text{ mEq/L}
Serum creatinine: 2.4 mg/dL2.4 \text{ mg/dL}
Blood urea nitrogen: 42 mg/dL42 \text{ mg/dL}
Serum bicarbonate: 18 mEq/L18 \text{ mEq/L}
Urinalysis: positive for nitrites, leukocyte esterase, and >50 WBCs/hpf>50 \text{ WBCs/hpf}.

The patient receives a 1-L1\text{-L} bolus of intravenous lactated Ringer solution. Blood and urine cultures are obtained.

Which of the following are appropriate next steps in the pharmacologic management of this patient? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Discontinue home metformin therapy; Initiate intravenous ceftriaxone therapy

Answer

The appropriate next steps are to discontinue home metformin therapy and initiate intravenous ceftriaxone therapy.
Discontinuing home metformin is critical because its renal clearance is severely impaired during acute kidney injury (AKI), heavily increasing the risk of life-threatening metformin-associated lactic acidosis, particularly in a patient with sepsis and hypoperfusion. Simultaneously, initiating intravenous ceftriaxone provides optimal empiric antimicrobial therapy for acute complicated pyelonephritis; it covers likely resistant gram-negative organisms (such as E. coli) and, unlike many other antibiotics, does not require renal dose adjustment, making it ideal for a patient with fluctuating renal function.

Step-by-Step Solution

1
Identify the primary acute diagnosis and its severity.
The patient has acute complicated pyelonephritis presenting with early sepsis.
The combination of fever, severe flank pain, dysuria, hypotension, and a strongly positive urinalysis points to a severe systemic infection originating from the urinary tract.
2
Evaluate the patient's current organ function, specifically renal status.
The patient has developed acute kidney injury (AKI) superimposed on chronic kidney disease.
Serum creatinine has acutely elevated from a baseline of 1.4 mg/dL to 2.4 mg/dL, secondary to sepsis-induced renal hypoperfusion and volume depletion.
3
Perform medication reconciliation to identify drugs that are now contraindicated.
Home metformin and lisinopril must be discontinued.
Metformin poses a high risk for lactic acidosis in the setting of AKI. Lisinopril impairs the compensatory efferent arteriolar vasoconstriction needed to maintain glomerular filtration, exacerbating both the AKI and the hypotension.
4
Select the optimal empiric antimicrobial therapy.
Intravenous ceftriaxone should be initiated.
Ceftriaxone adequately covers resistant gram-negative uropathogens and uniquely avoids the need for dose adjustment in fluctuating renal impairment.

Key Concept

In patients presenting with sepsis and acute kidney injury, simultaneous medication reconciliation (holding nephrotoxic or hemodynamically compromising home medications like ACE inhibitors and metformin) is as critical as initiating appropriate, non-nephrotoxic empiric antibiotics.
Question 3313Question →

An ambulatory care physician conducts a telehealth consultation with a 65-year-old female patient reporting a 48-hour history of spontaneous epistaxis and multiple large bruises on her extremities. Her medical history is notable for nonvalvular atrial fibrillation. To prevent thromboembolism, she has taken rivaroxaban daily for three years without hemorrhagic events. Four days prior to this consultation, she visited an urgent care center for acute bronchitis and was given a prescription for a 10-day course of clarithromycin. The patient denies experiencing headaches, visual disturbances, motor weakness, or dark stools. Vital signs are within normal limits. Which of the following is the most appropriate next step in the patient's management?

Show answer & explanation

Answer: Advise the patient to stop taking both clarithromycin and rivaroxaban immediately

Answer

Advise the patient to stop taking both clarithromycin and rivaroxaban immediately.
The correct response addresses a significant drug-drug interaction. Rivaroxaban is a direct Factor Xa inhibitor that is metabolized by the hepatic cytochrome P450 3A4 (CYP3A4) enzyme and transported by P-glycoprotein (P-gp). Clarithromycin is a potent inhibitor of both CYP3A4 and P-gp. When taken concurrently, clarithromycin drastically decreases the clearance of rivaroxaban, leading to supratherapeutic anticoagulant levels and subsequent bleeding manifestations such as epistaxis and ecchymoses. In a hemodynamically stable patient without life-threatening bleeding, the most appropriate next step in treatment evaluation and management is to hold both the offending interacting drug (clarithromycin) and the anticoagulant until the bleeding ceases and the medications are cleared from the system.

Step-by-Step Solution

1
Evaluate the patient's presentation and recent medication changes.
The patient developed spontaneous bleeding shortly after clarithromycin was added to her chronic rivaroxaban therapy.
Identifying recent additions to a medication regimen is essential for diagnosing adverse drug events.
2
Analyze the pharmacokinetic properties of the involved medications.
Clarithromycin is a potent inhibitor of CYP3A4 and P-glycoprotein. Rivaroxaban is a substrate for both.
Understanding metabolic pathways highlights that clarithromycin significantly increases rivaroxaban serum concentrations, elevating bleeding risk.
3
Determine the appropriate clinical intervention based on bleeding severity.
The patient has mild to moderate bleeding (epistaxis, ecchymoses) without hemodynamic instability or neurological symptoms.
For mild bleeding secondary to a drug interaction, the standard of care is discontinuing the interacting medications and monitoring, rather than administering reversal agents or ordering emergent imaging.

Key Concept

Monitoring and Treatment Evaluation for DOACs and CYP3A4 interactions
Question 3314Question →

A 35-year-old woman comes to the clinic for a routine health maintenance visit. She was diagnosed with severe Crohn disease 4 years ago, which is currently well-controlled on a regimen of infliximab and azathioprine. She feels well and has no acute complaints. She has a 10-pack-year smoking history but quit 2 years ago. Her most recent cervical cancer screening was normal 1 year ago, following three consecutive normal annual screenings. She received a tetanus, diphtheria, and acellular pertussis (Tdap) booster 4 years ago and the inactivated influenza vaccine 2 months ago. She has never received a pneumococcal vaccine. Which of the following is the most appropriate next step in preventive care for this patient?

Show answer & explanation

Answer: Administer the recombinant zoster vaccine

Answer

The correct answer is to administer the recombinant zoster vaccine.
The correct answer is to administer the recombinant zoster vaccine. This patient is significantly immunocompromised due to her treatment with infliximab (a tumor necrosis factor-alpha inhibitor) and azathioprine for Crohn disease. The Advisory Committee on Immunization Practices (ACIP) recommends two doses of the recombinant zoster vaccine (RZV) for the prevention of herpes zoster and its complications in adults aged 19 years and older who are or will be immunodeficient or immunosuppressed because of disease or therapy. Unlike older zoster vaccines, RZV is an inactivated, recombinant vaccine and is completely safe to administer to immunocompromised patients.

Step-by-Step Solution

1
Assess the patient's immune status based on her medical history and current medications.
The patient has Crohn disease and is taking infliximab (a TNF-alpha inhibitor) and azathioprine, rendering her severely immunocompromised.
Immunosuppression significantly alters standard adult vaccination and screening guidelines.
2
Evaluate the indications for the recombinant zoster vaccine (RZV) based on age and immune status.
RZV is recommended for adults aged 19 years and older who are immunocompromised.
Patients on immunosuppressive therapies are at a markedly increased risk for herpes zoster reactivation and its complications.
3
Review the safety of live-attenuated vaccines in this patient to rule out contraindicated options.
The MMR vaccine is contraindicated.
Live vaccines can cause disseminated infection in patients receiving potent immunosuppressants.
4
Determine the correct sequencing for pneumococcal vaccination in a vaccine-naive, immunocompromised adult.
She should receive a pneumococcal conjugate vaccine (e.g., PCV15, PCV20, or PCV21) first.
Administering PPSV23 alone as the initial vaccine is incorrect guideline application for this population.

Key Concept

Adults aged 19 years and older who are immunodeficient or immunosuppressed due to disease or therapy should receive two doses of the recombinant zoster vaccine (RZV). Furthermore, live-attenuated vaccines are contraindicated in these patients.
Question 3315Question →

A 5252-year-old man is hospitalized for a 55-day history of right-sided pleuritic chest pain, nonproductive cough, and subjective fevers. Eighteen months ago, he underwent bilateral lung transplantation for idiopathic pulmonary fibrosis. His daily medications include tacrolimus, mycophenolate mofetil, prednisone, and pantoprazole. He is also receiving therapeutic subcutaneous enoxaparin for a provoked deep vein thrombosis diagnosed 33 weeks ago.

Vital signs show a temperature of 38.2∘C38.2^\circ\text{C} (100.8∘F100.8^\circ\text{F}), heart rate of 98/min98/\text{min}, blood pressure of 135/85 mm Hg135/85\text{ mm Hg}, and respiratory rate of 18/min18/\text{min}. Oxygen saturation is 96%96\% on room air.

Laboratory studies are as follows:
Leukocyte count: 6,500/mm36,500/\text{mm}^3
Platelet count: 180,000/mm3180,000/\text{mm}^3
Serum creatinine: 1.1 mg/dL1.1\text{ mg/dL}
Aspartate aminotransferase (AST): 24 U/L24\text{ U/L}
Alanine aminotransferase (ALT): 28 U/L28\text{ U/L}

A chest computed tomography (CT) scan reveals a dense 3-cm3\text{-cm} consolidation in the right upper lobe surrounded by a halo of ground-glass attenuation. Serum galactomannan assay is markedly elevated. The patient is diagnosed with invasive pulmonary aspergillosis, and the decision is made to initiate intravenous voriconazole.

Which of the following is the most appropriate concurrent pharmacologic intervention?

Show answer & explanation

Answer: Reduce the maintenance dose of tacrolimus

Answer

The most appropriate concurrent pharmacologic intervention is to reduce the maintenance dose of tacrolimus.
The correct intervention is to reduce the maintenance dose of tacrolimus. Voriconazole, the primary treatment for invasive pulmonary aspergillosis, is a potent inhibitor of cytochrome P450 3A4 (CYP3A4). Tacrolimus is a calcineurin inhibitor with a narrow therapeutic index that relies heavily on CYP3A4 for metabolism. Coadministration of voriconazole without adjusting the tacrolimus dose will cause a profound accumulation of tacrolimus, precipitating severe acute kidney injury, neurotoxicity (e.g., tremors, seizures), and hemodynamic instability. Standard clinical protocol dictates preemptively reducing the tacrolimus dose by 50%50\% to 75%75\% when initiating voriconazole, followed by meticulous therapeutic drug monitoring of trough levels.

Step-by-Step Solution

1
Identify the primary diagnosis and the medical team's planned treatment.
The patient has invasive pulmonary aspergillosis (halo sign on CT, positive galactomannan) and will be started on voriconazole.
Establishing the new pharmacologic agent is required to evaluate potential drug-drug interactions with the patient's baseline regimen.
2
Analyze the pharmacokinetic profile of the newly planned medication.
Voriconazole is recognized as a potent inhibitor of the cytochrome P450 3A4 (CYP3A4) enzyme system.
CYP3A4 inhibition drastically alters the clearance of concurrent medications metabolized by this pathway.
3
Cross-reference the patient's existing medication list for CYP3A4 substrates.
Tacrolimus is a narrow-therapeutic-index medication that is heavily metabolized by CYP3A4.
Identifying the vulnerable substrate allows the clinician to predict the direction of the interaction (inhibition leads to substrate accumulation).
4
Formulate a management strategy for the identified drug-drug interaction.
The dose of tacrolimus must be preemptively reduced (typically by 50% to 75%) and trough levels monitored closely.
Failure to reduce the dose will result in toxic accumulation of tacrolimus, leading to severe nephrotoxicity, neurotoxicity, and potential graft dysfunction.

Key Concept

Preemptive dose reduction of calcineurin inhibitors (tacrolimus, cyclosporine) is mandatory when initiating potent CYP3A4 inhibitors (such as voriconazole) to prevent severe, life-threatening toxicity.
Question 3316Question →

A 58-year-old woman is evaluated in the intensive care unit for a rapidly declining platelet count. She was admitted 6 days ago for severe pneumonia and started on broad-spectrum antibiotics and prophylactic subcutaneous unfractionated heparin. Her platelet count on admission was 250,000/μL250,000/\mu L and is now 55,000/μL55,000/\mu L. She has no active bleeding, but a lower extremity ultrasound reveals a new deep vein thrombosis in the right femoral vein. The clinical team diagnoses highly probable heparin-induced thrombocytopenia (HIT) with thrombosis. Arrange the following steps regarding the ongoing monitoring and transition of pharmacotherapy for this patient in the most appropriate chronological sequence.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence begins with immediately stopping all heparin products, followed by initiating a non-heparin parenteral anticoagulant, monitoring platelets until they recover to at least 150,000/μL150,000/\mu L, initiating warfarin overlap, and finally discontinuing the parenteral anticoagulant once the INR is therapeutic for 48 hours.
The management of Heparin-Induced Thrombocytopenia (HIT) follows a strict, highly tested sequence. First, the inciting agent (all heparin products) must be immediately withdrawn to stop the underlying pathophysiology. Second, because HIT is profoundly prothrombotic (as evidenced by this patient's new deep vein thrombosis), immediate alternative parenteral anticoagulation (e.g., argatroban, bivalirudin, or fondaparinux) is required. Third, the clinician must monitor the patient's platelet count daily; this serves as the primary metric for treatment evaluation. Fourth, only after the platelet count has recovered to normal levels (≥150,000/μL\ge 150,000/\mu L) is it safe to initiate warfarin. Finally, standard bridging rules apply: the parenteral agent must be continued for at least 5 days AND until the INR is therapeutic (2.0-3.0) for at least 48 hours before it can be safely discontinued.

Step-by-Step Solution

1
Stop all heparin exposure.
Halts the formation of heparin-PF4-antibody complexes.
Continued exposure to even minimal amounts of heparin (like flushes) perpetuates the prothrombotic state.
2
Start a non-heparin parenteral anticoagulant (e.g., argatroban).
Provides immediate anticoagulation to treat the existing deep vein thrombosis.
Patients with HIT have an extremely high risk of progressive or new thrombosis, necessitating immediate alternative anticoagulation.
3
Monitor platelet count daily.
Identifies the resolution of the acute HIT phase once platelets reach ≥150,000/μL\ge 150,000/\mu L.
Platelet recovery indicates that the profound hypercoagulable state is subsiding, marking the safe window for transition to oral therapy.
4
Initiate oral warfarin therapy while continuing the parenteral anticoagulant.
Begins the transition to long-term outpatient anticoagulation.
Warfarin must be delayed until platelet recovery to avoid the rapid depletion of Protein C, which can paradoxically worsen thrombosis.
5
Discontinue the parenteral anticoagulant after 48 hours of a therapeutic INR.
Completes the transition to monotherapy with warfarin.
Bridging ensures that warfarin has achieved its full antithrombotic effect (depletion of prothrombin/Factor II) before the rapid-acting agent is removed.

Key Concept

Monitoring and Treatment Evaluation in Heparin-Induced Thrombocytopenia (HIT)
Estimated Time:1m 30s
Question 3317Question →

A 72-year-old man with a 6-year history of Parkinson disease is brought to the neurology clinic by his wife due to new-onset visual hallucinations over the past two weeks. He reports seeing unfamiliar people standing in his living room, which is causing him significant distress. His motor symptoms (tremor and bradykinesia) have been well-controlled recently. His current daily medication regimen includes carbidopa-levodopa, pramipexole, amantadine, and trihexyphenidyl. Vital signs are within normal limits. Neurologic examination shows mild resting tremor and rigidity, unchanged from his previous visit. Laboratory studies, including a urinalysis and basic metabolic panel, are unremarkable.

According to the standard step-wise approach for managing Parkinson disease-related psychosis, arrange the following pharmacologic modifications in the correct sequential order (from the first step to the final step).

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequential order is to first discontinue trihexyphenidyl, then discontinue amantadine, then discontinue pramipexole, and finally initiate quetiapine if symptoms persist.
The management of Parkinson disease psychosis involves a step-wise approach to minimize medication-induced delirium while attempting to preserve motor function. The first step is always to rule out general medical conditions (e.g., infections). Once ruled out, a sequential reduction of adjunctive Parkinson medications is performed in reverse order of their motor efficacy and forward order of their side effect profile. Anticholinergics (trihexyphenidyl) are the most deliriogenic and provide the least motor benefit, making them the first to be discontinued. If symptoms persist, amantadine is discontinued next. This is followed by MAO-B inhibitors (if present) and then dopamine agonists (pramipexole). Only if psychosis persists despite the withdrawal of these adjunctive therapies (or if severe motor deterioration prevents their withdrawal) should an atypical antipsychotic with low extrapyramidal risk, such as quetiapine or pimavanserin, be initiated.

Step-by-Step Solution

1
Identify the primary clinical problem
The patient is experiencing new-onset visual hallucinations (psychosis) induced by Parkinson disease medications, with secondary causes (e.g., infection, metabolic derangements) already ruled out.
Visual hallucinations are a common adverse effect of dopaminergic and anticholinergic therapies in advanced Parkinson disease and must be managed systematically.
2
Determine the first step in the medication taper protocol
Discontinue the anticholinergic agent (trihexyphenidyl).
Anticholinergics carry the highest risk for cognitive impairment and hallucinations with the least motor benefit, making them the absolute first target for discontinuation.
3
Determine the next sequential medications to withdraw if symptoms persist
Discontinue amantadine, followed by the dopamine agonist (pramipexole).
Amantadine has high neuropsychiatric toxicity and should be removed next. Dopamine agonists are tapered after amantadine because they provide greater motor control, even though they frequently trigger psychosis.
4
Determine the final intervention for refractory psychosis
Initiate an atypical antipsychotic (quetiapine).
If psychosis persists despite discontinuing adjunctive therapies, a low-potency atypical antipsychotic without significant D2 antagonism is added to avoid worsening motor symptoms.

Key Concept

The step-wise pharmacologic management of Parkinson disease psychosis involves sequentially discontinuing adjunctive medications in reverse order of motor efficacy (anticholinergics, then amantadine, then MAO-B inhibitors, then dopamine agonists) before initiating an atypical antipsychotic.
Question 3318Question →

A 68-year-old man is evaluated in the outpatient clinic for a 1-day history of severe right great toe pain, swelling, and redness. He reports the pain woke him from sleep and is so exquisite that he cannot bear the weight of a bedsheet on his foot. Medical history is notable for hypertension, type 2 diabetes mellitus, and chronic kidney disease stage 3b. One week ago, he was diagnosed with a peptic ulcer associated with Helicobacter pylori and was started on a 14-day eradication regimen. Current medications include lisinopril, amlodipine, clarithromycin, amoxicillin, and omeprazole. Vital signs are temperature 37.3°C (99.1°F), blood pressure 138/82 mmHg, and pulse 88/min. Physical examination shows a swollen, erythematous, and exquisitely tender right first metatarsophalangeal joint. Arthrocentesis is performed, and synovial fluid analysis reveals a leukocyte count of 25,000/mm³ and negatively birefringent, needle-shaped crystals. Gram stain is negative. Laboratory studies show:

TestResult
Leukocyte count11,200/mm³
Serum uric acid5.4 mg/dL
Serum creatinine1.7 mg/dL (baseline 1.6 mg/dL)

Which of the following is the most appropriate next step in pharmacologic management for this patient?

Show answer & explanation

Answer: Intra-articular triamcinolone

Answer

Intra-articular triamcinolone is the most appropriate pharmacologic intervention.
The patient is experiencing an acute gout flare, definitively diagnosed by the presence of negatively birefringent monosodium urate crystals in the synovial fluid. Standard first-line systemic therapies for acute gout include nonsteroidal anti-inflammatory drugs (NSAIDs) and colchicine. However, in this patient, NSAIDs (e.g., indomethacin) are contraindicated due to his underlying chronic kidney disease and concurrent use of an angiotensin-converting enzyme (ACE) inhibitor (lisinopril), a combination that carries a high risk of precipitating acute renal failure. Colchicine is also strictly contraindicated because the patient is taking clarithromycin for Helicobacter pylori eradication. Clarithromycin is a potent inhibitor of both cytochrome P450 3A4 (CYP3A4) and P-glycoprotein; coadministration with colchicine can lead to fatal colchicine toxicity (neuromyopathy, cytopenias), particularly in patients with baseline renal impairment. Therefore, a localized intra-articular glucocorticoid injection (e.g., triamcinolone) is the safest and most effective targeted intervention. It provides rapid local symptom relief for monoarticular gout while completely bypassing the risks of systemic drug-drug interactions and nephrotoxicity.

Step-by-Step Solution

1
Analyze the synovial fluid and laboratory results.
Negatively birefringent crystals definitively confirm an acute gout flare, ruling out septic arthritis despite the normal serum uric acid level.
Establishing the correct diagnosis is the necessary first step before selecting pharmacotherapy.
2
Evaluate the safety of NSAIDs for this specific patient.
Indomethacin is contraindicated.
The patient has chronic kidney disease and is taking an ACE inhibitor; NSAIDs can precipitate severe acute renal failure in this setting.
3
Evaluate the safety of colchicine for this specific patient.
Colchicine is contraindicated.
The patient is taking clarithromycin, a strong CYP3A4 and P-glycoprotein inhibitor, which would cause fatal colchicine toxicity.
4
Select the optimal alternative therapy.
Intra-articular triamcinolone is chosen.
Localized glucocorticoid injection provides rapid anti-inflammatory relief for monoarticular gout without systemic drug interactions or nephrotoxicity.

Key Concept

Pharmacologic management of acute gout in patients with complex comorbidities and critical drug-drug interactions.
Question 3319Question →

A 62-year-old man with a 12-year history of type 2 diabetes mellitus and chronic kidney disease is evaluated during a routine follow-up visit. One month ago, his hemoglobin A1c was 8.1% and his estimated glomerular filtration rate (eGFR) was 45 mL/min/1.73 m 2^2. At that time, dapagliflozin was added to his medication regimen, which also includes metformin and lisinopril, to optimize glycemic control and slow the progression of diabetic nephropathy. Today, the patient reports feeling well overall. He denies urinary frequency, dysuria, dizziness, or orthopnea. He mentions having mild, intermittent bilateral knee pain due to osteoarthritis and asks for a medication recommendation. His blood pressure is 126/78 mm Hg and heart rate is 74/min.

Laboratory studies obtained today show:

TestResult
Serum sodium138 mEq/L
Serum potassium4.6 mEq/L
Serum urea nitrogen24 mg/dL
Serum creatinine1.8 mg/dL (Baseline 1.5 mg/dL)
eGFR37 mL/min/1.73 m2^2

Which of the following is the most appropriate next step in the management of this patient?

Show answer & explanation

Answer: Continue the current regimen and recommend oral acetaminophen for the knee pain

Answer

The most appropriate next step is to continue the current medication regimen without modifications and recommend oral acetaminophen for the patient's knee osteoarthritis pain.
The correct answer is to continue the current regimen and recommend oral acetaminophen for the knee pain. This patient has experienced a 20% increase in serum creatinine (from 1.5 mg/dL to 1.8 mg/dL) one month after initiating dapagliflozin, an SGLT2 inhibitor. SGLT2 inhibitors cause afferent arteriolar vasoconstriction by increasing sodium delivery to the macula densa, which lowers intraglomerular pressure. This hemodynamic change is the mechanism behind their long-term renoprotective effect, but it causes an expected, mild initial drop in eGFR. Current clinical guidelines state that an initial serum creatinine increase of up to 30% from baseline is acceptable and should not prompt discontinuation of the drug. Furthermore, the patient's osteoarthritis should be managed with acetaminophen. Oral NSAIDs (like naproxen) are contraindicated in patients with chronic kidney disease, as they inhibit prostaglandin-mediated afferent arteriolar vasodilation, increasing the risk of severe acute kidney injury, particularly in patients taking ACE inhibitors.

Step-by-Step Solution

1
Analyze the patient's change in renal function after initiating the SGLT2 inhibitor.
The serum creatinine increased from 1.5 mg/dL to 1.8 mg/dL, representing exactly a 20% increase.
To determine if the laboratory change falls within the acceptable safety threshold for this class of medications.
2
Evaluate the clinical guidelines for SGLT2 inhibitor monitoring.
An initial increase in serum creatinine of up to 30% is an expected, hemodynamically mediated effect that correlates with long-term renoprotection. The medication should be continued.
To make the correct evidence-based clinical decision regarding the continuation or discontinuation of the new medication.
3
Assess the patient's request for osteoarthritis pain medication in the context of his comorbidities.
The patient has chronic kidney disease and is taking an ACE inhibitor. NSAIDs are contraindicated due to the risk of precipitating acute kidney injury.
To select an analgesic (acetaminophen) that provides safe symptom management without exacerbating renal impairment.

Key Concept

An initial increase in serum creatinine of up to 30% is an expected hemodynamic effect of SGLT2 inhibitors and does not warrant discontinuation. Oral NSAIDs are contraindicated in patients with CKD taking ACE inhibitors.
Question 3320Question →

A 45-year-old man is evaluated in the hospital prior to discharge. He was admitted three days ago for acute dyspnea and was found to have a new-onset nonischemic cardiomyopathy with a left ventricular ejection fraction of 20%. He has been treated with intravenous furosemide and is now breathing comfortably on room air. He has no orthopnea, and his volume status is clinically optimized. Medical history is notable for hypertension and an episode of severe lip swelling and airway compromise requiring epinephrine after taking lisinopril two years ago. Current vital signs are blood pressure 118/75 mmHg, heart rate 72/min, and respirations 14/min.

Laboratory results obtained this morning are as follows:

TestResultReference Range
Sodium138 mEq/L136-145 mEq/L
Potassium5.8 mEq/L3.5-5.0 mEq/L
Chloride102 mEq/L98-106 mEq/L
Bicarbonate24 mEq/L22-28 mEq/L
Blood urea nitrogen22 mg/dL8-23 mg/dL
Creatinine1.3 mg/dL0.7-1.3 mg/dL

Which of the following pharmacologic interventions are appropriate to initiate prior to discharge? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Metoprolol succinate; Dapagliflozin; Isosorbide dinitrate and hydralazine

Answer

The appropriate interventions to initiate are metoprolol succinate, dapagliflozin, and the combination of isosorbide dinitrate and hydralazine.
This patient requires initiation of guideline-directed medical therapy for newly diagnosed heart failure with reduced ejection fraction (HFrEF). Standard quad-therapy components generally include an ARNI/ACEi/ARB, an evidence-based beta-blocker, a mineralocorticoid receptor antagonist (MRA), and an SGLT2 inhibitor. Metoprolol succinate is an evidence-based beta-blocker that should be started in stable, euvolemic patients. Dapagliflozin reduces mortality and hospitalizations in HFrEF regardless of diabetes status and is safe given the patient's adequate renal function. Because the patient has a history of ACE-inhibitor-induced angioedema, all ACE inhibitors, ARBs, and ARNIs (e.g., sacubitril-valsartan) are strictly contraindicated. In patients who cannot tolerate these agents, the combination of isosorbide dinitrate and hydralazine is the recommended alternative to provide mortality-reducing afterload and preload reduction.

Step-by-Step Solution

1
Assess the clinical state and primary diagnosis.
The patient has newly diagnosed heart failure with reduced ejection fraction (HFrEF) with an ejection fraction of 20%, and is now euvolemic and hemodynamically stable.
Establishing baseline stability is required before safely initiating guideline-directed medical therapy (GDMT) prior to discharge.
2
Review the patient's medical history for contraindications to standard GDMT.
The patient has a history of life-threatening angioedema secondary to lisinopril.
A history of ACE-inhibitor-induced angioedema acts as an absolute contraindication to all ACE inhibitors, ARBs, and ARNIs (e.g., sacubitril-valsartan) due to cross-reactivity and bradykinin accumulation.
3
Evaluate the current laboratory values, specifically electrolytes and renal function.
The patient's serum potassium is significantly elevated at 5.8 mEq/L.
Hyperkalemia is an absolute contraindication to initiating mineralocorticoid receptor antagonists (MRAs) such as spironolactone, which would further increase potassium levels.
4
Select the appropriate, safe pharmacological agents to form a modified GDMT regimen.
Metoprolol succinate, dapagliflozin, and the combination of isosorbide dinitrate and hydralazine are selected.
Beta-blockers and SGLT2 inhibitors remain safe and indicated. Hydralazine and nitrates serve as the evidence-based alternative for mortality reduction in HFrEF when renin-angiotensin-aldosterone system inhibitors are contraindicated.

Key Concept

Initiation of guideline-directed medical therapy for HFrEF requires careful adjustment for absolute contraindications, specifically avoiding ARNIs/ACEis/ARBs in patients with prior angioedema and avoiding MRAs in patients with significant hyperkalemia.
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