Patient Management

2074 questions

Question 1381Question →

A 62-year-old man presents to the clinic for a routine health maintenance visit. His medical history is significant for type 2 diabetes mellitus and stage 3a chronic kidney disease. He smoked one pack of cigarettes daily from age 20 to 50, but quit 12 years ago. He is currently asymptomatic and reports good medication adherence.

His preventive care history includes the following:
- Colonoscopy at age 55 revealed no polyps or abnormalities.
- Recombinant zoster vaccine series was completed at age 55.
- Tetanus, diphtheria, and acellular pertussis (Tdap) booster was administered 5 years ago.
- Annual influenza and updated COVID-19 vaccines were administered last month.
- One-time hepatitis C antibody screening was negative 3 years ago.
- He has never received any pneumococcal vaccinations.

Physical examination is unremarkable. Which of the following preventive interventions are currently indicated for this patient? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Annual low-dose computed tomography of the chest; Administration of a pneumococcal conjugate vaccine

Answer

Annual low-dose computed tomography of the chest AND Administration of a pneumococcal conjugate vaccine
Annual low-dose computed tomography (LDCT) of the chest is indicated because the patient meets the criteria of being aged 50 to 80 years, having at least a 20 pack-year smoking history (he has 30 pack-years), and having quit within the past 15 years (he quit 12 years ago). Administration of a pneumococcal conjugate vaccine is also indicated because adults aged 19 to 64 years with certain underlying medical conditions, such as diabetes mellitus and chronic kidney disease, require pneumococcal vaccination.

Step-by-Step Solution

1
Evaluate the patient's smoking history and age for lung cancer screening.
The patient is 62 years old with a 30 pack-year history, having quit 12 years ago.
Guidelines recommend annual LDCT for ages 50 to 80 with 20 or more pack-years who currently smoke or quit within the last 15 years.
2
Assess the patient's indication for pneumococcal vaccination.
The patient has type 2 diabetes mellitus and chronic kidney disease.
Adults aged 19 to 64 with these comorbidities are at higher risk and require pneumococcal vaccination.
3
Determine if the patient meets criteria for abdominal aortic aneurysm screening.
The patient is a male former smoker but is only 62 years old.
AAA screening is recommended beginning at age 65 for men who have ever smoked.
4
Check colorectal cancer screening status.
The patient had a normal colonoscopy at age 55.
The next screening is due in 10 years (at age 65). Interval non-invasive testing is not indicated.
5
Evaluate the indication for aspirin for primary prevention.
The patient is 62 years old.
Aspirin is no longer recommended for primary prevention of cardiovascular disease in adults aged 60 and older.

Key Concept

Application of age- and risk-based preventive screening and immunization guidelines in the ambulatory setting.
Question 1382Question →

A 28-year-old man with type 1 diabetes mellitus is receiving care in the intensive care unit for severe diabetic ketoacidosis. He is currently being managed with intravenous fluid resuscitation and a continuous intravenous regular insulin infusion. Arrange the following clinical milestones and monitoring-based interventions in the correct chronological sequence required for a safe transition to maintenance subcutaneous therapy.

Drag items to arrange them in the correct order

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Answer

The correct sequence begins with monitoring blood glucose until it reaches 200 mg/dL, immediately adding dextrose to the IV fluids, continuing to monitor until the anion gap closes, administering subcutaneous insulin, and finally discontinuing the IV insulin infusion two hours later.
The standard protocol for managing diabetic ketoacidosis (DKA) requires rigorous sequential monitoring and treatment modification. Initially, IV fluids and an insulin infusion are started. Because glucose normalizes faster than the ketoacidosis resolves, when the blood glucose falls to 200 mg/dL, 5% dextrose must be added to the IV fluids. This prevents hypoglycemia and allows the insulin infusion to continue suppressing lipolysis and ketogenesis. The physician must then monitor serial basic metabolic panels until the anion gap closes (≤ 12 mEq/L), which signals the resolution of DKA. Once resolved, the transition to subcutaneous insulin is initiated by administering a long-acting basal dose. Finally, because subcutaneous insulin takes 1 to 2 hours to achieve therapeutic systemic absorption, the IV insulin infusion must be maintained for an overlapping 2-hour period before being discontinued to prevent a relapse of DKA.

Step-by-Step Solution

1
Monitor capillary blood glucose hourly until it reaches the 200 mg/dL threshold.
Identifies the point where the patient is at risk for hypoglycemia if pure saline is continued.
Blood glucose typically normalizes much faster than the metabolic acidosis resolves.
2
Add 5% dextrose to the intravenous fluid regimen.
Maintains blood glucose levels in a safe range (150-200 mg/dL).
Allows the continuous insulin infusion to be maintained at a rate sufficient to clear ketones without inducing iatrogenic hypoglycemia.
3
Monitor serial chemistry panels every 2 to 4 hours to assess the anion gap.
Confirms the closure of the anion gap (typically ≤ 12 mEq/L) and normalization of bicarbonate.
Closure of the anion gap is the definitive marker that diabetic ketoacidosis has resolved and continuous IV insulin is no longer strictly required for ketone suppression.
4
Administer the first dose of subcutaneous basal insulin.
Begins the transition to long-term maintenance therapy.
Subcutaneous insulin must be given once the acidosis is resolved and the patient is preparing to resume an oral diet.
5
Maintain the IV insulin infusion for an additional 2 hours before discontinuing it.
Provides an insulin overlap.
Subcutaneous insulin has a delayed onset of action. The overlap prevents a window of insulin deficiency and subsequent rebound ketoacidosis.

Key Concept

Monitoring and Sequencing the Transition off Intravenous Insulin in Diabetic Ketoacidosis
Question 1383Question →

During a scheduled annual wellness examination, a 60-year-old woman is evaluated in the primary care clinic. She feels well and has no acute complaints. Her medical history is notable for seropositive rheumatoid arthritis, which has been well-controlled on a stable regimen of adalimumab and methotrexate for the past four years. She has a 10 pack-year smoking history, currently smoking half a pack of cigarettes daily. Her family history is significant for her mother being diagnosed with breast cancer at age 72 and her father having a stroke at age 80.

Review of her preventive health record reveals the following:
- Screening colonoscopy at age 52 was normal.
- Screening mammography 6 months ago was normal.
- Pap smear with human papillomavirus (HPV) co-testing 2 years ago was normal.
- Hepatitis C virus antibody test 1 year ago was negative.

Her immunizations are up to date, including a 20-valent pneumococcal conjugate vaccine (PCV20) at age 58, two doses of the recombinant zoster vaccine at age 50, and an inactivated influenza vaccine 3 weeks ago.

Her body mass index is 21 kg/m². Physical examination shows no joint effusions, tenderness, or deformities.

Which of the following is the most appropriate next step in preventive care for this patient?

Show answer & explanation

Answer: Dual-energy x-ray absorptiometry

Answer

The most appropriate next step is performing dual-energy x-ray absorptiometry (DEXA) to screen for osteoporosis.
The correct answer is dual-energy x-ray absorptiometry (DEXA). The United States Preventive Services Task Force (USPSTF) recommends screening for osteoporosis with bone measurement testing (e.g., DEXA scan) in women 65 years and older, as well as in postmenopausal women younger than 65 years who are at increased risk of osteoporosis. Increased risk is defined as having a 10-year risk of a major osteoporotic fracture equal to or greater than that of a 65-year-old white woman with no additional risk factors (which is approximately 8.4% using the FRAX tool). This patient has multiple significant clinical risk factors for osteoporosis, including a diagnosis of rheumatoid arthritis, current tobacco use, and a low-normal body mass index (21 kg/m²). These factors place her well above the risk threshold, making a DEXA scan the most appropriate and indicated next step in her preventive care.

Step-by-Step Solution

1
Analyze the patient's demographics, past medical history, and social history.
The patient is a 60-year-old postmenopausal woman with rheumatoid arthritis, active tobacco use (10 pack-years), and a BMI of 21 kg/m².
Identifying these clinical factors is necessary to calculate patient-specific risks for various diseases targeted by screening guidelines.
2
Evaluate the status of her routine cancer and infectious disease screenings based on the provided dates.
Colorectal cancer (colonoscopy 8 years ago), breast cancer (mammogram 6 months ago), cervical cancer (Pap/HPV 2 years ago), and HCV screenings are all up to date. She is also fully vaccinated for her age and risk profile.
This eliminates several options by confirming that these specific screenings and vaccines are not currently due.
3
Assess her eligibility for specialized screenings based on her unique risk factors.
While she does not meet the 20 pack-year requirement for lung cancer screening (LDCT) and AAA screening is not routinely indicated for women, her rheumatoid arthritis and smoking status significantly increase her osteoporosis risk.
The USPSTF recommends bone density screening for women under 65 if their 10-year fracture risk meets or exceeds 8.4%. Her secondary causes of osteoporosis (RA) and lifestyle factors exceed this threshold.

Key Concept

The United States Preventive Services Task Force (USPSTF) recommends screening for osteoporosis with bone measurement testing in postmenopausal women younger than 65 years who are at increased risk of osteoporosis (10-year fracture risk ≥8.4%).
Question 1384Question →

Match each clinical scenario evaluated in the primary care setting with the most appropriate, evidence-based preventive care intervention.

Click a left item, then click its matching right item

Items

A 41-year-old female with no significant past medical history or family history of malignancy.
A 54-year-old male with a 25 pack-year smoking history who successfully quit smoking 10 years ago.
A 66-year-old male with essential hypertension who reports having smoked approximately 200 cigarettes total in his early twenties.
A 31-year-old female at 29 weeks gestation who received a tetanus booster 3 years ago following a minor laceration.

Matches

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Answer

The 41-year-old female requires screening mammography. The 54-year-old former smoker requires annual LDCT of the chest. The 66-year-old male who previously smoked requires a one-time abdominal aortic ultrasound. The 31-year-old pregnant female requires Tdap vaccination.
Each patient meets specific age and risk factor thresholds established by current USPSTF and ACIP guidelines for preventive screening and vaccination. The 41-year-old female meets the updated age threshold of 40 for starting mammography. The 54-year-old male fits the 50-80 age range, >20 pack-year history, and <15 years since quitting criteria for LDCT. The 66-year-old male meets the 65-75 age range and >100 lifetime cigarette exposure criteria for AAA screening. The 31-year-old pregnant female is within the 27-36 week gestation window requiring Tdap vaccination.

Step-by-Step Solution

1
Evaluate the 41-year-old female for cancer screening eligibility.
She is eligible for breast cancer screening.
Current USPSTF guidelines recommend starting biennial screening mammography at age 40 for average-risk women, rather than waiting until age 50.
2
Assess the 54-year-old male's smoking history for lung cancer screening.
He meets criteria for low-dose computed tomography (LDCT).
He falls within the 50-80 age range, has greater than a 20 pack-year smoking history, and his quit date is within the last 15 years.
3
Determine vascular screening needs for the 66-year-old male.
He requires an abdominal aortic aneurysm (AAA) screening.
He is a male aged 65-75 with a history of smoking. A lifetime exposure of at least 100 cigarettes qualifies a patient as an 'ever smoker' for AAA screening purposes.
4
Review the immunization requirements for the 31-year-old pregnant female.
She requires the Tdap vaccine.
Tdap is indicated in every pregnancy between 27 and 36 weeks of gestation to provide passive immunity to the infant, regardless of when her last tetanus booster was administered.

Key Concept

Application of age- and risk-appropriate preventive screening and immunization guidelines
Question 1385Question →

A 38-year-old man is evaluated in the hospital on day 4 of admission for an acute left lower extremity deep vein thrombosis. He has a known history of primary antiphospholipid syndrome. Upon admission, he was started on a continuous intravenous unfractionated heparin infusion and oral warfarin.

Daily INR values since admission are as follows:

Hospital DayINR Result
Day 11.1
Day 21.2
Day 31.7
Day 4 (today)2.4

Today's laboratory results show an activated partial thromboplastin time (aPTT) of 68 seconds (therapeutic goal: 60-80 seconds). His platelet count is 210,000/mm³ (baseline 225,000/mm³ on admission). The patient reports that his leg swelling has significantly improved, though he still experiences mild residual leg pain. He has no signs of clinical bleeding.

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

Show answer & explanation

Answer: Continue both the unfractionated heparin infusion and oral warfarin

Answer

Continue both the unfractionated heparin infusion and oral warfarin
The most appropriate next step in management is to continue both the unfractionated heparin infusion and oral warfarin. When initiating a vitamin K antagonist (warfarin) for the treatment of an acute deep vein thrombosis, patients must receive concurrent bridging therapy with a rapid-acting parenteral anticoagulant. This overlap must be maintained for a strict minimum of 5 days AND until the INR is in the therapeutic range (typically 2.0-3.0) for at least 24 hours. Because the patient is only on day 4 of admission and his INR just entered the therapeutic range today (it was 1.7 yesterday), neither of the required safety thresholds has been fulfilled. Therefore, both medications must be continued to prevent a transient hypercoagulable state.

Step-by-Step Solution

1
Evaluate the current duration of the parenteral and oral anticoagulant overlap.
The patient has been on combined unfractionated heparin and warfarin therapy for exactly 4 days.
Current standard-of-care guidelines mandate a minimum of 5 days of overlap for safe warfarin initiation.
2
Analyze the patient's current INR in the context of therapeutic goals and timeline requirements.
The INR reached the therapeutic range (2.4) for the first time today; yesterday it was subtherapeutic (1.7).
Heparin can only be discontinued safely when the INR has been therapeutic (2.0 or greater) for a minimum of 24 consecutive hours.
3
Synthesize the duration and laboratory parameters to determine the immediate management step.
Unfractionated heparin must be continued concurrently with warfarin.
Neither the minimum 5-day duration rule nor the 24-hour therapeutic INR requirement has been satisfied.

Key Concept

For the treatment of venous thromboembolism, bridging therapy with a parenteral anticoagulant (such as unfractionated heparin) and warfarin must be continued concurrently for a minimum of 5 days AND until the INR is therapeutic (2.0 or greater) for at least 24 hours.
Question 1386Question →

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 1387Question →

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 1388Question →

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 1389Question →

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 1390Question →

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 1391Question →

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 1392Question →

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

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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 1393Question →

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

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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 1394Question →

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 1395Question →

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 1396Question →

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 1397Question →

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 1398Question →

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 1399Question →

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 1400Question →

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.
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