Patient Management

2074 questions

All types2,074 Multiple choice1,048 Multiple select393 Matching221 Ordering412

Question 1921Question →

A 24-year-old man is evaluated in the intensive care unit 4 hours after admission for diabetic ketoacidosis. He has a 10-year history of type 1 diabetes mellitus. On initial presentation to the emergency department, he was lethargic and reporting severe nausea and vomiting. His initial blood glucose was $680\text{ mg/dL}$ , and arterial blood gas showed a pH of $7.15$ . He was started on a continuous intravenous regular insulin infusion at $0.1\text{ units/kg/hr}$ and intravenous fluid resuscitation with 0.9% sodium chloride. His mental status has since improved, and he is now awake and alert.

Current vital signs are temperature $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ), blood pressure $118/76\text{ mmHg}$ , heart rate $92/\text{min}$ , and respiratory rate $18/\text{min}$ .

Laboratory results are as follows:

Parameter	Initial (Admission)	Current (4 hours later)
Serum glucose	$680\text{ mg/dL}$	$220\text{ mg/dL}$
Serum sodium	$132\text{ mEq/L}$	$138\text{ mEq/L}$
Serum potassium	$5.6\text{ mEq/L}$	$4.4\text{ mEq/L}$
Serum chloride	$98\text{ mEq/L}$	$106\text{ mEq/L}$
Serum bicarbonate	$10\text{ mEq/L}$	$14\text{ mEq/L}$

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

Continue the current insulin infusion and add 5% dextrose to the intravenous fluids

Discontinue the insulin infusion and transition to subcutaneous insulin glargine

Decrease the insulin infusion rate by 50% and maintain the current intravenous fluids

Administer intravenous sodium bicarbonate and add potassium chloride to the intravenous fluids

Switch the intravenous fluids to 0.45% sodium chloride alone and continue the insulin infusion

Show answer & explanation

Answer: Continue the current insulin infusion and add 5% dextrose to the intravenous fluids

Answer

The most appropriate next step is to continue the current insulin infusion and add 5% dextrose to the intravenous fluids.

The correct approach is to continue the insulin infusion and add 5% dextrose to the intravenous fluids. This patient's laboratory results demonstrate that his serum glucose has dropped below 250 mg/dL, but his anion gap remains elevated at 18 mEq/L (

138 - [106 + 14]

). Diabetic ketoacidosis (DKA) is considered resolved when the anion gap normalizes (typically

\leq 12\text{ mEq/L}

) and the serum bicarbonate is

> 15-18\text{ mEq/L}

. Because the anion gap is still elevated, the patient is still in DKA and requires continuous intravenous insulin to suppress lipolysis and ketogenesis. To prevent iatrogenic hypoglycemia while the insulin infusion is maintained, 5% dextrose must be added to the maintenance intravenous fluids.

Step-by-Step Solution

Calculate the current anion gap to determine if diabetic ketoacidosis (DKA) has resolved.

The current anion gap is calculated as Sodium - (Chloride + Bicarbonate) = 138 - (106 + 14) = 18 mEq/L.

Resolution of DKA is defined by the normalization of the anion gap (typically < 12 mEq/L) and bicarbonate levels, not by the normalization of blood glucose.

Evaluate the current serum glucose level in the context of the treatment protocol.

The serum glucose has fallen from 680 mg/dL to 220 mg/dL (now < 250 mg/dL).

When glucose drops below 200-250 mg/dL during DKA treatment, the risk of iatrogenic hypoglycemia increases significantly if insulin is continued without glucose supplementation.

Determine the appropriate fluid and insulin management step.

Dextrose (5%) must be added to the intravenous fluids while continuing the insulin infusion.

Insulin must be continued to suppress lipolysis and ketogenesis until the anion gap closes. Adding dextrose prevents hypoglycemia during this critical phase of ketoacidosis clearance.

Key Concept

In the management of diabetic ketoacidosis, when serum glucose falls below 200-250 mg/dL but the anion gap remains elevated, dextrose must be added to the intravenous fluids to allow the continuation of the insulin infusion for the clearance of ketones.

Question 1922Question →

A 68-year-old woman presents to the clinic for a routine health maintenance visit. Her medical history includes hypertension and osteoarthritis. She takes amlodipine and uses as-needed acetaminophen for joint pain. She mentions experiencing mild, intermittent lower back pain after gardening, which resolves entirely with rest; she denies any radiating pain, leg weakness, or changes in bowel or bladder function. She smoked one pack of cigarettes daily for 30 years before quitting 8 years ago.

Review of her preventive care records reveals the following:
- Screening mammogram 1 year ago (normal)
- Colonoscopy 6 years ago (normal)
- Dual-energy x-ray absorptiometry (DEXA) scan at age 65 (normal bone mineral density)
- Total hysterectomy with bilateral salpingo-oophorectomy at age 55 for symptomatic uterine fibroids

Her immunizations are up to date, including an inactivated influenza vaccine last month, a recombinant zoster vaccine series completed at age 65, and a Tdap booster 5 years ago. She has never received any pneumococcal vaccinations.

Which of the following interventions are indicated for this patient at today's visit? (Select all that apply)

Select all that apply

Low-dose computed tomography of the chest

Administration of 20-valent pneumococcal conjugate vaccine

Screening mammography

Fecal immunochemical testing

Magnetic resonance imaging of the lumbar spine

Show answer & explanation

Answer: Low-dose computed tomography of the chest; Administration of 20-valent pneumococcal conjugate vaccine

Answer

The indicated interventions for this patient are low-dose computed tomography of the chest and administration of the 20-valent pneumococcal conjugate vaccine.

Based on current guidelines, two interventions are indicated. First, annual lung cancer screening with low-dose computed tomography (LDCT) is recommended by the USPSTF for adults aged 50 to 80 years who have a 20 pack-year smoking history and either currently smoke or quit within the past 15 years. This patient is 68, has a 30 pack-year history, and quit 8 years ago, fully meeting these criteria. Second, the ACIP recommends that all adults ≥65 years of age who have not previously received a pneumococcal conjugate vaccine receive a single dose of PCV20 (or PCV15 followed by PPSV23). Because this patient has no history of pneumococcal vaccination, administering PCV20 is appropriate.

Step-by-Step Solution

Evaluate the patient's smoking history and age for lung cancer screening eligibility.

The patient is 68 years old, has a 30 pack-year smoking history, and quit 8 years ago.

Current guidelines recommend annual low-dose computed tomography (LDCT) for adults aged 50-80 with a ≥20 pack-year history who smoke or quit within the last 15 years.

Review the patient's age and vaccination history for indicated adult immunizations.

The patient is over 65 and has never received a pneumococcal vaccine.

All adults ≥65 years require pneumococcal vaccination (PCV20 alone, or PCV15 followed by PPSV23) to prevent invasive pneumococcal disease.

Review the timing of previous cancer screenings.

Mammogram was 1 year ago (due every 2 years) and colonoscopy was 6 years ago (due every 10 years).

Applying appropriate screening intervals prevents over-screening and unnecessary testing.

Assess the clinical presentation of back pain.

The back pain is mechanical, relieved by rest, with no red flags.

Determining the presence or absence of red flags guides the decision of whether advanced imaging is necessary.

Key Concept

Application of age- and risk-based preventive screening guidelines (USPSTF) and adult immunization schedules (ACIP).

Question 1923Question →

A $45$ -year-old woman presents to the emergency department with a temperature of $38.6^{\circ}\mathrm{C}$ ( $101.5^{\circ}\mathrm{F}$ ) measured at home. She is currently receiving adjuvant chemotherapy for early-stage breast cancer, with her last cycle administered $10$ days ago. She reports mild fatigue but no cough, dyspnea, abdominal pain, dysuria, or diarrhea. She is tolerating oral intake and lives with her husband $10$ minutes away from the hospital.

Vital signs are temperature $38.4^{\circ}\mathrm{C}$ ( $101.1^{\circ}\mathrm{F}$ ), blood pressure $118/76\mathrm{ mmHg}$ , pulse $92/\mathrm{min}$ , and respirations $14/\mathrm{min}$ . Physical examination reveals a well-appearing woman in no acute distress. There is no induration or erythema around her totally implantable venous access port.

Laboratory results show:

Test	Result	Reference Range
Hemoglobin	$11.2\mathrm{ g/dL}$	$12.0-16.0\mathrm{ g/dL}$
Platelets	$135,000/\mathrm{mm}^3$	$150,000-400,000/\mathrm{mm}^3$
Leukocytes	$800/\mathrm{mm}^3$	$4,500-11,000/\mathrm{mm}^3$
Absolute neutrophil count	$350/\mathrm{mm}^3$	$1,500-8,000/\mathrm{mm}^3$
Serum creatinine	$0.8\mathrm{ mg/dL}$	$0.6-1.2\mathrm{ mg/dL}$

Hepatic panel is within normal limits. Chest radiograph and urinalysis are unremarkable. Blood and urine cultures are obtained.

Which of the following is the most appropriate initial disposition and management plan?

Discharge home with oral ciprofloxacin and amoxicillin-clavulanate

Admit to the general medical floor and initiate intravenous cefepime

Admit to the intensive care unit and initiate intravenous vancomycin and cefepime

Discharge home without antibiotics and schedule an outpatient follow-up in 24 hours

Admit to an observation unit for 24 hours of intravenous fluids and withhold antibiotics pending culture results

Show answer & explanation

Answer: Discharge home with oral ciprofloxacin and amoxicillin-clavulanate

Answer

Discharge home with oral ciprofloxacin and amoxicillin-clavulanate

The most appropriate disposition for this patient is discharge to home with empiric oral antibiotics. This patient presents with febrile neutropenia, defined as a single oral temperature of

\ge 38.3^{\circ}\mathrm{C}

(

101.0^{\circ}\mathrm{F}

) and an absolute neutrophil count (ANC)

< 500/\mathrm{mm}^3

. The critical next step in management is risk stratification to determine the appropriate care setting. This patient meets the criteria for low-risk febrile neutropenia (e.g., a high MASCC score) because she has a solid malignancy, is hemodynamically stable, has no significant medical comorbidities (such as COPD or heart failure), is tolerating oral intake, and has reliable outpatient support. The standard of care for low-risk patients is outpatient management. The chosen antibiotic regimen must provide broad-spectrum coverage, particularly against Pseudomonas aeruginosa (covered by ciprofloxacin) and other Gram-positive and anaerobic organisms (covered by amoxicillin-clavulanate).

Step-by-Step Solution

Identify the primary clinical syndrome from the patient's presentation and laboratory results.

The patient has a fever (

38.4^{\circ}\mathrm{C}

) and an absolute neutrophil count (ANC) of

350/\mathrm{mm}^3

, establishing the diagnosis of febrile neutropenia.

Febrile neutropenia is a medical emergency that requires immediate risk stratification to guide disposition and treatment.

Risk stratify the patient using clinical criteria (e.g., MASCC or CISNE scores).

The patient is low-risk: she has a solid tumor (breast cancer), normal vital signs, no medical comorbidities, tolerates oral intake, and lives close to the hospital.

Disposition decisions in febrile neutropenia depend entirely on whether the patient is classified as high-risk or low-risk.

Determine the appropriate care setting and treatment regimen for a low-risk patient.

Outpatient disposition (discharge home) with broad-spectrum oral antibiotics covering Pseudomonas aeruginosa and Gram-positive organisms is indicated.

Evidence shows that outpatient management with oral fluoroquinolones (ciprofloxacin) and amoxicillin-clavulanate is safe and effective for low-risk febrile neutropenia, avoiding unnecessary hospitalization.

Key Concept

Patients with low-risk febrile neutropenia (solid tumors, stable vitals, no comorbidities, tolerating PO) should be managed in the outpatient setting with broad-spectrum oral antibiotics.

Estimated Time:1m 30s

Question 1924Question →

A $42$ -year-old woman with a history of bipolar I disorder is evaluated during a routine follow-up visit. She has been stable and euthymic on a fixed dose of lithium carbonate for the past $3$ years. Two weeks ago, she was diagnosed with primary hypertension by her primary care physician and started on hydrochlorothiazide. Today, she reports feeling well and has no new symptoms. Her blood pressure is $126/82$ mmHg, and her pulse is $72$ /min. Physical examination reveals no abnormalities, and there is no resting tremor.

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

Measurement of serum lithium concentration

Substitution of hydrochlorothiazide with lisinopril

Measurement of serum thyroid-stimulating hormone concentration

24

-hour urine collection for volume and osmolality

Continuation of current management with routine follow-up

Show answer & explanation

Answer: Measurement of serum lithium concentration

Answer

The most appropriate next step in management is the measurement of serum lithium concentration.

The correct answer is the measurement of serum lithium concentration. Lithium has a narrow therapeutic index (

0.6

1.2

mEq/L). Thiazide diuretics, such as hydrochlorothiazide, induce mild volume depletion and sodium loss. This physiological state triggers a compensatory increase in sodium reabsorption in the proximal convoluted tubule of the kidney. Because lithium is reabsorbed via the same transport mechanisms as sodium, the proximal reabsorption of lithium significantly increases. This can rapidly elevate serum lithium levels into the toxic range, even if the patient is currently asymptomatic. Therefore, when a thiazide diuretic is initiated in a patient stabilized on lithium, a serum lithium level must be checked within

1

2

weeks so that the lithium dose can be proactively adjusted (typically reduced) to prevent neurologic toxicity.

Step-by-Step Solution

Identify the patient's current medication regimen and recent changes.

The patient is on chronic lithium therapy and was recently started on hydrochlorothiazide for hypertension.

Recognizing medication changes is critical for identifying potential adverse drug-drug interactions.

Analyze the pharmacokinetic interaction between lithium and hydrochlorothiazide.

Thiazide diuretics induce sodium depletion, which leads to a compensatory increase in sodium reabsorption in the proximal tubule. Because lithium is handled similarly to sodium, its reabsorption is also increased.

Increased lithium reabsorption can rapidly elevate serum lithium concentrations to toxic levels.

Determine the necessary monitoring or intervention based on this interaction.

A serum lithium concentration should be measured to ensure it remains within the narrow therapeutic index.

Proactive monitoring allows for timely dose adjustment of lithium before the onset of clinical toxicity.

Key Concept

Thiazide diuretics decrease the renal clearance of lithium, leading to increased serum lithium concentrations and risk of toxicity. Therefore, serum lithium levels must be monitored closely when a thiazide diuretic is initiated.

Alternative Method

If a patient on lithium requires a new antihypertensive agent and frequent lab monitoring is not feasible, initiating a calcium channel blocker (like amlodipine) is often preferred as it has minimal impact on lithium clearance compared to thiazides, ACE inhibitors, or ARBs.

Estimated Time:1m 0s

Question 1925Question →

Match each patient's clinical presentation with the most appropriate initial disposition or care setting transition.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The correct matches are: the patient with severe pneumonia (CURB-65 = 5) to the intensive care unit; the stable patient with DVT to outpatient management; the stroke patient tolerating 3 hours of therapy to an inpatient rehabilitation facility; the patient with advanced dementia seeking comfort to hospice care; and the hip fracture patient tolerating 1 hour of therapy to a skilled nursing facility.

Each care setting is designed for specific patient needs based on acuity, rehabilitative capacity, and care goals. The ICU is for severe illness requiring intensive monitoring, such as a CURB-65 score of 5. Outpatient management is appropriate for stable acute conditions with low complication risk, like a stable DVT. An IRF is reserved for patients with significant deficits who can tolerate rigorous therapy (3 hours per day). An SNF is suitable for patients needing skilled care but with lower therapy endurance. Hospice is indicated for terminally ill patients prioritizing comfort.

Step-by-Step Solution

Evaluate the clinical severity and hemodynamic stability of each patient.

Identified that the patient with pneumonia is critically ill (high CURB-65 score), while the patient with DVT is clinically stable for ambulatory care.

Severity of illness determines whether critical care, general inpatient, or outpatient management is required.

Assess rehabilitation potential and therapy endurance for post-acute patients.

Differentiated the stroke patient who can tolerate 3 hours of therapy from the hip fracture patient who can only tolerate 1 hour.

Tolerance for 3 hours of daily therapy is the primary distinguishing factor between Inpatient Rehabilitation Facility (IRF) and Skilled Nursing Facility (SNF) placement.

Incorporate patient and family goals of care.

Identified that the patient with advanced dementia requires comfort-focused care rather than aggressive interventions.

Goals of care directly influence the transition to palliative or hospice settings.

Key Concept

Appropriate disposition requires synthesizing objective severity scores, functional capacity, therapy endurance, and patient-centered goals of care.

Question 1926Question →

A 24-year-old nulliparous female presents to the outpatient clinic after discovering a lump in her right breast three days ago. She states she felt it while showering and notes it is painless. She has no nipple discharge, skin changes, or cyclical breast pain. Her menstrual periods are regular, occurring every 28 days, and her last menstrual period was 10 days ago. She has no significant past medical history and takes no medications other than a daily multivitamin. There is no family history of breast or ovarian cancer. Vital signs are within normal limits. Physical examination reveals a 2-cm, well-circumscribed, firm, and freely mobile mass located in the upper outer quadrant of the right breast. There is no overlying erythema, skin dimpling, or nipple retraction. Axillary examination reveals no palpable lymphadenopathy. Which of the following is the most appropriate next step in the diagnostic workup of this patient's condition?

Targeted ultrasonography of the right breast

Diagnostic mammography

Core needle biopsy of the mass

Magnetic resonance imaging (MRI) of the breasts

Reassurance and clinical follow-up in six months

Show answer & explanation

Answer: Targeted ultrasonography of the right breast

Answer

Targeted ultrasonography of the right breast is the most appropriate next step in evaluation.

In a patient under the age of 30 presenting with a new palpable breast mass, targeted ultrasonography is the most appropriate initial diagnostic imaging modality. At this age, breast tissue is typically radiographically dense, which significantly reduces the sensitivity of mammography. Ultrasound can effectively characterize the lesion, distinguishing between cystic and solid masses, and helps guide whether further intervention, such as observation, aspiration, or core needle biopsy, is necessary. Although the mass has clinical features suggesting a benign fibroadenoma, imaging is required to establish the diagnosis.

Step-by-Step Solution

Analyze the patient's demographics and physical examination findings.

The patient is a 24-year-old female with a new, clinically benign-appearing (firm, mobile, well-circumscribed) palpable breast mass.

Patient age is the primary determinant for selecting the initial imaging modality in breast mass evaluation.

Apply age-based diagnostic sequencing guidelines for palpable breast masses.

For women under 30 years of age, targeted ultrasound is the preferred initial test. For women 30 years and older, diagnostic mammography is preferred.

Younger women have radiographically dense breast tissue, which limits the sensitivity of mammography. Ultrasound effectively distinguishes between solid masses (which may require biopsy) and simple cysts (which may be observed or aspirated).

Select the correct non-invasive diagnostic test to sequence before any invasive procedure.

Targeted ultrasonography must be selected before considering a core needle biopsy.

Proper test sequencing dictates that non-invasive imaging should precede invasive diagnostic procedures to accurately guide further management.

Key Concept

In women under 30 years of age presenting with a palpable breast mass, targeted ultrasonography is the initial diagnostic imaging modality of choice due to the radiographically dense nature of young breast tissue.

Question 1927Question →

During a routine outpatient visit, a $42$ -year-old man reports a $4$ -week history of unquenchable thirst and excessive urination. He estimates drinking over $6 \text{ L}$ of water daily and wakes up $3$ to $4$ times each night to void. His only past medical history is bipolar I disorder. He has been maintained on lithium carbonate for the past $3$ years, with excellent mood stability and no recent psychiatric hospitalizations. Vital signs are within normal limits.

Laboratory results are as follows:
Serum sodium: $148 \text{ mEq/L}$
Serum potassium: $4.1 \text{ mEq/L}$
Serum creatinine: $0.9 \text{ mg/dL}$
Serum lithium: $0.8 \text{ mEq/L}$ (therapeutic range: $0.6-1.2 \text{ mEq/L}$ )
Urine osmolality: $135 \text{ mOsm/kg H}_2\text{O}$

Following the administration of exogenous desmopressin, his urine osmolality remains largely unchanged at $140 \text{ mOsm/kg H}_2\text{O}$ . The patient's psychiatrist strongly advises against altering the bipolar treatment regimen, citing a history of severe, treatment-resistant mania prior to starting this specific medication. Which of the following is the most appropriate pharmacologic intervention to manage this patient's polyuria?

Amiloride

Hydrochlorothiazide

Indomethacin

Desmopressin

Tolvaptan

Show answer & explanation

Answer: Amiloride

Answer

Amiloride is the preferred pharmacologic treatment for lithium-induced nephrogenic diabetes insipidus because it blocks lithium's entry into the collecting duct cells without significantly altering systemic lithium clearance.

The correct answer is amiloride. Lithium causes nephrogenic diabetes insipidus by entering the principal cells of the collecting duct via epithelial sodium channels (ENaC) and interfering with the cAMP pathway, preventing aquaporin-2 insertion into the luminal membrane. Amiloride is an ENaC inhibitor that blocks lithium's entry into these cells, directly counteracting its toxic cellular effect. Crucially, amiloride is preferred over other typical NDI treatments (like thiazides or NSAIDs) because it does not significantly decrease the renal clearance of lithium, thereby maintaining stable and therapeutic serum lithium levels.

Step-by-Step Solution

Interpret the clinical presentation and laboratory findings.

The patient has polyuria, polydipsia, mild hypernatremia (

148 \text{ mEq/L}

), and inappropriately dilute urine (

135 \text{ mOsm/kg H}_2\text{O}

) that does not respond to exogenous desmopressin.

This establishes the diagnosis of nephrogenic diabetes insipidus (NDI), which is a well-known adverse effect of chronic lithium therapy.

Determine the optimal management strategy given the constraint.

The psychiatrist advises continuing lithium. Therefore, a pharmacologic intervention that treats NDI without causing lithium toxicity must be selected.

Discontinuing the offending agent is the general primary treatment for drug-induced NDI, but the risk of manic relapse necessitates medical management of the side effect instead.

Evaluate the mechanism of available NDI treatments regarding lithium pharmacokinetics.

Amiloride is chosen over hydrochlorothiazide and indomethacin.

Lithium enters the collecting duct principal cells via the epithelial sodium channel (ENaC). Amiloride directly blocks ENaC, preventing lithium accumulation in these cells. Unlike thiazides and NSAIDs, amiloride does not significantly decrease lithium clearance, thus avoiding systemic lithium toxicity.

Key Concept

Management of lithium-induced nephrogenic diabetes insipidus involves using amiloride to block ENaC channels, preventing lithium entry into principal cells while avoiding the decreased lithium clearance seen with thiazides and NSAIDs.

Question 1928Question →

A 55-year-old man is evaluated in the urgent care clinic for severe pain, swelling, and redness in his right knee that began abruptly overnight. The pain is exacerbated by minimal movement, and he has been unable to bear weight on the right leg today. He has a history of end-stage renal disease secondary to IgA nephropathy, for which he received a deceased-donor renal transplant 3 years ago. His maintenance immunosuppressive regimen consists of cyclosporine, mycophenolate mofetil, and prednisone 5 mg daily. He also takes amlodipine for hypertension. His temperature is 37.6°C (99.7°F), blood pressure is 138/86 mmHg, and pulse is 92/min. Physical examination reveals marked erythema, warmth, and a moderate effusion of the right knee. Arthrocentesis yields 15 mL of cloudy yellow synovial fluid. Synovial fluid analysis shows a leukocyte count of 28,000/mm³ with 85% neutrophils. Polarized light microscopy demonstrates negatively birefringent, needle-shaped crystals. Gram stain of the fluid is negative. Serum creatinine is 1.7 mg/dL (baseline 1.6 mg/dL). Which of the following is the most appropriate next step in the pharmacologic management of this patient?

Intra-articular triamcinolone acetonide

Oral colchicine

Oral indomethacin

Oral allopurinol

Intravenous vancomycin and ceftriaxone

Show answer & explanation

Answer: Intra-articular triamcinolone acetonide

Answer

Intra-articular triamcinolone acetonide

The correct answer is intra-articular triamcinolone acetonide. This patient is presenting with an acute gout flare, confirmed by the pathognomonic finding of negatively birefringent, needle-shaped monosodium urate crystals in an inflammatory synovial fluid. The management of acute gout typically involves NSAIDs, colchicine, or glucocorticoids. However, this patient's status as a renal transplant recipient on a specific immunosuppressive regimen severely restricts his options. Intra-articular glucocorticoids are highly effective for monoarticular gout and represent the safest choice for this patient, as they act locally and avoid the severe systemic drug interactions and nephrotoxic risks associated with the alternatives.

Step-by-Step Solution

Analyze the clinical presentation and synovial fluid results.

The patient has an acute monoarthritis. Synovial fluid shows 28,000 WBCs/mm³, negatively birefringent needle-shaped crystals, and a negative Gram stain, confirming an acute gout flare without superimposed septic arthritis.

Establishing the correct diagnosis is required before selecting targeted pharmacotherapy.

Evaluate the patient's medical history and current medication list for potential contraindications or interactions with standard gout therapies.

The patient is a renal transplant recipient taking cyclosporine (a calcineurin inhibitor and potent P-glycoprotein inhibitor). He also has a baseline elevated creatinine (1.6 mg/dL).

Standard first-line treatments for acute gout include NSAIDs, colchicine, and systemic or intra-articular glucocorticoids. Comorbidities dictate which options are safe.

Select the safest and most effective pharmacologic intervention based on the patient's specific constraints.

NSAIDs are contraindicated due to the risk of calcineurin inhibitor-induced nephrotoxicity. Colchicine is contraindicated due to a severe drug-drug interaction with cyclosporine. Intra-articular glucocorticoids are safe and effective.

Intra-articular injection treats the local inflammation effectively while avoiding the systemic toxicities and drug interactions associated with oral alternatives.

Key Concept

Management of acute gout flares in patients with significant comorbidities requires careful avoidance of NSAIDs in renal impairment/calcineurin inhibitor use, and avoidance of colchicine in the presence of strong P-glycoprotein or CYP3A4 inhibitors (e.g., cyclosporine). Intra-articular glucocorticoids are the safest option for monoarticular flares in these populations.

Question 1929Question →

A 36-year-old woman comes to the clinic for a routine health maintenance examination. She feels well and has no specific complaints. Her medical history is unremarkable, and she takes no daily medications. She is a lifelong non-smoker and drinks alcohol occasionally in social settings. Her last cervical cancer screening with a Papanicolaou (Pap) test and human papillomavirus (HPV) co-testing was 3 years ago and the results were normal. During the visit, the patient expresses anxiety about her cancer risk. She reports that her maternal aunt was diagnosed with breast cancer at age 48, and her maternal grandmother was diagnosed with ovarian cancer at age 62. The patient asks if she should undergo genetic testing for a hereditary cancer syndrome. Vital signs are within normal limits. Physical examination, including a clinical breast examination, reveals no abnormalities. Which of the following is the most appropriate next step in management?

Administer a brief familial risk assessment tool

Refer the patient directly for BRCA1 and BRCA2 genetic testing

Reassure the patient and advise initiating screening mammography at age 40

Order a serum CA-125 level and transvaginal ultrasound

Schedule the patient for a screening breast magnetic resonance imaging

Show answer & explanation

Answer: Administer a brief familial risk assessment tool

Answer

Administer a brief familial risk assessment tool

The correct next step is to administer a brief familial risk assessment tool. This patient has a family history that is highly suspicious for a hereditary cancer syndrome (breast cancer in a relative under age 50 and a relative with ovarian cancer). The United States Preventive Services Task Force (USPSTF) recommends that primary care clinicians assess women with a personal or family history of breast, ovarian, tubal, or peritoneal cancer using an appropriate brief familial risk assessment tool (e.g., the Ontario Family History Assessment Tool, Pedigree Assessment Tool, or FHS-7). If the tool indicates a positive result, the patient should then be referred for formal genetic counseling, and if indicated post-counseling, genetic testing. Proceeding directly to genetic testing or advanced imaging without this systematic assessment violates standard sequencing of preventive care.

Step-by-Step Solution

Evaluate the patient's family history for hereditary cancer risk factors.

The patient has a second-degree relative with ovarian cancer and a second-degree relative with early-onset breast cancer (diagnosed before age 50).

Identifying high-risk family history is the critical first step in determining the need for specialized genetic screening and altering routine preventive care.

Apply the appropriate evidence-based guideline for the identified risk profile.

The USPSTF recommends a specific stepwise approach for women with a personal or family history associated with an increased risk for BRCA1/2 gene mutations.

Guidelines dictate the specific sequence of interventions to ensure appropriate patient selection, maximize benefit, and minimize psychological distress from unnecessary testing.

Determine the next sequential clinical intervention.

The required first intervention is administering a brief familial risk assessment tool.

A validated clinical tool must be used to formally quantify risk; if the result is positive, the patient is then referred for genetic counseling, which must precede any actual genetic testing.

Key Concept

The initial management of a patient with a family history suggestive of a BRCA1/2 mutation is the administration of a brief familial risk assessment tool, not immediate genetic testing.

Question 1930Question →

During a comprehensive annual wellness exam, an asymptomatic postmenopausal patient discusses her current osteoporosis regimen. She has been strictly adherent to weekly oral alendronate for the past 5 years. She has remained physically active and reports no history of clinical fractures, bone pain, or loss of height. A dual-energy x-ray absorptiometry (DEXA) scan obtained prior to this visit reveals a femoral neck T-score of $-2.1$ , indicating stability compared to her prior assessments. Her renal function and serum calcium levels are normal.

Based on current clinical guidelines, arrange the following management and monitoring steps in the most appropriate chronological sequence for this patient's ongoing care.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological sequence is to first calculate the updated fracture risk, then discontinue the oral alendronate to initiate a drug holiday, follow up with annual clinical evaluations for fracture signs, and finally order a repeat DEXA scan in 2 to 4 years.

The patient has completed 5 years of oral bisphosphonate therapy and has a stable bone density without prior fractures, making her a candidate for a drug holiday. The protocol requires first formally establishing her low-to-moderate risk profile. Once confirmed, the alendronate is discontinued to reduce the risk of adverse events like atypical femur fractures. Monitoring then transitions to annual clinical checks for height loss or new bone pain, followed by a repeat DEXA scan in 2 to 4 years to definitively reassess the need for treatment resumption.

Step-by-Step Solution

Assess current fracture risk

Confirmation of low-to-moderate risk status

Determines eligibility for a therapeutic pause, as high-risk patients should continue therapy rather than stop.

Discontinue oral bisphosphonate

Initiation of the drug holiday

Mitigates the risk of atypical femur fractures and osteonecrosis of the jaw after 5 years of stable therapy.

Perform annual clinical monitoring

Early detection of height loss or clinical fractures

Ensures the patient remains clinically stable without antiresorptive coverage during the first few years off the drug.

Order a follow-up DEXA scan

Quantitative reassessment of bone mineral density in 2 to 4 years

Guides the decision on whether to extend the holiday or resume pharmacological treatment based on long-term bone density trends.

Key Concept

The management of osteoporosis in low-to-moderate risk patients involves initiating a bisphosphonate drug holiday after 5 years of oral therapy, followed by sequential clinical monitoring annually and densitometric monitoring every 2 to 4 years.

Question 1931Question →

Match each of the following ambulatory adult patients with the most appropriate next step in preventive care or screening based on current United States Preventive Services Task Force (USPSTF) guidelines.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The 52-year-old smoker matches with LDCT. The 38-year-old with obesity matches with blood glucose screening. The 66-year-old woman matches with bone measurement testing. The 23-year-old sexually active woman matches with chlamydia and gonorrhea screening.

Each match reflects current evidence-based guidelines from the USPSTF. LDCT is indicated based on age (50-80) and smoking history (>20 pack-years). Blood glucose screening is indicated based on age (35-70) and BMI (overweight/obese). Bone measurement testing is indicated for all women 65 and older. STI screening is indicated for all sexually active women under 25.

Step-by-Step Solution

Evaluate the 52-year-old man.

Low-dose computed tomography (LDCT) is indicated.

USPSTF recommends annual LDCT for adults aged 50-80 with a 20 pack-year smoking history who still smoke.

Evaluate the 38-year-old man.

Blood glucose screening is indicated.

USPSTF recommends diabetes screening in adults aged 35-70 years who have overweight or obesity (BMI ≥ 25 kg/m²).

Evaluate the 66-year-old woman.

Bone measurement testing is indicated.

USPSTF recommends osteoporosis screening for all women 65 years and older.

Evaluate the 23-year-old woman.

Chlamydia and gonorrhea screening is indicated.

USPSTF recommends screening for chlamydia and gonorrhea in sexually active women younger than 25.

Key Concept

Application of age- and risk-appropriate preventive screening guidelines for adults in the ambulatory setting.

Estimated Time:1m 30s

Question 1932Question →

Admitted for the management of an acute deep vein thrombosis, a $33$ -year-old female with systemic lupus erythematosus requires inpatient anticoagulation. She recently returned from a long international flight and developed sudden left calf swelling. Venous duplex ultrasonography confirms a new proximal thrombus. Her medical history is also notable for two spontaneous abortions and a prior diagnosis of antiphospholipid syndrome. She is prescribed an intravenous unfractionated heparin infusion. Before initiating the medication, baseline laboratory tests are obtained:

Laboratory Test	Result	Reference Range
Hemoglobin	$12.5$ g/dL	$12.0$ - $15.5$ g/dL
Platelet count	$195,000/\text{mm}^3$	$150,000$ - $400,000/\text{mm}^3$
Creatinine	$0.8$ mg/dL	$0.6$ - $1.1$ mg/dL
Prothrombin time (PT)	$12.2$ seconds	$11.0$ - $14.0$ seconds
Activated partial thromboplastin time (aPTT)	$68$ seconds	$25.0$ - $35.0$ seconds

Which of the following is the most appropriate laboratory test to monitor and titrate this patient's intravenous therapy?

Serial activated partial thromboplastin time (aPTT) measurements

Prothrombin time and International Normalized Ratio (PT/INR)

Anti-factor Xa level

Thrombin time

Serial D-dimer measurements

Show answer & explanation

Answer: Anti-factor Xa level

Answer

Anti-factor Xa level

The correct answer identifies the anti-factor Xa level as the best monitoring parameter. This patient has antiphospholipid syndrome (APS), which is strongly associated with the presence of lupus anticoagulant. Lupus anticoagulant binds to phospholipids in the laboratory assay, causing an artifactual prolongation of the baseline activated partial thromboplastin time (aPTT). Because standard unfractionated heparin protocols rely on tracking the prolongation of the aPTT, using this test in a patient whose aPTT is already prolonged at baseline would misleadingly suggest the heparin dose is therapeutic or supratherapeutic. This leads to profound under-dosing and clinical failure. The anti-factor Xa assay directly measures the ability of heparin-bound antithrombin to inhibit factor Xa and is unaffected by antiphospholipid antibodies.

Step-by-Step Solution

Evaluate the patient's baseline diagnosis and laboratory findings.

The patient has antiphospholipid syndrome (APS) and a significantly prolonged baseline aPTT (

68

seconds) with a normal PT and platelet count.

Establishing the baseline coagulation status is essential before initiating and titrating any anticoagulant infusion.

Identify the mechanism behind the baseline laboratory abnormality.

The prolonged aPTT is an in vitro artifact caused by the lupus anticoagulant (an antiphospholipid antibody) binding to the phospholipids used in the laboratory assay.

Understanding whether a prolonged aPTT represents a true bleeding diathesis or an artifact dictates the choice of therapeutic monitoring.

Determine the optimal monitoring strategy for unfractionated heparin in this context.

Because the baseline aPTT is already artificially prolonged, standard aPTT titration protocols will be highly inaccurate and risk under-dosing. The anti-factor Xa assay directly measures heparin's inhibitory effect on factor Xa without relying on phospholipid reagents.

Anti-factor Xa levels provide an accurate assessment of heparin's anticoagulant effect regardless of lupus anticoagulant interference.

Key Concept

In patients with antiphospholipid syndrome and a lupus anticoagulant, the baseline aPTT is often artifactually prolonged. Consequently, unfractionated heparin therapy cannot be reliably monitored with aPTT and must instead be titrated using an anti-factor Xa assay to prevent dangerous under-dosing.

Question 1933Question →

A $65$ -year-old man comes to the clinic for a follow-up visit. He has a history of an unprovoked pulmonary embolism $6$ months ago and is on maintenance anticoagulation with rivaroxaban $20 \text{ mg}$ daily. Two weeks ago, he was evaluated by a neurologist for new-onset focal impaired awareness seizures and was started on phenytoin. The patient reports no recurrent chest pain, shortness of breath, or bleeding episodes. His vital signs and physical examination are unremarkable. Renal and hepatic function tests are within normal limits. Which of the following is the most appropriate next step in the management of this patient's pharmacotherapy?

Discontinue rivaroxaban, initiate enoxaparin, and begin warfarin therapy

Continue the current dose of rivaroxaban and monitor anticoagulant efficacy using the prothrombin time (PT)

Discontinue phenytoin, initiate carbamazepine, and maintain the current dose of rivaroxaban

Switch rivaroxaban to dabigatran and continue treatment without routine laboratory monitoring

Maintain the current medication regimen and order a non-contrast computed tomography scan of the head

Show answer & explanation

Answer: Discontinue rivaroxaban, initiate enoxaparin, and begin warfarin therapy

Answer

Discontinue rivaroxaban, initiate enoxaparin, and begin warfarin therapy.

The correct answer addresses the severe pharmacokinetic interaction between rivaroxaban and phenytoin. Phenytoin is a potent inducer of both Cytochrome P450 3A4 (CYP3A4) and P-glycoprotein (P-gp). Because rivaroxaban is metabolized by CYP3A4 and serves as a substrate for P-gp efflux pumps, coadministration with phenytoin rapidly accelerates its clearance, resulting in subtherapeutic plasma levels and an unacceptable risk of recurrent venous thromboembolism. Direct oral anticoagulants (DOACs) lack widely available, validated assays for routine dose titration. Therefore, the safest clinical approach is to transition the patient to warfarin. Although warfarin metabolism (via CYP2C9) is also induced by phenytoin, its anticoagulant effect can be objectively quantified using the International Normalized Ratio (INR), allowing the clinician to safely titrate the dose upward to achieve the target range of

2.0

3.0

. Because the patient has been unprotected for two weeks and warfarin initiation temporarily exacerbates hypercoagulability (due to rapid depletion of Protein C and S), an immediate parenteral bridge with enoxaparin is mandatory until the INR reaches the therapeutic range.

Step-by-Step Solution

Analyze the pharmacokinetic properties of the current medication regimen.

Phenytoin is identified as a strong dual inducer of CYP3A4 and P-glycoprotein (P-gp), while rivaroxaban is a substrate for both.

Identifying drug-drug interactions is critical when a new medication is added to a patient on a direct oral anticoagulant (DOAC).

Determine the clinical consequence of the drug-drug interaction.

The induction of CYP3A4 and P-gp significantly increases the clearance of rivaroxaban, leading to subtherapeutic plasma concentrations and a high risk of recurrent pulmonary embolism.

DOAC levels cannot be routinely monitored to titrate around strong inducers, making coadministration contraindicated.

Select a safe and monitorable alternative anticoagulant.

Warfarin is chosen because its anticoagulant effect can be directly and objectively monitored using the International Normalized Ratio (INR), allowing for precise dose adjustments despite hepatic enzyme induction.

Objective laboratory monitoring ensures therapeutic anticoagulation when pharmacokinetic variables are altered.

Implement a safe transition strategy.

Enoxaparin (a low-molecular-weight heparin) is initiated concurrently with warfarin.

Because the patient's rivaroxaban is currently ineffective, and warfarin causes a transient hypercoagulable state by depleting Protein C and S, a parenteral bridge is required until the INR is therapeutic.

Key Concept

Patients requiring strong CYP3A4 and P-glycoprotein inducers (e.g., phenytoin, carbamazepine) should not receive DOACs due to unpredictable reductions in anticoagulant efficacy; warfarin with proper bridging and INR monitoring is the standard alternative.

Question 1934Question →

A female renal transplant recipient is evaluated in the ambulatory care center for a persistent cough, low-grade fever, and purulent sputum production. She has been clinically stable on a maintenance immunosuppressive regimen of tacrolimus, mycophenolate mofetil, and prednisone for the past three years. Her most recent renal function and drug trough levels from two weeks ago were within target ranges. A chest radiograph reveals a new focal infiltrate in the right lower lobe, and the physician decides to prescribe a 7-day course of oral clarithromycin for atypical bacterial coverage. In addition to treating the respiratory infection, which of the following are the most appropriate immediate steps in monitoring and treatment evaluation for this patient? (Select exactly two options)

Select all that apply

Empirically reduce the daily dosage of tacrolimus

Obtain a serum tacrolimus trough concentration in 2 to 3 days

Hold mycophenolate mofetil for the duration of antibiotic therapy

Monitor the activated partial thromboplastin time every 48 hours

Schedule an urgent ultrasound-guided percutaneous renal biopsy

Show answer & explanation

Answer: Empirically reduce the daily dosage of tacrolimus; Obtain a serum tacrolimus trough concentration in 2 to 3 days

Answer

The correct steps are to empirically reduce the daily dosage of tacrolimus and to obtain a serum tacrolimus trough concentration in 2 to 3 days.

Clarithromycin is a potent inhibitor of the cytochrome P450 3A4 (CYP3A4) isoenzyme, which is primarily responsible for the hepatic and intestinal metabolism of tacrolimus. When a strong CYP3A4 inhibitor is added to a patient stabilized on tacrolimus, the clearance of tacrolimus is drastically reduced, leading to supratherapeutic levels and a high risk of nephrotoxicity and neurotoxicity. Standard clinical management dictates an immediate empirical dose reduction of tacrolimus (often by 30% to 50%) along with early reassessment of the tacrolimus trough level (typically within 48 to 72 hours) to ensure the new dose maintains the patient within the narrow therapeutic index.

Step-by-Step Solution

Identify the critical drug-drug interaction between the newly prescribed medication and the patient's maintenance regimen.

Clarithromycin is identified as a strong CYP3A4 inhibitor, whereas tacrolimus is a major CYP3A4 substrate.

Recognizing this interaction is essential because adding a strong inhibitor will drastically increase the serum concentration of the substrate.

Determine the necessary pharmacological adjustment.

The daily dosage of tacrolimus must be empirically reduced at the time clarithromycin is initiated.

Preemptive dose reduction prevents acute tacrolimus toxicity, which can manifest as severe acute kidney injury, neurotoxicity, or new-onset diabetes.

Establish an ongoing monitoring plan.

A serum tacrolimus trough level should be scheduled for 2 to 3 days after initiating therapy.

Because the exact degree of CYP3A4 inhibition varies among individuals, early and serial therapeutic drug monitoring is required to titrate the tacrolimus dose back to the target therapeutic window.

Key Concept

CYP3A4 inhibitors (e.g., macrolide antibiotics like clarithromycin) significantly increase serum concentrations of calcineurin inhibitors (e.g., tacrolimus), requiring preemptive dose reduction and close therapeutic drug monitoring to prevent toxicity.

Question 1935Question →

A 65-year-old woman is evaluated in the intensive care unit for refractory shock. She was admitted two days ago for severe community-acquired pneumonia and initially improved on broad-spectrum intravenous antibiotics. Over the past 4 hours, her condition has deteriorated. Her blood pressure is 70/40 mmHg despite the administration of 3 liters of intravenous isotonic crystalloids. The decision is made to initiate a continuous norepinephrine infusion via a central venous catheter. The physician prepares the right internal jugular vein site with chlorhexidine, applies sterile drapes, and utilizes ultrasound guidance for the procedure. Arrange the following procedural steps of the Seldinger technique for central venous catheter placement in the correct chronological sequence.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological sequence for the Seldinger technique is: 1) Access the vessel with the introducer needle, 2) Advance the guidewire through the needle, 3) Withdraw the introducer needle, 4) Advance and remove the tissue dilator over the guidewire, and 5) Thread the central venous catheter over the guidewire and remove the guidewire.

The Seldinger technique is the universal standard for establishing safe central venous access. The procedure follows a strict chronological order to maintain vascular access while minimizing trauma. The sequence begins with venous puncture using a small introducer needle. A guidewire is then passed through the needle to hold the place in the vessel. The rigid needle is removed, leaving the flexible wire. A dilator is temporarily advanced over the wire to enlarge the tissue tract, followed by the definitive central venous catheter. Once the catheter is securely in the vessel, the guidewire is completely removed.

Step-by-Step Solution

Venous Access

Target vessel punctured

To establish an initial tract into the vascular lumen under direct visualization.

Guidewire Insertion

Guidewire secured in vessel

To maintain access and establish a secure, flexible pathway into the vein.

Needle Removal

Needle removed, wire remains

To clear the pathway over the wire so larger instruments can be passed.

Tract Dilation

Subcutaneous tract enlarged

To accommodate the larger diameter of the central venous catheter without causing tissue trauma during insertion.

Catheter Placement

Catheter in place, wire removed

To position the catheter for fluid and medication infusion, followed by necessary wire removal to prevent embolism.

Key Concept

The Seldinger technique is the foundational method for safe, over-the-wire central venous catheter placement and other vascular procedures.

Estimated Time:1m 30s

Question 1936Question →

A 61-year-old woman is recovering on the medical step-down unit after a prolonged intensive care course for severe acute respiratory distress syndrome (ARDS). She has been successfully extubated but has developed significant critical illness myopathy and profound deconditioning. She is now medically stable and ready for discharge planning. Arrange the following steps of the care transition process in the most appropriate chronological sequence to ensure a safe and effective discharge.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence is to first assess functional needs via PT/OT, use those findings to determine the required level of care, discuss the plan with the family, submit documentation for authorization, and finally provide a clinical handoff to the accepting provider.

Safe and effective disposition planning follows a strict logical sequence. It begins with data gathering (PT/OT evaluation) to objectively measure deficits. This data is then used to synthesize a medical recommendation (determining the appropriate level of care). Because healthcare is collaborative, this recommendation must be validated with the patient and family (family meeting). Only after a destination type is agreed upon can the administrative process begin (submitting for insurance authorization). Finally, once the transfer is approved and a bed is ready, the clinical transition is completed via a structured physician handoff and discharge summary transmission.

Step-by-Step Solution

Identify the patient's immediate barrier to discharge.

The patient has critical illness myopathy and requires rehabilitation, necessitating PT/OT evaluation.

Disposition planning cannot proceed without objective data on the patient's physical capabilities and therapy tolerance.

Translate the physical assessment into a disposition recommendation.

The team decides between an Inpatient Rehabilitation Facility (IRF) or Skilled Nursing Facility (SNF).

Different facilities have distinct admission criteria (e.g., ability to tolerate 3 hours of therapy daily for IRF).

Engage stakeholders in shared decision-making.

A family meeting is held to agree on the post-acute care setting.

Patient autonomy and family resources must align with the medical recommendation before a specific facility is targeted.

Execute the administrative transfer requirements.

Clinical notes are sent to the insurance company and the chosen facility for authorization.

A patient cannot be transferred without financial clearance and an accepted bed offer from the receiving facility.

Perform the clinical transition of care.

A verbal handoff is given and the discharge summary is sent.

Patient safety during transitions relies on accurate communication of the hospital course, pending labs, and active issues to the next provider.

Key Concept

The chronological workflow for complex hospital discharges requires objective functional assessment, followed by clinical decision-making, patient/family consensus, administrative authorization, and finally, structured clinical handoff.

Question 1937Question →

A 76-year-old man is brought to the emergency department from a nursing facility due to progressive abdominal distension, severe cramping abdominal pain, and failure to pass stool or flatus for the past 3 days. His medical history is notable for Parkinson disease, chronic constipation, and hypertension. His daily medications include carbidopa-levodopa, lisinopril, and an osmotic laxative.

His temperature is 37.1°C (98.8°F), blood pressure is 138/82 mm Hg, heart rate is 88/min, and respiratory rate is 16/min.

Physical examination reveals a markedly distended abdomen that is tympanitic to percussion. The abdomen is mildly tender diffusely but lacks rebound tenderness, rigidity, or guarding. Bowel sounds are absent.

An upright plain abdominal radiograph demonstrates a massively dilated loop of colon extending from the left lower quadrant toward the right upper quadrant, adopting a "coffee bean" appearance. There is no evidence of pneumoperitoneum.

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

Flexible sigmoidoscopy

Exploratory laparotomy

Intravenous neostigmine

Computed tomography of the abdomen and pelvis with intravenous contrast

Discharge to the nursing facility with an aggressive bowel regimen

Show answer & explanation

Answer: Flexible sigmoidoscopy

Answer

Flexible sigmoidoscopy

The correct answer is flexible sigmoidoscopy. The patient's presentation of progressive abdominal distension, obstipation, and a plain abdominal radiograph demonstrating a massively dilated colon loop pointing toward the right upper quadrant (the classic "coffee bean" sign) is highly specific for a sigmoid volvulus. Patients with a history of chronic constipation, neurologic conditions (e.g., Parkinson disease), or psychiatric disorders are at high risk. Because the patient's vital signs are stable and the physical examination shows no signs of peritonitis (such as rigidity or rebound tenderness) or bowel ischemia, the standard first-line management is non-operative. Flexible sigmoidoscopy allows for direct visualization, endoscopic detorsion of the twisted bowel segment, and placement of a decompression tube. Once the patient is decompressed and optimized, an elective sigmoid colectomy is typically performed during the same hospitalization due to the high risk of recurrence.

Step-by-Step Solution

Analyze the clinical presentation and radiograph

The patient has a large bowel obstruction with a classic "coffee bean" sign on the X-ray.

Identifying the specific type of obstruction (sigmoid volvulus) dictates the specific procedural intervention.

Assess the patient for signs of complications

The patient is hemodynamically stable and lacks peritoneal signs (no rigidity or rebound tenderness).

The presence of peritonitis or hemodynamic instability would mandate emergent surgical intervention.

Determine the most appropriate initial procedural intervention

Endoscopic detorsion via flexible sigmoidoscopy.

It is the standard first-line therapy for uncomplicated sigmoid volvulus to relieve the obstruction non-invasively.

Key Concept

In a hemodynamically stable patient with a sigmoid volvulus and no clinical signs of peritonitis or bowel ischemia, the initial treatment of choice is endoscopic detorsion and decompression via flexible sigmoidoscopy.

Question 1938Question →

A $72$ -year-old man is evaluated in the clinic for a routine follow-up. One week ago, he was started on oral amiodarone for the suppression of highly symptomatic, recurrent atrial fibrillation. His other medical conditions include hypertension, hyperlipidemia, and type 2 diabetes mellitus. His current medications include lisinopril, simvastatin $80\text{ mg}$ daily, and metformin. He feels well and reports no new symptoms. As part of the ongoing monitoring and treatment evaluation plan for this patient, which of the following are appropriate management steps? (Select all that apply)

Select all that apply

Perform baseline and periodic assessment of thyroid-stimulating hormone (TSH) levels

Obtain a baseline chest radiograph and periodically evaluate for pulmonary toxicity

Maintain the current simvastatin dosage, as there are no clinically significant pharmacokinetic interactions to address

Order a baseline high-resolution computed tomography (HRCT) scan of the chest to definitively exclude underlying interstitial lung disease

Plan to discontinue the antiarrhythmic agent immediately if asymptomatic,

1.5

-fold elevations in serum aminotransferases are detected

Show answer & explanation

Answer: Perform baseline and periodic assessment of thyroid-stimulating hormone (TSH) levels; Obtain a baseline chest radiograph and periodically evaluate for pulmonary toxicity

Answer

The appropriate management steps are to perform baseline and periodic assessment of thyroid-stimulating hormone (TSH) levels and to obtain a baseline chest radiograph to evaluate for pulmonary toxicity.

Amiodarone is a highly efficacious antiarrhythmic agent with a complex safety profile involving substantial end-organ toxicities and drug interactions. Standard of care for monitoring its use includes baseline and periodic evaluation of thyroid function (TSH) because its high iodine content and intrinsic mechanisms can induce either hyperthyroidism or hypothyroidism. Additionally, baseline pulmonary screening with a chest radiograph is mandated to monitor for amiodarone-induced interstitial pneumonitis, a potentially fatal complication.

Step-by-Step Solution

Identify the high-risk pharmacotherapy recently initiated.

The patient was started on amiodarone, a class III antiarrhythmic with significant multi-organ toxicities and profound drug-drug interactions.

Recognizing the safety profile of amiodarone dictates the necessary baseline monitoring and treatment adjustments.

Determine the standard screening and monitoring requirements for amiodarone.

Baseline evaluation of hepatic (LFTs), thyroid (TSH), pulmonary (CXR/PFTs), and ophthalmic function is required to establish a baseline and monitor for ongoing drug toxicity.

Amiodarone can cause fatal pulmonary fibrosis, thyroid dysfunction, and hepatotoxicity; establishing a baseline is critical for longitudinal treatment evaluation.

Evaluate the patient's existing medication regimen for potential interactions with the new agent.

The patient is taking high-dose simvastatin (

80\text{ mg}

). Amiodarone inhibits CYP3A4, which significantly increases simvastatin serum concentrations.

Failing to adjust the simvastatin dose (maximum recommended dose with amiodarone is

20\text{ mg}

/day) drastically increases the risk of rhabdomyolysis. Therefore, maintaining the current dose is incorrect.

Key Concept

Patients initiating amiodarone therapy require rigorous baseline and periodic monitoring of pulmonary, thyroid, and hepatic function, alongside careful review of drug interactions (e.g., CYP3A4 inhibition affecting statins).

Question 1939Question →

A 22-year-old woman is evaluated in the intensive care unit for ongoing management of acetaminophen toxicity. She presented to the emergency department 4 hours after an intentional ingestion of an unknown quantity of acetaminophen, at which time her serum acetaminophen level was 180 µg/mL. She was promptly started on a standard 21-hour intravenous N-acetylcysteine (NAC) protocol. She is currently asymptomatic, denies nausea or abdominal pain, and is tolerating oral intake. She is currently at the 20th hour of the NAC infusion.

Laboratory results drawn 1 hour ago (at hour 19 of the infusion) show:

Laboratory Test	Current Result	Admission Result
Acetaminophen	< 10 µg/mL	180 µg/mL
Aspartate aminotransferase (AST)	850 U/L	45 U/L
Alanine aminotransferase (ALT)	920 U/L	50 U/L
Total bilirubin	1.1 mg/dL	0.8 mg/dL
INR	1.1	1.0
Creatinine	0.8 mg/dL	0.8 mg/dL

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

Continue intravenous N-acetylcysteine at the current maintenance rate

Discontinue intravenous N-acetylcysteine and transition to oral N-acetylcysteine

Discontinue intravenous N-acetylcysteine and recheck transaminases in 12 hours

Consult hepatology for urgent liver transplantation evaluation

Administer fresh frozen plasma and continue intravenous N-acetylcysteine

Show answer & explanation

Answer: Continue intravenous N-acetylcysteine at the current maintenance rate

Answer

Continue intravenous N-acetylcysteine at the current maintenance rate

The decision to discontinue N-acetylcysteine (NAC) therapy following the standard 21-hour intravenous protocol requires all of the following criteria to be met: the patient must be clinically asymptomatic, the serum acetaminophen concentration must be undetectable, the INR must be less than 1.5, and the serum transaminases (AST and ALT) must be normal or clearly trending downward. Although this patient's acetaminophen level is undetectable and her INR is normal, her transaminases have increased significantly since admission and have not yet demonstrated a downward trend. Therefore, the NAC infusion must be continued at the maintenance rate (6.25 mg/kg/hr) beyond the initial 21 hours. The infusion should be maintained, and laboratory values should be rechecked every 12 hours until the transaminases peak and begin to definitively decline.

Step-by-Step Solution

Evaluate the patient's current clinical status and laboratory parameters against the established stopping criteria for the 21-hour intravenous N-acetylcysteine (NAC) protocol.

The patient is asymptomatic, has an undetectable acetaminophen level, and a normal INR. However, her transaminases (AST and ALT) have risen significantly since admission and have not yet peaked or demonstrated a downward trend.

Stopping NAC prematurely in the setting of ongoing active liver injury can lead to fulminant hepatic failure.

Determine the appropriate management modification for a patient who does not meet all criteria to discontinue NAC.

The correct action is to continue the continuous maintenance infusion of IV NAC.

Guidelines mandate that the maintenance rate (6.25 mg/kg/hr) be continued continuously until all stopping criteria (including down-trending transaminases) are met.

Key Concept

Evaluation of criteria for discontinuing N-acetylcysteine therapy in acetaminophen toxicity

Question 1940Question →

During morning rounds, a physician evaluates a $54$ -year-old woman who has been hospitalized for the past $48$ hours for community-acquired pneumonia. Upon initial presentation to the emergency department, she was acutely ill with a temperature of $39.2^\circ\text{C}$ ( $102.6^\circ\text{F}$ ), a heart rate of $115/\text{min}$ , a respiratory rate of $24/\text{min}$ , and an oxygen saturation of $91\%$ breathing ambient air. A chest radiograph demonstrated a right lower lobe consolidation. Blood and sputum cultures were collected, and she was subsequently started on empiric intravenous ceftriaxone and oral azithromycin.

Currently, the patient states that her cough has decreased in frequency and her pleuritic chest discomfort is much less severe. Vital signs today reveal a temperature of $38.3^\circ\text{C}$ ( $100.9^\circ\text{F}$ ), a heart rate of $92/\text{min}$ , a respiratory rate of $18/\text{min}$ , and a blood pressure of $118/76 \text{ mm Hg}$ . Her oxygen saturation has improved to $96\%$ on room air. The initial cultures have shown no microbial growth to date. Morning laboratory results indicate a leukocyte count of $13,500/\mu\text{L}$ , which is a decline from her admission value of $17,000/\mu\text{L}$ .

Which of the following is the most appropriate next step in the monitoring and treatment evaluation of this patient?

Continue the current antimicrobial regimen and maintain routine clinical monitoring

Broaden the antimicrobial coverage by initiating piperacillin-tazobactam and vancomycin

Obtain a computed tomography scan of the chest with intravenous contrast

Transition the patient to oral levofloxacin and process her for hospital discharge

Perform a flexible bronchoscopy with bronchoalveolar lavage to identify a specific pathogen

Show answer & explanation

Answer: Continue the current antimicrobial regimen and maintain routine clinical monitoring

Answer

The most appropriate next step is to continue the current antimicrobial regimen and maintain routine clinical monitoring.

The correct answer is to continue current management because the patient is demonstrating an appropriate and expected clinical response 48 hours after the initiation of empiric antibiotic therapy for community-acquired pneumonia (CAP). Her subjective symptoms are resolving, her vital signs are normalizing, and her leukocytosis is trending downward. While she remains mildly febrile, it is completely expected for a fever to persist for up to 72 hours (or longer in some cases) following the start of effective antimicrobial therapy. Because all other clinical indicators point toward recovery, the most appropriate management is simply to continue the current regimen and observe.

Step-by-Step Solution

Evaluate the patient's current clinical status compared to admission.

The patient's symptoms are improving, her leukocytosis is resolving, and her hemodynamics and oxygenation are normalizing, although a low-grade fever persists.

Determining the overall trajectory of the illness is essential before deciding whether to alter the current therapeutic plan.

Determine the expected timeline for defervescence in community-acquired pneumonia.

Fever in successfully treated community-acquired pneumonia typically takes 48 to 72 hours to resolve.

Understanding the normal physiological response timeline prevents inappropriate reactions to isolated persistent symptoms.

Select the most appropriate management plan based on the clinical trajectory.

Continuing the current regimen and observing is the safest and most effective choice.

Since the patient is improving exactly as expected, unnecessary escalations, imaging, or premature discharge would introduce risks without providing any clinical benefit.

Key Concept

Patients with community-acquired pneumonia who demonstrate objective clinical improvement (e.g., stabilizing heart rate, improving oxygenation, resolving leukocytosis) should be continued on their current antimicrobial regimen, as fever can normally persist for 48 to 72 hours after initiation of appropriate therapy.

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