Internal Medicine

3151 questions

Question 461Question →

A 65-year-old man is brought to the emergency department due to severe, sudden-onset shortness of breath that awakened him from sleep. The patient has a history of essential hypertension, hyperlipidemia, type 2 diabetes mellitus, and a 35-pack-year history of smoking. Current medications include amlodipine, metformin, and atorvastatin.

Temperature is 37.1°C (98.8°F), blood pressure is 210/115 mmHg, heart rate is 115/min, and respiratory rate is 28/min. Pulse oximetry is 88% on room air.

Physical examination reveals an anxious, diaphoretic man in severe respiratory distress, utilizing accessory muscles of respiration. Lung auscultation reveals a prolonged expiratory phase with diffuse bilateral wheezing and scattered crackles in the lower lung fields. Cardiac examination shows a tachycardic, regular rhythm with a prominent S4 gallop and no murmurs. There is 1+ bilateral pitting edema of the lower extremities.

Arterial blood gas on room air shows:
MeasurementValueReference Range
pH7.267.35 - 7.45
PaCO2PaCO_258 mmHg35 - 45 mmHg
PaO2PaO_255 mmHg75 - 105 mmHg
HCO3−HCO_3^-25 mEq/L22 - 28 mEq/L
Recent outpatient laboratory results from two days ago show:
MeasurementValueReference Range
Thyroid-stimulating hormone (TSH)1.2 µU/mL0.4 - 4.0 µU/mL
Free thyroxine (T4)0.7 ng/dL0.9 - 1.7 ng/dL

Chest radiograph demonstrates bilateral perihilar alveolar opacities, indistinct pulmonary vascular margins, and cephalization of the pulmonary veins. There is no focal lobar consolidation.

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

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Answer: Intravenous nitroglycerin and noninvasive positive-pressure ventilation

Answer

Intravenous nitroglycerin and noninvasive positive-pressure ventilation
The patient is presenting with sympathetic crashing acute pulmonary edema (SCAPE), characterized by extreme sympathetic drive, severe vasoconstriction, and a rapid spike in afterload that overwhelms the left ventricle. This leads to flash pulmonary edema. The wheezing occurs due to peribronchial edema, often termed 'cardiac asthma'. The most appropriate initial step is aggressive afterload and preload reduction with intravenous nitroglycerin, combined with noninvasive positive-pressure ventilation (NIPPV). NIPPV serves dual purposes: it mechanically stents open fluid-filled alveoli to improve gas exchange (correcting the acute respiratory acidosis), and it increases intrathoracic pressure, which physiologically decreases both venous return (preload) and left ventricular transmural pressure (afterload).

Step-by-Step Solution

1
Evaluate the patient's vital signs and acute respiratory presentation.
The patient exhibits severe hypertension (210/115 mmHg), tachycardia, tachypnea, and hypoxia.
Recognizing a hypertensive emergency is crucial to identifying the underlying cause of the respiratory failure.
2
Analyze the physical examination and imaging findings.
The presence of an S4 gallop, diffuse wheezing, crackles, and a chest radiograph showing perihilar opacities with cephalization confirms acute fluid overload.
This differentiates cardiogenic pulmonary edema ('cardiac asthma') from a primary airway obstruction like a COPD exacerbation.
3
Interpret the arterial blood gas results.
A pH of 7.26 and PaCO2 of 58 mmHg indicates an acute, uncompensated respiratory acidosis.
This confirms impending respiratory failure due to increased work of breathing, mandating immediate ventilatory support rather than metabolic buffering.
4
Interpret the outpatient thyroid laboratory results.
A low Free T4 with a normal TSH indicates euthyroid sick syndrome.
This rules out myxedema coma and prevents the dangerous administration of exogenous thyroid hormone during an acute cardiac event.
5
Determine the optimal therapeutic intervention.
Select aggressive afterload reduction (nitroglycerin) and positive pressure ventilation (NIPPV).
Nitroglycerin rapidly decreases left ventricular afterload and preload, while NIPPV improves alveolar gas exchange and further reduces cardiac work.

Key Concept

Sympathetic crashing acute pulmonary edema (SCAPE)
Question 462Question →

A 7171-year-old woman is evaluated in the surgical step-down unit for a sudden onset of shortness of breath and a nonproductive cough. She is currently on postoperative day 33 following an uncomplicated right total knee arthroplasty. Her medical history is significant for coronary artery disease, heart failure with preserved ejection fraction, and a 4040-pack-year smoking history with known chronic obstructive pulmonary disease. Her temperature is 37.4∘C37.4^\circ\text{C} (99.3∘F99.3^\circ\text{F}), blood pressure is 168/96 mmHg168/96\text{ mmHg}, pulse is 108/min108/\text{min}, and respirations are 26/min26/\text{min}. Oxygen saturation is 89%89\% on room air. Physical examination reveals distended neck veins with a jugular venous pressure of 11 cm H2O11\text{ cm H}_2\text{O}. Chest auscultation demonstrates a prolonged expiratory phase with diffuse bilateral wheezes and scattered bibasilar crackles. Cardiac examination reveals a regular tachycardia with a distinct S4 gallop and no murmurs. Her lower extremities show bilateral 2+2+ pitting edema, which is unchanged from her preoperative baseline. Which of the following is the most appropriate next step in management?

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Answer: Intravenous loop diuretic therapy

Answer

Intravenous loop diuretic therapy is the most appropriate next step to manage this patient's acute decompensated heart failure.
The correct answer is the administration of intravenous loop diuretics. This patient is experiencing acute decompensated heart failure (ADHF). In the postoperative period, third-spaced fluids mobilize back into the intravascular space, frequently precipitating volume overload in patients with underlying heart failure (such as her known HFpEF). Her presentation of elevated jugular venous pressure, bibasilar crackles, and an S4 gallop strongly points to left and right-sided volume overload. The diffuse wheezing she is experiencing is known as 'cardiac asthma,' which occurs when pulmonary venous congestion leads to peribronchial edema, narrowing the small airways. The most critical next step is rapid diuresis to decrease preload and resolve the pulmonary edema.

Step-by-Step Solution

1
Analyze the patient's vital signs and physical examination findings.
The patient has severe hypertension (168/96 mmHg168/96\text{ mmHg}), tachypnea, hypoxia, elevated JVP (11 cm H2O11\text{ cm H}_2\text{O}), bilateral crackles, wheezing, and an S4 gallop.
Identifying the constellation of symptoms distinguishes between primary pulmonary and cardiovascular etiologies.
2
Differentiate the cause of wheezing in the context of her comorbidities.
Despite her COPD history, the presence of crackles, an S4 gallop (indicating a stiff, non-compliant left ventricle), and elevated JVP strongly suggests fluid overload (acute decompensated heart failure) leading to peribronchial edema, clinically presenting as 'cardiac asthma'.
Postoperative fluid mobilization frequently triggers acute decompensated heart failure in patients with a history of heart failure with preserved ejection fraction.
3
Determine the most urgent therapeutic intervention.
Administration of an intravenous loop diuretic (e.g., furosemide) to rapidly reduce intravascular volume and alleviate pulmonary congestion.
Immediate preload reduction is required to resolve the pulmonary edema and improve oxygenation.

Key Concept

Patients with acute decompensated heart failure can present with wheezing (cardiac asthma) due to peribronchial edema. Elevated jugular venous pressure, bibasilar crackles, and an S3 or S4 gallop help differentiate this from a primary COPD or asthma exacerbation, directing the immediate need for intravenous diuresis.
Estimated Time:1m 15s
Question 463Question →

Following a transurethral resection of the prostate four weeks ago, a 65-year-old man presents to the emergency department reporting two weeks of worsening fatigue, night sweats, and shortness of breath with mild exertion. He has no other significant past medical history and takes no daily medications. Vital signs show a temperature of 38.4°C (101.1°F), heart rate of 98/min, and blood pressure of 118/72 mm Hg. Cardiac auscultation reveals a new grade 3/6 holosystolic murmur at the apex radiating to the left axilla. Dermatologic examination shows dark red, linear lesions in the nail beds of both hands. Laboratory evaluation reveals a leukocyte count of 14,500/mm³. A transesophageal echocardiogram demonstrates a 1.4-cm mobile vegetation on the mitral valve with moderate regurgitation. Gram stain of blood cultures drawn at admission shows gram-positive cocci in pairs and short chains. Subsequent speciation confirms *Enterococcus faecalis*. The susceptibility report indicates the organism is susceptible to ampicillin, vancomycin, and daptomycin, but testing demonstrates high-level resistance to gentamicin. Which of the following is the most appropriate definitive intravenous pharmacotherapy for this patient?

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Answer: Ampicillin and ceftriaxone

Answer

Ampicillin and ceftriaxone
The correct answer provides the standard-of-care bactericidal regimen for *Enterococcus faecalis* infective endocarditis, particularly when the isolate exhibits high-level aminoglycoside resistance (HLAR). *E. faecalis* is inherently tolerant to cell-wall active agents alone, meaning monotherapy is often bacteriostatic rather than bactericidal. Eradication of endovascular vegetations requires bactericidal activity. Traditionally, this was achieved by combining ampicillin with an aminoglycoside (like gentamicin). However, if an isolate has HLAR (due to modifying enzymes), the aminoglycoside cannot enter the cell, and synergy is lost. In these cases, the combination of ampicillin and ceftriaxone is utilized. Although enterococci are intrinsically resistant to cephalosporins, ceftriaxone saturates penicillin-binding proteins 2 and 3 (PBP2 and PBP3), while ampicillin binds PBP4 and PBP5. This dual blockade yields potent synergistic bactericidal activity against *E. faecalis* and avoids the nephrotoxicity associated with aminoglycosides.

Step-by-Step Solution

1
Analyze the clinical presentation and diagnostic findings.
The patient has subacute infective endocarditis (fever, new murmur, splinter hemorrhages, echocardiographic vegetation) following a genitourinary procedure, with blood cultures growing Enterococcus faecalis.
Establishing the diagnosis and identifying the specific pathogen is the prerequisite for selecting targeted antimicrobial therapy.
2
Evaluate the antimicrobial susceptibility profile provided in the stem.
The isolate is susceptible to ampicillin but demonstrates high-level resistance to gentamicin (HLAR).
Enterococcal endocarditis requires bactericidal therapy, which typically necessitates combination therapy for synergy. The susceptibility data dictates which combination is viable.
3
Determine the appropriate synergistic regimen given the resistance profile.
Because HLAR is present, an ampicillin-aminoglycoside combination will not yield synergy. Therefore, dual beta-lactam therapy with ampicillin and ceftriaxone must be utilized.
Ampicillin and ceftriaxone work synergistically against E. faecalis by binding complementary penicillin-binding proteins (PBPs), providing effective bactericidal activity without relying on aminoglycosides.

Key Concept

Treatment of Enterococcus faecalis infective endocarditis with high-level aminoglycoside resistance (HLAR).
Question 464Question →

A gastroenterology team is evaluating several adult patients presenting with elevated liver function tests and suspected chronic liver disease. Match each clinical diagnosis with its most specific characteristic serologic marker or initial diagnostic laboratory finding.

Click a left item, then click its matching right item

Items

Primary biliary cholangitis
Primary sclerosing cholangitis
Autoimmune hepatitis (Type 1)
Wilson disease

Matches

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Answer

Primary biliary cholangitis matches with elevated titers of anti-mitochondrial antibodies (AMA). Primary sclerosing cholangitis matches with positive perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA). Autoimmune hepatitis (Type 1) matches with elevated titers of anti-smooth muscle antibodies (ASMA). Wilson disease matches with decreased serum ceruloplasmin.
Each specific chronic liver disease has a signature serological or biochemical marker that serves as a cornerstone for its initial diagnosis, allowing clinicians to differentiate between hepatocellular and cholestatic patterns of autoimmune and metabolic injuries.

Step-by-Step Solution

1
Analyze the characteristic autoantibody profile for middle-aged women presenting with pruritus and isolated alkaline phosphatase elevation.
Identify Primary biliary cholangitis as matching with anti-mitochondrial antibodies (AMA).
AMA is highly sensitive and specific for Primary biliary cholangitis.
2
Identify the primary serologic marker associated with biliary stricturing disease that frequently co-occurs with ulcerative colitis.
Match Primary sclerosing cholangitis with p-ANCA.
Up to 80% of patients with Primary sclerosing cholangitis have a positive p-ANCA, distinguishing it serologically from other cholestatic diseases.
3
Determine the autoimmune markers for hepatocellular injury patterns characterized by plasma cell infiltrates.
Match Autoimmune hepatitis with anti-smooth muscle antibodies (ASMA).
Type 1 AIH is classically associated with positive ASMA and anti-nuclear antibodies (ANA).
4
Identify the diagnostic biochemical abnormalities for a patient with neuropsychiatric symptoms and liver disease.
Match Wilson disease with decreased serum ceruloplasmin.
A defect in the ATP7B gene leads to impaired incorporation of copper into ceruloplasmin, lowering its serum levels.

Key Concept

Diagnostic laboratory and serologic markers for autoimmune and metabolic liver diseases
Estimated Time:1m 30s
Question 465Question →

Emergency medical services transport a 64-year-old male to the trauma bay following multiple episodes of massive, bright red rectal bleeding at his residence. He is somnolent and profoundly diaphoretic. Initial vital signs reveal a temperature of 36.8°C (98.2°F), heart rate of 134/min, respiratory rate of 24/min, and blood pressure of 76/42 mm Hg. Collateral history from his partner indicates he takes daily high-dose naproxen for lumbar osteoarthritis. The abdomen is soft and non-tender without organomegaly. Digital rectal examination demonstrates a vault full of fresh blood and clots. Two large-bore peripheral intravenous catheters have just been inserted. Arrange the following subsequent management steps in the most appropriate chronological order for evaluating and treating this hemodynamically unstable patient.

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Answer

The correct sequential order is: 1) Initiate rapid volume resuscitation, 2) Perform urgent esophagogastroduodenoscopy (EGD), 3) Obtain computed tomography (CT) angiography, 4) Perform catheter-directed angiography with embolization, 5) Proceed to surgical bowel resection.
The management algorithm for hemodynamically unstable patients presenting with massive hematochezia begins with immediate volume resuscitation, addressing the patient's hemorrhagic shock. Once intravenous access is established and fluids/blood are running, the next critical step is an EGD. This is because a brisk upper GI bleed can present as bright red blood per rectum and is a highly lethal, yet easily treatable, etiology. If the EGD is negative, the source is confirmed as lower GI. In an unstable patient with active bleeding, CT angiography is the diagnostic modality of choice to rapidly localize the active bleeding vessel without requiring bowel preparation. This is directly followed by therapeutic catheter-directed angiography to embolize the vessel. Surgical bowel resection is reserved strictly as a salvage option if embolization fails or is not feasible.

Step-by-Step Solution

1
Address profound hemodynamic instability
Initiate rapid volume resuscitation
Airway, Breathing, and Circulation (ABC) protocols mandate immediate intravascular volume repletion in the setting of class III or IV hemorrhagic shock prior to diagnostic imaging or scopes.
2
Rule out a massive upper gastrointestinal hemorrhage
Perform urgent esophagogastroduodenoscopy (EGD)
Brisk upper gastrointestinal bleeding (e.g., peptic ulcer disease from NSAID use) can mimic lower GI bleeding by presenting as massive hematochezia due to rapid transit time. It must be rapidly excluded or treated.
3
Localize the active lower gastrointestinal bleeding source
Obtain CT angiography of the abdomen and pelvis
With an upper GI source ruled out, CT angiography is the most rapid and accurate test to pinpoint the site of active extravasation in an unstable patient. Colonoscopy is contraindicated as it is unsafe and poorly visualized without bowel preparation.
4
Attempt minimally invasive hemostasis
Perform catheter-directed angiography with embolization
Angiography allows for the targeted occlusion of the specific bleeding vessel that was identified non-invasively on the CT angiography.
5
Perform definitive salvage therapy if previous steps fail
Proceed to surgical bowel resection
Surgery is the highly morbid treatment of last resort if less invasive angiographic techniques fail to achieve or maintain hemostasis.

Key Concept

In hemodynamically unstable patients presenting with massive hematochezia, an upper gastrointestinal bleeding source must be excluded with an EGD immediately after resuscitation, prior to pursuing lower GI investigations.
Question 466Question →

A 6565-year-old man is evaluated in the intensive care unit on day 33 of admission for septic shock secondary to severe community-acquired pneumonia. He has a past medical history of severe chronic obstructive pulmonary disease and heart failure with preserved ejection fraction. He was intubated on the day of admission and remains mechanically ventilated.

Current vital signs include a temperature of 37.2∘C37.2^\circ\text{C} (99.0∘F99.0^\circ\text{F}), blood pressure of 105/65 mm Hg105/65\text{ mm Hg} on vasopressors, and heart rate of 98/min98\text{/min}.

Physical examination reveals diminished breath sounds bilaterally with prolonged expiration and scattered expiratory wheezing. Jugular venous pressure is normal, and there are no pulmonary crackles or peripheral edema.

Blood and sputum cultures obtained on admission have finalized, growing *Streptococcus pneumoniae* susceptible to penicillin and ceftriaxone. He is currently receiving continuous intravenous norepinephrine, vancomycin, and piperacillin-tazobactam.

An arterial blood gas analysis is obtained on the current ventilator settings:
pH: 7.227.22
PaCO2\text{PaCO}_2: 35 mm Hg35\text{ mm Hg}
PaO2\text{PaO}_2: 82 mm Hg82\text{ mm Hg}
HCO3−\text{HCO}_3^-: 14 mEq/L14\text{ mEq/L}

Based on the current clinical data, which of the following actions are appropriate in the ongoing management of this patient? (Select all that apply)

Select all that apply

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Answer: Switch the current antibiotic regimen to intravenous ceftriaxone; Increase the mechanical ventilator's respiratory rate

Answer

The appropriate actions are to switch the antibiotic regimen to intravenous ceftriaxone and increase the mechanical ventilator's respiratory rate.
The correct management involves two independent clinical interventions based on the provided data. First, applying principles of antimicrobial stewardship, the empiric broad-spectrum antibiotics (vancomycin and piperacillin-tazobactam) should be narrowed to ceftriaxone because the blood and sputum cultures have definitively grown *Streptococcus pneumoniae* susceptible to this agent. Continuing broad-spectrum coverage offers no benefit and increases the risk of adverse events. Second, the patient's arterial blood gas demonstrates a severe primary metabolic acidosis (low pH, low bicarbonate). Using Winter's formula (Expected PaCO2=(1.5×HCO3−)+8±2\text{PaCO}_2 = (1.5 \times \text{HCO}_3^-) + 8 \pm 2), the expected compensatory PaCO2\text{PaCO}_2 for a bicarbonate of 14 mEq/L14\text{ mEq/L} is calculated to be 29±2 mm Hg29 \pm 2\text{ mm Hg}. Because the patient's actual PaCO2\text{PaCO}_2 is 35 mm Hg35\text{ mm Hg}, he has an inadequate respiratory compensation, defining a superimposed primary respiratory acidosis (likely due to his underlying severe COPD and inadequate ventilator settings). To correct this mixed acid-base disorder, the mechanical ventilator's minute ventilation must be augmented, typically by increasing the respiratory rate.

Step-by-Step Solution

1
Analyze the culture and susceptibility results to determine the optimal antibiotic regimen.
Cultures show *Streptococcus pneumoniae* susceptible to ceftriaxone.
Empiric broad-spectrum coverage should be de-escalated to targeted therapy once a pathogen is definitively identified.
2
Evaluate the arterial blood gas to identify the primary acid-base disorder.
pH is 7.227.22 (acidemia), and HCO3−\text{HCO}_3^- is 14 mEq/L14\text{ mEq/L}, indicating a primary metabolic acidosis.
Identifying the primary disorder is the first step in diagnosing complex acid-base derangements.
3
Apply Winter's formula to determine the expected respiratory compensation for the metabolic acidosis.
Expected PaCO2=(1.5×14)+8±2=29±2 mm Hg\text{PaCO}_2 = (1.5 \times 14) + 8 \pm 2 = 29 \pm 2\text{ mm Hg}.
This determines if the patient has an isolated disorder or a mixed acid-base disorder.
4
Compare actual PaCO2\text{PaCO}_2 to expected PaCO2\text{PaCO}_2 to direct mechanical ventilation changes.
Actual PaCO2\text{PaCO}_2 (35 mm Hg35\text{ mm Hg}) is higher than the expected range (27−31 mm Hg27-31\text{ mm Hg}), indicating a superimposed respiratory acidosis.
A higher than expected PaCO2\text{PaCO}_2 means the mechanical ventilator is not providing adequate minute ventilation to compensate for the metabolic acidosis.

Key Concept

The management of critically ill patients requires continuous de-escalation of empiric therapies based on susceptibility data (antimicrobial stewardship) and accurate interpretation of mixed acid-base disorders using compensation formulas like Winter's formula.
Estimated Time:1m 30s
Question 467Question →

A 48-year-old woman is admitted to the hospital with a 2-day history of fever, chills, and progressive right lower extremity swelling and redness. Her past medical history is unremarkable. On admission, her temperature is 38.6°C (101.5°F), blood pressure is 110/70 mmHg, and pulse is 108/min. Physical examination reveals a 10×810 \times 8 cm area of well-demarcated erythema, warmth, and exquisite tenderness over the right calf. Two sets of peripheral blood cultures are obtained, and the patient is started on empiric intravenous vancomycin and piperacillin-tazobactam.

By hospital day 3, her temperature has normalized, and the erythema has significantly receded. The admission blood cultures grow *Staphylococcus aureus* in all four bottles. Antimicrobial susceptibility testing reveals the following:

AntimicrobialInterpretation
CefazolinSusceptible
DaptomycinSusceptible
OxacillinSusceptible
PenicillinResistant
Trimethoprim-sulfamethoxazoleSusceptible
VancomycinSusceptible

A subsequent transthoracic echocardiogram shows no valvular vegetations. Which of the following is the most appropriate next step in the pharmacologic management of this patient?

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Answer: Discontinue the current antibiotics and begin intravenous cefazolin

Answer

Discontinue the current antibiotics and begin intravenous cefazolin
The correct course of action is to de-escalate the broad-spectrum empiric antibiotic regimen to targeted therapy with an anti-staphylococcal beta-lactam. The patient's blood cultures are positive for Staphylococcus aureus that is susceptible to oxacillin, meaning it is methicillin-susceptible S. aureus (MSSA). For the treatment of MSSA bacteremia, narrow-spectrum beta-lactam antibiotics (such as cefazolin, nafcillin, or oxacillin) are the gold standard. They possess superior, more rapid bactericidal activity against MSSA compared to vancomycin, leading to improved clearance of bacteremia and significantly reduced mortality. Good antimicrobial stewardship dictates switching to the most effective, narrowest-spectrum agent once susceptibility data is available.

Step-by-Step Solution

1
Interpret the blood culture and susceptibility data.
The blood cultures grew Staphylococcus aureus that is susceptible to oxacillin, identifying the organism as methicillin-susceptible Staphylococcus aureus (MSSA).
Accurate interpretation of oxacillin susceptibility is required to distinguish MSSA from MRSA, which dictates definitive therapy.
2
Determine the definitive treatment of choice for MSSA bacteremia.
Intravenous anti-staphylococcal beta-lactams, such as cefazolin, nafcillin, or oxacillin, are the gold standard treatments for MSSA.
Clinical trials and guidelines show that beta-lactams are more rapidly bactericidal and are associated with significantly lower mortality and failure rates compared to vancomycin for MSSA bacteremia.
3
Apply antimicrobial stewardship principles to modify the empiric regimen.
The empiric broad-spectrum regimen of vancomycin and piperacillin-tazobactam must be discontinued and de-escalated to intravenous cefazolin.
Continuing broad-spectrum agents or inferior treatments exposes the patient to unnecessary drug toxicity, increases the risk of antimicrobial resistance, and worsens clinical outcomes.

Key Concept

De-escalation of empiric antibiotics to targeted therapy; specifically, the superiority of anti-staphylococcal beta-lactams (e.g., cefazolin, nafcillin) over vancomycin for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia.
Question 468Question →

A male patient, aged 5555, arrives at the acute care clinic complaining of worsening shortness of breath and chest discomfort over the past two days. He recently recovered from a severe viral respiratory infection. He describes the chest pain as sharp and states that it lessens significantly when he sits up and leans forward. Within the last two hours, he has felt increasingly dizzy. Vital signs show a temperature of 37.8∘C37.8^\circ\text{C} (100.0∘F100.0^\circ\text{F}), a blood pressure of 88/7288/72 mm Hg, a heart rate of 118118/min, and a respiratory rate of 2222/min. Physical examination reveals prominent distention of the neck veins and heart sounds that are noticeably faint on auscultation. An exaggerated drop in systolic blood pressure during inspiration is observed. Arrange the following management steps in the most appropriate chronological sequence for this patient.

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Answer

The correct sequence is to first perform a bedside transthoracic echocardiogram to confirm the diagnosis, then administer an intravenous normal saline bolus to temporize hemodynamics, followed by urgent percutaneous pericardiocentesis for definitive acute treatment, and finally a surgical pericardial window if the effusion recurs.
In a patient presenting with hypotension, jugular venous distention, distant heart sounds, and pulsus paradoxus following a viral illness, cardiac tamponade is the most likely diagnosis. The initial step is to rapidly confirm the presence of a pericardial effusion with a bedside transthoracic echocardiogram. Because the patient is hypotensive, temporizing measures such as an intravenous normal saline bolus should be administered to increase right-sided filling pressures and maintain cardiac output. Once the diagnosis is confirmed and the patient is temporarily stabilized, urgent percutaneous pericardiocentesis must be performed to drain the fluid and relieve the elevated intrapericardial pressure. Finally, if the effusion recurs or cannot be adequately managed percutaneously, a surgical pericardial window is the appropriate definitive procedure.

Step-by-Step Solution

1
Diagnose the condition
Bedside transthoracic echocardiogram
Confirms the clinical suspicion of cardiac tamponade by demonstrating a pericardial effusion with right-sided heart chamber collapse during diastole.
2
Temporize hemodynamics
Intravenous normal saline bolus
Increases right ventricular preload to overcome elevated intrapericardial pressure, temporarily improving stroke volume and blood pressure.
3
Perform definitive acute treatment
Urgent percutaneous pericardiocentesis
Directly removes the pericardial fluid, relieving the pressure on the heart and definitively restoring normal hemodynamics.
4
Manage potential recurrence
Surgical pericardial window
Provides continuous drainage and is indicated if the effusion reaccumulates after initial pericardiocentesis.

Key Concept

Management sequence for cardiac tamponade: Diagnosis (Echocardiogram) → Temporization (IV fluids) → Acute treatment (Pericardiocentesis) → Long-term management of recurrence (Pericardial window).
Question 469Question →

A 45-year-old man comes to the clinic reporting a 4-month history of progressive fatigue, cold intolerance, and decreased libido. He says he feels sluggish and lacks the energy to perform his job as an accountant. His medical history is unremarkable, and he takes no medications. Vital signs show a blood pressure of 105/70 mm Hg and a heart rate of 56/min. Physical examination reveals delayed relaxation of the deep tendon reflexes and somewhat soft, small testes. Laboratory studies show:

Serum thyroid-stimulating hormone (TSH): 1.6 μ\mu U/mL (Normal: 0.4–4.0 μ\mu U/mL)
Serum free thyroxine (T4): 0.6 ng/dL (Normal: 0.9–1.7 ng/dL)

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

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Answer: Assessment of morning serum cortisol

Answer

Assessment of morning serum cortisol
The correct answer is the assessment of morning serum cortisol. This patient presents with classical symptoms of hypothyroidism (fatigue, cold intolerance, delayed deep tendon reflexes). However, his laboratory results reveal a low free T4 with a TSH level that is within the normal range. In a normal hypothalamic-pituitary-thyroid axis, a low free T4 should trigger a robust increase in TSH secretion. The presence of an inappropriately normal (or low) TSH alongside a low free T4 is the hallmark of central (secondary) hypothyroidism. Furthermore, his decreased libido and small testes point to concurrent central hypogonadism, raising high clinical suspicion for panhypopituitarism (e.g., caused by a pituitary adenoma). When a patient has panhypopituitarism, they often have concurrent central adrenal insufficiency. A critical principle in endocrinology is that thyroid hormone replacement must never be initiated before ruling out or treating adrenal insufficiency. Levothyroxine increases the metabolic clearance of cortisol; in a patient with limited adrenal reserve, this can rapidly precipitate a life-threatening adrenal crisis. Therefore, evaluating the adrenal axis with a morning serum cortisol is the mandatory next step.

Step-by-Step Solution

1
Interpret the thyroid function tests in the context of the patient's symptoms.
The patient has symptomatic hypothyroidism with a low free T4 level, but the TSH is within the normal range. This is an inappropriately normal TSH response, diagnostic of central (secondary) hypothyroidism.
A healthy pituitary would secrete high levels of TSH in response to low T4 (primary hypothyroidism). A lack of TSH elevation indicates a pituitary or hypothalamic failure.
2
Identify additional clinical clues indicating a broader syndrome.
The patient also complains of decreased libido and has soft, small testes, which suggests concurrent central hypogonadism.
Multiple anterior pituitary hormone deficiencies point toward a diagnosis of panhypopituitarism (e.g., due to a nonfunctioning pituitary macroadenoma).
3
Determine the safest next step in management.
Before initiating levothyroxine therapy, the patient must be evaluated for central adrenal insufficiency by assessing morning serum cortisol.
Thyroid hormone increases the metabolic clearance of cortisol. Administering levothyroxine to a patient with undiagnosed adrenal insufficiency can acutely lower circulating cortisol levels and precipitate a life-threatening adrenal crisis.

Key Concept

Patients with central hypothyroidism (low free T4, inappropriately normal/low TSH) must be evaluated for concurrent adrenal insufficiency before initiating levothyroxine therapy to prevent an adrenal crisis.
Estimated Time:1m 30s
Question 470Question →

Match the following specific cardiovascular physical examination findings with their most likely underlying structural or pathophysiological etiology.

Click a left item, then click its matching right item

Items

A systolic ejection murmur at the left upper sternal border with a second heart sound (S2S_2) that remains widely split throughout the respiratory cycle.
A harsh crescendo-decrescendo systolic murmur where the aortic component of the second heart sound (A2A_2) follows the pulmonic component (P2P_2) during expiration.
A blowing, decrescendo early diastolic murmur associated with visible capillary pulsations in the nail beds upon applying gentle pressure.
A mid-diastolic rumbling murmur accompanied by an extra high-frequency sound that occurs 4040 milliseconds after the second heart sound.
A harsh systolic murmur at the lower left sternal border that decreases in intensity when the patient transitions from a standing to a squatting position.

Matches

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Answer

The correct pairings match specific auscultatory and peripheral vascular signs to their underlying hemodynamic mechanisms: fixed split S2S_2 with atrial shunting, paradoxical split S2S_2 with fixed LV outflow obstruction, capillary pulsations with aortic incompetence, short A2A_2-OS interval with high left atrial pressure, and preload-dependent murmur with dynamic LV outflow obstruction.
Each pairing correctly links a highly specific physical exam finding to its precise underlying hemodynamic principle. Recognizing fixed versus paradoxical splitting, recognizing peripheral signs of wide pulse pressure, identifying the severity indicator of a short A2A_2-OS interval, and analyzing the response to preload-altering maneuvers is essential for diagnosing these structural heart diseases.

Step-by-Step Solution

1
Analyze the respiratory variation of S2S_2.
Fixed splitting points to an atrial septal defect due to constant right-sided volume overload regardless of the respiratory cycle.
Understanding normal vs. abnormal splitting of the second heart sound helps differentiate septal defects from normal physiology.
2
Evaluate abnormal S2S_2 sequences in the context of a systolic murmur.
Paradoxical splitting (A2A_2 after P2P_2) in the presence of a harsh crescendo-decrescendo murmur indicates prolonged left ventricular ejection, classic for severe aortic stenosis.
Severe fixed obstruction delays the closure of the aortic valve until after the pulmonic valve closes.
3
Interpret peripheral signs associated with a diastolic murmur.
Capillary pulsations (Quincke's pulse) alongside a blowing diastolic murmur indicate a widened pulse pressure due to severe aortic regurgitation.
Aortic incompetence allows backflow into the left ventricle, lowering diastolic pressure while increasing stroke volume, resulting in hyperdynamic peripheral signs.
4
Assess extra diastolic sounds and their timing.
A short A2A_2-to-opening snap interval reflects a very high left atrial pressure indicative of severe mitral stenosis.
The higher the left atrial pressure, the faster it exceeds falling left ventricular pressure during isovolumetric relaxation, causing an earlier opening snap.
5
Apply hemodynamic maneuvers to a sternal border murmur.
A murmur that softens with squatting characterizes the dynamic obstruction seen in hypertrophic cardiomyopathy.
Squatting increases venous return (preload) and systemic vascular resistance (afterload), expanding the left ventricular cavity and thereby relieving the dynamic obstruction.

Key Concept

Pathophysiology and Dynamic Auscultation of Structural Heart Diseases
Question 471Question →

Match each clinical presentation of a central nervous system infection (or related exposure) to the most appropriate targeted antimicrobial therapy or prophylaxis regimen.

Click a left item, then click its matching right item

Items

A 74-year-old man presenting with acute fever, nuchal rigidity, and altered mental status; cerebrospinal fluid analysis shows marked neutrophilic pleocytosis.
A 28-year-old woman presenting with acute fever, headache, severe behavioral changes, and focal seizures; neuroimaging reveals right temporal lobe edema.
A 19-year-old asymptomatic college student who is the roommate of a patient recently hospitalized with confirmed Neisseria meningitidis meningitis.
A 45-year-old man with advanced HIV presenting with subacute headache and an opening pressure of 350 mm H2O on lumbar puncture; cerebrospinal fluid testing is positive for an encapsulated yeast.

Matches

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Answer

Match the older adult with meningitis to ceftriaxone, vancomycin, and ampicillin; the temporal lobe encephalitis to acyclovir; the meningococcal contact to ciprofloxacin or rifampin; and the HIV patient with cryptococcal meningitis to amphotericin B and flucytosine.
Each pair correctly matches a classic central nervous system infection presentation (or related exposure) with its definitive first-line therapy or prophylaxis according to current infectious disease guidelines.

Step-by-Step Solution

1
Identify the likely pathogen or clinical requirement for each scenario based on the patient's age, immune status, and key clinical findings.
The 74-year-old requires Listeria coverage. The 28-year-old has HSV encephalitis. The 19-year-old requires Neisseria prophylaxis. The 45-year-old has Cryptococcal meningitis.
Patient demographics and specific diagnostic clues (like temporal lobe edema or an encapsulated yeast) point to distinct infectious etiologies.
2
Select the guideline-recommended pharmacotherapy for each identified condition.
Listeria is covered by ampicillin. HSV requires acyclovir. Neisseria prophylaxis is achieved with ciprofloxacin or rifampin. Cryptococcus induction utilizes amphotericin B and flucytosine.
Standard of care for these central nervous system infections and exposures dictates these highly specific antimicrobial regimens.

Key Concept

Empiric and targeted antimicrobial management of central nervous system infections is heavily dependent on patient age, immune status, characteristic neuroimaging findings, and exposure history.
Estimated Time:1m 30s
Question 472Question →

A team of internal medicine residents is reviewing the post-infarction clinical course of several patients admitted to the cardiac intensive care unit. Match each described clinical presentation with the most likely underlying mechanical or structural complication of acute myocardial infarction.

Click a left item, then click its matching right item

Items

Sudden onset of profound hypotension, marked jugular venous distension, and clear lung fields 5 days after an anterior myocardial infarction; bedside ultrasound reveals a large pericardial fluid collection.
Acute respiratory distress, biventricular failure, and a new harsh, loud holosystolic murmur at the left lower sternal border with a palpable thrill 4 days after an anterior myocardial infarction.
Rapid development of severe pulmonary edema, hypotension, and a new soft, blowing holosystolic murmur at the apex radiating to the axilla 3 days after an inferior myocardial infarction.
Presentation with an acute ischemic stroke and persistent ST-segment elevations in leads V1-V4 on a routine ECG, 6 weeks following a large anterior myocardial infarction.

Matches

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Answer

The correct matches correlate the timing, location of the initial infarct, and physical exam findings to the specific structural breakdown: Presentation 1 matches Ventricular free wall rupture, Presentation 2 matches Interventricular septal rupture, Presentation 3 matches Posteromedial papillary muscle rupture, and Presentation 4 matches Left ventricular aneurysm.
Each clinical vignette uniquely matches a specific post-infarction complication based on strict diagnostic criteria involving timing, infarct location, and physical exam findings. Free wall rupture causes acute tamponade (clear lungs, jugular venous distension). Septal rupture creates a left-to-right shunt with a harsh parasternal murmur. Papillary muscle rupture causes acute mitral regurgitation and is heavily associated with inferior infarctions due to a single blood supply. Left ventricular aneurysms form late, causing mural thrombi and persistent electrocardiographic ST elevations.

Step-by-Step Solution

1
Analyze the first presentation for timing, initial infarct location, and hemodynamic profile.
Identifies tamponade physiology (hypotension, jugular venous distension, clear lungs, pericardial effusion) occurring 5 days after an anterior myocardial infarction.
This constellation of findings is the hallmark of ventricular free wall rupture, leading to accumulation of blood in the pericardial space.
2
Analyze the second presentation focusing on murmur characteristics.
Identifies a harsh left lower sternal border holosystolic murmur with a thrill and biventricular failure.
These physical exam findings indicate a new left-to-right shunt, which is pathognomonic for an interventricular septal rupture.
3
Analyze the third presentation focusing on the infarct location and resultant murmur.
Identifies an inferior myocardial infarction followed by acute pulmonary edema and a soft apical murmur.
The posteromedial papillary muscle has a single blood supply and is highly vulnerable during inferior infarcts. Rupture causes acute mitral regurgitation (apical murmur) and isolated left heart failure (pulmonary edema).
4
Analyze the fourth presentation for the timeline and electrocardiographic findings.
Identifies a late complication (6 weeks) featuring persistent ST elevation and a systemic embolic event (stroke).
This is the classic presentation for a left ventricular aneurysm, which promotes mural thrombus formation and maintains ST elevations long after the acute event.

Key Concept

Mechanical Complications of Acute Myocardial Infarction
Question 473Question →

Match each patient's clinical presentation with the most likely corresponding auscultatory finding and its characteristic response to dynamic maneuvers.

Click a left item, then click its matching right item

Items

A 22-year-old athlete with a family history of sudden cardiac death experiences exertional syncope.
A 78-year-old man presents with exertional dyspnea and demonstrates a delayed and diminished carotid pulse.
A 28-year-old woman with Marfan syndrome presents with occasional palpitations and atypical chest pain.
A 45-year-old man with a history of untreated syphilis presents with widened pulse pressure and bounding peripheral pulses.
A 4-week-old infant with poor weight gain, tachypnea, and diaphoresis during feeding.

Matches

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Answer

Hypertrophic cardiomyopathy matches with the systolic murmur that increases with Valsalva; aortic stenosis matches with the late-peaking murmur that decreases upon standing; mitral valve prolapse matches with the click that moves closer to S1 upon standing; aortic regurgitation matches with the diastolic murmur that increases with handgrip; and ventricular septal defect matches with the holosystolic murmur that increases with handgrip.
Each accurate match links a classic clinical presentation of a structural or valvular cardiac abnormality with its expected auscultatory findings, specifically evaluating the pathophysiological principles of how dynamic maneuvers alter cardiac hemodynamics and murmur intensity.

Step-by-Step Solution

1
Analyze the first vignette to identify the underlying pathology and murmur behavior.
The athlete with exertional syncope has hypertrophic obstructive cardiomyopathy (HOCM), which produces a systolic murmur that increases with decreased preload (Valsalva).
Decreased preload reduces left ventricular volume, which exacerbates the dynamic outflow tract obstruction caused by the hypertrophied septum.
2
Analyze the second vignette to identify the underlying pathology and murmur behavior.
The elderly man with pulsus parvus et tardus has severe aortic stenosis, which produces a late-peaking systolic murmur that decreases upon standing.
Standing decreases preload; having less blood volume crossing the fixed stenotic aortic valve results in a softer murmur.
3
Analyze the third vignette to identify the underlying pathology and murmur behavior.
The woman with Marfan syndrome has mitral valve prolapse, matching the click and late systolic murmur that move closer to S1 upon standing.
Standing decreases left ventricular volume, causing the redundant mitral valve leaflets to prolapse earlier during systole.
4
Analyze the fourth vignette to identify the underlying pathology and murmur behavior.
The man with syphilis and bounding pulses has aortic regurgitation, matching the early diastolic murmur that increases with handgrip.
Sustained handgrip increases systemic vascular resistance (afterload), driving more blood backward across the incompetent aortic valve during diastole.
5
Analyze the fifth vignette to identify the underlying pathology and murmur behavior.
The infant with heart failure has a ventricular septal defect (VSD), matching the holosystolic murmur that increases with handgrip.
Increased afterload from handgrip raises left ventricular pressure relative to right ventricular pressure, augmenting the left-to-right shunt and the resulting murmur.

Key Concept

Identifying valvular and structural heart diseases from clinical vignettes and correlating them with characteristic murmur alterations induced by bedside hemodynamic maneuvers.
Question 474Question →

Paramedics arrive at the emergency department with an 8080-year-old male who developed sudden, severe shortness of breath one hour ago while watching television. The patient has a medical history significant for poorly controlled hypertension, type 2 diabetes mellitus, and a 4545-pack-year history of smoking. Upon arrival, he is in acute respiratory distress, utilizing accessory muscles to breathe, and cannot speak more than a few words at a time. Vital signs include a blood pressure of 225/115 mm Hg225/115 \text{ mm Hg}, a heart rate of 115/min115/\text{min}, and a respiratory rate of 30/min30/\text{min}. Oxygen saturation is 86%86\% on ambient air. Physical examination shows profound diaphoresis. Pulmonary auscultation reveals prominent expiratory wheezing diffusely, along with fine crackles at both lung bases. Cardiovascular examination is notable for a rapid, regular rhythm and a distinct fourth heart sound (S4). Evaluation of the neck shows flat jugular veins, and there is no peripheral edema. Which of the following is the most appropriate initial pharmacologic therapy for this patient?

Show answer & explanation

Answer: Intravenous nitroglycerin

Answer

Intravenous nitroglycerin
This patient's abrupt onset of severe dyspnea, extreme hypertension, S4 gallop, and diffuse wheezing with crackles are highly characteristic of acute flash pulmonary edema, specifically sympathetic crashing acute pulmonary edema (SCAPE). The wheezing is a result of peribronchial edema, often referred to as 'cardiac asthma'. In SCAPE, an acute sympathetic surge leads to massive vasoconstriction and an extreme increase in afterload. This causes a sudden shift of fluid from the systemic to the pulmonary circulation, which explains the absence of signs of total body volume overload such as jugular venous distention and peripheral edema. The most appropriate initial pharmacologic therapy is rapid afterload and preload reduction using an intravenous vasodilator like nitroglycerin. This intervention quickly redistributes fluid back to the systemic circulation, resolving the pulmonary congestion.

Step-by-Step Solution

1
Analyze the patient's vital signs and physical exam findings.
The patient exhibits extreme hypertension (225/115 mm Hg225/115 \text{ mm Hg}), respiratory distress with hypoxia, an S4 gallop, and diffuse wheezing with basilar crackles, notably without jugular venous distention or peripheral edema.
Identifying the primary pathophysiologic process is essential to differentiate between causes of acute respiratory failure.
2
Differentiate between cardiogenic and pulmonary causes of wheezing.
Despite the smoking history, the abrupt symptom onset, severely elevated blood pressure, and S4 gallop strongly suggest acute flash pulmonary edema rather than a COPD exacerbation.
Heart failure can present with wheezing due to peribronchial edema, a condition clinically termed 'cardiac asthma'.
3
Select the most appropriate initial pharmacologic therapy for hypertensive emergency causing flash pulmonary edema.
Intravenous nitroglycerin is the treatment of choice.
It rapidly reduces both preload and afterload, shifting fluid from the pulmonary vasculature back to the systemic circulation to quickly relieve dyspnea.

Key Concept

Differentiating acute flash pulmonary edema ('cardiac asthma') from COPD exacerbation and selecting rapid afterload/preload reduction with intravenous vasodilators (e.g., nitroglycerin) as the initial management.
Estimated Time:1m 15s
Question 475Question →

A 62-year-old woman with a history of chronic obstructive pulmonary disease (COPD) presents to the emergency department complaining of progressive shortness of breath over the past three days. She reports an increased frequency of cough and a change in her sputum from clear to thick and yellow-green. She denies chest pain, orthopnea, or paroxysmal nocturnal dyspnea. Her daily medications include a long-acting muscarinic antagonist and a short-acting beta-agonist as needed. Vital signs are temperature 37.8∘C37.8^\circ\text{C} (100.0∘F100.0^\circ\text{F}), blood pressure 135/85 mmHg135/85\text{ mmHg}, heart rate 108/min108\text{/min}, and respiratory rate 26/min26\text{/min}. Oxygen saturation is 86%86\% on room air.

Physical examination reveals a patient in moderate respiratory distress, using accessory muscles of respiration. Auscultation demonstrates a prolonged expiratory phase and diffuse end-expiratory wheezing bilaterally. Cardiac examination shows a rapid, regular rhythm with no murmurs, gallops, or jugular venous distention. There is no peripheral edema.

Chest radiograph shows hyperinflated lung fields with flattened diaphragms, but no focal consolidations or pleural effusions.

Arterial blood gas on room air reveals:
pH: 7.287.28
PaCO2\text{PaCO}_2: 66 mmHg66\text{ mmHg}
PaO2\text{PaO}_2: 54 mmHg54\text{ mmHg}
HCO3−\text{HCO}_3^-: 30 mEq/L30\text{ mEq/L}

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

Select all that apply

Show answer & explanation

Answer: Initiate noninvasive positive pressure ventilation; Administer systemic glucocorticoids

Answer

The correct steps are to initiate noninvasive positive pressure ventilation (NPPV) and administer systemic glucocorticoids.
The patient is experiencing a severe acute exacerbation of COPD, evidenced by worsening dyspnea, increased sputum volume, and sputum purulence. Her arterial blood gas demonstrates acute-on-chronic respiratory acidosis (pH <7.35< 7.35 and PaCO2>45 mmHg\text{PaCO}_2 > 45\text{ mmHg}). This specific acid-base derangement in a COPD patient is a primary indication for noninvasive positive pressure ventilation (NPPV), which decreases the work of breathing, improves gas exchange, and reduces the need for endotracheal intubation. Concurrently, systemic glucocorticoids (e.g., oral prednisone or intravenous methylprednisolone) are standard of care for all moderate-to-severe COPD exacerbations to reduce airway inflammation, shorten recovery time, and improve lung function.

Step-by-Step Solution

1
Identify the primary clinical syndrome.
The patient is experiencing an acute exacerbation of COPD characterized by increased dyspnea, increased sputum volume, and sputum purulence.
Recognizing the cardinal symptoms of COPD exacerbation guides both respiratory and pharmacological management.
2
Analyze the arterial blood gas (ABG).
pH of 7.28 and PaCO2 of 66 mmHg indicate a primary respiratory acidosis. The elevated HCO3- (30 mEq/L) reflects partial metabolic compensation.
Determining the acid-base status is necessary to decide on the appropriate level of respiratory support.
3
Determine the indications for respiratory support.
Because the pH is below 7.35 due to hypercapnia, noninvasive positive pressure ventilation (NPPV) is strongly indicated.
NPPV has been shown to decrease mortality, reduce the need for endotracheal intubation, and improve pH and PaCO2 in severe COPD exacerbations.
4
Select appropriate medical therapy.
In addition to bronchodilators and targeted antibiotics (for purulent sputum), systemic glucocorticoids are required.
Systemic glucocorticoids decrease airway inflammation, improve forced expiratory volume in 1 second (FEV1), and reduce the risk of relapse.

Key Concept

Management of acute exacerbation of COPD with acute-on-chronic respiratory acidosis
Question 476Question →

Complaints of a racing heart, persistent heat intolerance, and frequent loose stools have brought a 31-year-old medical assistant to the clinic. She reports unintentionally losing 44 kg (8.88.8 lb) over the past month. She denies any neck pain, dysphagia, or recent viral illnesses. Her past medical history is unremarkable, and she denies taking any prescribed medications or over-the-counter supplements. Vital signs show a blood pressure of 138/78138/78 mm Hg and a regular pulse of 112112/min. Physical examination reveals an anxious-appearing woman with a fine, symmetric resting tremor in her outstretched fingers. The neck is supple, and the thyroid gland is not palpable. No proptosis or localized pretibial edema is noted.

Laboratory studies yield the following results:
- Thyroid-stimulating hormone (TSH): 0.020.02 μ\mu U/mL (Normal: 0.4−4.20.4-4.2 μ\mu U/mL)
- Free T4: 3.43.4 ng/dL (Normal: 0.8−1.80.8-1.8 ng/dL)
- Free T3: 6.26.2 pg/mL (Normal: 2.3−4.22.3-4.2 pg/mL)

A 24-hour radioactive iodine uptake scan demonstrates an uptake of 1%1\% (Normal: 15%−30%15\%-30\%).

Which of the following laboratory findings is most likely present in this patient?

Show answer & explanation

Answer: Decreased serum thyroglobulin concentration

Answer

Decreased serum thyroglobulin concentration
This patient is experiencing thyrotoxicosis, as evidenced by her suppressed TSH and elevated free T4 and T3 levels. The critical branch point in her workup is the severely decreased 2424-hour radioactive iodine uptake (RAIU). A low RAIU indicates that the thyroid gland is not actively synthesizing hormone. The differential diagnosis for thyrotoxicosis with a low RAIU includes subacute (de Quervain) thyroiditis, painless (silent) thyroiditis, iodine-induced thyrotoxicosis, struma ovarii, and factitious (exogenous) thyrotoxicosis.

Subacute thyroiditis is ruled out by the absence of an exquisitely tender goiter and viral prodrome. Painless thyroiditis typically presents with a non-tender but palpable goiter. This patient's completely non-palpable thyroid gland and her access to medications as a medical assistant strongly point toward factitious thyrotoxicosis (surreptitious ingestion of thyroid hormone). In factitious thyrotoxicosis, the exogenous hormone suppresses TSH secretion, which in turn halts the endogenous production of both thyroid hormones and thyroglobulin. Consequently, serum thyroglobulin levels will be characteristically decreased. In contrast, all endogenous causes of low-uptake thyrotoxicosis (subacute thyroiditis, painless thyroiditis, struma ovarii) result in elevated serum thyroglobulin due to the destruction of thyroid follicles or ectopic production.

Step-by-Step Solution

1
Interpret the initial thyroid function tests and clinical presentation.
The patient has overt, TSH-suppressed thyrotoxicosis with a normal physical examination (no goiter, no exophthalmos).
To establish the baseline biochemical state and correlate it with the absence of typical autoimmune physical findings.
2
Analyze the radioactive iodine uptake (RAIU) scan results.
The RAIU is severely decreased (1%1\%).
To differentiate true hyperthyroidism (high uptake, indicating overproduction) from destructive or exogenous causes of thyrotoxicosis (low uptake).
3
Formulate a differential diagnosis for low-uptake thyrotoxicosis and match it to the patient's presentation.
The differential includes subacute thyroiditis (painful goiter), painless thyroiditis (non-tender goiter), struma ovarii (pelvic mass), and factitious thyrotoxicosis. The lack of neck pain, absence of a palpable goiter, and her profession (medical assistant) point to factitious (exogenous) thyrotoxicosis.
To systematically rule out competing etiologies based on key negative clinical findings.
4
Determine the confirmatory laboratory test pattern for the suspected diagnosis.
Exogenous intake of thyroid hormone suppresses TSH, which halts endogenous synthesis of thyroglobulin. Therefore, the serum thyroglobulin concentration will be decreased.
To definitively confirm factitious thyrotoxicosis and rule out endogenous destructive processes.

Key Concept

The measurement of serum thyroglobulin is the crucial next step in differentiating factitious (exogenous) thyrotoxicosis (low thyroglobulin) from endogenous destructive thyroiditides (elevated thyroglobulin) in patients presenting with thyrotoxicosis and a low radioactive iodine uptake.
Estimated Time:1m 30s
Question 477Question →

A 55-year-old man with a history of decompensated alcohol-related cirrhosis is brought to the emergency department after vomiting a large amount of bright red blood. On arrival, his blood pressure is 85/50 mmHg, and his heart rate is 122/min. He appears pale and lethargic but is maintaining his airway.

Arrange the following management steps in the most appropriate chronological sequence for this patient's acute condition.

Drag items to arrange them in the correct order

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Answer

The correct sequence of steps for managing acute suspected variceal hemorrhage is: establish IV access for volume resuscitation, administer IV octreotide and prophylactic antibiotics, perform urgent EGD for band ligation, and consider TIPS if bleeding is refractory.
The management of acute variceal hemorrhage follows a strict algorithmic approach prioritizing the ABCs. The patient is in hypovolemic shock, so establishing large-bore IV access for fluid (and subsequent blood product) resuscitation is the immediate first step. Following access, medical therapy with a splanchnic vasoconstrictor (octreotide) and prophylactic antibiotics (ceftriaxone) is initiated to reduce portal pressure and prevent infection. Once the patient is medically optimized, an urgent EGD is performed (typically within 12 hours) to identify the source and perform endoscopic band ligation. Finally, if bleeding persists or recurs despite medical and endoscopic therapy, a transjugular intrahepatic portosystemic shunt (TIPS) is placed as a salvage intervention.

Step-by-Step Solution

1
Assess the patient's hemodynamic status.
The patient is hypotensive and tachycardic, indicating hemorrhagic shock.
Airway, Breathing, and Circulation (ABCs) dictate that establishing IV access for aggressive fluid resuscitation is the mandatory first step.
2
Initiate empiric medical therapy for suspected variceal bleeding.
Administer octreotide and prophylactic antibiotics (e.g., ceftriaxone).
These medications reduce splanchnic pressure and mortality in cirrhotic patients with GI bleeds and must be given early, before endoscopy.
3
Proceed with definitive diagnostic and therapeutic intervention.
Perform an urgent EGD to locate the bleed and perform variceal band ligation.
Endoscopy is the gold standard for stopping active variceal hemorrhage once the patient is hemodynamically stable.
4
Plan for salvage therapy if initial measures fail.
Evaluate for a TIPS procedure.
If bleeding cannot be controlled medically and endoscopically, a shunt is required to decompress the portal system.

Key Concept

Algorithm for acute variceal hemorrhage management in cirrhosis
Question 478Question →

A 54-year-old man arrives at the emergency department due to the sudden onset of left-sided chest pain and shortness of breath that began 22 hours ago. The chest pain worsens with deep inspiration. Over the past 66 months, he has experienced worsening fatigue, frequent headaches, and intense generalized pruritus that is particularly severe after taking hot showers. He also describes a burning sensation in his palms and soles. His temperature is 37.1∘C37.1^\circ\text{C} (98.8∘F98.8^\circ\text{F}), blood pressure is 142/88 mm Hg142/88\text{ mm Hg}, pulse is 112/min112\text{/min}, and respirations are 24/min24\text{/min}. Pulse oximetry shows an oxygen saturation of 90%90\% on room air. Physical examination reveals a plethoric face and engorged retinal veins. The spleen is palpated 4 cm4\text{ cm} below the left costal margin. The lungs are clear to auscultation bilaterally. The right calf is visibly swollen, erythematous, and tender to palpation.

Laboratory studies reveal:
Hemoglobin: 19.2 g/dL19.2\text{ g/dL}
Hematocrit: 59%59\%
Leukocyte count: 15,200 /mm315,200\text{ /mm}^3
Platelet count: 620,000 /mm3620,000\text{ /mm}^3

Arterial blood gas analysis (room air):
pH: 7.517.51
PaCO 2_2: 29 mm Hg29\text{ mm Hg}
PaO 2_2: 60 mm Hg60\text{ mm Hg}

Which of the following is the most appropriate initial step in the management of this patient's acute presentation?

Show answer & explanation

Answer: Initiation of therapeutic low-molecular-weight heparin

Answer

Initiation of therapeutic low-molecular-weight heparin
The patient's presentation of acute dyspnea, pleuritic chest pain, hypoxemia, tachycardia, and a swollen, tender calf is highly suspicious for a deep vein thrombosis (DVT) that has embolized to the lungs, causing a pulmonary embolism (PE). This patient also has classic signs of polycythemia vera (PV), a myeloproliferative neoplasm characterized by the clonal proliferation of all three hematopoietic cell lines (resulting in elevated hemoglobin, leukocytes, and platelets). Clinical features of PV include aquagenic pruritus, erythromelalgia (burning pain in the hands and feet), facial plethora, and splenomegaly. Patients with PV have a significantly increased risk of arterial and venous thrombosis due to hyperviscosity and abnormal platelet function. In a hemodynamically stable patient with a high pretest probability of PE (based on the Wells score), the most appropriate initial step in management is the initiation of empiric therapeutic anticoagulation, such as low-molecular-weight heparin (LMWH), while awaiting definitive diagnostic imaging like a CT pulmonary angiography.

Step-by-Step Solution

1
Identify the underlying chronic systemic condition from the patient's history and labs.
The combination of elevated hemoglobin, leukocytes, and platelets, along with aquagenic pruritus, erythromelalgia, facial plethora, and splenomegaly, indicates a diagnosis of polycythemia vera.
Recognizing polycythemia vera establishes that the patient is in a severely hypercoagulable state with a high risk for both arterial and venous thromboses.
2
Diagnose the etiology of the acute presentation.
Sudden onset of pleuritic chest pain, dyspnea, tachycardia, hypoxemia, and a swollen, tender calf in a hypercoagulable patient points definitively to a deep vein thrombosis (DVT) complicated by a pulmonary embolism (PE).
Matching acute respiratory symptoms and asymmetric leg swelling to the most life-threatening complication of the underlying disease.
3
Determine the most appropriate immediate intervention for this acute condition.
Because the patient is hemodynamically stable but has a high clinical probability of PE (modified Wells criteria), immediate empiric anticoagulation with an agent like low-molecular-weight heparin is indicated.
Prompt anticoagulation prevents further clot propagation and reduces mortality while awaiting definitive diagnostic imaging such as CT pulmonary angiography.

Key Concept

Patients with polycythemia vera are at an elevated risk for thrombotic events. In a hemodynamically stable patient with a high clinical probability of an acute pulmonary embolism, empiric therapeutic anticoagulation should be initiated immediately, even before obtaining confirmatory imaging.
Estimated Time:1m 30s
Question 479Question →

A 70-year-old woman is currently hospitalized on the general medical ward for a deep vein thrombosis of the left lower extremity, which is being treated with a direct oral anticoagulant. On hospital day 3, she reports a sudden increase in shortness of breath, a "tight" chest, and a productive cough with greenish sputum that started yesterday. Her past medical history includes severe emphysema and hypertension. She appears anxious and is utilizing her scalene muscles for respiration. Her temperature is 37.4∘C37.4^\circ\text{C} (99.3∘F99.3^\circ\text{F}), pulse is 108/min108/\text{min}, respirations are 26/min26/\text{min}, and blood pressure is 142/88 mm Hg142/88 \text{ mm Hg}. Oxygen saturation is 86%86\% on room air. Physical examination is notable for a prolonged expiratory phase and prominent diffuse polyphonic rhonchi. Jugular veins are not distended. A bedside echocardiogram shows a normal left ventricular ejection fraction and normal right ventricular size. An arterial blood gas analysis reveals a pH of 7.277.27, PaCO2PaCO_2 of 65 mm Hg65 \text{ mm Hg}, PaO2PaO_2 of 52 mm Hg52 \text{ mm Hg}, and HCO3−HCO_3^- of 29 mEq/L29 \text{ mEq/L}.

Which of the following are the most appropriate immediate steps in the management of this patient's respiratory status? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Application of bilevel positive airway pressure; Administration of systemic methylprednisolone

Answer

The correct management steps are the application of bilevel positive airway pressure and the administration of systemic methylprednisolone.
The correct management consists of applying noninvasive positive pressure ventilation and administering systemic corticosteroids. The patient is experiencing an acute exacerbation of chronic obstructive pulmonary disease (COPD) complicated by acute-on-chronic hypercapnic respiratory failure, as evidenced by a pH less than 7.307.30 and an elevated PaCO2PaCO_2. Bilevel positive airway pressure improves gas exchange, decreases the work of breathing, and reduces mortality and intubation rates. Systemic corticosteroids (e.g., methylprednisolone) are indicated to reduce airway inflammation, improve forced expiratory volume in 1 second (FEV1FEV_1), and shorten recovery time.

Step-by-Step Solution

1
Analyze the patient's clinical presentation and vital signs.
The patient is experiencing an acute exacerbation of chronic obstructive pulmonary disease (COPD), characterized by increased dyspnea, wheezing, and purulent sputum.
To establish the primary diagnosis driving the respiratory failure.
2
Interpret the arterial blood gas values.
The ABG reveals a pH of 7.27, PaCO2 of 65 mm Hg, and HCO3 of 29 mEq/L, indicating acute-on-chronic hypercapnic respiratory acidosis.
To determine the severity of respiratory failure and guide ventilatory support.
3
Evaluate the indications for noninvasive positive pressure ventilation (NIPPV).
The patient has a COPD exacerbation with a pH < 7.30, which is a strong indication for NIPPV (bilevel positive airway pressure) to improve gas exchange and avoid intubation.
To select the appropriate level of respiratory support.
4
Identify the appropriate pharmacologic management for the exacerbation.
Standard therapy includes systemic corticosteroids (e.g., methylprednisolone) to reduce inflammation, along with bronchodilators and targeted antibiotics (not broad-spectrum carbapenems).
To treat the underlying inflammatory trigger of the exacerbation.

Key Concept

The acute management of a severe COPD exacerbation complicated by hypercapnic respiratory failure requires noninvasive positive pressure ventilation (when pH < 7.30), systemic corticosteroids, bronchodilators, and narrow-spectrum antibiotics if purulent sputum is present.
Estimated Time:1m 30s
Question 480Question →

Evaluate the following four adult patients who have presented to the emergency department with acute cardiopulmonary distress. Match each patient's clinical presentation to the single most appropriate initial pharmacological or procedural treatment strategy.

Click a left item, then click its matching right item

Items

A 68-year-old man with a 40-pack-year smoking history presents with acute worsening of dyspnea, increased sputum volume, and distinct sputum purulence.
A 32-year-old woman taking combined oral contraceptives presents with sudden-onset pleuritic chest pain, tachypnea, and a normal chest radiograph.
A 58-year-old man presents with severe substernal chest pressure, diaphoresis, and new ST-segment elevations in leads II, III, and aVF.
A 72-year-old man presents with progressive orthopnea, paroxysmal nocturnal dyspnea, an S3 gallop, and bilateral basilar crackles.

Matches

Show answer & explanation

Answer

The correct pairings are: the COPD exacerbation is treated with bronchodilators, steroids, and antibiotics; the pulmonary embolism is treated with therapeutic anticoagulation; the acute inferior STEMI is treated with antiplatelet therapy and urgent PCI; and the acute decompensated heart failure is treated with intravenous loop diuretics.
Each clinical vignette provides pathognomonic clues for a specific cardiopulmonary emergency. The COPD patient's three cardinal symptoms necessitate the classic triad of bronchodilators, steroids, and antibiotics. The hypercoagulable young woman with sudden pleuritic pain has a pulmonary embolism requiring anticoagulation. The patient with ST-segment elevations requires immediate mechanical reperfusion via PCI. Finally, the older man with signs of fluid overload (S3 gallop, crackles) requires diuresis to manage acute decompensated heart failure.

Step-by-Step Solution

1
Analyze the first patient's presentation (68-year-old with increased dyspnea and purulent sputum).
Identify acute COPD exacerbation, which requires bronchodilators, steroids, and antibiotics.
The combination of three cardinal symptoms (increased dyspnea, sputum volume, and purulence) warrants the full COPD exacerbation treatment bundle.
2
Analyze the second patient's presentation (32-year-old on OCPs with sudden pleuritic chest pain).
Identify acute pulmonary embolism, which requires immediate therapeutic anticoagulation.
Sudden pleuritic pain and tachypnea in a patient with estrogen exposure is highly suspicious for PE; anticoagulation is the first-line therapy to prevent propagation.
3
Analyze the third patient's presentation (58-year-old with inferior ST elevations).
Identify acute inferior STEMI, which requires antiplatelet therapy and urgent percutaneous coronary intervention (PCI).
ST-segment elevations indicate transmural myocardial ischemia requiring emergent revascularization.
4
Analyze the fourth patient's presentation (72-year-old with orthopnea and S3 gallop).
Identify acute decompensated heart failure (ADHF), which requires intravenous loop diuretics.
The S3 gallop and crackles indicate volume overload and elevated left ventricular filling pressures, which are alleviated by diuresis.

Key Concept

Recognition of classic acute cardiopulmonary emergencies and selection of their first-line, mortality-reducing, or symptom-alleviating interventions.
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Internal Medicine Practice Questions — USMLE Step 2 CK — Page 24 | Examkin