Internal Medicine

3151 questions

All types3,151 Multiple choice1,611 Multiple select73 Numeric81 Matching714 Ordering672

Match each of the following acute cardiovascular clinical presentations to the most appropriate initial pharmacological intervention.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Acute heart failure matches with loop diuretics; stable SVT matches with adenosine; acute aortic dissection matches with beta-blockers; symptomatic bradycardia matches with atropine.

Each cardiovascular emergency has a specific, evidence-based initial pharmacological therapy. Loop diuretics relieve volume overload in heart failure. Adenosine halts AV-nodal dependent re-entrant arrhythmias. Beta-blockers reduce sheer stress in aortic dissection. Atropine increases heart rate in symptomatic bradycardia.

Step-by-Step Solution

Evaluate the presentation of shortness of breath, crackles, and jugular venous distention in a hypertensive patient.

Identify acute decompensated heart failure with pulmonary edema.

Initial management focuses on rapid preload reduction and diuresis using an intravenous loop diuretic.

Analyze the case of stable, regular, narrow-complex tachycardia at 165/min.

Identify paroxysmal supraventricular tachycardia (PSVT).

Adenosine is the drug of choice for acute termination of stable PSVT due to its rapid-onset AV nodal blockade.

Assess the presentation of tearing back pain, asymmetric pulses, and severe hypertension.

Identify acute aortic dissection.

Anti-impulse therapy with an intravenous beta-blocker is paramount to lower blood pressure and wall shear stress before any vasodilators are considered.

Review the case of hypotension and dizziness associated with a heart rate of 38/min.

Identify symptomatic, hemodynamically unstable bradycardia.

Atropine is indicated as the first-line pharmacological measure for symptomatic bradycardia to block vagal tone and augment the heart rate.

Key Concept

The precise initial pharmacological stabilization of acute, life-threatening cardiovascular emergencies relies on recognizing the underlying pathophysiological derangement.

Estimated Time:1m 30s

Question 3142Question →

An internal medicine physician evaluates a 42-year-old male during an outpatient consultation for refractory dyspepsia and frequent loose stools. Over the past eight months, the patient has experienced burning epigastric pain that is only transiently relieved by food intake. His medical history is notable for recurrent duodenal ulcers, for which he successfully completed a course of *Helicobacter pylori* eradication therapy a year ago. Following his physician's instructions, he discontinued all proton pump inhibitors fourteen days ago. He currently takes no medications. Vital signs are normal. Abdominal examination demonstrates localized epigastric tenderness to deep palpation without guarding.

Laboratory testing reveals the following:

Laboratory Test	Result	Reference Range
Serum calcium	$9.2$ mg/dL	$8.4 - 10.2$ mg/dL
Fasting serum gastrin	$480$ pg/mL	$< 110$ pg/mL
Gastric fluid pH	$1.8$	$1.5 - 3.5$

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

Secretin stimulation test

Somatostatin receptor scintigraphy

Empiric oral ciprofloxacin and metronidazole

Diagnostic laparoscopy

Measurement of serum vasoactive intestinal peptide

Show answer & explanation

Answer: Secretin stimulation test

Answer

The correct answer is the secretin stimulation test.

The correct answer is the secretin stimulation test. This patient presents with classic features of Zollinger-Ellison syndrome (ZES), including multiple duodenal ulcers and chronic diarrhea (caused by the inactivation of pancreatic enzymes by massive gastric acid secretion). The diagnostic algorithm for ZES begins with stopping proton pump inhibitors and measuring a fasting serum gastrin level alongside gastric pH. If the gastric pH is

< 4.0

and the gastrin level is

> 1000

pg/mL, the diagnosis is confirmed. However, if the gastrin level is indeterminate (between

110

and

1000

pg/mL), a secretin stimulation test must be performed. Secretin paradoxically stimulates the release of gastrin from gastrinoma cells, leading to a marked rise in serum gastrin levels, which confirms the diagnosis.

Step-by-Step Solution

Analyze the clinical presentation.

The patient has refractory dyspepsia, recurrent duodenal ulcers despite prior H. pylori treatment, and chronic diarrhea, which strongly suggests a hypersecretory state like Zollinger-Ellison syndrome (ZES).

Recognizing the classic triad of recurrent peptic ulcer disease, chronic diarrhea, and resistance to standard therapy points toward a gastrinoma.

Interpret the initial diagnostic laboratory findings.

Gastric pH is low (

1.8

), confirming an acidic environment. Fasting serum gastrin is elevated (

480

pg/mL), but it is not completely diagnostic on its own.

A fasting serum gastrin level

> 1000

pg/mL in the presence of a gastric pH

< 4.0

is definitively diagnostic for ZES. A level between

110

and

1000

pg/mL is indeterminate and requires further testing.

Determine the appropriate confirmatory diagnostic test.

A secretin stimulation test is the next required step to confirm the diagnosis.

Normal gastric G cells are inhibited by secretin, but gastrinoma cells are paradoxically stimulated by it. An increase in serum gastrin of

> 120

pg/mL over the baseline after secretin administration confirms ZES.

Key Concept

Diagnosis of Zollinger-Ellison Syndrome

Estimated Time:1m 0s

Question 3143Question →

Emergency medical services bring a 68-year-old male to the resuscitation bay due to progressive, severe difficulty breathing and purulent sputum production over the past 72 hours. He has a 40-pack-year smoking history and advanced chronic obstructive pulmonary disease (COPD). He reports poor oral intake over the last week. At a pulmonary clinic visit two weeks ago, a sputum culture grew *Haemophilus influenzae* susceptible to azithromycin and ceftriaxone.

On arrival, he is in acute respiratory distress, using accessory muscles of respiration. Vital signs are:
- Temperature: $37.8^\circ\text{C}$ ( $100.0^\circ\text{F}$ )
- Blood pressure: $102/65\text{ mmHg}$
- Heart rate: $115/\text{min}$
- Respiratory rate: $30/\text{min}$
- Oxygen saturation: $85\%$ on room air

Physical examination reveals a barrel-shaped chest, prolonged expiratory phase, and diffuse bilateral wheezing. Jugular venous pressure is normal, and there is no peripheral edema. Chest radiograph reveals hyperinflated lungs and a flattened diaphragm without focal infiltrates or cardiomegaly. Arterial blood gas analysis on room air shows:
- pH: $7.20$
- $\text{PaCO}_2$ : $50\text{ mmHg}$
- $\text{PaO}_2$ : $52\text{ mmHg}$
- $\text{HCO}_3^-$ : $19\text{ mEq/L}$

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

Select all that apply

Initiate noninvasive positive pressure ventilation

Provide inhaled albuterol and intravenous methylprednisolone

Administer a bolus of intravenous furosemide

Start intravenous piperacillin-tazobactam

Administer an infusion of sodium bicarbonate

Show answer & explanation

Answer: Initiate noninvasive positive pressure ventilation; Provide inhaled albuterol and intravenous methylprednisolone

Answer

Initiate noninvasive positive pressure ventilation AND Provide inhaled albuterol and intravenous methylprednisolone

This patient is experiencing a severe acute exacerbation of chronic obstructive pulmonary disease (COPD) complicated by acute respiratory failure and a mixed acid-base disorder. The clinical presentation—accessory muscle use, diffuse wheezing, hyperinflated lungs, and absence of volume overload signs—points squarely to COPD rather than acute decompensated heart failure. Initial management of a severe COPD exacerbation includes short-acting bronchodilators (albuterol) and systemic corticosteroids (methylprednisolone) to reduce airway inflammation and resistance. Furthermore, this patient requires noninvasive positive pressure ventilation (NPPV). NPPV is strongly indicated for COPD exacerbations with respiratory acidosis (pH

< 7.35

and

\text{PaCO}_2 > 45\text{ mmHg}

) or severe dyspnea, as it decreases the work of breathing, improves gas exchange, and reduces the need for endotracheal intubation.

Step-by-Step Solution

Evaluate clinical presentation and radiologic findings.

The patient demonstrates severe respiratory distress, wheezing, and hyperinflated lungs without signs of fluid overload.

Accurate clinical assessment differentiates a true COPD exacerbation from acute decompensated heart failure, guiding targeted therapy rather than inappropriate diuresis.

Analyze the arterial blood gas data using Winter's formula.

The expected PaCO2 (

1.5 \times 19 + 8 = 36.5 \pm 2\text{ mmHg}

) is much lower than the actual PaCO2 (

50\text{ mmHg}

), confirming a mixed metabolic and uncompensated respiratory acidosis.

Identifying the uncompensated respiratory failure dictates the urgent need for ventilatory support rather than simply attempting to correct the metabolic acidosis with bicarbonate.

Select appropriate targeted therapies.

NPPV, bronchodilators, and systemic corticosteroids are indicated, while narrow-spectrum antibiotics should be utilized based on prior culture data.

These combined interventions directly address airway inflammation, bronchoconstriction, and ventilatory failure while strictly adhering to antibiotic stewardship principles.

Key Concept

Management of severe COPD exacerbations complicated by acute respiratory failure, and the interpretation of mixed acid-base disorders using Winter's formula.

Question 3144Question →

A 72-year-old woman comes to the clinic reporting progressive shortness of breath with exertion over the past 4 months. She can now walk only half a block before needing to stop to catch her breath. She has a history of hypertension, type 2 diabetes mellitus, and chronic obstructive pulmonary disease (COPD). She has a 40-pack-year smoking history but quit 5 years ago. She uses her tiotropium and albuterol inhalers daily, but they have not relieved her recent symptoms. Blood pressure is $158/92$ mm Hg, pulse is $84$ /min, and respirations are $18$ /min. Pulse oximetry is $94\%$ on room air. Jugular venous pressure is elevated at $9$ cm $H_2O$ . Lung auscultation reveals diminished breath sounds bilaterally without wheezes or crackles. Cardiac examination shows a regular rate and rhythm, a loud pulmonic component of the second heart sound ( $P_2$ ), and a fourth heart sound ( $S_4$ ). There is 2+ pitting edema in the lower extremities. Transthoracic echocardiography demonstrates an estimated left ventricular ejection fraction of $65\%$ , severe left atrial enlargement, marked concentric left ventricular hypertrophy, and right ventricular dilation. Estimated pulmonary artery systolic pressure is $58$ mm Hg. Which of the following is the most likely primary mechanism for this patient's elevated pulmonary artery pressure?

Retrograde transmission of elevated left ventricular filling pressures

Hypoxia-induced diffuse pulmonary arteriolar vasoconstriction

Progressive loss of the alveolar-capillary membrane surface area

Chronic airway inflammation with mucous hypersecretion

Impaired intrinsic contractility of the left ventricular myocardium

Show answer & explanation

Answer: Retrograde transmission of elevated left ventricular filling pressures

Answer

Retrograde transmission of elevated left ventricular filling pressures

The correct answer is retrograde transmission of elevated left ventricular filling pressures. This patient presents with signs of right-sided heart failure (elevated jugular venous pressure, peripheral edema) and elevated pulmonary artery systolic pressure. While her history of COPD makes cor pulmonale a diagnostic consideration, the echocardiogram reveals marked concentric left ventricular hypertrophy, severe left atrial enlargement, and a normal left ventricular ejection fraction (

65\%

). These findings are diagnostic of heart failure with preserved ejection fraction (HFpEF). In HFpEF, the stiff, non-compliant left ventricle requires elevated filling pressures (high left ventricular end-diastolic pressure) to maintain cardiac output. This elevated pressure is transmitted retrogradely into the left atrium, pulmonary veins, and eventually the pulmonary arterial system, leading to Group 2 pulmonary hypertension. The presence of an

S_4

further supports the clinical diagnosis of a stiff, non-compliant left ventricle.

Step-by-Step Solution

Analyze the patient's clinical and echocardiographic findings to identify the primary pathology.

The patient has progressive dyspnea, edema, and elevated jugular venous pressure. Echocardiography shows severe left atrial enlargement, concentric left ventricular hypertrophy, and a normal ejection fraction (

65\%

These findings, along with an

S_4

gallop, are classic for heart failure with preserved ejection fraction (HFpEF).

Determine the cause of the elevated pulmonary artery systolic pressure (

58

mm Hg) in the context of HFpEF.

The pulmonary hypertension is classified as Group 2 (due to left heart disease).

In HFpEF, the stiff, non-compliant left ventricle requires higher filling pressures (elevated left ventricular end-diastolic pressure). This high pressure is transmitted backwards.

Differentiate from COPD-related pulmonary hypertension (cor pulmonale).

Although the patient has COPD, the marked left-sided structural changes point to left heart disease as the primary driver of her symptoms and elevated pulmonary pressures.

Cor pulmonale (Group 3 pulmonary hypertension) would primarily show right-sided enlargement without the severe left atrial and left ventricular changes seen in this patient.

Key Concept

Group 2 pulmonary hypertension occurs due to retrograde transmission of elevated left-sided filling pressures in patients with left heart disease, such as heart failure with preserved ejection fraction (HFpEF).

Question 3145Question →

A 66-year-old man is evaluated in the intensive care unit on day 4 of his admission. He was initially intubated and placed on mechanical ventilation for acute hypercapnic respiratory failure secondary to a severe exacerbation of chronic obstructive pulmonary disease (COPD). Two days ago, he developed a temperature of $38.5^\circ\text{C}$ ( $101.3^\circ\text{F}$ ), increased purulent endotracheal secretions, and a new right lower lobe consolidation on chest radiograph. Empiric therapy with intravenous vancomycin and cefepime was initiated for presumed ventilator-associated pneumonia.

Today, his temperature is $37.2^\circ\text{C}$ ( $99.0^\circ\text{F}$ ), blood pressure is $132/82$ mm Hg, pulse is $84$ /min, and respirations are $16$ /min. He is awake, cooperative, and breathing comfortably on pressure support ventilation. Physical examination shows a prolonged expiratory phase with scattered wheezes and trace bilateral pedal edema.

An arterial blood gas on his current ventilator settings shows:

Parameter	Value	Reference Range
pH	$7.41$	$7.35-7.45$
PaCO $_2$	$54$ mm Hg	$35-45$ mm Hg
PaO $_2$	$76$ mm Hg	$75-105$ mm Hg
HCO $_3^-$	$33$ mEq/L	$22-28$ mEq/L

Endotracheal aspirate cultures obtained two days ago now grow *Streptococcus pneumoniae*. Susceptibility testing shows the organism is sensitive to ceftriaxone, levofloxacin, and penicillin.

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

Continue intravenous vancomycin and cefepime for a full 7-day course

De-escalate antibiotic therapy to intravenous ceftriaxone

Increase the ventilator pressure support to normalize the PaCO

_2

Administer intravenous furosemide

Add intravenous azithromycin to the current regimen

Show answer & explanation

Answer: De-escalate antibiotic therapy to intravenous ceftriaxone

Answer

The most appropriate next step is to de-escalate antibiotic therapy to intravenous ceftriaxone.

This patient developed ventilator-associated pneumonia (VAP) and was appropriately started on empiric broad-spectrum antibiotics (vancomycin and cefepime) to cover resistant organisms like MRSA and Pseudomonas aeruginosa. The endotracheal aspirate culture has now returned positive for *Streptococcus pneumoniae* that is sensitive to ceftriaxone. In the setting of clinical improvement (normalizing temperature and stable vital signs), the most appropriate next step is to de-escalate his antimicrobial regimen to a targeted, narrow-spectrum agent like ceftriaxone. Continuing broad-spectrum antibiotics when a susceptible organism is identified is inappropriate and increases the risk of antimicrobial resistance, Clostridioides difficile infection, and drug toxicity.

Step-by-Step Solution

Interpret the clinical response and culture results.

The patient is improving clinically, and cultures show *Streptococcus pneumoniae* sensitive to ceftriaxone.

To determine the need for ongoing broad-spectrum antibiotics.

Apply principles of antibiotic stewardship.

Broad-spectrum agents (vancomycin and cefepime) are discontinued in favor of targeted therapy (ceftriaxone).

To reduce the risk of adverse effects, toxicity, and the development of antimicrobial resistance.

Evaluate the arterial blood gas.

The ABG shows a fully compensated chronic respiratory acidosis with a normal pH (

7.41

) and elevated bicarbonate (

33

mEq/L).

To verify that the patient's current ventilator settings are appropriate and do not require adjustment.

Key Concept

Antibiotic stewardship in ventilator-associated pneumonia (VAP) requires prompt de-escalation from empiric broad-spectrum therapy to targeted narrow-spectrum agents once culture and sensitivity results are available.

Estimated Time:1m 30s

Question 3146Question →

A 62-year-old woman is evaluated on hospital day 3. She initially presented with fever, severe right upper quadrant pain, and jaundice. She was diagnosed with acute ascending cholangitis. On admission, she was started on empiric intravenous piperacillin-tazobactam and subsequently underwent urgent endoscopic retrograde cholangiopancreatography (ERCP) with successful sphincterotomy and stone extraction. Her symptoms have now resolved, and she has been afebrile for 48 hours. Vital signs are within normal limits. Blood cultures drawn at admission are now positive for *Escherichia coli*. The susceptibility report is shown below:

Antimicrobial	Interpretation
Ampicillin	Resistant
Ceftriaxone	Susceptible
Ciprofloxacin	Susceptible
Piperacillin-tazobactam	Susceptible
Meropenem	Susceptible

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

Switch to intravenous ceftriaxone

Continue intravenous piperacillin-tazobactam

Switch to intravenous meropenem

Add intravenous vancomycin

Switch to intravenous ampicillin

Show answer & explanation

Answer: Switch to intravenous ceftriaxone

Answer

Switch to intravenous ceftriaxone

The patient developed acute ascending cholangitis and has now achieved source control through an ERCP with sphincterotomy. Her blood cultures have isolated *Escherichia coli* that is susceptible to ceftriaxone. According to the core principles of antimicrobial stewardship, once culture and susceptibility data become available, an empiric broad-spectrum antibiotic regimen (such as piperacillin-tazobactam) should be promptly de-escalated to a targeted, narrower-spectrum agent. Ceftriaxone provides excellent, targeted coverage for this specific *E. coli* isolate, minimizing collateral damage to the patient's normal flora and reducing the risk of antibiotic resistance.

Step-by-Step Solution

Evaluate the patient's clinical status and source control.

The patient has clinically improved (afebrile, symptoms resolved) after successful source control via ERCP.

Determining clinical stability is necessary before altering empiric antibiotic regimens.

Analyze the blood culture and susceptibility results.

Cultures grew E. coli that is resistant to ampicillin but susceptible to ceftriaxone, ciprofloxacin, piperacillin-tazobactam, and meropenem.

Culture data dictates the definitive antibiotic therapy.

Apply principles of antimicrobial stewardship to select the most appropriate agent.

De-escalate from empiric broad-spectrum therapy (piperacillin-tazobactam) to a targeted, narrower-spectrum agent (ceftriaxone).

Narrowing the antibiotic spectrum prevents the emergence of multidrug-resistant organisms and reduces adverse effects.

Key Concept

Antimicrobial Stewardship in Biliary Infections

Estimated Time:1m 15s

Question 3147Question →

A 65-year-old man is brought to the emergency department at 3:00 AM due to sudden, severe difficulty breathing. He states he woke up gasping for air and had to sit upright on the edge of his bed. His medical history includes hypertension, type 2 diabetes mellitus, and a 40-pack-year smoking history. Current medications include amlodipine and metformin. His temperature is $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ), blood pressure is $185/105\text{ mmHg}$ , pulse is $112/\text{min}$ , and respirations are $28/\text{min}$ . Pulse oximetry shows an oxygen saturation of $86\%$ on room air. Physical examination reveals distended neck veins when sitting at a 45-degree angle. Cardiac auscultation reveals a regular tachycardia with a prominent third heart sound (S3). Lung auscultation reveals bilateral basilar crackles extending halfway up the posterior lung fields, without wheezing. Bilateral 1+ pitting edema is present in the lower extremities. Arterial blood gas on room air shows a pH of $7.31$ , $\text{pCO}_2$ of $52\text{ mmHg}$ , and $\text{pO}_2$ of $58\text{ mmHg}$ . Laboratory studies show a normal leukocyte count. Thyroid function tests reveal a TSH of $1.5\text{ \mu U/mL}$ (normal: $0.5-5.0$ ) and a free T4 of $0.6\text{ ng/dL}$ (normal: $0.9-2.4$ ). A Gram stain of a sputum sample reveals normal respiratory flora with no predominant organisms. Chest radiography shows bilateral fluffy alveolar opacities, prominent hila, and cephalization of the pulmonary vessels. Which of the following is the most appropriate initial step in the management of this patient?

Albuterol and ipratropium nebulization

Intravenous ceftriaxone and azithromycin

Intravenous sodium bicarbonate

Intravenous furosemide

Intravenous levothyroxine

Show answer & explanation

Answer: Intravenous furosemide

Answer

Intravenous furosemide

The correct answer provides the mainstay treatment for acute decompensated heart failure (ADHF). The patient's presentation of paroxysmal nocturnal dyspnea, an S3 gallop, jugular venous distention, basilar crackles, and radiographic findings of alveolar opacities with cephalization are classic for ADHF. Intravenous loop diuretics, such as furosemide, are the initial pharmacotherapy of choice because they rapidly decrease circulating volume and promote venodilation, thereby reducing cardiac preload and improving pulmonary congestion.

Step-by-Step Solution

Analyze the patient's vital signs and physical examination findings.

The patient exhibits severe hypertension, hypoxia, an S3 gallop, jugular venous distention, and bilateral basilar crackles without wheezing.

To identify the primary pathophysiologic process driving the acute dyspnea.

Evaluate the laboratory and imaging results.

Chest radiography confirms cardiogenic pulmonary edema. The arterial blood gas demonstrates acute respiratory acidosis secondary to fluid accumulation in the alveoli. Infectious and primary endocrine etiologies are not supported by the normal leukocyte count, normal sputum flora, and normal TSH.

To rule out alternative diagnoses such as a COPD exacerbation, bacterial pneumonia, or a thyroid-related crisis.

Determine the most appropriate initial pharmacological management.

The standard of care for acute decompensated heart failure (ADHF) with volume overload is prompt preload reduction and diuresis with intravenous loop diuretics (e.g., furosemide), often combined with noninvasive positive pressure ventilation and vasodilators given his severe hypertension.

Intravenous furosemide provides rapid symptomatic relief by actively removing excess intravascular volume and promoting immediate venodilation.

Key Concept

Diagnosis and acute pharmacological management of acute decompensated heart failure (ADHF)

Question 3148Question →

A 65-year-old man with a 40-pack-year smoking history is evaluated in the clinic for preoperative clearance prior to an elective inguinal hernia repair. He has not seen a physician in five years. A routine chest radiograph reveals a 1.4-cm, well-circumscribed, noncalcified nodule in the right upper lobe. The patient currently reports no cough, hemoptysis, or unintentional weight loss. Arrange the following management steps in the most appropriate sequential order for the evaluation of this pulmonary finding.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence for evaluating a solitary pulmonary nodule is to first review prior imaging, followed by a high-resolution CT scan, then a PET scan, and finally a tissue biopsy.

The standard evidence-based algorithmic approach to a solitary pulmonary nodule begins with comparing the current imaging to past radiographs to check for stability. If unavailable or growing, a dedicated chest CT is obtained to characterize the nodule. For nodules >8 mm with an intermediate to high malignancy risk, a PET scan is performed to assess metabolic activity and stage the patient, followed lastly by a tissue biopsy for definitive diagnosis if the PET scan is highly suspicious.

Step-by-Step Solution

Determine the stability of the nodule.

Review prior medical records and chest imaging.

To quickly identify if the nodule is long-standing and benign (stable for >24 months), which safely prevents unnecessary invasive procedures and radiation exposure.

Characterize the nodule's morphological features.

Obtain a high-resolution CT scan of the chest.

To accurately measure the nodule and assess high-risk features (such as spiculated margins) if old films are unavailable or show evidence of interval growth.

Assess metabolic activity and clinical stage.

Perform a positron emission tomography (PET) scan.

To evaluate the likelihood of malignancy based on glucose uptake and to screen for mediastinal lymph node involvement or distant metastases in nodules >8 mm.

Establish a definitive histopathological diagnosis.

Perform a tissue biopsy.

To confirm the presence of cancer and determine the specific histologic subtype before initiating definitive therapy or major surgery.

Key Concept

Diagnostic algorithm for a solitary pulmonary nodule (SPN)

Question 3149Question →

Match each of the following characteristic arterial pulse abnormalities observed during physical examination with its most closely associated underlying cardiovascular pathology.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Pulsus parvus et tardus indicates Severe aortic stenosis; Pulsus paradoxus indicates Cardiac tamponade; Water-hammer pulse indicates Chronic severe aortic regurgitation; Pulsus alternans indicates Advanced left ventricular systolic dysfunction.

Each cardiovascular pathology alters systemic hemodynamics in a highly specific manner that manifests in the peripheral arterial pulse. Aortic stenosis physically restricts outflow resulting in a slow upstroke; cardiac tamponade causes exaggerated respiratory variation in filling; aortic regurgitation creates an abnormally wide pulse pressure due to diastolic backflow; and a failing myocardium struggles to maintain consistent stroke volume, resulting in alternating strong and weak pulses.

Step-by-Step Solution

Analyze Pulsus parvus et tardus.

Identify the underlying mechanism as obstruction to forward flow.

The narrowed aortic valve limits peak forward stroke volume, creating a weak and slow-rising systemic pulse, typical of severe aortic stenosis.

Analyze Pulsus paradoxus.

Identify the underlying mechanism as exaggerated ventricular interdependence.

Increased right heart filling during inspiration forces the interventricular septum toward the left ventricle, compromising left-sided stroke volume inside a fluid-filled pericardial sac, typical of cardiac tamponade.

Analyze Water-hammer pulse.

Identify the underlying mechanism as widened pulse pressure.

Incompetence of the aortic valve allows blood to flow back into the left ventricle during diastole, causing a rapid collapse of arterial pressure after a bounding systolic phase, characteristic of severe aortic regurgitation.

Analyze Pulsus alternans.

Identify the underlying mechanism as beat-to-beat alteration in stroke volume.

Incomplete recovery of failing myocardial cells between beats leads to alternating stronger and weaker contractions, indicating severe left ventricular systolic dysfunction.

Key Concept

Characteristic arterial pulse abnormalities correspond directly to distinct hemodynamic derangements caused by specific structural cardiac pathologies.

Question 3150Question →

A 54-year-old man is evaluated during morning rounds on his fourth day of hospitalization for acute pancreatitis. The patient originally presented with severe, radiating epigastric pain and a serum lipase level of $3,200 \text{ U/L}$ . His medical history is significant for alcohol use disorder and hypertension. Currently, he reports ongoing abdominal discomfort but feels slightly better than on admission. He has been receiving aggressive intravenous hydration and pain control. Vital signs are temperature $38.4^\circ\text{C}$ ( $101.1^\circ\text{F}$ ), blood pressure $122/78 \text{ mm Hg}$ , heart rate $104/\text{min}$ , and respiratory rate $18/\text{min}$ . Physical examination reveals a distended abdomen with hypoactive bowel sounds and diffuse tenderness to palpation, most pronounced in the epigastrium. There is no rebound tenderness or guarding. Laboratory studies show a leukocyte count of $15,200/\text{mm}^3$ with $85\%$ neutrophils. A contrast-enhanced CT scan of the abdomen is performed, demonstrating edematous enlargement of the pancreas with non-enhancement of approximately $40\%$ of the glandular parenchyma. Moderate peripancreatic fluid collections are present, but there is no evidence of gas within the tissue. Which of the following is the most appropriate next step in the management of this patient?

Begin intravenous imipenem-cilastatin therapy

Perform CT-guided fine-needle aspiration of the pancreas

Consult general surgery for open necrosectomy

Maintain supportive care and continue enteral feeding

Initiate total parenteral nutrition to provide bowel rest

Show answer & explanation

Answer: Maintain supportive care and continue enteral feeding

Answer

Maintain supportive care and continue enteral feeding

This patient has acute necrotizing pancreatitis and is exhibiting signs of systemic inflammatory response syndrome (SIRS), including fever, tachycardia, and leukocytosis. In the first week of severe acute pancreatitis, these findings are overwhelmingly driven by profound tissue inflammation rather than active bacterial infection. A contrast-enhanced CT scan confirms sterile necrosis (demonstrated by the absence of gas bubbles in the non-enhancing tissue). The current standard of care for sterile necrotizing pancreatitis is aggressive supportive care, including continued hydration, pain control, and early enteral nutrition. Enteral feeding (via nasogastric or nasojejunal tube) is vastly superior to parenteral nutrition because it helps maintain the intestinal mucosal barrier. This prevents the translocation of gut flora into the systemic circulation and necrotic tissues, thereby significantly lowering the risk of subsequent infected necrosis. Prophylactic antibiotics are not indicated and do not improve clinical outcomes.

Step-by-Step Solution

Evaluate the patient's clinical timeline and imaging findings.

The patient is on day 4 of admission with extensive pancreatic necrosis. The CT scan confirms sterile necrosis, as there is no gas within the necrotic collections.

Establishing whether the necrosis is sterile or infected is critical for determining the need for antibiotics or procedural intervention.

Differentiate Systemic Inflammatory Response Syndrome (SIRS) from active infection.

The patient's fever, tachycardia, and leukocytosis in the first week of severe pancreatitis are driven by intense cytokine release (SIRS), not necessarily a bacterial infection.

Misinterpreting SIRS as an active infection leads to inappropriate antibiotic stewardship and unnecessary invasive testing.

Select the appropriate evidence-based management strategy.

Prophylactic antibiotics are withheld. Supportive care is maintained, and enteral nutrition is prioritized over parenteral nutrition.

Enteral feeding preserves the gut mucosal barrier, preventing bacterial translocation and significantly reducing the risk of subsequently developing infected necrosis.

Key Concept

Management of sterile acute necrotizing pancreatitis involves supportive care and early enteral nutrition without prophylactic antibiotics.

Estimated Time:1m 30s

Question 3151Question →

A 72-year-old man is evaluated in the intensive care unit for increasing lethargy and rapid breathing. He was admitted two days ago for urosepsis and has been receiving intravenous ceftriaxone. Urine cultures returned earlier today growing *Escherichia coli* that is susceptible to ceftriaxone. His medical history includes severe chronic obstructive pulmonary disease and heart failure with preserved ejection fraction.

Upon admission, an advance directive was placed in his chart explicitly stating his desire for all life-sustaining interventions, including intubation and mechanical ventilation, in the event of critical illness. However, his wife, who is at the bedside, is distressed by his deterioration and requests that no breathing machine be used.

Vital signs are temperature 37.5°C (99.5°F), blood pressure 110/70 mm Hg, pulse 115/min, and respirations 28/min. Physical examination reveals a lethargic patient who only briefly opens his eyes to painful stimuli. His breathing is labored with prominent use of accessory muscles, prolonged expiration, and faint bilateral expiratory wheezes. Jugular venous distention is absent and trace pedal edema is present.

Laboratory Test	Result
Sodium	139 mEq/L
Potassium	4.8 mEq/L
Chloride	104 mEq/L
Bicarbonate	14 mEq/L
Blood urea nitrogen	35 mg/dL
Creatinine	1.6 mg/dL
Lactate	5.1 mmol/L

Arterial blood gas (on room air):

Parameter	Result
pH	7.23
PaCO2	35 mm Hg
PaO2	60 mm Hg

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

Perform endotracheal intubation and initiate mechanical ventilation

Administer intravenous furosemide

Broaden antibiotic therapy to intravenous vancomycin and piperacillin-tazobactam

Withhold intubation and initiate comfort care measures as requested by the wife

Continue current management and reassess arterial blood gases in 2 hours

Show answer & explanation

Answer: Perform endotracheal intubation and initiate mechanical ventilation

Answer

The most appropriate next step is to perform endotracheal intubation and initiate mechanical ventilation.

This patient is in impending hypercapnic respiratory failure secondary to a chronic obstructive pulmonary disease (COPD) exacerbation and sepsis. His arterial blood gas reveals a primary metabolic acidosis (bicarbonate 14 mEq/L, pH 7.23). Using Winter's formula (

1.5 \times 14 + 8 \pm 2

), his expected

\text{PaCO}_2

should be between 27 and 31 mm Hg. His actual

\text{PaCO}_2

of 35 mm Hg represents a superimposed primary respiratory acidosis, demonstrating an inability to mount an adequate respiratory compensation due to respiratory muscle fatigue. Clinically, this manifests as increasing lethargy and labored breathing. Immediate airway protection with endotracheal intubation is required. Ethically, his previously documented advance directive explicitly requesting mechanical ventilation must be honored over the contradictory wishes of his wife, as it represents his competent, autonomous choice.

Step-by-Step Solution

Analyze the primary acid-base disturbance.

The patient has a primary anion gap metabolic acidosis (pH 7.23,

\text{HCO}_3^-

14 mEq/L) likely secondary to lactic acidosis from sepsis.

Identifying the primary disorder is required to calculate the expected compensatory response.

Calculate the expected respiratory compensation.

Using Winter's formula (

1.5 \times 14 + 8 \pm 2

), the expected

\text{PaCO}_2

is between 27 and 31 mm Hg.

This determines if the patient's respiratory drive is adequate for the degree of metabolic acidosis.

Compare actual and expected

\text{PaCO}_2

The actual

\text{PaCO}_2

(35 mm Hg) is higher than expected, indicating a superimposed primary respiratory acidosis.

This unmasks impending respiratory failure due to respiratory muscle fatigue.

Evaluate the ethical priority of decision-makers.

The patient's advance directive requests mechanical ventilation, which overrides the wife's contradictory request.

An advance directive represents the patient's autonomous, competent wishes and is legally binding.

Determine the appropriate clinical intervention.

Emergent endotracheal intubation must be performed.

The patient requires definitive airway management for respiratory failure, in accordance with his wishes.

Key Concept

Management of acute respiratory failure with mixed acid-base disorders and the ethical priority of advance directives over surrogate wishes.

Estimated Time:1m 30s

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Internal Medicine

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