Internal Medicine

3151 questions

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

A 59-year-old woman is brought to the emergency department by her family due to a 3-day history of progressively worsening shortness of breath, right-sided chest discomfort, and a productive cough with rust-colored sputum. She has a past medical history of advanced chronic obstructive pulmonary disease (COPD) and essential hypertension. Her current home medications include a daily fluticasone-salmeterol inhaler and amlodipine. On arrival, she appears in moderate respiratory distress, utilizing accessory muscles of respiration but remains fully alert and cooperative.

Temperature is $38.8^\circ\text{C}$ ( $101.8^\circ\text{F}$ ), blood pressure is $138/82\text{ mmHg}$ , pulse is $112/\text{min}$ , and respiratory rate is $28/\text{min}$ . Pulse oximetry reveals an oxygen saturation of $87\%$ on room air.

Physical examination shows a jugular venous pressure of $6\text{ cm H}_2\text{O}$ . Auscultation of the lungs reveals a prolonged expiratory phase with diffuse expiratory wheezing, as well as coarse crackles and bronchial breath sounds localized to the right lower lung base. Cardiac examination shows a regular tachycardia without murmurs or gallops. There is no lower extremity edema.

Laboratory results:
- Leukocyte count: $16,500/\text{mm}^3$ (with $85\%$ segmented neutrophils)
- Brain natriuretic peptide (BNP): $45\text{ pg/mL}$

Arterial blood gas (on room air):
- pH: $7.24$
- PaCO $_2$ : $70\text{ mmHg}$
- PaO $_2$ : $52\text{ mmHg}$
- HCO $_3^-$ : $29\text{ mEq/L}$

A sputum Gram stain shows abundant polymorphonuclear leukocytes and numerous Gram-positive, lancet-shaped diplococci. A chest radiograph demonstrates hyperinflated lung fields, flattened diaphragms, and a dense alveolar consolidation in the right lower lobe.

Which of the following interventions should be included in the immediate management bundle for this patient? (Select all that apply)

Select all that apply

Provide mechanical ventilatory support via a noninvasive positive pressure mask

Administer an intravenous infusion of sodium bicarbonate

Initiate empiric antimicrobial therapy with vancomycin and cefepime

Administer an intravenous loop diuretic

Initiate targeted antimicrobial therapy with ceftriaxone and azithromycin

Show answer & explanation

Answer: Provide mechanical ventilatory support via a noninvasive positive pressure mask; Initiate targeted antimicrobial therapy with ceftriaxone and azithromycin

Answer

The correct interventions are providing mechanical ventilatory support via a noninvasive positive pressure mask and initiating targeted antimicrobial therapy with ceftriaxone and azithromycin.

The correct combination of interventions addresses both the respiratory failure and the underlying infection. Noninvasive positive pressure ventilation (NPPV) is strongly indicated for COPD exacerbations presenting with acute hypercapnic respiratory failure (defined as pH

\le 7.35

and PaCO

_2 \ge 45\text{ mmHg}

). It decreases mortality, reduces the work of breathing, and lowers the rate of endotracheal intubation. Concurrently, the patient's community-acquired pneumonia, driven by Streptococcus pneumoniae (identified as Gram-positive lancet-shaped diplococci on Gram stain), requires targeted inpatient antimicrobial therapy. A combination of a beta-lactam and a macrolide, such as ceftriaxone and azithromycin, provides excellent coverage for this typical pathogen while adequately treating potential atypical organisms.

Step-by-Step Solution

Analyze the patient's presentation and imaging.

The patient has a COPD exacerbation complicated by right lower lobe community-acquired pneumonia (CAP).

This establishes the primary etiology of her acute respiratory distress and guides both ventilatory and pharmacological management.

Evaluate the arterial blood gas (ABG) findings.

The ABG shows a pH of

7.24

and PaCO

_2

70\text{ mmHg}

, confirming acute-on-chronic hypercapnic respiratory failure.

An acute respiratory acidosis with a pH

< 7.35

in an alert COPD patient is the primary indication for noninvasive positive pressure ventilation (NPPV) to reduce the work of breathing.

Interpret the sputum Gram stain.

The presence of Gram-positive lancet-shaped diplococci points directly to Streptococcus pneumoniae.

Identifying the likely pathogen allows for targeted antimicrobial therapy rather than excessively broad-spectrum coverage.

Select the appropriate pharmacological bundle.

Standard inpatient CAP therapy (ceftriaxone and azithromycin) is selected over broad-spectrum agents or heart failure medications.

The clinical picture rules out acute decompensated heart failure (normal BNP, normal JVP), and targeted antibiotics reflect proper antimicrobial stewardship.

Key Concept

The management of COPD exacerbations complicated by pneumonia includes noninvasive positive pressure ventilation (NPPV) for acute hypercapnic respiratory failure and targeted antibiotics based on sputum Gram stain findings, avoiding overly broad antimicrobial coverage and inappropriate diuresis.

Question 2742Question →

Match each valvular heart disease with its most characteristic constellation of physical examination findings.

Click a left item, then click its matching right item

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Answer

Severe Aortic Stenosis matches with pulsus parvus et tardus and a crescendo-decrescendo systolic murmur. Chronic Severe Aortic Regurgitation matches with a widened pulse pressure and an early diastolic decrescendo murmur. Severe Mitral Stenosis matches with a loud S1, an opening snap, and a mid-diastolic rumbling murmur. Chronic Severe Mitral Regurgitation matches with a laterally displaced apical impulse, an S3 gallop, and a holosystolic murmur.

Each valvular pathology has distinct hemodynamic consequences that manifest as specific physical examination findings, allowing for accurate clinical matching based on pulse characteristics, extra heart sounds, and murmur timing.

Step-by-Step Solution

Identify the timing of the murmur (systolic vs. diastolic) for each clinical presentation.

Two presentations describe systolic murmurs, while the other two describe diastolic murmurs.

Murmur timing narrows the diagnosis to either stenosis or regurgitation of a specific valve during that phase of the cardiac cycle.

Evaluate the associated peripheral vascular findings.

Pulsus parvus et tardus is specific to outflow obstruction (aortic stenosis). Widened pulse pressure and bounding pulses are specific to aortic runoff (aortic regurgitation).

Peripheral pulse characteristics are often pathognomonic for left-sided valvular lesions and help confirm the specific pathology.

Analyze additional cardiac auscultation and palpation findings.

An opening snap points to mitral stenosis, while an S3 gallop with a displaced point of maximal impulse indicates volume overload typical of chronic mitral regurgitation.

Extra heart sounds and the location of the apical impulse differentiate between various mitral pathologies.

Key Concept

Physical examination and auscultatory findings of major valvular heart diseases.

Question 2743Question →

Match each of the following serum laboratory profiles with the most likely underlying endocrinologic diagnosis.

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Answer

The laboratory profiles correctly map to Humoral hypercalcemia of malignancy (elevated calcium, suppressed PTH, elevated PTHrP), Primary hyperparathyroidism (elevated calcium, high PTH, high urinary calcium), Familial hypocalciuric hypercalcemia (elevated calcium, normal/high PTH, low urinary calcium), Severe nutritional vitamin D deficiency (low calcium, high PTH, low vitamin D), and Primary hypoparathyroidism (low calcium, low PTH, high phosphate).

The correct matches rely on the physiological feedback loops governing mineral metabolism. Hypercalcemia should normally suppress PTH; when it does, one must look for external drivers like PTHrP from malignancy. When hypercalcemia fails to suppress PTH, the defect lies in the parathyroid or the calcium sensors (differentiated by urine calcium). Conversely, hypocalcemia should stimulate PTH; if PTH is high, it is a secondary response (like in Vitamin D deficiency), but if PTH is low, the glands themselves have failed.

Step-by-Step Solution

Evaluate the serum calcium and parathyroid hormone (PTH) levels to determine if their relationship follows physiological feedback loops.

Identifies whether the primary defect is located in the parathyroid gland itself or is driven by an external factor.

PTH should normally be suppressed by hypercalcemia and stimulated by hypocalcemia. Deviations from this indicate autonomous parathyroid pathology or altered receptor sensing.

For hypercalcemic states with suppressed PTH, assess for non-parathyroid sources of hypercalcemia.

Points to conditions like malignancy (elevated PTHrP) or exogenous toxicity.

Intact feedback mechanisms properly suppress parathyroid gland activity when calcium is elevated by an external source.

For hypercalcemic states with inappropriately normal or elevated PTH, evaluate 24-hour urinary calcium excretion.

Differentiates primary hyperparathyroidism from familial hypocalciuric hypercalcemia (FHH).

FHH is characterized by defective calcium sensing, leading to anomalous renal calcium retention despite hypercalcemia, whereas primary hyperparathyroidism features hypercalciuria due to the massive filtered calcium load.

Key Concept

Diagnostic interpretation of calcium, phosphorus, and parathyroid hormone laboratory profiles to differentiate parathyroid disorders from other causes of disrupted mineral metabolism.

Question 2744Question →

A diverse group of patients presents to the nephrology clinic with various renal abnormalities. Match each patient's clinical presentation with the most likely underlying glomerular pathology.

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Answer

The lung mass with thrombosis matches Membranous nephropathy; the synpharyngitic hematuria matches IgA nephropathy; the Hepatitis C with purpura matches Membranoproliferative glomerulonephritis; and the HIV patient with nephrotic syndrome matches Focal segmental glomerulosclerosis.

Glomerular diseases often present similarly with edema and urinalysis abnormalities. Accurate diagnosis relies heavily on recognizing classic associations: Membranous nephropathy with solid tumors and thrombosis, IgA nephropathy with concurrent respiratory infections, Membranoproliferative glomerulonephritis with Hepatitis C, and Focal segmental glomerulosclerosis with HIV and heroin use.

Step-by-Step Solution

Analyze the presentation of the 55-year-old man with a lung mass.

Identify a nephrotic syndrome (heavy proteinuria, edema) complicated by thrombosis in the setting of a solid malignancy.

Solid tumors and high thrombotic risk (due to loss of antithrombin III) strongly point to membranous nephropathy.

Analyze the presentation of the 28-year-old man with episodic hematuria.

Identify recurrent nephritic syndrome occurring concurrently with a viral upper respiratory infection.

Concurrent (synpharyngitic) onset of hematuria is the hallmark of IgA nephropathy.

Analyze the presentation of the 62-year-old woman with Hepatitis C.

Identify a nephritic syndrome (RBC casts) combined with systemic signs of cryoglobulinemia (purpura, arthralgias).

Hepatitis C and cryoglobulinemia are classically linked to membranoproliferative glomerulonephritis.

Analyze the presentation of the 45-year-old man with HIV.

Identify massive proteinuria and declining renal function in an immunocompromised patient.

HIV-associated nephropathy is a well-known, rapidly progressive variant of focal segmental glomerulosclerosis.

Key Concept

Differentiating glomerular diseases based on unique clinical associations and patient demographics.

Estimated Time:1m 30s

Question 2745Question →

A $58$ -year-old man is evaluated in the intensive care unit for worsening respiratory distress. He was admitted $24$ hours ago for septic shock secondary to community-acquired pneumonia and was started on broad-spectrum intravenous antibiotics and a norepinephrine infusion. He is currently receiving high-flow nasal cannula oxygen therapy. He appears restless and is using accessory muscles of respiration.

Vital signs:

Parameter	Value
Temperature	$38.6^\circ\text{C}$ ( $101.5^\circ\text{F}$ )
Blood pressure	$95/60\text{ mm Hg}$
Pulse	$122/\text{min}$
Respirations	$34/\text{min}$
Pulse oximetry	$91\%$

Laboratory results:

Test	Result
Sodium	$139\text{ mEq/L}$
Potassium	$4.6\text{ mEq/L}$
Chloride	$103\text{ mEq/L}$
Bicarbonate	$12\text{ mEq/L}$
Blood urea nitrogen	$42\text{ mg/dL}$
Creatinine	$2.1\text{ mg/dL}$
Lactate	$5.5\text{ mmol/L}$

Arterial blood gas (on high-flow oxygen):

Parameter	Value
pH	$7.18$
$\text{PaCO}_2$	$34\text{ mm Hg}$
$\text{PaO}_2$	$65\text{ mm Hg}$

Which of the following best describes this patient's current acid-base status?

Primary metabolic acidosis with adequate respiratory compensation

Primary metabolic acidosis with a superimposed respiratory acidosis

Primary metabolic acidosis with a superimposed respiratory alkalosis

Primary respiratory acidosis with adequate metabolic compensation

Primary respiratory alkalosis with a superimposed metabolic acidosis

Show answer & explanation

Answer: Primary metabolic acidosis with a superimposed respiratory acidosis

Answer

Primary metabolic acidosis with a superimposed respiratory acidosis

This patient has severe acidemia (pH

7.18

) driven by a low serum bicarbonate (

12\text{ mEq/L}

), which establishes a primary metabolic acidosis (lactic acidosis due to septic shock). To determine if the respiratory compensation is adequate, Winter's formula must be applied: Expected

\text{PaCO}_2 = (1.5 \times \text{HCO}_3^-) + 8 \pm 2

. For this patient, the expected

\text{PaCO}_2 = (1.5 \times 12) + 8 = 26 \pm 2\text{ mm Hg}

(range

24-28\text{ mm Hg}

). The patient's actual

\text{PaCO}_2

34\text{ mm Hg}

. Because the actual

\text{PaCO}_2

is greater than the expected range, there is a concurrent, superimposed respiratory acidosis. Clinically, despite the patient's tachypnea (respiratory rate of

34/\text{min}

), his alveolar ventilation is insufficient to meet his high metabolic demands, indicating respiratory muscle fatigue and impending respiratory failure.

Step-by-Step Solution

Determine the primary acid-base disorder by evaluating the pH and bicarbonate levels.

The patient has a severely low pH of 7.18 (acidemia) and a low serum bicarbonate of 12 mEq/L.

An acidemia driven by a reduced bicarbonate level indicates a primary metabolic acidosis (in this case, secondary to elevated lactate from septic shock).

Calculate the expected respiratory compensation using Winter's formula.

Expected PaCO2 = (1.5 × 12) + 8 = 26 ± 2. Therefore, the expected compensatory range is 24 to 28 mm Hg.

Winter's formula determines if the lungs are appropriately compensating for a primary metabolic acidosis by increasing ventilation to blow off CO2.

Compare the patient's actual PaCO2 to the expected PaCO2 range.

The actual PaCO2 is 34 mm Hg, which is higher than the maximum expected value of 28 mm Hg.

An actual PaCO2 that exceeds the expected compensatory range indicates a concurrent, superimposed respiratory acidosis.

Key Concept

Evaluation of complex acid-base disturbances using Winter's formula to identify mixed metabolic and respiratory disorders.

Estimated Time:1m 30s

Question 2746Question →

A 62-year-old man is evaluated in the medical intensive care unit on hospital day 5. He was originally admitted for severe right lower lobe pneumonia complicated by septic shock. He remains intubated and is receiving broad-spectrum antibiotics along with low-dose norepinephrine. His spouse notes that prior to this illness, he was generally healthy but complained of mild, intermittent fatigue over the last several months. To investigate his prolonged requirement for ventilatory support and persistent lethargy, a comprehensive metabolic and endocrine panel is obtained.

Laboratory results are as follows:

Test	Result	Reference Range
Thyroid-stimulating hormone (TSH)	0.15 $\mu$ U/mL	0.4 - 4.0 $\mu$ U/mL
Free T4	0.7 ng/dL	0.9 - 2.4 ng/dL
Total T3	45 ng/dL	80 - 200 ng/dL

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

Reassess thyroid function testing following clinical recovery

Initiate intravenous levothyroxine therapy

Perform magnetic resonance imaging of the brain

Administer a cosyntropin stimulation test

Obtain a serum thyroid-stimulating immunoglobulin level

Show answer & explanation

Answer: Reassess thyroid function testing following clinical recovery

Answer

The most appropriate management is to reassess the patient's thyroid function testing following recovery from his acute critical illness.

The correct action is to observe and repeat the thyroid function tests once the patient recovers from his septic shock. This patient's laboratory profile (low TSH, low free T4, low T3) in the setting of severe critical illness is the classic presentation of euthyroid sick syndrome (also known as non-thyroidal illness syndrome). Pathophysiologically, the acute stress of systemic illness alters the peripheral deiodination of T4, favoring the production of inactive reverse T3 over active T3. As the severity of the illness progresses, TSH and free T4 levels can also decrease. This is generally considered a protective, physiologic down-regulation of metabolism during severe stress. Thyroid hormone supplementation has not been shown to improve clinical outcomes and may be harmful. The best approach is to treat the underlying condition and retest thyroid function after recovery.

Step-by-Step Solution

Analyze the patient's clinical context and laboratory findings.

The patient is critically ill with septic shock. Labs show a low TSH, low free T4, and significantly low total T3.

Recognizing the context of severe systemic illness is essential to properly interpreting thyroid function tests.

Formulate a diagnosis based on the pattern of thyroid hormone alterations.

The pattern of low T3, normal-to-low T4, and normal-to-low TSH in a critically ill patient is diagnostic of euthyroid sick syndrome (non-thyroidal illness syndrome).

Critical illness reduces the peripheral conversion of T4 to T3 by 5'-deiodinase, initially dropping T3. In prolonged illness, TSH and T4 levels also fall as a physiologic adaptation.

Determine the appropriate management for the established diagnosis.

Observation and reassessment after clinical recovery.

There is no evidence that treating euthyroid sick syndrome with thyroid hormone replacement improves morbidity or mortality. The condition typically resolves spontaneously once the underlying acute illness is treated.

Key Concept

Euthyroid sick syndrome (Non-thyroidal illness syndrome)

Estimated Time:1m 30s

Question 2747Question →

A 58-year-old woman is brought to the emergency department by ambulance following an episode of profuse, bright red vomiting at home. She has a documented history of primary biliary cholangitis and decompensated cirrhosis. Upon arrival, her blood pressure is 82/45 mm Hg, and her pulse is 128/min. She appears lethargic and pale. Physical examination reveals scleral icterus, shifting dullness in the abdomen, and spider angiomas on her chest. Arrange the following interventions in the most appropriate sequential order for managing this patient's acute presentation.

Drag items to arrange them in the correct order

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Answer

The correct sequence begins with hemodynamic resuscitation, followed by empiric pharmacotherapy to lower portal pressure and prevent infection, then endoscopic intervention for source control, and finally a salvage TIPS procedure if initial therapies fail.

The management of suspected acute variceal hemorrhage requires a strict stepwise approach. Initial large-bore intravenous access and volume resuscitation are paramount for this patient presenting in hemorrhagic shock. Following immediate stabilization, pharmacotherapy with octreotide (to decrease portal splanchnic blood flow) and prophylactic antibiotics (to prevent severe infections like spontaneous bacterial peritonitis) must be administered. Only after resuscitation and medical therapy are initiated should the patient undergo emergent EGD for targeted hemostasis (e.g., band ligation). TIPS is strictly a salvage therapy for refractory bleeding and is the final step in the algorithm.

Step-by-Step Solution

Assess hemodynamic status and perform initial fluid resuscitation.

Intravenous access is secured and intravascular volume is restored.

The patient is in hemorrhagic shock; restoring perfusion is the highest priority.

Administer targeted medical therapy for suspected variceal bleeding.

Octreotide reduces splanchnic blood flow while antibiotics prevent severe bacterial infections.

Early medical intervention significantly improves survival and reduces rebleeding rates in cirrhotic patients, even prior to endoscopic confirmation.

Perform endoscopic intervention.

The bleeding source is identified and variceal ligation is performed.

Endoscopy provides definitive initial hemostasis and should be performed once the patient is hemodynamically stable.

Consider salvage therapy.

A TIPS procedure is utilized to shunt blood away from the portal system.

This is indicated only if the patient continues to bleed despite maximal endoscopic and medical management.

Key Concept

Acute Variceal Hemorrhage Management Sequence

Question 2748Question →

A $28$ -year-old man is evaluated in the hospital on day $5$ of an admission for a severe flare of ulcerative colitis. On admission, stool studies were negative for Clostridioides difficile toxin and routine enteric pathogens, and he was started on intravenous methylprednisolone. Despite $5$ days of high-dose corticosteroid therapy, he continues to have $10$ to $12$ bloody bowel movements daily accompanied by abdominal cramps. Vital signs show a temperature of $38.3^\circ\text{C}$ ( $100.9^\circ\text{F}$ ), heart rate of $115$ /min, and blood pressure of $110/70\text{ mm Hg}$ . Physical examination reveals a non-distended abdomen with left lower quadrant tenderness, but no guarding or rebound. Laboratory studies show a hemoglobin of $9.2\text{ g/dL}$ , leukocyte count of $14,000/\text{mm}^3$ , and C-reactive protein of $65\text{ mg/L}$ . Abdominal radiography reveals colonic mucosal thickening without colonic dilation. Which of the following is the most appropriate next step in management?

Flexible sigmoidoscopy with biopsy

Intravenous infliximab therapy

Total abdominal colectomy with end ileostomy

Cytomegalovirus serologic testing

Intravenous piperacillin-tazobactam

Show answer & explanation

Answer: Flexible sigmoidoscopy with biopsy

Answer

Flexible sigmoidoscopy with biopsy

The correct answer is flexible sigmoidoscopy with biopsy. This patient has steroid-refractory severe ulcerative colitis. Before escalating to salvage medical therapies such as infliximab or cyclosporine, it is imperative to rule out superimposed cytomegalovirus (CMV) colitis. CMV frequently reactivates in the inflamed colonic mucosa of immunosuppressed patients (such as those on high-dose steroids). If a biologic agent is given to a patient with unrecognized CMV colitis, it can lead to toxic megacolon, perforation, or systemic viral dissemination. Flexible sigmoidoscopy with mucosal biopsy (for histopathology and immunohistochemistry) is the diagnostic test of choice to identify CMV inclusion bodies.

Step-by-Step Solution

Analyze the patient's clinical trajectory

The patient has severe ulcerative colitis that has not improved after 5 days of intravenous corticosteroids.

Establishing the diagnosis of steroid-refractory ulcerative colitis dictates the need for a change in management strategy.

Evaluate for complications of severe colitis

The abdominal X-ray shows no colonic dilation, and the physical exam lacks peritoneal signs.

This rules out toxic megacolon and perforation, meaning emergent surgical intervention is not currently indicated.

Identify the next required diagnostic step before escalating medical therapy

Superimposed cytomegalovirus (CMV) colitis must be excluded via flexible sigmoidoscopy with biopsy.

Patients on high-dose corticosteroids are at high risk for CMV reactivation in the colon. Initiating salvage immunosuppressants (e.g., infliximab, cyclosporine) in the presence of active CMV colitis can lead to severe, potentially fatal viral dissemination.

Key Concept

In patients with severe ulcerative colitis who are refractory to intravenous corticosteroids, flexible sigmoidoscopy with biopsy should be performed to evaluate for superimposed cytomegalovirus (CMV) colitis before initiating salvage medical therapies.

Estimated Time:1m 30s

Question 2749Question →

An 82-year-old woman arrives at the emergency department via ambulance due to the sudden onset of severe respiratory distress that began 3 hours ago. Her medical history includes ischemic cardiomyopathy with a left ventricular ejection fraction of 40%, diet-controlled type 2 diabetes mellitus, and chronic obstructive pulmonary disease (COPD) for which she uses an as-needed bronchodilator. Yesterday, she was diagnosed with an uncomplicated urinary tract infection; urine culture results returned today showing *Escherichia coli* that is susceptible to all tested antibiotics, including the oral nitrofurantoin she is currently taking.

On arrival, her temperature is 37.2°C (99.0°F), blood pressure is 188/102 mm Hg, pulse is 114/min, and respirations are 28/min. Pulse oximetry shows 86% on room air. Physical examination reveals a patient in moderate distress, speaking in short sentences. The jugular venous pressure is estimated at 11 cm H2O. Chest auscultation reveals scattered expiratory wheezes and bilateral basilar crackles. Cardiac examination shows tachycardia with a regular rhythm and a distinct S3 gallop.

Laboratory results are as follows:
Leukocytes: 11,500/mm³
B-type natriuretic peptide: 1,350 pg/mL
Thyroid-stimulating hormone (TSH): 0.2 mU/L (normal: 0.5–5.0 mU/L)
Free thyroxine (T4): 0.6 ng/dL (normal: 0.9–1.7 ng/dL)

Arterial blood gas (on room air):
pH: 7.28
PaCO₂: 25 mm Hg
PaO₂: 55 mm Hg
HCO₃⁻: 11 mEq/L
Lactate: 4.2 mmol/L (normal: 0.5–1.0 mmol/L)

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

Intravenous furosemide and noninvasive positive pressure ventilation

Inhaled albuterol and intravenous methylprednisolone

Intravenous piperacillin-tazobactam

Intravenous levothyroxine

Intravenous sodium bicarbonate

Show answer & explanation

Answer: Intravenous furosemide and noninvasive positive pressure ventilation

Answer

The most appropriate next step is to administer intravenous furosemide and initiate noninvasive positive pressure ventilation (NIPPV).

The correct answer addresses the patient's acute decompensated heart failure (ADHF). The presentation of acute respiratory distress, severe hypertension, hypoxia, elevated jugular venous pressure, bibasilar crackles, and an S3 gallop is highly specific for left ventricular failure leading to flash pulmonary edema. Noninvasive positive pressure ventilation (NIPPV) is the ideal initial respiratory intervention; it improves oxygenation and provides positive intrathoracic pressure, which decreases both venous return (preload) and left ventricular transmural pressure (afterload). Intravenous loop diuretics (furosemide) provide rapid relief of volume overload. Together, these therapies rapidly stabilize the patient's hemodynamics and respiratory status.

Step-by-Step Solution

Analyze the primary clinical presentation and vital signs.

The patient has acute, severe respiratory distress with severe hypertension (188/102 mm Hg), hypoxia, elevated JVP, bibasilar crackles, and an S3 gallop.

These findings are classic for acute decompensated heart failure (ADHF) presenting as hypertensive emergency with flash pulmonary edema.

Differentiate between ADHF and COPD exacerbation.

Despite the history of COPD and presence of wheezing (cardiac asthma), the markedly elevated BNP (1,350 pg/mL) and S3 gallop confirm a cardiac etiology.

Distinguishing the root cause of wheezing is critical because treating ADHF with only bronchodilators and steroids will not resolve the life-threatening cardiogenic pulmonary edema.

Evaluate the arterial blood gas (ABG) for acid-base status.

The ABG shows a metabolic acidosis (pH 7.28, HCO3 11 mEq/L) likely due to lactic acidosis (4.2 mmol/L). Using Winter's formula (

PaCO_2 = 1.5 \times 11 + 8 \pm 2 = 24.5 \pm 2

), the measured PaCO2 of 25 mm Hg indicates appropriate respiratory compensation.

Confirming compensation ensures there is no superimposed respiratory failure requiring immediate intubation, and that direct buffering with bicarbonate is not necessary.

Review the extraneous lab findings (thyroid panel, leukocytes).

The low T4 and low TSH indicate euthyroid sick syndrome. The mild leukocytosis is stress-related, and the UTI is already appropriately treated based on sensitivity data.

Recognizing distractors prevents inappropriate interventions like broad-spectrum antibiotics or thyroid hormone replacement.

Key Concept

Management of Acute Decompensated Heart Failure (ADHF) and differentiation from overlapping pulmonary conditions.

Estimated Time:2m 0s

Question 2750Question →

Autoimmune and cholestatic liver diseases frequently present with overlapping clinical features, such as fatigue, pruritus, jaundice, and elevated alkaline phosphatase or transaminases. Accurate non-invasive diagnosis often relies on the identification of specific circulating autoantibodies. Match each hepatobiliary disorder with its most characteristic diagnostic serological marker.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Primary biliary cholangitis matches with Anti-mitochondrial antibodies (AMA). Primary sclerosing cholangitis matches with Perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA). Type 1 Autoimmune hepatitis matches with Anti-smooth muscle antibodies (ASMA). Type 2 Autoimmune hepatitis matches with Anti-liver kidney microsome type 1 (anti-LKM1) antibodies.

Each hepatobiliary condition has a distinct, classic autoantibody profile that is critical for non-invasive diagnosis. AMA is highly sensitive and specific for Primary biliary cholangitis. p-ANCA is frequently found in Primary sclerosing cholangitis, reflecting its underlying immunological relationship with ulcerative colitis. Autoimmune hepatitis is divided into Type 1 (ASMA and/or ANA positive) and Type 2 (anti-LKM1 positive).

Step-by-Step Solution

Identify the serological marker for Primary biliary cholangitis (PBC).

PBC is matched with Anti-mitochondrial antibodies (AMA).

AMA is the hallmark diagnostic marker for PBC, present in over 90% of cases and serving as a key diagnostic criterion.

Identify the serological marker for Primary sclerosing cholangitis (PSC).

PSC is matched with Perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA).

Although not entirely specific to the biliary tree, p-ANCA is positive in up to 80% of patients with PSC, which heavily correlates with its strong clinical association with inflammatory bowel disease.

Distinguish the serological markers for the subtypes of Autoimmune hepatitis (AIH).

Type 1 AIH is matched with Anti-smooth muscle antibodies (ASMA), and Type 2 AIH is matched with Anti-liver kidney microsome type 1 (anti-LKM1) antibodies.

AIH is subdivided based on specific autoantibody profiles. Type 1 (classic adult AIH) features ASMA and ANA, whereas Type 2 features anti-LKM1 and predominantly affects pediatric and young adult populations.

Key Concept

Serological Markers of Autoimmune Hepatobiliary Disease

Question 2751Question →

A 68-year-old man is evaluated in the outpatient clinic for worsening shortness of breath over the past week. He reports progressive difficulty walking short distances and a persistent, non-productive cough that is most prominent when he lies down to sleep. Medical history includes long-standing essential hypertension, obesity, and a 40-pack-year smoking history. Current medications are lisinopril and amlodipine. Vital signs are temperature $37.0^\circ C$ , blood pressure $168/95 \text{ mm Hg}$ , pulse $92\text{/min}$ , and respirations $22\text{/min}$ . Oxygen saturation is $92\%$ on room air. Physical examination reveals an obese man with mild respiratory effort. Jugular venous pressure is estimated at $9 \text{ cm H}_2\text{O}$ above the sternal angle. Pulmonary auscultation demonstrates bilateral end-expiratory wheezes and scattered bibasilar crackles. Cardiac examination reveals a regular rhythm with a distinct fourth heart sound (S4). Trace bilateral lower extremity edema is noted. Bedside spirometry indicates an $FEV_1/FVC$ ratio of $78\%$ . Which of the following pathophysiologic mechanisms best explains this patient's current symptoms?

Impaired left ventricular active relaxation and increased chamber stiffness

Chronic inflammation and hypersecretion of mucus in the tracheobronchial tree

Protease-mediated destruction of alveolar walls and permanent airspace enlargement

Right ventricular failure secondary to chronic hypoxic pulmonary vasoconstriction

Reversible smooth muscle bronchospasm triggered by environmental allergens

Show answer & explanation

Answer: Impaired left ventricular active relaxation and increased chamber stiffness

Answer

Impaired left ventricular active relaxation and increased chamber stiffness

The correct answer identifies the pathophysiology of Heart Failure with Preserved Ejection Fraction (HFpEF). This patient's presentation of orthopnea, elevated JVP, bibasilar crackles, and an S4 gallop in the setting of long-standing hypertension and obesity is classic for HFpEF. The wheezing represents 'cardiac asthma,' which is caused by peribronchial edema resulting from elevated left-sided filling pressures. Despite his smoking history, his normal

FEV_1/FVC

ratio rules out a primary obstructive airway disease like COPD.

Step-by-Step Solution

Analyze the patient's presenting symptoms and vital signs.

The patient has progressive dyspnea, orthopnea (coughing when lying down), and elevated blood pressure.

Identifying the core clinical syndrome is the first step in differentiating between cardiac and pulmonary etiologies.

Evaluate the physical examination findings.

Elevated JVP, bibasilar crackles, wheezes, and an S4 gallop are present.

An S4 gallop indicates a stiff, non-compliant left ventricle. Crackles and elevated JVP point to volume overload backing up into both pulmonary and systemic circuits.

Interpret the objective diagnostic data (spirometry).

The

FEV_1/FVC

ratio is

78\%

, which is normal (greater than

70\%

A normal ratio effectively rules out chronic obstructive pulmonary disease (COPD) as the primary cause of his wheezing, despite his heavy smoking history.

Synthesize the findings to determine the underlying pathophysiology.

The patient has Heart Failure with Preserved Ejection Fraction (HFpEF) presenting with 'cardiac asthma'.

HFpEF is driven by impaired active relaxation and increased left ventricular stiffness, leading to elevated filling pressures that cause peribronchial edema (wheezing) and alveolar fluid (crackles).

Key Concept

Heart Failure with Preserved Ejection Fraction (HFpEF) vs. COPD

Question 2752Question →

Emergency medical services transport a 54-year-old male to the trauma bay following an episode of massive hematemesis. His spouse reports that he has known alcoholic cirrhosis and has been increasingly confused over the past two days. Upon arrival, the patient is obtunded, withdrawing only to painful stimuli, and actively vomiting bright red blood. Vital signs show a heart rate of 132/min, blood pressure of 82/48 mm Hg, and respiratory rate of 24/min. Arrange the following clinical interventions in the most appropriate sequential order for managing this patient's condition.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence prioritizes the ABCs of resuscitation (Airway, Breathing, Circulation) followed by targeted medical therapy, definitive endoscopic intervention, and finally rescue radiologic procedures.

The patient is presenting with a massive acute variceal hemorrhage complicated by hemorrhagic shock and hepatic encephalopathy. In any critical care scenario, the airway must be secured first. Because he is obtunded and actively vomiting blood, endotracheal intubation is the immediate priority to prevent fatal aspiration. Once the airway is secure, restoring intravascular volume with large-bore intravenous catheters is necessary to treat his profound hypotension. After hemodynamic stabilization begins, medical therapies including octreotide (to reduce portal venous pressure) and ceftriaxone (to prevent infection) must be administered. Only after the patient is medically stabilized and the airway is protected should an urgent EGD be performed to definitively identify and ligate the bleeding varices. Finally, if EGD fails to control the bleeding, TIPS is indicated as a last-resort rescue therapy.

Step-by-Step Solution

Assess and secure the airway.

Endotracheal intubation

The patient is obtunded and actively vomiting blood, placing him at imminent risk of massive pulmonary aspiration.

Initiate hemodynamic resuscitation.

Insertion of two large-bore intravenous catheters and volume resuscitation

Severe hypotension (82/48 mm Hg) and tachycardia indicate class III/IV hemorrhagic shock requiring immediate crystalloid and blood product administration.

Administer targeted pharmacotherapy.

Administration of intravenous octreotide and prophylactic ceftriaxone

Octreotide causes splanchnic vasoconstriction to reduce variceal bleeding, while ceftriaxone prevents severe infectious complications commonly triggered by GI bleeding in cirrhotics.

Perform definitive diagnostic and therapeutic intervention.

Urgent esophagogastroduodenoscopy (EGD)

Allows direct visualization of the bleeding source and immediate therapeutic intervention such as variceal band ligation.

Evaluate for rescue interventions if primary therapy fails.

Transjugular intrahepatic portosystemic shunt (TIPS) placement

Utilized as a salvage procedure only if standard endoscopic and medical management fails to control the variceal hemorrhage.

Key Concept

Sequential management of acute variceal hemorrhage in cirrhosis prioritizing airway protection

Question 2753Question →

A $31$ -year-old woman comes to the clinic for follow-up of palpitations, generalized anxiety, and heat intolerance that began $3$ weeks ago. She delivered a healthy infant $4$ months ago. She has no significant past medical history and takes no medications. Her temperature is $37.1^\circ\text{C}$ ( $98.8^\circ\text{F}$ ), blood pressure is $128/78\text{ mmHg}$ , and pulse is $112\text{/min}$ . Physical examination reveals a mild, diffusely enlarged, non-tender thyroid gland. There is no proptosis, lid lag, or pretibial myxedema. Laboratory results show:

Test	Result	Reference Range
Thyroid-stimulating hormone (TSH)	$0.05\text{ mU/L}$	$0.5$ - $5.0\text{ mU/L}$
Free thyroxine (T4)	$2.4\text{ ng/dL}$	$0.9$ - $1.7\text{ ng/dL}$

A radioactive iodine uptake (RAIU) scan demonstrates $2\%$ uptake at $24$ hours (normal: $10\%$ - $30\%$ ).

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

Administration of propranolol

Initiation of methimazole

Administration of prednisone

Referral for radioactive iodine ablation

Initiation of levothyroxine

Show answer & explanation

Answer: Administration of propranolol

Answer

Administration of propranolol is the most appropriate next step.

The correct answer is the administration of propranolol. This patient's presentation of thyrotoxicosis (palpitations, tachycardia, heat intolerance, low TSH, high Free T4) within one year of delivery, accompanied by a painless goiter and a low radioactive iodine uptake (RAIU), is classic for the hyperthyroid phase of postpartum thyroiditis. Postpartum thyroiditis is a variant of painless (silent) autoimmune thyroiditis. The low RAIU confirms that the excess circulating thyroid hormone is due to the destruction of thyroid follicles and release of preformed hormone, rather than de novo synthesis. Because this phase is self-limited and not driven by overproduction, antithyroid synthesis inhibitors are ineffective. The standard of care is symptomatic management of hyperadrenergic symptoms using a beta-blocker (e.g., propranolol) until the hyperthyroid phase resolves.

Step-by-Step Solution

Interpret the clinical presentation and initial laboratory findings.

The patient has symptoms of thyrotoxicosis (tachycardia, palpitations, heat intolerance) beginning after a recent pregnancy, supported by an elevated Free T4 and a suppressed TSH.

Establishing the biochemical presence of thyrotoxicosis is the required first step before determining the etiology.

Analyze the radioactive iodine uptake (RAIU) scan results.

The RAIU scan shows severely decreased uptake (

2\%

A low RAIU distinguishes destructive thyroiditis (release of preformed hormone) from conditions of hormone overproduction (like Graves disease, which would have high uptake).

Synthesize findings to determine the correct diagnosis and treatment.

A painless goiter in the postpartum period with hyperthyroid labs and a low RAIU indicates the hyperthyroid phase of postpartum thyroiditis. Symptom control with a beta-blocker is indicated.

Because postpartum thyroiditis is a transient destructive process, antithyroid medications are ineffective. Beta-blockers relieve the hyperadrenergic symptoms until the phase resolves.

Key Concept

Postpartum Thyroiditis Diagnostics and Management

Question 2754Question →

A 68-year-old man is evaluated in the intensive care unit for decreased urine output. Three days ago, he was admitted with severe community-acquired pneumonia and septic shock, which required aggressive intravenous fluid resuscitation and continuous norepinephrine infusion. Over the past 24 hours, his urine output has decreased to 250 mL. His blood pressure is 105/65 mm Hg, pulse is 98/min, and respirations are 18/min. Physical examination reveals warm extremities and trace bilateral pitting edema. Laboratory studies are obtained:

Parameter	Value
Serum sodium	140 mEq/L
Serum potassium	4.8 mEq/L
Serum chloride	102 mEq/L
Serum bicarbonate	20 mEq/L
Blood urea nitrogen	42 mg/dL
Serum creatinine	2.8 mg/dL
Urine sodium	50 mEq/L
Urine creatinine	25 mg/dL

Based on these findings, what is this patient's calculated fractional excretion of sodium (in percentage)?

Show answer & explanation

Answer: 4

Answer

The fractional excretion of sodium (FeNa) is calculated using the formula

FeNa = \frac{U_{Na} \times P_{Cr}}{P_{Na} \times U_{Cr}} \times 100

. By substituting the patient's laboratory values (

U_{Na}

= 50 mEq/L,

P_{Cr}

= 2.8 mg/dL,

P_{Na}

= 140 mEq/L,

U_{Cr}

= 25 mg/dL) into the equation, the result is

\frac{50 \times 2.8}{140 \times 25} \times 100

, which equals 4%. A FeNa > 2% in the setting of oliguric acute kidney injury strongly suggests intrinsic damage, such as acute tubular necrosis, which aligns with this patient's history of prolonged septic shock and ischemic injury.

Step-by-Step Solution

Extract the necessary laboratory values from the clinical vignette.

U_{Na} = 50

mEq/L,

P_{Cr} = 2.8

mg/dL,

P_{Na} = 140

mEq/L, and

U_{Cr} = 25

mg/dL.

These variables are required to calculate the fractional excretion of sodium (FeNa).

Apply the FeNa equation.

FeNa = \frac{U_{Na} \times P_{Cr}}{P_{Na} \times U_{Cr}} \times 100

This formula normalizes sodium excretion to the glomerular filtration rate, helping differentiate prerenal azotemia from intrinsic acute kidney injury.

Perform the calculation with the extracted values.

\frac{50 \times 2.8}{140 \times 25} \times 100 = \frac{140}{3500} \times 100 = 0.04 \times 100 = 4\%

To obtain the final FeNa percentage. A FeNa > 2% strongly indicates acute tubular necrosis (ATN).

Key Concept

Calculation and interpretation of the Fractional Excretion of Sodium (FeNa) in acute kidney injury.

Question 2755Question →

An ambulance transports a $65$ -year-old male to the acute care bay following two days of progressively worsening shortness of breath. The patient reports producing increased amounts of thick, yellowish sputum and feeling unusually fatigued. His past medical history is significant for ischemic cardiomyopathy with a left ventricular ejection fraction of $35\%$ , as well as severe chronic obstructive pulmonary disease.

Upon arrival, his temperature is $37.7^\circ\text{C}$ ( $99.9^\circ\text{F}$ ), blood pressure is $138/86\text{ mmHg}$ , heart rate is $108/\text{min}$ , and respiratory rate is $26/\text{min}$ . Pulse oximetry reveals an oxygen saturation of $87\%$ on room air.

Physical examination shows an alert patient in mild respiratory distress, utilizing accessory muscles of respiration. The jugular venous pressure is estimated at $6\text{ cm H}_2\text{O}$ (normal: $5-8\text{ cm H}_2\text{O}$ ). Cardiac auscultation reveals a regular rate and rhythm with normal heart sounds; no third heart sound ( $S_3$ ) or murmurs are appreciated. Pulmonary auscultation reveals a prolonged expiratory phase with diffuse bilateral wheezing, but no dependent crackles. There is chronic trace bilateral pedal edema.

Initial laboratory studies are as follows:
Serum B-type natriuretic peptide (BNP): $180\text{ pg/mL}$ (Baseline: $220\text{ pg/mL}$ )
Leukocyte count: $9,500/\mu\text{L}$
Thyroid-stimulating hormone (TSH): $1.2\text{ }\mu\text{U/mL}$ (Reference: $0.5-5.0\text{ }\mu\text{U/mL}$ )
Free T4: $0.6\text{ ng/dL}$ (Reference: $0.9-1.7\text{ ng/dL}$ )

Arterial blood gas (room air):
pH: $7.28$
pCO $_2$ : $64\text{ mmHg}$
pO $_2$ : $55\text{ mmHg}$
HCO $_3^-$ : $29\text{ mEq/L}$

A sputum Gram stain reveals numerous neutrophils and moderate gram-negative diplococci.

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

Administer intravenous furosemide and sublingual nitroglycerin

Calculate expected respiratory compensation using Winter's formula

Administer systemic glucocorticoids, nebulized bronchodilators, and an oral macrolide

Administer intravenous piperacillin-tazobactam and vancomycin

Initiate oral levothyroxine for primary hypothyroidism

Show answer & explanation

Answer: Administer systemic glucocorticoids, nebulized bronchodilators, and an oral macrolide

Answer

The most appropriate pharmacological step is to administer systemic glucocorticoids, nebulized bronchodilators, and an oral macrolide.

This patient is experiencing a severe acute exacerbation of chronic obstructive pulmonary disease (COPD), characterized by the cardinal symptoms of increased dyspnea, increased sputum volume, and increased sputum purulence. The physical examination supports this diagnosis (diffuse wheezing, use of accessory muscles) while actively ruling out acute decompensated heart failure (normal JVP, no S3, clear lung bases, BNP below baseline). In patients with COPD exacerbations presenting with all three cardinal symptoms (or two if one is increased purulence), antibiotics are indicated. The Gram stain showing gram-negative diplococci strongly suggests Moraxella catarrhalis, making an oral macrolide (e.g., azithromycin) an excellent targeted choice. Alongside antibiotics, standard pharmacological management includes systemic glucocorticoids and nebulized short-acting bronchodilators to reduce airway inflammation and relieve bronchospasm. (Note: Noninvasive positive pressure ventilation is also indicated for his acute-on-chronic respiratory acidosis with pH < 7.30, but the question specifically asks for the pharmacological step).

Step-by-Step Solution

Differentiate between an acute COPD exacerbation and an acute decompensated heart failure (ADHF) exacerbation based on physical exam and laboratory findings.

The normal jugular venous pressure, lack of dependent crackles, absent S3 gallop, and a BNP level below the patient's baseline effectively rule out ADHF, pointing toward a COPD exacerbation.

Patients with a dual history of COPD and heart failure require careful clinical differentiation, as the pharmacological therapies for one condition can sometimes worsen the other.

Analyze the sputum Gram stain to determine the most appropriate antimicrobial strategy.

The presence of gram-negative diplococci highly suggests Moraxella catarrhalis. Narrow-spectrum targeted therapy with a macrolide (like azithromycin) or a respiratory fluoroquinolone is indicated rather than broad-spectrum agents.

Antibiotic stewardship requires tailoring therapy to the likely pathogen based on rapid diagnostics and avoiding unnecessarily broad coverage (like vancomycin and piperacillin-tazobactam) in uncomplicated cases.

Select the comprehensive pharmacological bundle for a severe COPD exacerbation.

The standard of care includes systemic glucocorticoids (to reduce airway inflammation), short-acting bronchodilators (albuterol/ipratropium to relieve bronchospasm), and targeted antibiotics.

These interventions reduce symptom severity, shorten recovery time, and prevent treatment failure in COPD exacerbations.

Key Concept

Management of Acute COPD Exacerbations vs. Heart Failure Exacerbations

Estimated Time:1m 30s

Question 2756Question →

Chronic hepatobiliary diseases often present with overlapping clinical symptoms such as fatigue, pruritus, and elevated liver enzymes, making histopathological evaluation a critical component for definitive diagnosis. Match each hepatobiliary disorder with its most characteristic finding on liver biopsy.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The correct matches are: Primary biliary cholangitis pairs with florid duct lesions and granulomatous destruction; Primary sclerosing cholangitis pairs with concentric periductal fibrosis; Alpha-1 antitrypsin deficiency pairs with PAS-positive, diastase-resistant globules; and Autoimmune hepatitis pairs with lymphoplasmacytic infiltrate and interface hepatitis.

Each of these chronic liver diseases has a distinct pathophysiology that is reflected in its histology. PBC is a granulomatous destruction of small ducts. PSC is a fibrosing disease of larger ducts. Alpha-1 antitrypsin deficiency is a storage disorder of misfolded proteins. Autoimmune hepatitis is an inflammatory condition characterized by plasma cells.

Step-by-Step Solution

Analyze the histopathological description for Primary biliary cholangitis (PBC).

Match PBC with florid duct lesions and granulomatous destruction.

PBC exclusively affects small intrahepatic ducts via autoimmune granuloma formation.

Analyze the histopathological description for Primary sclerosing cholangitis (PSC).

Match PSC with concentric periductal fibrosis.

PSC involves larger intrahepatic and extrahepatic ducts, forming distinctive 'onion-skin' fibrosis around the ducts.

Analyze the histopathological description for Alpha-1 antitrypsin deficiency.

Match it with PAS-positive, diastase-resistant intracytoplasmic globules.

The disease is caused by misfolded protein aggregating in the endoplasmic reticulum of hepatocytes, which uniquely stains with Periodic acid-Schiff.

Analyze the histopathological description for Autoimmune hepatitis.

Match it with lymphoplasmacytic infiltrate and interface hepatitis.

Autoimmune hepatitis is driven by an intense immune response featuring prominent plasma cells extending from portal tracts into the parenchyma.

Key Concept

Histopathological diagnosis of chronic hepatobiliary diseases

Question 2757Question →

A 52-year-old man presents to the clinic with a 4-month history of a persistent, dry cough that worsens at night and a slightly hoarse voice in the mornings. He reports no fever, weight loss, hemoptysis, or shortness of breath with exertion. His medical history is significant for hypertension treated with amlodipine. He is a lifelong nonsmoker. Vital signs are within normal limits. Physical examination reveals a clear oropharynx and normal breath sounds bilaterally without wheezing or crackles. Chest radiography is unremarkable, and spirometry shows normal lung volumes with no reversibility following bronchodilator administration. Which of the following is the most appropriate next step in management?

Initiate an empirical trial of a daily proton pump inhibitor

Prescribe an as-needed albuterol metered-dose inhaler

Prescribe a 5-day course of oral azithromycin

Measure serum thyroid-stimulating hormone levels

Discontinue amlodipine and initiate lisinopril

Show answer & explanation

Answer: Initiate an empirical trial of a daily proton pump inhibitor

Answer

Initiate an empirical trial of a daily proton pump inhibitor

This patient presents with a chronic cough (lasting >8 weeks) and morning hoarseness. His normal chest radiograph rules out obvious underlying pulmonary pathology, and his normal spirometry effectively rules out asthma and COPD. The three most common causes of chronic cough in a nonsmoker with a normal chest radiograph are upper airway cough syndrome, asthma, and gastroesophageal reflux disease (GERD). The patient's nocturnal exacerbation of the cough and morning hoarseness are classic signs of extraesophageal GERD (laryngopharyngeal reflux). When extraesophageal GERD is suspected in a patient without 'alarm' symptoms (e.g., dysphagia, weight loss, anemia), the gold standard next step in management is an empirical 8-week trial of a daily proton pump inhibitor (PPI).

Step-by-Step Solution

Evaluate the clinical presentation of a chronic cough (lasting >8 weeks) with a normal chest radiograph.

The top differential diagnoses include upper airway cough syndrome (postnasal drip), asthma, and gastroesophageal reflux disease (GERD).

To narrow down the etiology based on epidemiological probability for chronic coughs.

Assess the specific symptoms and adjunctive test results (normal spirometry).

Asthma is highly unlikely due to the lack of bronchodilator reversibility on spirometry. The patient's nighttime exacerbation and morning hoarseness specifically point to extraesophageal GERD (laryngopharyngeal reflux).

To differentiate between the most common causes using objective data and classic clinical clues.

Determine the initial management for suspected extraesophageal GERD.

An empirical 8-week trial of a proton pump inhibitor (PPI) is indicated.

When 'alarm' symptoms (e.g., dysphagia, weight loss) are absent, PPIs serve as both a diagnostic tool and primary treatment for GERD-associated chronic cough.

Key Concept

Extraesophageal GERD is a leading cause of chronic cough and should be evaluated with an empirical trial of a proton pump inhibitor when chest radiography and spirometry are normal.

Estimated Time:1m 30s

Question 2758Question →

During morning rounds in the intensive care unit, the medical team discusses the care of a patient who was recently treated for a severe asthma exacerbation. The patient had a central venous catheter placed $5$ days ago, which was removed yesterday when he developed rigors and a temperature of $39.2^\circ\text{C}$ . Empiric intravenous vancomycin and piperacillin-tazobactam were started at that time. Today, the microbiology laboratory reports that two sets of blood cultures are positive for methicillin-susceptible *Staphylococcus aureus* (MSSA). The isolate is susceptible to oxacillin, cefazolin, and vancomycin. The patient's vital signs are now stable and he is afebrile. Which of the following is the most appropriate next step in pharmacotherapy?

Maintain the current regimen of vancomycin and piperacillin-tazobactam

De-escalate to intravenous vancomycin monotherapy

Transition therapy to intravenous cefazolin monotherapy

Switch to oral trimethoprim-sulfamethoxazole monotherapy

Retain vancomycin and replace piperacillin-tazobactam with intravenous gentamicin

Show answer & explanation

Answer: Transition therapy to intravenous cefazolin monotherapy

Answer

The most appropriate action is to transition therapy to intravenous cefazolin monotherapy.

Transitioning to intravenous cefazolin monotherapy is correct because MSSA bacteremia should be treated with a targeted anti-staphylococcal beta-lactam. Drugs like cefazolin, nafcillin, or oxacillin are considered superior to vancomycin for MSSA infections due to faster bacterial clearance and improved survival rates. Discontinuing the broad-spectrum empiric regimen in favor of this targeted therapy is the standard of care.

Step-by-Step Solution

Evaluate the clinical scenario and culture results.

The patient has a central line-associated bloodstream infection caused by methicillin-susceptible *Staphylococcus aureus* (MSSA).

Identifying the specific pathogen and its resistance profile is essential for transitioning from empiric to definitive therapy.

Determine the optimal definitive antimicrobial agent.

An anti-staphylococcal beta-lactam (cefazolin) is the drug of choice.

Beta-lactams offer superior bactericidal activity against MSSA compared to vancomycin, resulting in better survival rates.

Apply antimicrobial stewardship principles.

Broad-spectrum coverage (vancomycin and piperacillin-tazobactam) should be discontinued.

De-escalating to narrow-spectrum, targeted therapy minimizes toxicity and prevents the emergence of resistant organisms.

Key Concept

The optimal treatment for methicillin-susceptible *Staphylococcus aureus* (MSSA) bacteremia is an intravenous anti-staphylococcal beta-lactam, such as cefazolin, rather than vancomycin, as it provides superior clinical outcomes and aligns with antimicrobial stewardship principles.

Estimated Time:1m 30s

Question 2759Question →

A 52-year-old woman is evaluated on postoperative day 4 following a small bowel resection for severe intestinal strictures. Since the surgery, she has been receiving continuous low-wall suction via a nasogastric tube, which has drained 1.5 to 2 liters of bilious fluid daily. Over the last 12 hours, she has developed significant weakness, muscle cramps, and dizziness upon sitting up. Her temperature is 37.1°C (98.8°F), blood pressure is 96/60 mm Hg, heart rate is 110/min, and respiratory rate is 10/min. Physical examination reveals dry mucous membranes, flat jugular veins, and decreased skin turgor. Laboratory studies show the following:

- Serum sodium: 136 mEq/L
- Serum potassium: 2.8 mEq/L
- Serum chloride: 88 mEq/L
- Serum bicarbonate: 36 mEq/L
- Blood urea nitrogen: 42 mg/dL
- Serum creatinine: 1.6 mg/dL

Arterial blood gas (room air):
- pH: 7.52
- pCO $_2$ : 49 mm Hg
- pO $_2$ : 86 mm Hg

Urine chloride is 8 mEq/L. Which of the following is the most appropriate next step in management?

Intravenous administration of 0.9% sodium chloride

Intubation and mechanical ventilation

Intravenous administration of acetazolamide

Intravenous administration of 5% dextrose in water

Initiation of broad-spectrum antibiotics

Show answer & explanation

Answer: Intravenous administration of 0.9% sodium chloride

Answer

The most appropriate next step is intravenous administration of 0.9% sodium chloride to correct the volume deficit and provide the necessary chloride to reverse the alkalosis.

The correct answer is intravenous administration of 0.9% sodium chloride. This patient has a severe metabolic alkalosis secondary to gastric acid (HCl) and volume loss from continuous nasogastric suctioning. The resulting volume depletion activates the renin-angiotensin-aldosterone system (RAAS), which promotes sodium reabsorption in the distal tubule at the expense of potassium and hydrogen ion excretion (perpetuating the alkalosis). Because the primary drivers are volume and chloride depletion, this is termed a 'saline-responsive' metabolic alkalosis, confirmed by a urine chloride level of < 20 mEq/L. Administering isotonic saline expands the intravascular space, deactivates RAAS, and provides the chloride necessary for the kidneys to excrete excess bicarbonate.

Step-by-Step Solution

Analyze the acid-base status on the arterial blood gas.

The pH is 7.52 (alkalemia). The elevated serum bicarbonate (36 mEq/L) identifies this as a primary metabolic alkalosis.

Establishing the primary acid-base disorder is required to interpret the compensatory mechanisms.

Calculate expected respiratory compensation for the metabolic alkalosis.

Expected pCO

_2

40 + 0.7 \times (36 - 24) = 48.4

mm Hg. The measured pCO

_2

of 49 mm Hg represents perfect physiological compensation.

This confirms there is no superimposed primary respiratory disorder, and the hypoventilation is appropriately compensatory.

Determine the etiology of the metabolic alkalosis using patient history and urine studies.

NG suction causes massive loss of H

^+

and Cl

^-

(gastric acid) along with fluid. The low urine chloride (< 20 mEq/L) and elevated BUN/Cr ratio (> 20:1) confirm severe volume depletion.

Differentiating between saline-responsive (urine Cl < 20) and saline-resistant (urine Cl > 20) metabolic alkalosis dictates the treatment.

Select the optimal therapeutic intervention.

Volume resuscitation with 0.9% sodium chloride (normal saline).

Isotonic saline simultaneously expands the intravascular volume (turning off aldosterone) and replaces the depleted chloride, allowing the kidneys to excrete bicarbonate.

Key Concept

Patients with significant upper gastrointestinal fluid losses (via vomiting or nasogastric suction) develop a hypochloremic, hypokalemic metabolic alkalosis. Because this is a 'saline-responsive' alkalosis (urine Cl < 20 mEq/L), the definitive treatment is restoration of intravascular volume and chloride with intravenous 0.9% sodium chloride.

Estimated Time:1m 30s

Question 2760Question →

A 68-year-old man is evaluated in the intensive care unit for worsening respiratory distress. He was admitted 48 hours ago for septic shock secondary to a urinary tract infection. During his initial resuscitation, he received 4 liters of intravenous isotonic crystalloids. Blood cultures drawn on admission grew *Escherichia coli* susceptible to ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole. He is currently receiving empirical intravenous piperacillin-tazobactam. His medical history includes severe chronic obstructive pulmonary disease (COPD) and hypertension.

Vital signs are temperature 37.2°C (99.0°F), blood pressure 152/92 mm Hg, pulse 112/min, and respirations 32/min. Pulse oximetry shows 88% on a high-flow nasal cannula ( $FiO_2$ 60%). Physical examination reveals jugular venous distension to 9 cm $H_2O$ . Cardiac auscultation reveals a regular tachycardia with a prominent S3 gallop. Lung auscultation reveals bilateral basilar crackles. No significant wheezing is appreciated.

Arterial blood gas analysis on current settings shows:

Parameter	Value
pH	7.22
$P_aCO_2$	42 mm Hg
$P_aO_2$	60 mm Hg
$HCO_3^-$	17 mEq/L

Which of the following are the most appropriate next steps in management? (Select 2)

Select all that apply

Initiate a trial of noninvasive positive-pressure ventilation and administer intravenous furosemide

Transition current antimicrobial therapy to intravenous ceftriaxone

Administer systemic methylprednisolone and scheduled nebulized ipratropium-albuterol

Maintain current respiratory interventions as arterial blood gas analysis demonstrates appropriate respiratory compensation

Continue intravenous piperacillin-tazobactam to ensure adequate broad-spectrum coverage for a potential secondary hospital-acquired infection

Show answer & explanation

Answer: Initiate a trial of noninvasive positive-pressure ventilation and administer intravenous furosemide; Transition current antimicrobial therapy to intravenous ceftriaxone

Answer

The most appropriate next steps are to initiate noninvasive positive-pressure ventilation with intravenous furosemide, and to transition the antimicrobial therapy to intravenous ceftriaxone.

This patient requires simultaneous management of two distinct critical care issues. First, his respiratory distress is driven by acute decompensated heart failure (ADHF) following aggressive fluid resuscitation (4L of normal saline), evidenced by elevated JVP, an S3 gallop, and pulmonary crackles. Furthermore, his ABG reveals a primary metabolic acidosis (pH 7.22,

HCO_3^-

17 mEq/L) complicated by a superimposed acute respiratory acidosis. Using Winter's formula (

1.5 \times 17 + 8 \pm 2

), his expected

P_aCO_2

is 31.5 to 35.5 mm Hg. His actual

P_aCO_2

of 42 mm Hg indicates inadequate respiratory compensation, signaling severe respiratory muscle fatigue and impending failure. This requires immediate noninvasive positive-pressure ventilation (NPPV) and intravenous furosemide. Second, the patient is on unnecessarily broad-spectrum antibiotics (piperacillin-tazobactam) despite having culture results demonstrating an *Escherichia coli* isolate susceptible to narrower-spectrum agents. Good antimicrobial stewardship dictates immediate de-escalation to ceftriaxone.

Step-by-Step Solution

Analyze the clinical presentation to differentiate the cause of respiratory distress.

Recent 4L fluid resuscitation, JVD, S3 gallop, and crackles indicate cardiogenic pulmonary edema (ADHF), not a COPD exacerbation.

Accurate physical exam interpretation prevents incorrect administration of steroids and bronchodilators.

Evaluate the arterial blood gas for acid-base status and compensation.

Primary metabolic acidosis (

HCO_3^-

17) with expected

P_aCO_2

of 31.5-35.5. The actual

P_aCO_2

(42) is higher, revealing a superimposed respiratory acidosis.

Identifying the uncompensated/mixed acidosis confirms impending respiratory muscle fatigue requiring ventilatory support like NPPV.

Select interventions to manage the ADHF and impending respiratory failure.

NPPV and intravenous furosemide are indicated.

NPPV decreases work of breathing and improves oxygenation, while furosemide diureses the iatrogenic volume overload.

Apply principles of antimicrobial stewardship to the current regimen.

Transition from piperacillin-tazobactam to ceftriaxone.

Culture susceptibilities are known, and de-escalation prevents the emergence of resistant organisms.

Key Concept

In the intensive care setting, accurately diagnosing iatrogenic acute decompensated heart failure (ADHF) over a COPD exacerbation, recognizing concurrent respiratory failure via Winter's formula, and actively de-escalating antibiotics are critical simultaneous management priorities.

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